JP2000152254A - Wavelength selection type liquid crystal camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect an oil film or an organic film or the like on a water surface as an image with high contrast. SOLUTION: While a wavelength selection optical system 2 photographs a sea surface on which an oil film floats or the like and generates cyclicly a video signal with a short wavelength band and a video signal with a long wavelength band, a video processing section 3 applies image processing to the video signal with a short wavelength band and the video signal with a long wavelength band to generate a digitized video signal with a short wavelength band and a digitized video signal with a long wavelength band, a difference image extract section 4 extracts a difference between the video signal with a short wavelength band and the video signal with a long wavelength band so as to generate a video signal with high contrast such as a video image of an oil film or a video image of an organic film floating on a water surface and gives it to a display device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wavelength selection type liquid crystal camera device for extracting a specific subject image by combining an optical bandpass filter and an image pickup device. A wavelength-selectable liquid crystal camera device that uses a liquid crystal filter that changes the center wavelength of the transmission wavelength range to discriminate the light image from the subject into multiple wavelength ranges and visualizes images such as oil films floating on the sea surface. About.

[Summary of the Invention] The present invention relates to a wavelength-selective liquid crystal camera device for extracting a specific image by combining an optical band-pass filter and an image sensor.
A liquid crystal filter having an optical bandpass filter function and whose center wavelength can be varied by a voltage, and one or more imaging devices having a photoelectric conversion function provided after the liquid crystal filter; An optical system including a lens for transmitting an optical image, and an image operation unit that calculates a signal level difference for each pixel having the same spatial coordinates for a plurality of images having different wavelengths and outputs a value proportional to its absolute value. By constructing a wavelength-selective liquid crystal camera device with the above, imaging of foreign substances on the liquid surface, such as oil films and organic films floating on the sea surface or water surface, which were difficult to detect conventionally, metal and metal It is intended to visualize foreign substances on a solid surface such as a dielectric, and to visualize uneven coating of a transparent or translucent film applied to the solid surface.

[0003]

2. Description of the Related Art A full-color camera apparatus shown in FIG. 28 is conventionally known as one of wavelength-selective camera apparatuses.

A full-color camera device 200 shown in FIG.
Then, the lens 201 and each of the imaging devices 202, 203, 2
04, a dichroic prism 205 is provided to convert white light 206 from the object side into three primary color lights R, G, and B.
Has been broken down. In this case, each of the image sensors 202 and 20
CCDs (Charge Coupled Devices)
e), MOS (Metal Oxide Semiconductor), CPD
(Charge Priming Device), SIT (Static Inductio
n Transistor), CMD (Charge Modulation Devic)
e), an AMI (Amplified Mos Intelligent Imager) and other well-known solid-state image sensors are used. In addition, an imaging tube such as a plumbicon, a sachicon, a vidicon, a carnicon, and a harpicon is also used.

[0005] Each video signal generated by each of the image pickup devices 202 to 204 is supplied to each of the head amplifier circuits 207 and 20.
8, 209 and amplified respectively.
After various compensation processes are performed by the video processing circuits 210, 211, and 212, they are combined by the encoder circuit 213, converted into a color television signal, and supplied to the next-stage device.

In this full-color camera device 200, an iris or ND (Neutral Dens
ity) filter, IR (Infrared) filter to block infrared rays, pulse generators that send pulse signals to drive circuits and image processing circuits, contour compensation circuits to enhance video contours, power supplies, etc. are also used. Components are omitted because they do not relate to the essence of the full-color camera device 200.

[0007]

A transparent foreign substance on a liquid surface such as an oil film or an organic film floating on fresh water or seawater, a transparent foreign substance on a solid surface such as a metal or a dielectric, or a solid surface Since the transparent film or the semi-transparent coating unevenness applied to has a refractive index close to that of water, when the light absorptance is small, it hardly absorbs light (especially long-wavelength light of visible light or more), and is visually observed. It has the property that it is difficult to distinguish it from transparent substances such as water and glass.

Further, even if the absorptivity is high, when the film thickness is small, most of the light passes through the thin film, and it is difficult to visually discriminate from a transparent substance such as water or glass. For example,
In the case of an oil film floating on water, crude oil (absorption for green light) having a large absorption rate of 30,000 times or more of water absorption rate (about 2.3 × 10 ^-4 cm ^-1 for green light) The rate is about 8 cm ^-1 : Reference [1] VMZOLOTAREV, IAKITUSHINA, and SMSUTOVS
KIY, Optical Characteristics of Oils in the 0.4-15
μm Band, Oceanology Vol. 17, No. 6, pp. 736-739 (197
7).) However, when the thickness is 1 μm, only 1% of light is absorbed at most.

For this reason, it is difficult to clearly distinguish a sea surface image from an image such as an oil film with a conventionally known general wavelength selective camera device, and an oil film or an organic film floating on fresh water or sea water is difficult. It is difficult to detect a film or the like.

Similarly, the full-color camera apparatus 200 shown in FIG. 28 aims to capture an image as close as possible to the visual characteristics of human beings, so that the above-described oil film or organic film floating on the water surface can be easily observed by visual observation. Even if a subject that cannot be detected is photographed, it cannot be detected as a high-contrast image.

Further, such a full-color camera device 2
As a wavelength-selective camera device other than 00, there is also a wavelength-selective camera device in which a color filter that transmits light in a specific wavelength region and absorbs light in other regions is installed before and after the lens of the full-color camera device. .

However, this wavelength-selection type camera apparatus only narrows the wavelength selection area of the full-color camera apparatus, and the principle of imaging is not different from that of the full-color camera apparatus 200 shown in FIG.
It is difficult to make a high-contrast image of an oil film, an organic film, and the like floating on the water surface as in the full-color camera device 200 shown in FIG.

Hereinafter, the reason will be described in detail with reference to the drawings, taking an oil film floating on the sea surface as an example.

[0014] When an oil slick is floating on the lake surface or the sea surface,
As shown in FIG. 29, a three-layer structure including an upper layer (generally air) 215, a middle layer (liquid oil film or organic film) 216, and a lower layer (liquid such as fresh water or seawater) 217 can be considered. When the light 218 is incident on the middle layer 216 from the upper layer 215 side, the light 219 is radiated to the upper layer 215 side while being repeatedly reflected inside the thin film constituting the middle layer 216, and the light 220 is transmitted to the lower layer 217 side. Radiated. Since these many lights 219 (or light 220) interfere with each other, the intensity of light 219 reflected by the thin film and light 220 transmitted through the thin film has a weak wavelength dependence. From this, the oil film floating on the water surface can be regarded as a kind of reflection increasing film or antireflection film having poor performance.

Here, the upper layer 215, the middle layer 216, and the lower layer 2
17, the refractive indices of n ₁ , n ₂ , and n ₃ , respectively,
Assuming that the absorptance and the thickness of a 16 are a and L, respectively, the intensity I of the reflected light from the middle layer 216 is

I = [(r ₁ −r ₂ e ^−2ad ) ² + 4r ₁ r ₂ e ^−2ad sin ² (ψ / 2)] / [(1−r ₁ r ₂ e ^−2ad ) ² + 4r ₁ r ₂ e ^−2ad sin ² (ψ / 2)] (1) Here, as shown in FIG. 29, ψ is a phase difference between adjacent reflected light beams (light 219), and if the wavelength of the incident light 218 in vacuum is λ,

２ = (4πn ₂ d) [1- (n ₁ / n ₂ ) ² sin ² φ ₁ ] ^0.5 / λ (2) However, in this equation (2), the incident angle of the light 218 incident from the upper layer 215 to the middle 216 was phi _1. D is the middle layer 2 as shown in FIG.
Is the optical path length when crossing 16 only once,

D = L / [1- (1-n ₁ / n ₂ ) ² sin ² φ ₁ ] ^0.5 (3) Further, r ₁ is the upper layer 215 and the middle layer 216
And r ₂ is the amplitude reflectance at the interface between the middle layer 216 and the lower layer 217, and when the incident light 218 is P-wave light,

R ₁ = tan (φ ₁ −φ ₂ ) / tan (φ ₁ + φ ₂ ) r ₂ = tan (φ ₃ −φ ₂ ) / tan (φ ₃ + φ ₂ ) (4) Here, φ ₂ and φ ₃ are represented by the following equations.

[0016]

Φ ₂ = sin ⁻¹ [(n ₁ / n ₂ ) sin φ ₁ ] φ ₃ = sin ⁻¹ [(n ₁ / n ₃ ) sin φ ₁ ] (5)

When the incident light 218 is S-wave light, r ₁ and r ₂ are given by the following equations.

[0018]

R ₁ = −sin (φ ₁ −φ ₂ ) / sin (φ ₁ + φ ₂ ) r ₂ = −sin (φ ₃ −φ ₂ ) / sin (φ ₃ + φ ₂ ) (6)

The relationship between the reflected light (light 219) from the middle layer 216 and the wavelength can be obtained from the above equations (1) to (6). For example, the upper layer 215 is air (n ₁ =
1) The lower layer 217 is made of seawater (n ₃ = 1.33), the middle layer 21
6, the refractive index of the film is n ₂ = 1.5, and the absorptance is “a”.
= 0 cm ⁻¹ ”, the relationship between the normalized reflection intensity of the S-wave light (hereinafter, referred to as the reflectance of the middle layer 216) and the spectrum is shown in FIGS. 30 (a) to (e) and FIGS. 31 (a) to 31 (a). 30 (e), except that FIGS. 30 (a) to 30 (e) show the middle layer 216.
31 (a) to (e) show the case where the thickness L of the middle layer 216 is "L = 10 [mu] m", ignoring the refractive index dispersion of each layer. Here, a straight line (broken line) having no wavelength dependence indicates the reflectance of the sea surface without a film.

As is apparent from these figures, when the sea surface is constant spatially and temporally and the intensity of light 218 incident on the film is constant, the intensity of light reflected from the film and the sea surface without the film By measuring the difference between the reflected light intensities from, it is possible in principle to distinguish between the two.

In practice, however, the height and shape of the sea surface change greatly both temporally and spatially, and the intensity of the light 218 incident on the film greatly changes depending on the weather condition and the photographing direction. Therefore, it is extremely difficult to determine the location of the film only by detecting the difference between the reflectance of the film and the reflectance of the sea surface. This is true not only when the incident angle φ ₁ is small and the difference between the reflected light intensity from the film and the reflected light intensity from the sea surface without the film is very small, but also when the incident angle φ
_{The same} applies when ₁ is large.

Further, in an actual measurement, the reflectance is directly
Since the reflected light intensity cannot be measured and the reflected light intensity is measured and the reflectance must be calculated based on the measurement result, when the reflected light intensity is changed due to various factors as described above, Unless a human intervenes in the determination, even if an oil film or the like floats on the sea surface, it cannot be recognized. Therefore, in the conventional oil film detection method, it is practically impossible to automate the measurement,
It has been pointed out that there is also a problem with reliability, such as mistakes between the oil slick and the tide.

In the above description, the calculation is performed on the condition that the absorption of the film can be neglected, and FIG.
(E), as shown in FIGS. 31 (a) to (e), the reflectance of the S-wave light is obtained. When the absorption is considered, for example, the absorption a of the film is set to “a = 8 cm ⁻¹ ”. FIG. 32
(A) to (e) and FIGS. 33 (a) to (e),
The reflectance of the middle layer 216 has wavelength dependence. However, FIG.
2 shows the case where the thickness L of the middle layer 216 is “L = 1 μm”, and FIG. 33 shows the case where the thickness L of the middle layer 216 is “L = 10 μm”, ignoring the refractive index dispersion of each layer. Here, a straight line (broken line) having no wavelength dependence indicates the reflectance of the sea surface without a film.

As is apparent from these figures, even when the film has a high absorptance, the dependence of the film reflectivity is only slightly reduced, and FIGS. 30 (a) to 30 (e) and FIG. ~
Since there is no essential difference from (e), the wavelength region is narrowed using an optical band-pass filter as in a conventional wavelength-selective camera device, and the image is simply formed by photoelectric conversion using an image sensor. Thus, it is impossible to convert a very low-contrast image that is originally difficult or impossible to visually observe, such as an oil film floating on the sea surface, into a high-contrast easy-to-view image.

For this reason, when it is necessary to accurately and quickly detect an oil film or an organic film floating on the sea surface, for example, search for a distressed aircraft or ship, or accurately grasp the situation of crude oil spill from a tanker. Even at times, an oil film or the like cannot be visualized, and there has been a strong demand for the development of a wavelength-selective camera device capable of obtaining such an image.

For the same reason, it is not possible to visualize an oil film, an organic film, and other stains attached to the surface of a glass substrate such as a liquid crystal display or a plasma display. Because it is difficult to mass-produce displays and reduce their cost, a wavelength-selective camera that can visualize dirt such as oil films and organic films attached to the surface of glass substrates such as liquid crystal displays and plasma displays. Development of the device was strongly desired.

In view of the above circumstances, the present invention provides an oil film or an organic film floating on a sea surface or the like, or an oil film or an organic film adhered to the surface of a glass substrate such as a liquid crystal display or a plasma display even when the reflected light is strong. It is an object of the present invention to provide a wavelength-selectable liquid crystal camera device which can visualize dirt and the like with high contrast, and thereby can reliably find a dirt spot or a dirt on a glass substrate.

[0028]

In order to achieve the above object, according to the present invention, a light image obtained by a photographing operation is converted into a light image for each wavelength range, and a specific subject image is formed. In a wavelength selective liquid crystal camera device to be extracted, a liquid crystal filter having an optical bandpass filter function and capable of changing its center wavelength by a voltage, and a photoelectric image of a wavelength region selected by the liquid crystal filter being photoelectrically converted. An image operation for calculating a signal level difference between one image sensor for generating a video signal and two images having different wavelengths output from the image sensor, and generating a video signal based on an absolute value of the difference And a part.

According to a second aspect of the present invention, in the wavelength selective liquid crystal camera device according to the first aspect, the image pickup device includes a CCD,
MOS, CPD, SIT, AMI, etc., solid-state imaging device using silicon or solid-state imaging device using material showing high sensitivity in infrared region such as GaAs, InGaAs, or amorphous selenium, etc. It is characterized by being constituted by a solid-state imaging device using a material exhibiting high sensitivity, or an imaging tube such as a plumbicon, a sachicon, a vidicon, a carnicon, a harpicon, or the like.

According to a third aspect of the present invention, in the wavelength-selective liquid crystal camera device according to any one of the first and second aspects, the image calculation section outputs the video signal of each wavelength range output from the image sensor in frame units. A frame memory circuit that captures and stores video signals in a preset wavelength range,
The level difference between the video signal in the wavelength range stored in the frame memory circuit and the video signal having a wavelength range corresponding to the video signal and output from the image sensor in frame units is represented by the same spatial coordinates. And a difference circuit that calculates the absolute value of the level difference output from the difference circuit.

According to a fourth aspect of the present invention, in the wavelength selective liquid crystal camera device according to any one of the first to third aspects, the liquid crystal filter is formed of a transparent electrode formed in a film shape and a film shape. A structure in which a dielectric multilayer film, a layered liquid crystal layer, a film-shaped dielectric multilayer film, and a film-shaped transparent electrode are sandwiched between two plate-shaped transparent substrates. It has the same function as a Fabry-Perot interferometer.

According to a fifth aspect of the present invention, in the wavelength selective liquid crystal camera device according to any one of the first to fourth aspects, a burst AC voltage synchronized with a vertical signal of a television signal is applied to the liquid crystal filter. It is characterized in that the refractive index of the liquid crystal layer constituting the liquid crystal filter is changed to shift the center wavelength of the transmission characteristics of the liquid crystal filter.

According to a sixth aspect, in the wavelength-selective liquid crystal camera device according to any one of the first to fifth aspects, a full width at half maximum (Full width a) of the imaging element is provided in front of the imaging element.
An optical band-pass filter having a full width at half maximum wider than (t Half Maximum) is arranged, and the wavelength band of an optical image incident on the image sensor is limited by the optical band-pass filter.

According to a seventh aspect, in the wavelength-selective liquid crystal camera device according to any one of the first to sixth aspects, a polarizing film or a polarizing plate is disposed in front of the image pickup device, and the polarizing film or the polarizing plate is used. Among the respective lights constituting the light image of each wavelength range selected by the liquid crystal filter,
It is characterized in that light having a specific polarization plane is selected and made incident on the image sensor.

According to a eighth aspect, in the wavelength-selective liquid crystal camera device according to any one of the first to seventh aspects, the video signal generated by the image calculation unit is guided to a determination circuit.
The determination circuit compares a predetermined threshold value with the level of the video signal to determine the presence or absence of a specific subject image.

According to a ninth aspect of the present invention, in a wavelength selective liquid crystal camera device for extracting a specific subject image by converting an optical image obtained by a photographing operation into an optical image for each wavelength region, the optical bandpass filter function is provided. And a liquid crystal filter whose center wavelength can be changed by a voltage, and among the light images of the respective wavelength ranges selected by the liquid crystal filter, the light images of the respective wavelength ranges included on the short wavelength side are photoelectrically converted to obtain a short wavelength. For the short wavelength side image sensor that generates the wavelength side video signal, and for each pixel of each short wavelength side video signal output from this short wavelength side image sensor,
Calculate the signal level difference for each pixel with the same spatial coordinates,
A short-wavelength-side image calculation unit that generates a short-wavelength-side video signal based on the absolute value of the difference; and an optical image of each wavelength band selected by the liquid crystal filter, of each wavelength band included on the long wavelength side. The optical image is subjected to photoelectric conversion to generate a long-wavelength-side image signal, and the long-wavelength-side image sensor and each pixel of each long-wavelength-side image signal output from the long-wavelength image sensor have the same spatial coordinates. A long-wavelength-side image calculation unit that calculates a signal level difference for each pixel and generates a long-wavelength-side video signal based on the absolute value of the difference, and a long-wavelength-side video signal output from the long-wavelength-side image calculation unit And a video signal synthesizing unit for synthesizing the short-wavelength-side video signal output from the short-wavelength-side image calculation unit to generate a synthesized video signal.

According to a tenth aspect, in the wavelength-selective liquid crystal camera device according to the ninth aspect, the image pickup device includes a CC.
UV, short wavelength visible light such as solid-state image sensor using silicon such as D, MOS, CPD, SIT, AMI or solid-state image sensor using material having high sensitivity in infrared region such as GaAs and InGaAs, or amorphous selenium It is characterized by being constituted by a solid-state imaging device using a material exhibiting high sensitivity to light, or an imaging tube such as a plumbicon, a sachicon, a vidicon, a carnicon, a harpicone, or the like.

According to an eleventh aspect of the present invention, in the wavelength-selective liquid crystal camera device according to any one of the ninth and tenth aspects, the short-wavelength-side image calculation unit outputs the short-wavelength image output from the short-wavelength-side image sensor in frame units. Of the video signals of each wavelength range included on the wavelength side, a frame memory circuit that captures and stores a video signal of a preset wavelength range, and a video signal of the wavelength range stored in the frame memory circuit, A difference circuit that has a wavelength range corresponding to the video signal and calculates a level difference between the video signal output from the short-wavelength-side imaging device in frame units for each pixel having the same spatial coordinate; An absolute value circuit that calculates an absolute value of a level difference output from the circuit, wherein the long-wavelength-side image calculation unit is included on the long-wavelength side output from the long-wavelength-side image sensor in frame units. Among the video signals in the wavelength range, a frame memory circuit that captures and stores a video signal in a preset wavelength range, a video signal in the wavelength range stored in the frame memory circuit, and a video signal corresponding to the video signal. A difference circuit that has a wavelength range and calculates a level difference between a video signal output from the long-wavelength-side imaging device in frame units for each pixel having the same spatial coordinates, and a level output from the difference circuit. An absolute value circuit for calculating an absolute value of the difference.

According to a twelfth aspect, in the wavelength-selective liquid crystal camera device according to any one of the ninth, tenth, and eleventh aspects,
The liquid crystal filter includes a transparent electrode formed in a film shape, a dielectric multilayer film formed in a film shape, a layered liquid crystal layer, a dielectric multilayer film formed in a film shape, and a film formed. The transparent electrode is sandwiched between two transparent substrates formed in a plate shape, and has a function similar to that of a Fabry-Perot interferometer.

According to a thirteenth aspect, in the wavelength selective liquid crystal camera device according to any one of the ninth to twelfth aspects, a burst AC voltage synchronized with a vertical signal of a television signal is applied to the liquid crystal filter. It is characterized in that the refractive index of the liquid crystal layer constituting the liquid crystal filter is changed to shift the center wavelength of the transmission characteristics of the liquid crystal filter.

According to a fourteenth aspect, in the wavelength-selective liquid crystal camera device according to any one of the ninth to thirteenth aspects, the short-wavelength-side imaging element is provided in front of the short-wavelength-side imaging element and the long-wavelength-side imaging element. Full width a
t Half Maximum) and one or more optical bandpass filters having a full width at half maximum that is wider than the full width at half maximum of the long wavelength side image sensor, and the short wavelength side image sensor and the long wavelength It is characterized in that the wavelength range of the light image incident on the side image sensor is limited.

According to a fifteenth aspect, in the wavelength-selective liquid crystal camera device according to any one of the ninth to fourteenth aspects, one or more polarizing films are provided in front of the short-wavelength image sensor and the long-wavelength image sensor. Alternatively, one or more polarizing plates are arranged, and the polarizing film or the polarizing plate selects light having a specific polarization plane from among the light beams forming the light image in each wavelength range selected by the liquid crystal filter. Then, the light is incident on the short-wavelength image sensor and the long-wavelength image sensor.

According to a sixteenth aspect of the present invention, in the wavelength-selective liquid crystal camera device according to any one of the ninth to fifteenth aspects, the synthesized video signal generated by the video signal synthesizing unit is guided to a determination circuit, and the determination circuit preliminarily determines the synthesized video signal. By comparing the set threshold value with the level of the composite video signal,
It is characterized in that the presence or absence of a specific subject image is determined.

According to a seventeenth aspect, a wavelength-selective liquid crystal camera device for extracting a specific subject image by converting an optical image obtained by a photographing operation into an optical image for each wavelength region, has an optical bandpass filter function. A liquid crystal filter whose center wavelength can be changed by a voltage, and a light image of each wavelength region selected by the liquid crystal filter is separated into a red (R) region, a green (G) region, and a blue (B) region. A color image sensor that performs photoelectric conversion to generate an R color image signal, a G color image signal, and a B color image signal; and a R image signal, a G color image signal, and a B color image signal output from the color image sensor. For each pixel, a signal level difference is calculated for each of the pixels having the same spatial coordinates for each of the R, G, and B colors, and based on the absolute value of the difference, an R color video signal and a G color video are calculated. signal,
A color image operation unit for generating a B color image signal, and a color image signal for generating a composite color image signal by synthesizing an R color image signal, a G color image signal, and a B color image signal output from the color image operation unit And a combining unit.

According to an eighteenth aspect of the present invention, in the wavelength selective liquid crystal camera device according to the seventeenth aspect, the color imaging element is a solid-state imaging element using silicon, such as CCD, MOS, CPD, SIT, or AMI, or GaAs, InGaA.
A solid-state image sensor using a material exhibiting high sensitivity in the infrared region such as As, or a solid-state image sensor using a material exhibiting high sensitivity in ultraviolet light or short-wavelength visible light such as amorphous selenium, or plan bicone, sachicon, vidicon, Carnicon,
It is characterized by being constituted by any one of an image pickup tube such as a harpicon.

According to a nineteenth aspect, in the wavelength-selective liquid crystal camera device according to any one of the seventeenth and eighteenth aspects, the color image calculation unit is configured to output R, G, and G colors from the color image sensor.
A frame memory circuit that captures and stores video signals in wavelength ranges that are preset for each of R, G, and B colors, out of video signals in each wavelength range that are output in frame units for each color and B color; , R stored in the frame memory circuit.
A video signal in a wavelength range for each of the colors G, B, and B;
A difference circuit for calculating a level difference between a video signal output in a frame unit for each color and B color for each pixel having the same spatial coordinates, and an absolute value of the level difference output from the difference circuit is calculated. And an absolute value circuit.

In claim 20, claims 17, 18, and 19
In the wavelength-selective liquid crystal camera device according to any one of the above, the liquid crystal filter includes a transparent electrode formed in a film shape, a dielectric multilayer film formed in a film shape, a layered liquid crystal layer, and a film shape. It has a structure in which a formed dielectric multilayer film and a transparent electrode formed in a film shape are sandwiched between transparent plates formed in a plate shape, and has a function similar to that of a Fabry-Perot interferometer. .

According to a twenty-first aspect, in the wavelength selective liquid crystal camera device according to any one of the seventeenth to twentieth aspects, a burst-like AC voltage synchronized with a vertical signal of a television signal is applied to the liquid crystal filter. It is characterized in that the refractive index of the liquid crystal layer constituting the liquid crystal filter is changed to shift the center wavelength of the transmission characteristics of the liquid crystal filter.

According to a twenty-second aspect, in the wavelength-selective liquid crystal camera device according to any one of the seventeenth to twenty-first aspects, each half-value for each of R, G, and B of the color imaging device is provided in front of the color imaging device. Full width at Half Maxim
um) One or more optical band-pass filters having a full width at half maximum wider than the optical band-pass filter are provided, and the wavelength band of an optical image incident on the color imaging device is limited by the optical band-pass filters.

According to a twenty-third aspect, in the wavelength-selective liquid crystal camera device according to any one of the seventeenth to twenty-second aspects, one or more polarizing films or one or more polarizing plates are disposed in front of the color image pickup device. Then, by using the polarizing film or the polarizing plate, a light having a specific polarization plane is selected from the light constituting the light image in each wavelength range selected by the liquid crystal filter, and is incident on the color imaging device. It is characterized by:

According to a twenty-fourth aspect of the present invention, in the wavelength-selective liquid crystal camera device according to any one of the seventeenth to twenty-third aspects, the synthesized color video signal generated by the color video signal synthesizing section is guided to a determination circuit. By comparing a threshold value set in advance with the level of the composite video signal, the presence or absence of a specific subject image is determined.

According to a twenty-fifth aspect, in the wavelength-selective liquid crystal camera device according to any one of the first to twenty-fourth aspects, an optical shutter is disposed in front of the wavelength-selective liquid crystal camera device, and the optical shutter is operated. In this case, a light image is intermittently supplied to the wavelength-selective liquid crystal camera device.

According to a twenty-sixth aspect, in the wavelength selective liquid crystal camera device according to the twenty-fifth aspect, the optical shutter includes a nematic liquid crystal, a cholesteric liquid crystal, a smectic liquid crystal, LiNbO ₃ , LiTaO ₃ , KDP, DKDP, P
It is characterized by being composed of any one of electro-optical materials such as ZT and GaAs, or a combination thereof.

[0054]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <Description of First Embodiment of the Invention><Basic Description of First Embodiment> FIG. 1 shows a wavelength selective liquid crystal camera device according to the present invention. FIG. 3 is a block diagram showing a first embodiment corresponding to FIGS. In this figure, for the sake of simplicity, parts not related to the description of the present invention, such as an iris and an ND filter for attenuating the amount of incident light, components necessary for configuring the camera device, and a drive circuit A pulse generating circuit for sending a pulse signal to a video processing circuit, a contour compensating circuit for enhancing a contour of a video, a power supply circuit, and the like are omitted.

The wavelength-selective liquid crystal camera device 1 shown in FIG.
Includes a wavelength selection optical system 2, an image processing unit 3, and a difference image extraction unit 4. The wavelength selection optical system 2 captures an optical image obtained by photographing a subject such as a sea surface with a floating oil film, extracts light in a specified wavelength range, performs photoelectric conversion, and outputs a short wavelength range video signal and a long wavelength range. Wavelength range video signals are sequentially and cyclically generated. The image processing unit 3 sequentially generates a short-wavelength video signal and a long-wavelength video signal obtained by performing image processing on the short-wavelength video signal and the long-wavelength video signal output from the wavelength selection optical system 2 and digitizing the same. The difference image extracting unit 4 includes the image processing unit 3
While storing at least one of the short-wavelength video signal and the long-wavelength video signal output from the frame unit, based on the difference between the short-wavelength video signal and the long-wavelength video signal, the sea surface, water surface, etc. An image signal with a high contrast, such as an oil film image or an organic film image, floating on the surface is generated and supplied to a display device (not shown).

The wavelength selection optical system 2 includes a liquid crystal filter 5
, A lens 6 and an image sensor 7. The liquid crystal filter 5 has an optical band-pass filter function, captures a light image (white light image) from a subject, and forms an optical image in a short wavelength range constituting the light image according to an input AC voltage. And a light image in a long wavelength region constituting the light image are sequentially and cyclically extracted. The lens 6 is a liquid crystal filter 5
The light in the wavelength range selected by the above is imaged backward by a predetermined distance. The imaging device 7 is a CCD, MOS, CPD, S
High sensitivity in ultraviolet light and short wavelength visible light, such as solid-state imaging device using silicon such as IT and AMI, or material using high sensitivity in infrared region such as GaAs and InGaAs, or amorphous selenium. A solid-state image pickup device using a material, or an image pickup tube such as a planbicon, a sachicon, a vidicon, a carnicon, a harpicon, or the like, and each light image emitted from the lens 6 is subjected to light / electric conversion, and thus obtained. The short wavelength region video signal and the long wavelength region video signal are sequentially supplied to the image processing unit 3.

As shown in FIG. 2, the liquid crystal filter 5 includes a transparent substrate 8, a transparent electrode film 9, and a dielectric multilayer film 10.
Are sequentially laminated, and a transparent substrate 11, a transparent electrode film 12, and a dielectric multilayer film 13 are sequentially laminated, and a liquid crystal layer 1 is interposed between the dielectric multilayer film 13 and the dielectric multilayer film 10.
4 is interposed. The transparent electrode film 9 is composed of a metal film or the like laminated on one surface side of the transparent substrate 8 and is connected to a ground point. The dielectric multilayer films 10 and 11 are formed by laminating a required number of dielectric films having a refractive index corresponding to the reflectance and the effective wavelength region on the transparent electrode film 9 or 12 and functioning as a kind of mirror. The transmission wavelength range is determined by the same principle as that of the Perot interferometer. The transparent electrode film 12 is formed of a metal film or the like laminated on one surface side of the transparent substrate 11 and receives an external AC voltage. The liquid crystal layer 14 includes a nematic liquid crystal, a cholesteric liquid crystal, a smectic liquid crystal, a twisted nematic liquid crystal, and an electric field controlled birefringent mode liquid crystal (ELectrically Controllable).
Birefringence liquid crystal, Surface Stabilliz
ed) It is composed of a ferroelectric liquid crystal or the like.

The liquid crystal filter 5 takes in a light image (white light image) from the subject and has a constant amplitude as shown in FIGS. When a burst-like AC voltage synchronized with a vertical synchronization signal of a video signal is applied to the transparent electrode film 12, a plurality of light images belonging to a short wavelength region and a plurality of light images belonging to a long wavelength region are sequentially formed. Extract lens cyclically 6
Incident on

At this time, the alignment direction of the liquid crystal constituting the liquid crystal layer 14 is a homogeneous alignment in which the major axis of the liquid crystal molecules is parallel to each surface of the transparent substrates 8 and 11, or the major axis of the liquid crystal molecules is the transparent substrate. Any of the homeotropic orientations that are substantially perpendicular to the planes 8 and 11 is provided. However, in the former liquid crystal arrangement, the dielectric anisotropy needs to be “positive”, and in the latter liquid crystal arrangement, the dielectric anisotropy needs to be “negative”.

Table 1 shows the relationship between the refractive index dispersion of general fresh water and wavelength. Table 2 shows an example of the wavelength selection operation of the wavelength selection type liquid crystal camera device shown in FIG. If the upper layer side of the subject is air (refractive index n ₁ = 1) and the lower layer is fresh water having a refractive index dispersion as shown in Table 1 (a table quoted from a scientific chronological table), the difference in reflectance from fresh water is 1
%, As shown in Table 2, as the transmission wavelength range of the liquid crystal filter 5 shifts to the shorter wavelength side, the transmission wavelength range of the liquid crystal filter 5 when a burst AC voltage is input is increased. The liquid crystal filter 5 when the center wavelength λ ₁ and the burst AC voltage are not input.
Absolute value of the central wavelength lambda ₂ and the difference in transmission wavelength range of | λ ₁ -λ ₂ |
The value of the center wavelength λ _{1 and} the value of the center wavelength λ ₂ of the liquid crystal filter 5 are determined so that is smaller. It should be noted that the values shown in Table 2 are for reference only, and that the center wavelengths λ ₁ and λ _{2 of} the liquid crystal filter 5 may deviate slightly from these values.

[0061]

[Table 1]

[Table 2]

The image processing section 3, as shown in FIG.
Head amplifier circuit 15, video processing circuit 16, A / D
A conversion circuit 17 is provided. The head amplifier circuit 15
The short wavelength band video signal and the long wavelength band video signal sequentially output from the wavelength selection optical system 2 are amplified at a constant amplification factor. The video processing circuit 16 performs a preset image processing, for example, a transmission area compensation processing of the liquid crystal filter 5 and a liquid crystal filter for the short wavelength band video signal and the long wavelength band video signal sequentially output from the head amplifier circuit 15. 5 is performed. The A / D conversion circuit 17 A / D-converts the short wavelength band video signal and the long wavelength band video signal sequentially output from the video processing circuit 16 and digitizes the short wavelength band video signal,
A long-wavelength image signal is generated and supplied to the difference image extracting unit 4.

The difference image extracting unit 4 includes a frame memory circuit 18, a difference circuit 19, an absolute value circuit 20, a D / A
A conversion circuit 21 and an amplification circuit 22 are provided. The frame memory circuit 18 outputs a digital signal of a predetermined wavelength region among the digitized short wavelength region video signal and long wavelength region video signal output from the image processing unit 3 based on the input vertical synchronization signal. While a video signal, for example, a short wavelength band video signal is captured and stored in frame units, when a long wavelength band video signal is output from the image processing unit 3, the stored short wavelength band video signal is synchronized with this output. Output. The difference circuit 19 converts the short-wavelength band video signal output from the frame memory circuit 18 and the digitized long-wavelength band video signal output from the image processing unit 3 on a pixel basis based on the input vertical synchronization signal. Compare and calculate the level difference between each pixel of the same spatial coordinates, the video signal indicating the difference between the short wavelength band video signal and the long wavelength band video signal, for example, an image of an oil film floating on the water surface or an organic film. Generate a video signal with high contrast such as video. The absolute value circuit 20 calculates the absolute value of the video signal output from the difference circuit 19.
The D / A conversion circuit 21 converts a digital signal format video signal output from the absolute value circuit 20 into an analog signal format video signal. The amplifier circuit 22 includes a D / A conversion circuit 21
The video signal output from is amplified and supplied to the display device.

Next, the operation of this embodiment will be described with reference to FIGS.

First, when the wavelength-selective liquid crystal camera 1 shoots an image of the sea surface where the oil film floats, the wavelength-selective optical system 2 provided in the wavelength-selective liquid crystal camera 1
A light image (white light image) from a subject is taken in by the liquid crystal filter 5 of the present invention, and a short wavelength light image forming a light image and a long wavelength light forming an optical image in accordance with an input AC voltage. Are sequentially extracted cyclically.

Then, an image is formed on the image sensor 7 by the lens 6, and the short-wavelength band image signal obtained thereby is
The long-wavelength range video signal is sequentially supplied to the image processing unit 3,
A preamplification process, a transmission region compensation process of the liquid crystal filter 5, a transmittance compensation process of the liquid crystal filter 5, and the like are performed on the short wavelength region video signal and the long wavelength region video signal. The video signal and the long wavelength band video signal are digitized and supplied to the difference image extraction unit 4.

In this case, as shown in FIG. 3B, in the case of frames A, C, E, G and I of the video signal, FIG.
As shown in (a), a burst AC voltage is applied to the liquid crystal filter 5. For this reason, the refractive index of the liquid crystal constituting the liquid crystal layer 14 changes, and the center frequency of the liquid crystal filter 5, which is a kind of Fabry-Perot interferometer, changes to form a light image from the subject. A plurality of light images belonging to the short wavelength region are extracted from the light images of the respective wavelength regions,
This is imaged on the image sensor 7 to generate a short-wavelength band video signal, which is supplied to the image processing unit 3.

As shown in FIG. 3B, in the case of frames B, D, F, H, and J of the video signal, the liquid crystal filter 5 has a burst shape as shown in FIG. No AC voltage is applied. For this reason, the refractive index of the liquid crystal constituting the liquid crystal layer 14 returns to the original, and a kind of fabric
The center frequency of the liquid crystal filter 5, which is a Perot interferometer, changes, and each light image belonging to the long wavelength region is extracted from the light images of each wavelength region forming the light image from the subject. An image is formed on the image sensor 7 to generate a long-wavelength region video signal, which is supplied to the image processing unit 3.

When the digitized short-wavelength band video signal is output from the image processing unit 3, the short-wavelength band video signal is output by the frame memory circuit 18 of the difference image extraction unit 4 based on the input vertical synchronizing signal. After the video signal is captured and stored, when a digitized long wavelength band video signal is output from the image processing unit 3, the difference circuit 19 and the absolute value circuit 20 use the long wavelength band video signal to The short-wavelength band video signal stored in the memory circuit 18 is compared on a pixel-by-pixel basis, and the level difference between the pixels having the same spatial coordinates is calculated. Difference | A−B |, | B
−C |, | CD |, | DE |, | EF |,... (For example, a video signal having a high contrast such as an image of an oil film floating on the water surface or an image of an organic film) ) Is generated, and the D / A conversion circuit 21 and the amplification circuit 22
The video signal is converted into an analog signal and supplied to the display device.

At this time, as the liquid crystal filter 5, "1.
A 2 μm-thick homeotropically aligned nematic liquid crystal having an ordinary light refractive index of 5 ”and an extraordinary light refractive index of“ 1.7 ”is used, and the power reflectance of each of the dielectric multilayer films 10 and 13 is set to 0. Assuming that only the extraordinary light is selected by the polarizing plate by the liquid crystal filter 5 and before the liquid crystal filter 5 is applied with a burst-like AC voltage, the liquid crystal molecules are removed from each transparent substrate 8. 11 and is oriented almost perpendicularly, and as shown by the thick solid line in FIG. 5F, the full width at half maximum of about 2 nm from the short wavelength region to the long wavelength region (in FIG. 5, for simplicity, , Which is approximated by a straight line), and a burst AC voltage is applied to the liquid crystal filter 5 so that the extraordinary light has an effective refractive index of “1.53”. Figure 5
(F), a plurality of transmission regions having a full width at half maximum of about 2 nm (in FIG. 5, approximated by a straight line for simplicity) from the short wavelength region to the long wavelength region as shown by a thin solid line. Can be obtained.

Strictly speaking, the reflectance changes due to the refractive index dispersion of seawater, and as can be seen from the refractive index dispersion examples of water shown in Table 1, the amount of change is very small. In the wavelength region shown in the upper part, the refractive index dispersion of water may be neglected, and as shown in FIGS. 5 (a) to 5 (e), the reflectance of the sea surface without oil surface has almost wavelength dependency. Therefore, if the moving range of the center wavelength of the liquid crystal filter 5 (the spectral difference between the thick solid line and the thin solid line shown in FIG. The light image selected by the filter 5 is at the same level.

Thus, when there is no oil film on the sea surface, the short-wavelength range video signal output from the image processing unit 3
The long-wavelength range video signal is at the same level in pixel units,
A video signal indicating zero is output from the difference image extracting unit 4.

On the other hand, as shown in FIGS.
In seawater with an oil slick, regardless of the angle of incidence,
Although the reflectance of the oil film greatly changes according to the wavelength, when an AC voltage is applied, the reflectance (maximum transmittance) of the center wavelength of the light image transmitted through the liquid crystal filter 5 is 1 /
e / e or more with respect to the reflectance in the wavelength region having a transmittance of e or more and the transmittance (maximum transmittance) of the center wavelength of the light image transmitted through the liquid crystal filter 5 when no AC voltage is applied. Because the reflectance in the wavelength region with transmittance is at a different level, when photographing the sea surface with oil surface,
The short-wavelength band video signal and the long-wavelength band video signal output from the image processing unit 3 have different levels in pixel units, and the difference image extraction unit 4 outputs a video signal indicating an oil film.

At this time, the frame time difference between the light image in the short wavelength region output from the liquid crystal filter 5 and the light image in the long wavelength region is 1/30 second. Since it can be considered that the pixels constituting the short-wavelength band video signal and each pixel constituting the long-wavelength band video signal, it is possible to perform an operation for each pixel having the same spatial coordinates, Even if the sea surface is wavy due to strong winds, it is considered that the level difference between the two frames is calculated for each neighboring pixel that is only a few pixels away, and within this range, the incident angle greatly changes Not to do
An oil film on the sea surface can be detected even when the sea surface is calm or when the sea surface is wavy due to a strong wind or the like.

As described above, in this embodiment, the wavelength selection optical system 2 takes an image of the sea surface where the oil film floats, and generates a short-wavelength band video signal and a long-wavelength band video signal sequentially and cyclically. Meanwhile, the image processing unit 3 performs image processing on the short wavelength band video signal and the long wavelength band video signal,
A digitized short wavelength band video signal and a digitized long wavelength band video signal are generated, and the difference image extracting unit 4
By extracting the difference between the short wavelength range video signal and the long wavelength range video signal, a video signal with high contrast such as an oil film image or an organic film image floating on the water surface is generated, and this is output to the display device. Since the supply is performed, it is possible to detect an oil film, an organic film, and the like on the water surface, which have been conventionally difficult to detect, as a high-contrast image (the contents of claims 1, 2, 3, 4, and 5). .

Thus, even when a conventional helicopter or an aircraft is used to visually search for a distress site or the like, it is difficult to find an oil slick, for example, when the reflected light from the sea is strong (backlit state), Even if the waves are high,
Regardless of the state of the sea surface, when the oil slick of the distressed aircraft or ship is floating on the sea surface, this is reliably detected,
You can find out the distress site.

In this embodiment, the video signal output from the difference image extracting section 4 is set to a value other than zero only when the photographed sea surface has an oil film or an organic film. The video signal output from the difference image extracting unit 4 is guided to a determination circuit provided in the next-stage device or the like, and it is determined whether the video signal exceeds a preset threshold value. It can be easily automated. As a result, helicopters, aircraft, etc.
A plurality of wavelength-selective liquid crystal camera devices 1 shown in FIG. 1 are mounted, and each wavelength-selective liquid crystal camera device 1 simultaneously searches in all directions and automatically determines the presence or absence of an oil film or the like. Compared with this, it is possible to remarkably improve the search efficiency and perform quick disaster rescue (contents of claim 8).

Further, by combining the wavelength-selective liquid crystal camera device 1 shown in FIG. 1 with a GPS (Global Positioning System) device, the position of the oil film can be determined instantaneously. Can be further accelerated, and the situation of crude oil spill such as tankers can be easily mapped in real time.

<First Modification of First Embodiment>
In the wavelength-selective liquid crystal camera device 1 shown in FIG. 1, a liquid crystal filter 5 alternately extracts a short wavelength light image and a long wavelength light image included in a light image from a subject, and a lens 6. Thus, the light image in the short wavelength region and the light image in the long wavelength region are formed on the image sensor 7 as shown in FIG.
As shown in the figure, a wavelength selection optical system 2a in which an optical bandpass filter 23 is disposed is used in front of the image sensor 7, and the liquid crystal filter 5 is formed by the optical bandpass filter 23.
The light image in the short wavelength range and the light image in the long wavelength range selected in are band-pass filtered to narrow the wavelength range,
An image may be formed on the image sensor 7.

However, this optical bandpass filter 23
Is required to be wider than the full width at half maximum of the liquid crystal filter 5.

In this manner, similarly to the wavelength-selective liquid crystal camera device 1 shown in FIG. 1, it is possible to detect an oil film or an organic film on the water surface as an image with a high contrast, which has conventionally been difficult to detect. Yes (contents of claim 6).

In the first modified example, the lens 6
The optical bandpass filter 23 is arranged between the image sensor 7 and the optical bandpass filter 23.
Even if the optical band-pass filter 23 is arranged before the liquid crystal filter 5, or the optical band-pass filter 23 is arranged after the liquid crystal filter 5, the same effect as that of the first modification can be obtained. it can.

<Second Modification of First Embodiment>
In the wavelength-selective liquid crystal camera device 1 shown in FIG. 1, when an AC voltage is not applied, a light beam that senses only the ordinary refractive index of the liquid crystal is selected. Light rays felt both as the light refractive index are selected, and each light ray is made to enter the image sensor 7. As shown in FIG. 7, a polarizing film (or a polarizing plate) is provided behind the liquid crystal filter 5, as shown in FIG. 2) The wavelength selection optical system 2b provided with 24 may be used, and the polarizing film 24 may be used to remove the light beam that only senses the ordinary refractive index, and make the light beam enter the image sensor 7.

Even in this case, similarly to the wavelength selective liquid crystal camera device 1 shown in FIG. 1, it is possible to detect an oil film or an organic film on the water surface as an image with a high contrast, which has been difficult to detect conventionally. Yes (contents of claim 7).

In the second modification, the polarizing film 24 is disposed between the liquid crystal filter 5 and the lens 6. Even if the polarizing film 24 is arranged behind the lens 6 or the lens 6, the same effect as in the second modification can be obtained.

<Third Modification of First Embodiment>
In the wavelength selection type liquid crystal camera device 1 shown in FIG. 1, the wavelength selection type optical system 2, the image processing unit 3, and the difference image extraction unit 4
Although the camera device is configured in one housing, all of the difference image extracting unit 4 and all or a part of the image processing unit 3 may be separated from the camera device.

By doing so, the size and weight of the camera device can be reduced and the handling and operation of the camera device can be facilitated.

<< Description of Second Embodiment of the Invention >><Basic Description of Second Embodiment> FIG. 8 shows a wavelength-selective liquid crystal camera apparatus according to the ninth and tenth embodiments of the present invention. , 11, 12, 13, and 14 are block diagrams showing an example of a wavelength-selective liquid crystal camera device corresponding to FIG. In this figure, for the sake of simplicity, parts not related to the description of the present invention, such as an iris and an ND filter for attenuating the amount of incident light, components necessary for configuring the camera device, and a drive circuit A pulse generating circuit for sending a pulse signal to a video processing circuit, a contour compensating circuit for enhancing a contour of a video, a power supply circuit, and the like are omitted.

The wavelength-selective liquid crystal camera device 3 shown in FIG.
0 is the wavelength selection optical system 31 and the short wavelength side image processing unit 32
A short wavelength side difference image extraction unit 33, a long wavelength side image processing unit 34, a long wavelength side difference image extraction unit 35, and a video synthesis unit 36.
And The wavelength selection optical system 31 takes in the light image from the subject and divides the light image into two equal parts, extracts the short wavelength light image and the long wavelength light image, performs photoelectric conversion, and outputs the short wavelength side video signal and A long-wavelength side video signal for an optical image in a long-wavelength region is generated. Short wavelength side image processing unit 3
2 sequentially processes the short-wavelength-side video signal sequentially output from the wavelength selection optical system 31 to generate a digitized short-wavelength-side video signal. The short-wavelength difference image extraction unit 33 stores the short-wavelength video signal output from the short-wavelength image processing unit 32 on a frame-by-frame basis, and stores the short-wavelength video signal of the current frame and the short-wavelength video signal of one frame before. Based on the difference from the video signal, a short-wavelength-side video signal having a high contrast such as an image of an oil film floating on the sea surface or the water surface or an image of an organic film is generated and supplied to the image synthesizing unit 36. The long-wavelength-side image processing unit 34 performs image processing on the long-wavelength-side video signal sequentially output from the wavelength selection optical system 31 and sequentially generates a digitized long-wavelength-side video signal. The long-wavelength difference image extraction unit 35 stores the long-wavelength video signal output from the long-wavelength image processing unit 34 in frame units, On the basis of the difference from the side image signal, a long wavelength side image signal having a high contrast such as an image of an oil film floating on the sea surface or the water surface or an image of an organic film is generated. The video synthesizing unit 36 adds the short-wavelength-side video signal output from the short-wavelength-side difference image extraction unit 33 and the long-wavelength-side video signal output from the long-wavelength-side difference image extraction unit 35 to generate a composite television signal. Generate

The wavelength selection optical system 31 includes a liquid crystal filter 37, a lens 38, and a beam splitter 44. The liquid crystal filter 37 is configured in the same manner as each of the liquid crystal filters 5 shown in FIG. 1 and takes in a light image (white light image) from a subject and, in accordance with an input AC voltage, a light image in a short wavelength range. A light image in a long wavelength region is extracted. The lens 38 focuses the light image in the short wavelength region and the light image in the long wavelength region selected by the liquid crystal filter 37 and forms an image backward by a predetermined distance. The beam splitter 44 transmits half of the light image in the short wavelength range and half of the light image in the long wavelength range incident on the incident surface 39, emits the light from the second emission surface 40, and emits the light image in the short wavelength range. The other half of the light image in the long wavelength region, a reflection / transmission surface 41 for reflecting the other half of the light image in the long wavelength region, the light image in the short wavelength region reflected by the reflection / transmission surface 41, and the light image in the long wavelength region are totally reflected. A light image in the short wavelength range, a light image in the short wavelength range in the same horizontal direction as the light image in the long wavelength range, and a light image in the long wavelength range are output from the first output surface 42. A short-wavelength light image and a long-wavelength light image condensed by the lens 38 into two equal parts, which are output from the first emission surface 42 and the second emission surface 40, respectively. I do.

Further, the wavelength selection optical system 31 includes an optical band-pass filter 45, a short-wavelength-side image sensor 46, an optical band-pass filter 47, and a long-wavelength image sensor 48.
And The optical bandpass filter 45 transmits a light image in the short wavelength region side emitted from the first emission surface 42 of the beam splitter 44. Short wavelength side image sensor 46
Are solid-state imaging devices using silicon, such as CCD, MOS, CPD, SIT, and AMI, or GaAs, InGa
A solid-state imaging device using a material exhibiting high sensitivity in the infrared region such as As, or a solid-state imaging device using a material exhibiting high sensitivity in ultraviolet light or short-wavelength visible light such as amorphous selenium, or planbicon, sachicon, vidicon, Carnicon,
Consisting of one of the imaging tubes such as Harpicon,
The light image in the short wavelength region emitted from the optical band-pass filter 45 is subjected to optical / electrical conversion, and a short wavelength image signal is sequentially and cyclically generated. Optical bandpass filter 47
Transmits the light image on the long wavelength region side emitted from the second emission surface 40 of the beam splitter 44. The long-wavelength-side image sensor 48 is configured similarly to the short-wavelength-side image sensor 46, and optically / electrically converts the light image in the long wavelength region emitted from the optical band-pass filter 47 to convert the long-wavelength image signal. Generate sequentially and cyclically.

At this time, the lens 38 and the short wavelength side image pickup device 4
6, the optical path length between the lens 38 and the long-wavelength image sensor 4
Each optical path length in the beam splitter 44 is set so that the optical path lengths between the optical path lengths 8 and 8 are equal.

As shown in FIG. 9, the short-wavelength-side image processing section 32 includes a head amplifier circuit 49, a video processing circuit 50,
An A / D conversion circuit 51 for pre-amplifying the short-wavelength side video signal output from the wavelength selection optical system 31;
, And digitizes the obtained short-wavelength-side video signal and supplies it to the short-wavelength side difference image extraction unit 33. The head amplifier circuit 49 amplifies the short-wavelength side video signal sequentially output from the wavelength selection optical system 31 at a constant amplification factor. The video processing circuit 50 performs preset image processing, for example, compensation of the transmission area of the liquid crystal filter 37, compensation of the transmittance of the liquid crystal filter 37, and the like, on the short wavelength side video signal sequentially output from the head amplifier circuit 49. . The A / D conversion circuit 51 performs A / D conversion on the short wavelength side video signal sequentially output from the video processing circuit 50,
A digitized short-wavelength side video signal is generated.

The short-wavelength difference image extracting section 33 includes a frame memory circuit 52, a difference circuit 53, an absolute value circuit 54,
A D / A conversion circuit 55 and an amplification circuit 56;
When a short-wavelength-side video signal is output from the short-wavelength-side image processing unit 32 based on the input vertical synchronization signal, the short-wavelength-side video signal is captured and stored. When the converted short-wavelength-side video signal is output, the short-wavelength-side video signal is compared with the stored short-wavelength-side video signal one frame before in a pixel unit, and each pixel having the same spatial coordinate is compared. Calculates the level difference between the two signals, and displays the difference between the two signals. The short-wavelength difference video signal (for example, the short-wavelength side with a high contrast such as an oil film image or an organic film image floating on the water surface) After the video signal is converted to analog and amplified, the video
To supply.

The long wavelength side image processing section 34
As shown in FIG. 7, a head amplifier circuit 57, a video processing circuit 58, and an A / D conversion circuit 59 are provided. The head amplifier circuit 57 amplifies the long wavelength video signal sequentially output from the wavelength selection optical system 31 at a constant amplification factor. The video processing circuit 58 performs preset image processing, for example, compensation of the transmission area of the liquid crystal filter 37, compensation of the transmittance of the liquid crystal filter 37, and the like, on the long wavelength side video signal sequentially output from the head amplifier circuit 57. . A / D conversion circuit 59
A / D-converts the long-wavelength-side video signal sequentially output from the video processing circuit 58, generates a digitized long-wavelength-side video signal, and supplies it to the long-wavelength difference image extraction unit 35.

The long-wavelength difference image extracting section 35 includes a frame memory circuit 60, a difference circuit 61, an absolute value circuit 62,
A long-wavelength-side image processing unit 3 that includes a D / A conversion circuit 63 and an amplification circuit 64, based on an input vertical synchronization signal;
4, when the digitized long-wavelength-side video signal is output, it is captured and stored. When the long-wavelength-side video signal is output from the long-wavelength-side image processing unit 34, the length of the long-wavelength-side video signal is reduced. The wavelength-side video signal and the stored long-wavelength-side video signal one frame before are compared on a pixel-by-pixel basis, and a level difference between pixels having the same spatial coordinates is calculated.
The long-wavelength-side video signal indicating the difference between the long-wavelength-side video signal and the long-wavelength-side video signal thus obtained (for example, the long-wavelength side having a high contrast such as an image of an oil film floating on the water surface or an image of an organic film) After the video signal is converted into an analog signal and amplified, it is supplied to the video synthesizing unit 36.

As shown in FIG. 8, the video synthesizing section 36 includes an adding circuit 65 and an amplifying circuit 66. The addition circuit 65 adds the short-wavelength-side video signal output from the short-wavelength-side difference image extraction unit 33 and the long-wavelength-side video signal output from the long-wavelength side difference image extraction unit 35 to generate a combined television signal. Generate. The amplification circuit 66 amplifies the composite television signal output from the addition circuit 65 and supplies the amplified television signal to a display device or the like, thereby forming an oil film image or the like.

As described above, in this embodiment, the wavelength selection optical system 31 takes an image of the sea surface or the like on which the oil film floats, and sequentially generates the short wavelength side video signal and the long wavelength side video signal, The short-wavelength image signal and the long-wavelength image signal are image-processed by the short-wavelength image processing unit 32 and the long-wavelength image processing unit 34, and the digitized short-wavelength image signal and the long-wavelength image are processed. After the signal is generated, the difference between the short-wavelength side video signal and the short-wavelength side video signal is extracted by the short-wavelength side difference image extracting unit 33, and the image of the oil film floating on the water surface or the image of the organic film is extracted. The short wavelength side video signal with high contrast is generated, and the difference between the long wavelength side video signal and the long wavelength side video signal is extracted by the long wavelength side difference image extraction unit 35, and the oil film floating on the water surface or the like is extracted. Images and organic film images It generates a long-wavelength video signal with a high contrast and supplies a composite television signal that combines them to the display device, so that no matter what the state of the water surface is, an oil film on the water surface or An organic film or the like can be detected as an image with high contrast (the contents of claims 9, 10, 11, 12, 13, and 14).

[0099] This makes it difficult to find an oil slick even if a conventional helicopter or an aircraft is used to visually search a distress site, for example, when the reflected light from the sea surface is strong (backlit state) or when it is raining. , Even when the waves are high,
Regardless of the state of the sea surface, when the oil slick of the distressed aircraft or ship is floating on the sea surface, this is reliably detected,
You can find out the distress site.

Further, in this embodiment, the short wavelength side difference image extracting section 33 and the short wavelength side difference image extracting section 35 output from the long wavelength side difference image Since the side video signal and the long-wavelength side video signal are set to values other than zero, the synthesized television signal output from the video synthesis unit 36 is guided to a determination circuit (not shown) and set in advance. The search for the distress site can be easily automated simply by determining whether or not the threshold value is exceeded. As a result, a plurality of wavelength-selective liquid crystal camera devices 30 shown in FIG. 8 are mounted on a helicopter, an aircraft, or the like.
If all directions are searched simultaneously and the presence / absence of an oil slick or the like is automatically determined, search efficiency can be significantly improved and quick disaster rescue can be performed, as compared with the conventional visual inspection. Content).

Also, by combining the wavelength-selective liquid crystal camera device 30 shown in FIG. 8 with a GPS (Global Positioning System) device, the position of the oil film can be determined instantaneously, thereby finding the location of a distress site or the like. Can be further accelerated, and the situation of crude oil spill such as tankers can be easily mapped in real time.

<First Modification of Second Embodiment>
8, the liquid crystal filter 37, the lens 38, the beam splitter 44,
A wavelength selection optical system 31 constituted by two optical band-pass filters 45 and 47, a short-wavelength-side image sensor 46, and a long-wavelength-side image sensor 48 is used, as shown in FIG. The wavelength selection optical system 31a including the liquid crystal filter 37, the lens 38, the prism type band pass filter 67, the short wavelength side image sensor 46, and the long wavelength side image sensor 48 may be used. (Contents of Claim 14).

In this case, the prism type band pass filter 67 includes a prism 69, a prism 74, an optical low pass filter 75, an optical high pass filter 77,
And an optical low-pass filter 79. The prism 69 is a prism whose front surface 68 is cut at 45 degrees. The prism 74 includes a front surface 70 (rear surface 71) and a slope 7
This is a parallelogram prism cut so that the angle between 2, 73 is 45 degrees and 135 degrees. The optical low-pass filter 75 is disposed on the joint surface between the inclined surface 73 of the prism 74 and the front surface 68 of the prism 69, and has a low-pass characteristic as shown in FIGS. It transmits the light image belonging to it and reflects the light image belonging to the short wavelength region. The optical high-pass filter 77 is joined to the exit surface 76 of the prism 69,
As shown in FIG. 12, the cutoff wavelength λ ₇₅ of the transmission wavelength characteristic of the optical low-pass filter 75 (here, the transmittance of the optical low-pass filter 75 is the maximum transmittance of 50).
% Is defined as a cut-off wavelength), and has a cut-off wavelength characteristic shifted to a longer wavelength side, and is shorter than the cut-off wavelength λ ₇₇ in the long-wavelength side light image transmitted through the optical low-pass filter 75. A light image of a wavelength (a light image in a hatched portion) is transmitted. The optical low-pass filter 79 is joined to the exit surface 78 (rear surface 71) of the prism 74, and
As shown in FIG. 3, the optical low-pass filter 7 has a cut-off wavelength λ ₇₉ shifted to a shorter wavelength side than the cut-off wavelength λ ₇₅ of the reflection wavelength characteristic of the optical low-pass filter 75.
Among the light images on the short wavelength side reflected at 5, the light image having a wavelength longer than the cutoff wavelength λ ₇₉ (the light image in the hatched portion) is transmitted.

Of course, also in the prism type band pass filter 67, the optical path length between the lens 38 and the short wavelength side image sensor 46 is the same as the optical path length between the lens 38 and the long wavelength side image sensor 48. Thus, each optical path length in the prism type band pass filter 67 is set.

In the wavelength selection optical system 31a, the light image in the short wavelength range and the light image in the long wavelength range selected by the liquid crystal filter 37 are output. ) 80 having entered into the filtering operation of the optical low-pass filter 75, the filtering operation of the optical high-pass filter 77, as shown in FIG. 12, select the optical image that belongs to the long wavelength region around a wavelength lambda _a Then, this is made incident on the long-wavelength-side imaging element 48 to generate a long-wavelength-side video signal and a long-wavelength-side video signal, and the filtering operation of the optical low-pass filter 75 and the filtering operation of the optical low-pass filter 79 are performed. as shown in FIG. 13, by selecting the optical image belonging to a short wavelength region around a wavelength lambda _b, short wavelength it It is incident on the image sensor 46 to generate a short wavelength side video signal.

As described above, the wavelength selection optical system 31a constituted by the liquid crystal filter 37, the lens 38, the prism type band pass filter 67, the short wavelength side image pickup device 46 and the long wavelength side image pickup device 48 is used. However, the light image in the short wavelength region and the light image in the long wavelength region selected by the liquid crystal filter 37 are bisected into two light images that are not inverted left and right, and the short wavelength side video signal and the long wavelength Side video signal.

<Second Modification of Second Embodiment>
In the first modified example shown in FIG. 11, a liquid crystal filter 37, a lens 38, a prism type bandpass filter 67, a short wavelength side image sensor 46, and a long wavelength side image sensor 48 constitute a wavelength selection optical system 31a. However, as shown in FIG. 14, the liquid crystal filter 37 and the lens 38
, A prism-type low-pass filter 81, an optical low-pass filter 82, an optical high-pass filter 83, a short-wavelength-side imaging device 46, and a long-wavelength-side imaging device 48, constitute a wavelength selection optical system 31 b. The optical image from the subject may be wavelength-discriminated using the selection optical system 31b to generate a short-wavelength-side video signal and a long-wavelength-side video signal (contents of claim 14).

In this case, the prism type low-pass filter 8
1 includes a prism 85, a prism 90, and an optical low-pass filter 91. The prism 85 is a prism whose front surface 84 is cut at 45 degrees. The prism 90 is a parallelogram prism cut so that the angle between the front surface 86 (rear surface 87) and the inclined surfaces 88 and 89 is 45 degrees and 135 degrees. The optical low-pass filter 91 is disposed on the joint surface between the inclined surface 89 of the prism 90 and the front surface 84 of the prism 85, and has the same low-pass characteristics as the optical low-pass filter 75 shown in FIG. The light image belonging to the region is transmitted and the light image belonging to the short wavelength region is reflected.

In the prism type low-pass filter 81, when the light image in the short wavelength region and the light image in the long wavelength region enter the incident surface (front surface 86) 92 from the lens 38, the filtering operation of the optical low-pass filter 91 causes After transmitting the light image on the long wavelength side and emitting the light image from the emission surface 93 to be incident on the optical high-pass filter 83, the optical image on the short wavelength side is reflected by the optical low-pass filter 91, Is reflected by the total reflection surface 94, emitted from the emission surface 95, and made incident on the optical low-pass filter 82.

The optical low-pass filter 82 is composed of a filter plate having the same low-pass characteristics as the optical low-pass filter 79 shown in FIG. 11 (low-pass characteristics shown in FIG. 13). After the light image on the short wavelength side emitted from the light source 95, FIG.
As shown in, select the optical image of the short wavelength side having a center wavelength lambda _b, which is incident on the short wavelength side imaging device 46 to generate a short wavelength side video signal.

The optical high-pass filter 83 is formed of a filter plate having the same high-pass characteristics (high-pass characteristics as shown in FIG. 12) as the optical high-pass filter 77 shown in FIG. of the light image of the long-wavelength side which is emitted from the emission surface 93, as shown in FIG. 12, by selecting the optical image of the long-wavelength side around the wavelength lambda _a, which in the long wavelength side image sensor 48 Then, a long-wavelength image signal is generated.

As described above, the liquid crystal filter 37, the lens 38, the prism type low-pass filter 81, the optical low-pass filter 82, and the optical high-pass filter 83
Even if the wavelength selection optical system 31b composed of the short wavelength side image sensor 46 and the long wavelength side image sensor 48 is used, the light image from the subject is discriminated in wavelength, and the short wavelength side video signal and the long And a wavelength-side video signal.

<Third Modification of Second Embodiment>
In the second modification shown in FIG. 14, the liquid crystal filter 37, the lens 38, the prism type low-pass filter 81, the optical low-pass filter 82, and the optical high-pass filter 8
3, a short wavelength side image sensor 46, and a long wavelength side image sensor 48
Constitutes the wavelength selection optical system 31b. However, as shown in FIG. 15, the liquid crystal filter 37, the lens 38, the prism type low-pass filter 96, and the two optical band-pass filters 97 and 98 are provided. A wavelength selection optical system 31c is constituted by the short wavelength side image pickup element 46 and the long wavelength side image pickup element 48. Using this wavelength selection optical system 31c, a light image from a subject is discriminated in wavelength, and A video signal and a long-wavelength-side video signal may be generated (contents of claim 14).

In this case, the prism type low-pass filter 9
6 includes a prism 100, a prism 105, and an optical low-pass filter 106. Prism 100
Is a prism whose front surface 99 side is cut at 45 degrees. The prism 105 is a parallelogram-type prism cut so that the angle between the front surface 101 (rear surface 102) and the inclined surfaces 103 and 104 is 45 degrees and 135 degrees.
The optical low-pass filter 96 is arranged on the joint surface between the inclined surface 104 of the prism 105 and the front surface 99 of the prism 100, and has the same low-pass characteristics as the optical low-pass filter 91 shown in FIG. The light image belonging to the region is transmitted and the light image belonging to the short wavelength region is reflected. In the prism type low-pass filter 96, when the light image in the short wavelength region and the light image in the long wavelength region are incident on the incident surface 107 from the lens 38, the optical low-pass filter 106 performs the filtering operation to belong to the long wavelength region. The optical image is transmitted, emitted from the emission surface 108, and made incident on the optical band-pass filter 98.
After reflecting the light image on the short wavelength side, this is reflected to the total reflection surface 109.
Then, the light is reflected from the light exiting surface 110 and is incident on the optical bandpass filter 97.

The optical band-pass filter 97 has the configuration shown in FIG.
As shown in FIG. 7, a filter having a band-pass characteristic for extracting light having a wavelength included in a predetermined region around a wavelength λ _d from an optical image on the short wavelength side selected by the low-pass filtering characteristic of the optical low-pass filter 106. And a prism type low-pass filter 96.
Out of the light image on the short wavelength side emitted from the emission surface 110 of
As shown in FIG. 16, by selecting an optical image of a predetermined wavelength region centering wavelength lambda _d, which is incident on the short wavelength side imaging device 46 to generate a short wavelength side video signal.

Further, the optical band-pass filter 98
As shown in FIG. 17, a band-pass characteristic for extracting light having a wavelength included in a predetermined region around a wavelength λ _c from an optical image in a long wavelength region selected by the low-pass filtering characteristic of the optical low-pass filter 106 is shown. A light image on the long wavelength side emitted from the emission surface 108 of the prism type low-pass filter 96,
Of the light image on the long wavelength side, as shown in FIG. 17, the wavelength lambda _c
, A light image in a predetermined wavelength region around the center is selected, and the selected light image is made incident on the long-wavelength-side image sensor 48 to generate a long-wavelength-side video signal.

As described above, the liquid crystal filter 37, the lens 38, the prism type low-pass filter 96, the two optical band-pass filters 97 and 98, the short-wavelength image pickup device 46, and the long-wavelength image pickup device 48 A wavelength selection optical system 31c is formed by using the wavelength selection optical system 31c. Even when the wavelength selection optical system 31c is used, it is possible to discriminate the wavelength of a light image from a subject and generate a short wavelength side video signal and a long wavelength side video signal. it can.

<Fourth Modification of Second Embodiment>
8, the liquid crystal filter 37, the lens 38, and the beam splitter 44 are provided.
And two optical band-pass filters 45 and 47, a short-wavelength-side imaging device 46, and a long-wavelength-side imaging device 48. A wavelength selection optical system from which the two optical bandpass filters 45 and 47 constituting the optical system 31 are removed may be used.

In the wavelength-selective liquid crystal camera device 30 shown in FIG. 8, the liquid crystal filter 37, the lens 38, the beam splitter 44, the two optical bandpass filters 45 and 47, and the short-wavelength imaging device 46 And a long-wavelength-side image pickup element 48, the wavelength selection optical system 31 is used. Instead of the beam splitter 44 forming the wavelength selection optical system 31, a prism shown in FIG. With a low-pass filter 81,
A wavelength selection optical system from which the two optical bandpass filters 45 and 47 are removed may be used.

<Fifth Modification of Second Embodiment>
In the wavelength-selective liquid crystal camera device 30 shown in FIG. 8, when an AC voltage is not applied, a light beam that senses only the ordinary light refractive index of the liquid crystal is selected. The liquid crystal filter 37 selects the light beam which is sensed as both the light refraction index and makes each light beam enter the short wavelength side image sensor 46 and the long wavelength side image sensor 48.
A polarizing film (or a polarizing plate) is arranged in front of, behind, behind the lens 38, or in front of the short-wavelength-side imaging element 46 and the long-wavelength-side imaging element 48. It may be possible to remove the light beam that feels the above and make the light beam enter the short-wavelength image sensor 46 and the long-wavelength image sensor 48.

Even in this case, similarly to the wavelength-selective liquid crystal camera device 30 shown in FIG. 8, an oil film or an organic film on the water surface, which has been difficult to detect conventionally, can be detected as an image with high contrast. Yes (contents of claim 15).

<Sixth Modification of Second Embodiment>
In the wavelength selection type liquid crystal camera device 30 shown in FIG. 8, the wavelength selection type optical system 31, the short wavelength side image processing unit 32, the short wavelength side difference image extraction unit 33, the long wavelength side image processing unit 34, Although the camera device is configured by putting the wavelength side difference image extracting unit 35 and the image synthesizing unit 36 in one housing, all of the image synthesizing unit 36 and the short wavelength side difference image extracting unit 3
3, all the long wavelength side difference image extraction unit 35, all or a part of the short wavelength side image processing unit 32, and all or a part of the long wavelength side image processing unit 34 are separated from the camera device. You may do it.

By doing so, the size and weight of the camera device can be reduced and the handling and operation of the camera device can be facilitated.

<< Description of Third Embodiment of the Invention >><Basic Description of Third Embodiment> FIG. 18 shows a wavelength selective liquid crystal camera according to the present invention. , 19, 20, and 21 are block diagrams illustrating an example of a wavelength-selective liquid crystal camera device corresponding to FIG. In this figure, for the sake of simplicity, parts not related to the description of the present invention, such as an iris and an ND filter for attenuating the amount of incident light, components necessary for configuring the camera device, and a drive circuit A pulse generating circuit for sending a pulse signal to a video processing circuit, a contour compensating circuit for enhancing a contour of a video, a power supply circuit, and the like are omitted.

The wavelength-selective liquid crystal camera device 1 shown in FIG.
Reference numeral 11 includes a full-color wavelength selection optical system 112, an R color image processing unit 113, and an R color difference image extraction unit 114. The full-color wavelength selection optical system 112 takes in a light image from a subject and separates the light into three primary colors of R, G, and B. Each of R, G, and B has a short wavelength light image and a long wavelength light image. Is extracted, photoelectrically converted, and a short wavelength image signal (R color short wavelength image signal) for the R light image, a long wavelength image signal (R color long wavelength image signal), and a short signal for the G light image are obtained. Wavelength range video signal (G color short wavelength range video signal), long wavelength range video signal (G color long wavelength range video signal), short wavelength range video signal for B light image (B color short wavelength range video signal) , A video signal in a long wavelength range (B color long wavelength range video signal) is sequentially generated. The R-color image processing unit 113 includes the full-color wavelength selection optical system 1
An R color short wavelength band video signal and an R color long wavelength band video signal are sequentially generated by performing image processing on the R color short wavelength band video signal and the R color long wavelength band video signal which are sequentially output from 12.
The R color difference image extraction unit 114 stores at least one of the R color short wavelength band video signal and the R color long wavelength band video signal output from the R color image processing unit 113 in frame units, Based on the difference between the wavelength band video signal and the R color long wavelength band video signal, an R color video signal with a high contrast such as an oil film image or an organic film image floating on the sea surface or water surface is generated.

Further, the wavelength selection type liquid crystal camera device 111
Are a G color image processing unit 115 and a G color difference image extraction unit 116
, A B color image processing unit 117, and a B color difference image extraction unit 118
And an encoder circuit 119. The G color image processing unit 115 includes a G color short wavelength region video signal sequentially output from the full color wavelength selection optical system 112, a G color short wavelength region video signal obtained by performing image processing on the G color long wavelength region video signal, and digitizing; G color long wavelength region video signals are sequentially generated. The G color difference image extracting unit 116 stores at least one of the G color short wavelength region video signal and the G color long wavelength region video signal output from the G color image On the basis of the difference between the wavelength range video signal and the G color long wavelength range video signal, a G color video signal with a high contrast such as an oil film image or an organic film image floating on the sea surface or water surface is generated. The B-color image processing unit 117 includes a B-color short-wavelength band video signal sequentially output from the full-color wavelength selection optical system 112, a B-color short-wavelength band video signal obtained by image-processing the B-color long-wavelength band video signal, A B color long wavelength band video signal is sequentially generated. The B color difference image extracting unit 118 stores at least one of the B color short wavelength band video signal and the B color long wavelength band video signal output from the B color image processing unit 117 in frame units, Based on the difference between the wavelength range video signal and the B color long wavelength range video signal, a B color video signal having a high contrast such as an oil film image or an organic film image floating on the sea surface or water surface is generated. Encoder circuit 119
Are the R color difference image extraction unit 114 and the G color difference image extraction unit 11
6, R output from the B color difference image extraction unit 118
By combining the color video signal, the G color video signal, and the B color video signal,
Generate a composite color television signal.

The full-color wavelength selection optical system 112 includes a liquid crystal filter 120, a lens 121, a dichroic prism 123, an R color image sensor 124, a G color image, similarly to the liquid crystal filters 5 and 37 shown in FIGS. Image sensor 1
25, and a B-color image sensor 126, which captures a light image (white light image) from a subject and, in accordance with an input AC voltage, forms a light image in a short wavelength range and forms a light image. The light image in the short wavelength region and the light image in the long wavelength region are sequentially extracted cyclically with the light image in the long wavelength region constituting the light image, and the light image in the R color and the light image in the G color are extracted. , B light image, and then R, G, and B light images are respectively photoelectrically converted, and the resulting R color short wavelength band image signal is obtained by: The R color long wavelength band video signal is sequentially supplied to the R color image processing unit 113, and the G short wavelength band video signal and the G long wavelength band video signal are sequentially supplied to the G color image processing unit 115. Further, the B color short wavelength band video signal and the B color long wavelength band video signal are sequentially supplied to the B color image processing unit 117. The liquid crystal filter 120 captures a light image (white light image) from a subject, and extracts a light image in a short wavelength range and a light image in a long wavelength range according to an input AC voltage. The lens 121 condenses the light image in the short wavelength region and the light image in the long wavelength region extracted by the liquid crystal filter 120 and forms an image backward by a predetermined distance. Dichroic prism 1
Reference numeral 23 denotes a light image in the short wavelength range and a light image in the long wavelength range, which are condensed by the lens 121, for the R color image, the G color image, and the B color image.
Color light image. The R color image sensor 124 has a CC
UV, short wavelength visible light such as solid-state image sensor using silicon such as D, MOS, CPD, SIT, AMI or solid-state image sensor using material having high sensitivity in infrared region such as GaAs and InGaAs, or amorphous selenium A short-wavelength light of R color emitted from the dichroic prism 123, which is formed of a solid-state image sensor using a material exhibiting high sensitivity to light, or an image pickup tube such as a plumbicon, a sachicon, a vidicon, a carnicon, and a harpicone. The image and the light image in the long wavelength region are subjected to optical / electric conversion, and an R color short wavelength region video signal and an R color long wavelength region video signal are sequentially and cyclically generated. The G color image sensor 125 is an R color image sensor 124
The light image in the short wavelength region and the light image in the long wavelength region of the G color emitted from the dichroic prism 123 are optically / electrically converted to produce a G color short wavelength region image signal and a G color long wavelength region image. The signals are generated sequentially and cyclically. B color image sensor 12
Reference numeral 6 is configured similarly to the R-color image sensor 124 and the G-color image sensor 125, and optically / electrically converts the light image in the short wavelength region and the light image in the long wavelength region of the B color emitted from the dichroic prism 123. The B color short wavelength band video signal and the B color long wavelength band video signal are sequentially and cyclically generated.

As shown in FIG. 19, the R color image processing section 113 includes a head amplifier circuit 127 and a video processing circuit 128.
And an A / D conversion circuit 129. The pre-amplification process and the liquid crystal filter 120 for the R color short wavelength band video signal and the R color long wavelength band video signal output from the full color wavelength selection optical system 112 are provided. Area compensation processing, liquid crystal filter 1
Then, the R color short wavelength band video signal and the R color long wavelength band video signal are digitized and supplied to the R color difference image extraction unit 114. The head amplifier circuit 127 includes the full-color wavelength selection optical system 11
The R color short wavelength band video signal and the R color long wavelength band video signal sequentially output from 2 are amplified at a constant amplification factor. The video processing circuit 128 converts the R color short wavelength band video signal and the R color long wavelength band video signal sequentially output from the head amplifier circuit 127 into
Image processing set in advance, for example, the liquid crystal filter 12
Compensation for the transmission region of 0, the transmittance of the liquid crystal filter 120, and the like are performed. The A / D conversion circuit 129 performs A / D conversion of the R color short wavelength band video signal and the R color long wavelength band video signal sequentially output from the video processing circuit 128, and digitizes the R color short wavelength band. A video signal and an R color long wavelength band video signal are generated.

The R color difference image extraction unit 114 includes a frame memory circuit 130, a difference circuit 131, and an absolute value circuit 132.
And a D / A conversion circuit 133 and an amplification circuit 134, and when a digitized R color short wavelength band video signal is output from the R color image processing unit 113 based on the input vertical synchronization signal. When the R color image processing unit 113 outputs a digitized R color long wavelength band video signal, the R color long wavelength band video signal and the stored R color short The level difference between each pixel having the same spatial coordinates is calculated by comparing the wavelength range video signal with the pixel unit, and the difference between the R color short wavelength range video signal and the R color long wavelength range video signal obtained by this is calculated. (For example, an R-color image signal having a high contrast such as an image of an oil film floating on the water surface or an image of an organic film) is converted into an analog signal and supplied to the encoder circuit 119. The frame memory circuit 130, based on the input vertical synchronization signal,
Of the digitized R color short wavelength band video signal and R color long wavelength band video signal output from the R color image processing unit 113,
When a video signal in a preset wavelength region, for example, an R-color short-wavelength region video signal is captured and stored in frame units, when the R-color long-wavelength region video signal is output from the R-color image processing unit 113, In synchronization with this, the stored R-color short wavelength band video signal is output. The difference circuit 131, based on the input vertical synchronizing signal,
The R color short wavelength band video signal output from the R 30 and the R color long wavelength band video signal output from the R color image processing unit 113 are compared on a pixel basis, and the level difference between each pixel having the same spatial coordinates is calculated. Then, an R color video signal indicating the difference between the R color short wavelength band video signal and the R color long wavelength band video signal is generated. Value circuit 13
2 calculates the absolute value of the R color video signal output from the difference circuit 131. The D / A conversion circuit 133 converts the digital signal format R color video signal output from the absolute value circuit 132 into an analog signal format R color video signal. The amplification circuit 134 amplifies the R color video signal output from the D / A conversion circuit 133.

The G color image processing section 115, like the R color image processing section 115, includes a head amplifier circuit 127, a video processing circuit 128, and an A / D conversion circuit 129, as shown in FIG. And full-color wavelength selection optical system 1
A pre-amplification process is performed on the G color short wavelength band video signal and the G color long wavelength band video signal output from the
The G color difference image extraction unit 116 digitizes the G color short wavelength band video signal and the G color long wavelength band video signal obtained by performing Supply.

The G chrominance image extraction unit 116, like the R chrominance image extraction unit 114, includes a frame memory circuit 130, a difference circuit 131, an absolute value circuit 132, and a D / A conversion circuit 1
33, and an amplifier circuit 134. When the G color image processing section 115 outputs a digitized G color short wavelength band video signal based on the input vertical synchronizing signal, it takes in the digitized video signal. When the G color image processing unit 115 outputs the digitized G color long wavelength band video signal, the G color long wavelength band video signal and the stored G color short wavelength band video signal are stored. Is compared in pixel units,
A level difference between the pixels having the same spatial coordinates is calculated, and a G color video signal (for example, floating on the water surface) indicating a difference between the G color short wavelength band video signal and the G color long wavelength band video signal obtained by this is calculated. The G-color image signal having a high contrast, such as an image of an oil film or an image of an organic film, is converted into an analog signal and supplied to the encoder circuit 119.

The B-color image processing section 117 also has the same configuration as the R-color image processing section 113 and the G-color image processing section 115 as shown in FIG.
As shown in FIG. 7, a head amplifier circuit 143, a video processing circuit 144, and an A / D conversion circuit 145 are provided, and a B-color short wavelength band video signal and a B-color long wavelength output from the full-color wavelength selection optical system 112 are provided. A pre-amplification process, a transmission region compensation process of the liquid crystal filter 120, a transmittance compensation process of the liquid crystal filter 120, and the like are performed on the band image signal. The video signal is digitized and supplied to the B color difference image extraction unit 118.

The B chrominance image extraction unit 118 includes a frame memory circuit 146, a difference circuit 147, an absolute value circuit 148, and a D / A conversion circuit, similarly to the R chrominance image extraction unit 114 and the G chrominance image extraction unit 116. 149 and the amplifier circuit 150
When a digitized B-color short-wavelength region video signal is output from the B-color image processing unit 117 based on the input vertical synchronization signal, the B-color image signal is captured and stored. When a digitized B color long wavelength region video signal is output from the image processing unit 117,
The color long wavelength region video signal and the stored B color short wavelength region video signal are compared in pixel units, and the level difference between each pixel having the same spatial coordinates is calculated. The B color video signal indicating the difference between the wavelength range video signal and the B color long wavelength range video signal (for example, a B color video signal with a high contrast such as an oil film image or an organic film image floating on the water surface) is converted into an analog signal. Then, it is supplied to the encoder circuit 119.

The encoder circuit 119 outputs the R color video signal output from the R color difference image extraction unit 114, the G color video signal output from the G color difference image extraction unit 116, and the output from the B color difference image extraction unit 118. It takes in the B color video signal and combines it by a preset combining method,
A composite color television signal is generated and supplied to a display device or the like, and an oil film image or the like is imaged.

As described above, in this embodiment, the full-color wavelength selection optical system 112 takes an image of the sea surface or the like on which the oil film floats, and outputs a video signal in the short wavelength range and a long wavelength signal for each of R, G, and B. The image signals in the short wavelength region and the long wavelength region are generated by the R color image processing unit 113, the G color image processing unit 115, and the B color image After the image signal is processed to generate a digitized video signal in the short wavelength range and a video signal in the long wavelength range, the R color difference image extraction unit 114, the G color difference image extraction unit 116, the B color difference R, G, B by the image extraction unit 118
For each of R, G, and B, the difference between the video signal in the short wavelength range and the video signal in the long wavelength range is extracted, and the contrast of the image of the oil film floating on the water surface or the image of the organic film is increased. The video signal is generated and the composite color television signal obtained by combining the video signal is supplied to the display device. Therefore, regardless of the state of the water surface, the oil film on the water surface or the organic A film or the like can be detected as a full-color image with high contrast.

[0136] This makes it difficult to find an oil slick even if a conventional helicopter or an aircraft is used to visually search the distress site, for example, when the reflected light from the sea surface is strong (backlit state) or when it is rainy. , Even when the waves are high,
Regardless of the state of the sea surface, when the oil slick of the distressed aircraft or ship is floating on the sea surface, this is reliably detected,
You can find out the distress site.

In this embodiment, only when there is an oil film or an organic film on the photographed sea surface or the like, the image is output from the R color difference image extraction unit 114, the G color difference image extraction unit 116, and the B color difference image extraction unit 118. Since the R, G, and B color video signals have non-zero values, the composite color television signal output from the encoder circuit 119 is guided to a determination circuit (not shown). By simply determining whether or not a predetermined threshold value is exceeded, the search for a distress site can be easily automated. As a result, a plurality of wavelength-selective liquid crystal camera devices 111 shown in FIG. 18 are mounted on a helicopter, an aircraft, or the like, and each wavelength-selective liquid crystal camera device 111 is caused to simultaneously search in all directions and automatically determine the presence or absence of an oil film or the like. If this is the case, it is possible to remarkably improve the search efficiency and perform quick disaster rescue as compared with the conventional visual observation (contents of claim 24).

Further, a wavelength selection type liquid crystal camera device 111 shown in FIG. 18 and a GPS (Global Positioning System)
In combination with the device, the position of the oil slick can be determined instantaneously, which can further speed up the discovery of distress spots and the like, and easily map the oil spill situation of tankers and the like in real time. Can be

<First Modification of Third Embodiment>
In the wavelength-selective liquid crystal camera device 111 shown in FIG. 18, the liquid crystal filter 120 alternately extracts the short wavelength light image and the long wavelength light image included in the light image from the subject, and outputs the dichroic prism. The light image in the short wavelength region and the light image in the long wavelength region are separated into R color, G color, and B color by the 123, and are separated on the R image sensor 124, the G image sensor 125, and the B image sensor 126. An image is formed, but an optical bandpass filter 151 is arranged in front of the dichroic prism 123 as in a full-color wavelength selection optical system 112a shown in FIG. After performing bandpass filtering on the light image in the short wavelength region and the light image in the long wavelength region selected by the liquid crystal filter 120 to narrow the wavelength range, the dichroic prism is used. By 123, R-color, G-color, B
After being separated into colors, the R color image sensor 124 and the G color image sensor 12
The image may be formed on the fifth and fifth B-color image pickup elements 126, respectively (the contents of claim 22).

However, this optical bandpass filter 15
The full width half maximum of 1 is set to the R color image sensor 124, the G color image sensor 125, and the B color image sensor 126
Needs to be wider than the full width at half maximum of the light image incident on.

In this manner, as in the case of the wavelength-selective liquid crystal camera device 111 shown in FIG. 18, it is possible to detect an oil film or an organic film on the water surface, which has conventionally been difficult to detect, as a high-contrast full-color image. Can be.

In the first modification, the optical band-pass filter 1 is provided before the dichroic prism 123.
51, but the R image sensor 124,
If one optical band-pass filter is arranged before the liquid crystal filter 120 if it is before the G image sensor 125 and the B image sensor 126, three optical band-pass filters are arranged after the dichroic prism 123. May be.

As described above, the same effect as that of the first modification can be obtained regardless of where the optical band-pass filter is provided before the R image sensor 124, the G image sensor 125, and the B image sensor 126. Can be.

<Second Modification of Third Embodiment>
In the wavelength-selective liquid crystal camera device 111 shown in FIG. 18, the R image pickup element 124 converts a light ray that senses only the ordinary light refractive index of the liquid crystal and a light ray that is applied with a voltage and senses both the ordinary light refractive index and the extraordinary light refractive index. , G image sensor 125, B image sensor 1
26, a polarizing film (or polarizing plate) 1 is provided behind the liquid crystal filter 120 as in a full-color wavelength selection optical system 112b shown in FIG.
52, and the polarizing film 152 removes a light beam that senses only the ordinary refractive index.
4. The light may be incident on the G image sensor 125 and the B image sensor 126 (the contents of claim 23).

In this manner, similarly to the wavelength-selective liquid crystal camera device 111 shown in FIG. 18, it is possible to detect an oil film or an organic film on the water surface, which has conventionally been difficult to detect, as a high-contrast full-color image. it can.

In the second modification, the polarizing film 152 is provided between the liquid crystal filter 120 and the lens 121.
Is arranged, but in front of the R image sensor 124, the G image sensor 125, and the B image sensor 126, in front of the liquid crystal filter 120, behind the lens 121, or each emission surface of the dichroic prism 123, etc. May be provided with a polarizing film.

<Third Modified Example of Third Embodiment>
In the wavelength selection type liquid crystal camera device 111 shown in FIG. 18, the full color wavelength selection type optical system 112 and the R color image processing unit 1
13, the R color difference image extraction unit 114, and the G color image processing unit 1
15, a G color difference image extraction unit 116, and a B color image processing unit 1
17, the B color difference image extracting unit 118, and the encoder circuit 1
Although the camera device is configured by putting the camera device 19 in one housing, all of the encoder circuit 119, all of the R color difference image extraction unit 114, and all of the G color difference image extraction unit 116
, All of the B color difference image extraction unit 118, all or a part of the R color image processing unit 113, and the G color image processing unit 11
5 or the B color image processing unit 117 may be separated from the camera device.

By doing so, the size and weight of the camera device can be reduced and the handling and operation of the camera device can be facilitated.

<< Description of Liquid Crystal Used in First to Third Embodiments >> In the first to third embodiments described above, the liquid crystal filters 5, 37, and 120 are used as ferroelectric liquid crystals or liquid crystal filters. When using a liquid crystal filter having an excellent response speed, such as an antiferroelectric liquid crystal, which can quickly switch from one transmission characteristic to the other transmission characteristic depending on the presence or absence of an AC voltage, no problem occurs.

Further, as the liquid crystal filters 5, 37, and 120, liquid crystals having a low response speed, such as a nematic liquid crystal and a cholesteric liquid crystal, which cannot switch quickly from one transmission characteristic to the other transmission characteristic depending on the presence or absence of an AC voltage, can be used. When using a filter, it is necessary to consider the transient operation, so when using a liquid crystal with such characteristics in a display device, etc.
Although this is a major problem, the wavelength-selective liquid crystal camera devices 1, 30, and 111 according to the present invention hardly cause a problem. Hereinafter, the reason will be described in detail.

First, each of the liquid crystal filters 5, 37, 120,
For example, each dielectric multilayer film 1 constituting the liquid crystal filter 5
The power reflectivity of 0 and 13 is “R”, the amount of phase change when light vertically incident on the liquid crystal layer 14 passes through the liquid crystal layer only once is “δ”, and the incident light is linearly polarized light. Assuming that the light absorptance of each layer constituting the liquid crystal filter 5 such as the liquid crystal layer 14 and the dielectric multilayer films 10 and 13 is neglected, the transmittance T of the liquid crystal filter 5 is ignored.
Can be expressed by the following equation.

[0152]

T = [1 + 4R sin ² (δ / 2) / (1-R) ² ] ⁻¹ (7) Further, the wavelength of light in vacuum is “λ”, and the liquid crystal layer 14 is formed. Assuming that the refractive index of the liquid crystal is “n” and the thickness is “D”, the phase change amount δ can be expressed by the following equation.

Δ = 4πnD / λ (8)

Here, assuming that “R = 0.7”, (7)
When the relationship between the transmittance T and the wavelength λ is calculated from the equations (8) and (8), a graph shown in FIG. 24 is obtained. As is clear from this graph, the refractive index of the liquid crystal constituting the liquid crystal layer 14 is obtained. n, the center wavelength (the transmittance T of the liquid crystal filter 5)
Only the wavelength at which the maximum is shifted), but the transmittance curve does not change.

Thus, when the response of the liquid crystal is slow, the wavelength filter 5 operates so as to settle down to a certain wavelength while selecting various wavelengths. At this time, as shown in Table 1, the refractive index of water depends on the wavelength. However, since the refractive index of fresh water or seawater hardly changes with a wavelength change caused by the liquid crystal, even if the liquid crystal filter 5 performs a transient operation, if there is no oil film on the sea surface, the brightness of the water surface is high. Becomes constant, the signal level difference between the two frames disappears, and an image showing zero is displayed on the display device.

On the other hand, as shown in FIG. 5, when there is an oil film on the sea surface, even if the wavelength slightly changes, the reflected light intensity of the oil film greatly changes.
Performs a transient operation, a signal level difference appears between the two frames, and an image of the oil film is displayed on the display device.

However, considering the transient characteristics, the two light amounts transmitted through the liquid crystal filter 5 (the total value of the thick solid line and the total value of the thin solid line) do not always match. Adjusts the transmittance characteristics, the reflectance characteristics, and the like of the video processing circuit 16 that constitutes the image processing unit 3 so that an image of a certain object is captured and the photoelectric conversion signals for two different wavelengths match. ) Must be kept.

Strictly speaking, a slight transient effect also appears in ferroelectric liquid crystals and the like. Therefore, it is better to take a picture of blank paper and adjust the setup in the same manner as in the case of nematic liquid crystals.

In a rare case, when a sea surface with an oil film is photographed, light from a specific angle of incidence is incident, and the light amount of the light image in the short wavelength range output from the liquid crystal filter 5 is determined. Although it is conceivable that the light amount of the light image in the long wavelength region coincides, even in such a special case, the wavelength-selective liquid crystal camera device 1 receives light images from various incident angles φ ₁ It does not lose track of the oil slick.

Similarly, as shown in FIG. 25, the sea surface 153 constantly fluctuates due to waves, winds, and the like, and light images from various angles of incidence are output to the helicopter 154 from the angles of incidence when the sea surface 153 is in a mirror state. Since the light is taken into the mounted wavelength-selective liquid crystal camera device 1, even if the reflectance becomes the same level at a specific incident angle, the reflectance becomes different at another incident angle, and almost no oil film is lost. There is no.

In particular, when the light image on the short wavelength side and the light image on the long wavelength side are separated as in the wavelength selection type liquid crystal camera device 30 shown in FIG. As in the liquid crystal camera device 111, a light image of R color, G
In the case where a plurality of video signals having different wavelengths are created, for example, when the video signal is divided into a color light image and a B color video signal, an oil film or an organic film is detected in any wavelength region. Therefore, it is possible to reliably detect an oil film, an organic film, and the like so that the oil film and the like are not lost.

<< Explanation of Oil Film Detection Sensitivity in First to Third Embodiments >> Next, using each of the above-described wavelength-selective liquid crystal camera devices 1, 30, and 111, an oil film floating on the sea surface is removed. When detecting, the image sensor 7, the short wavelength side image sensor 46, the long wavelength side image sensor 48, the R color image sensor 124,
The relationship between the resolution of the G color image sensor 125 and the B color image sensor 126 and the oil film detection sensitivity will be described.

<Search Capability in Resting State> First, the minimum of the image pickup device 7 used in each of the wavelength-selective liquid crystal camera devices 1, 30, 111 described above, for example, the wavelength-selective liquid crystal camera device 1 shown in FIG. Each pixel (pixel) that is the unit of detection
If the distance is large or the shooting distance is short, a plurality of light rays with different incident angles φ1 enter _one pixel,
The output of each pixel is a value obtained by adding the luminance of each light beam.

At this time, the incident angle φ ₁ of each light beam is different, and if the angle difference is large, the wavelength dependence of the luminance obtained from the reflectance is reduced, and the oil film detection sensitivity may be reduced. This point will be described in detail.

Now, as the image sensor 7 used in the wavelength-selective liquid crystal camera device 1, the number of vertical pixels is set to about "450", the number of horizontal pixels is set to about "600", and the light receiving portion of the pixel is used. Assuming that an image sensor formed in a square shape is used, as shown in FIG.
The wavelength selection type liquid crystal camera device 1 is attached to the camera, and the image capture angle of the wavelength selection type liquid crystal camera device 1 (the optical axis 156 of the wavelength selection type liquid crystal camera device 1 and the light beam 157 from the subject,
158) to a predetermined value, for example, “± 25
In addition, the lens 6 is adjusted to “degree”, and the photographing direction of the wavelength-selective liquid crystal camera device 1 is adjusted so that the optical axis 156 of the wavelength-selective liquid crystal camera device 1 is orthogonal to the sea surface 159. 300m-1 from 159
Let us consider a case in which the helicopter 155 is skipped so as to reach 000 m to search for an oil film floating on the sea surface 159.

In this case, the helicopter 155 is located 300 m to 1000 m above the sea surface 159, for example, 800 m above the sea surface 159.
When the sea surface 159 is photographed by the wavelength-selective liquid crystal camera device 1 while flying over the sky m, the photographing operation of the imaging device 7 of the wavelength-selective liquid crystal camera device 1 causes the photographing operation of the image pickup device 7 as shown in FIG. And the diameter "746
m "in a rectangular area ABCD (about 597 m
× about 448 m), light rays from a portion of “about 1 m ² ” on the sea surface 159 can be detected by the image sensor 7.
Is incident on one pixel.

This area is equal to the sea level 1 due to waves and beats.
Compared with the fluctuation of 59, the value is sufficiently small. Therefore, only by using the wavelength-selective liquid crystal camera device 1 according to the present invention, even with the usual search method conventionally used, sufficient detection sensitivity can be obtained. An oil film floating on the sea surface 159 can be detected. Further, if an image sensor used in a high-definition television camera device such as a high-definition television camera device is used, the minimum area S that can be decomposed is set to “0.
Since it can be 2 m ² ″, the exploration ability can be further improved.

<Exploration Capability and Exploration Range in Moving State> In order to extend the exploration range, when the helicopter 155 is moved and the oil film floating on the sea surface 159 is explored, the above-described disassembly is possible. To detect up to the minimum area S, it is desirable to set the flight speed V (Km / h) of the helicopter 155 to the following value.

[0169]

S ^0.5 ≦ (V × 10 ³ ) / (3.6 × 10 ³ × 30) (9) Thus, the flight speed V (Km / Km /
Even if h) is restricted, when the flight speed V of the helicopter 155 is about 108 km / h, the search area S per pixel constituting the image sensor 7 can be S ≒ 1 m ² ,
As a result, while securing a sufficient resolution at the time of oil film detection, “64.8 km ² (108 ×
0.6 Km ² ) ”.

<Exploration Capability in High Speed Moving State, Exploration Range>
In this way, in the method of searching while moving, since the continuous shooting method is used as the shooting method, the image can be changed only between the upper and lower two pixel columns between adjacent TV frames, This is sufficient when an image of a video signal is visually observed to detect an oil film or the like, but in the wavelength-selective liquid crystal camera device 1 according to the present invention,
By providing a determination circuit in the next-stage apparatus so as to perform shooting at a distance equal to the number of vertical pixels of the imaging device 7 such as a CCD, the flying speed of the helicopter 155 or the like performing the search is further increased. So that a wider area can be searched.

However, when photographing is performed by such a method, an optical shutter is provided in front of the image pickup device 7, and this optical shutter is operated to allow each pixel to emit light from a sea surface area smaller than the spatial resolution. Since it is necessary to insert the optical shutter, it is desirable that the opening time t of the optical shutter and the flight speed V (Km / h) of the helicopter 155 or the like performing the search satisfy the following expression.

[0172]

S ^0.5 ≦ (V × 10 ³ × t) / (3.6 × 10 ³ ) (10) Thus, the aperture of the optical shutter provided in the wavelength-selective liquid crystal camera device 1 mounted on the helicopter 155 Time t is changed to "t
= 5 (milliseconds), "V ≤ 720 (Km /
h) ", which is approximately 6.
It can be enlarged seven times (720 × 0.6 = 432 Km ² ) (contents of claim 25).

Further, a plurality of wavelength-selective liquid crystal camera devices 1 are mounted on a single helicopter 155 or an aircraft, and the photographing directions of the respective wavelength-selective liquid crystal camera devices 1 are made different from each other to search for different directions. Then, the exploration range can be further expanded. For example, if three wavelength-selective liquid crystal camera devices 1 are used to simultaneously monitor the left, right, and right below, the exploration range per hour is about 1300 km ^2.
This allows the entire area of Tokyo Bay to be searched within one hour.

<Selection of Optical Shutter> As the above-described optical shutter, a material such as a nematic liquid crystal, a cholesteric liquid crystal, and a smectic liquid crystal can be used. In this case, if a 90-degree twisted nematic liquid crystal is used as an optical shutter, white light can be modulated,
This allows it to be used over a wide wavelength range, and if a ferroelectric liquid crystal or antiferroelectric liquid crystal, which is a type of smectic liquid crystal, is used, an optical image can be picked up at a high speed of 1 millisecond or less. Yes (contents of Claim 26).

As an optical shutter, LiNbO ₃ ,
Electric materials such as LiTaO ₃ , KDP, DKDP, PZT, and GaAs can also be used. However, although the transmission / non-transmission of an optical image can be controlled at a very high speed as a characteristic of each electric material, a large applied voltage is required for driving.

For these reasons, it is desirable to use a ferroelectric liquid crystal or an antiferroelectric liquid crystal as the optical shutter.

[0177]

As described above, according to the present invention, in the wavelength-selective liquid crystal camera device according to claims 1 to 8, even if the reflected light from the sea surface is strong, the oil film or the organic film floating on the sea surface or the like can be obtained. It is possible to visualize high-contrast oil films and dirt on organic films attached to the surface of a film or a glass substrate such as a liquid crystal display or a plasma display.
As a result, it is possible to reliably find out, for example, the distress site and the stain on the glass substrate.

In the wavelength-selective liquid crystal camera device according to the ninth to sixteenth aspects, even when the reflected light from the sea surface is strong, or in any state of the sea surface, the oil film floating on the sea surface or the like can be used. High-contrast images of oil films and dirt on organic films attached to the surface of organic films or glass substrates such as liquid crystal displays and plasma displays can be visualized with high contrast. be able to.

In the wavelength-selective liquid crystal camera device according to the present invention, the oil film floating on the sea surface or the like, even when the reflected light from the sea surface is strong or in any state of the sea surface. High-contrast color imaging of oil films and dirt on the organic film, or on the surface of glass substrates such as liquid crystal displays and plasma displays, etc. You can find out.

In the wavelength selective liquid crystal camera device according to the twenty-fifth and twenty-sixth aspects, even when the reflected light from the sea surface is strong while flying over the search range at a high speed with a helicopter or an airplane, Even in such a state, an oil film or an organic film floating on the sea surface or the like can be imaged with high contrast, whereby a distress site or the like can be quickly and reliably found.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of a wavelength-selective liquid crystal camera device according to the first, second, third, fourth and fifth aspects of the embodiment of the wavelength-selective liquid crystal camera device according to the present invention.

FIG. 2 is a sectional view showing a detailed configuration of the liquid crystal filter shown in FIG.

FIG. 3 is a waveform diagram showing a relationship between an AC voltage input to the liquid crystal filter shown in FIG. 1 and each frame.

FIG. 4 is a block diagram illustrating a detailed circuit configuration of an image processing unit and a difference image extracting unit illustrated in FIG. 1;

5 is a graph showing an example of a wavelength selection operation of the wavelength selection type liquid crystal camera device shown in FIG.

FIG. 6 is a block diagram showing a first modification of the wavelength selective liquid crystal camera device shown in FIG.

FIG. 7 is a block diagram showing a second modification of the wavelength selection type liquid crystal camera device shown in FIG.

FIG. 8 is a block diagram showing an embodiment of a wavelength selection type liquid crystal camera device according to the present invention;
FIG. 4 is a block diagram illustrating an example of a wavelength selection type liquid crystal camera device corresponding to No. 4;

9 is a block diagram illustrating a detailed circuit configuration of a short wavelength side image processing unit and a short wavelength side difference image extraction unit illustrated in FIG. 10;

FIG. 10 is a block diagram illustrating a detailed circuit configuration of a long wavelength side image processing unit and a long wavelength side difference image extraction unit illustrated in FIG. 8;

FIG. 11 shows a first example of the wavelength selective liquid crystal camera device shown in FIG.
It is a block diagram showing a wavelength selection optical system used in a modification.

12 is a graph illustrating an example of wavelength selection characteristics of an optical low-pass filter and an optical high-pass filter that constitute the wavelength selection optical system shown in FIG.

13 is a graph showing an example of wavelength selection characteristics of each optical low-pass filter constituting the wavelength selection optical system shown in FIG.

FIG. 14 shows a second example of the wavelength selective liquid crystal camera device shown in FIG.
It is a block diagram showing a wavelength selection optical system used in a modification.

FIG. 15 shows a third example of the wavelength-selective liquid crystal camera device shown in FIG.
It is a block diagram showing a wavelength selection optical system used in a modification.

16 is a graph showing an example of wavelength selection characteristics of an optical low-pass filter and one optical band-pass filter that constitute the wavelength selection optical system shown in FIG.

17 is a graph illustrating an example of wavelength selection characteristics of an optical low-pass filter and another optical band-pass filter that constitute the wavelength selection optical system illustrated in FIG.

FIG. 18 is a view showing a wavelength-selective liquid crystal camera device according to an embodiment of the present invention;
FIG. 3 is a block diagram showing an example of a wavelength-selective liquid crystal camera device corresponding to FIG.

19 is a block diagram illustrating a detailed circuit configuration of an R color image processing unit and an R color difference image extraction unit illustrated in FIG. 18;

20 is a block diagram illustrating a detailed circuit configuration of a G color image processing unit and a G color difference image extraction unit illustrated in FIG. 18;

21 is a block diagram illustrating a detailed circuit configuration of a B color image processing unit and a B color difference image extraction unit illustrated in FIG. 18;

FIG. 22 is a block diagram showing a full-color wavelength selection optical system used in a first modification of the wavelength selection type liquid crystal camera device shown in FIG.

FIG. 23 is a block diagram showing a full-color wavelength selection optical system used in a second modification of the wavelength selection type liquid crystal camera device shown in FIG.

FIG. 24 is a graph showing a relationship between a liquid crystal refractive index and a transmission characteristic of each liquid crystal filter used in each wavelength selection type liquid crystal camera device according to the present invention.

FIG. 25 is a schematic view showing an example of an oil film detecting operation of each wavelength-selective liquid crystal camera device according to the present invention.

FIG. 26 is a side view illustrating a detection range when an oil film floating on the sea surface is detected using each wavelength-selective liquid crystal camera device according to the present invention.

FIG. 27 is a schematic diagram illustrating a detection range when an oil film floating on the sea surface is detected using each wavelength-selective liquid crystal camera device according to the present invention.

FIG. 28 is a block diagram illustrating an example of a conventionally known general full-color camera device.

FIG. 29 is a cross-sectional view modeling an oil film floating on the sea surface.

30 is a graph showing the relationship between the reflectance and the wavelength when the middle layer shown in FIG. 29 has a thickness of 1 μm and does not absorb light.

FIG. 31 is a graph showing the relationship between the reflectance and the wavelength when the middle layer shown in FIG. 29 has a thickness of 10 μm and does not absorb light.

FIG. 32 is a graph showing the relationship between the reflectance and the wavelength when the middle layer shown in FIG. 29 has a thickness of 1 μm and absorbs light.

FIG. 33 is a graph showing the relationship between the reflectance and the wavelength when the middle layer shown in FIG. 29 has a thickness of 10 μm and absorbs light.

[Explanation of symbols]

1: wavelength selection type liquid crystal camera device, 2: wavelength selection optical system,
2a: wavelength selection optical system, 2b: wavelength selection optical system, 3: image processing unit, 4: difference image extraction unit, 5: liquid crystal filter, 6:
Lens, 7: imaging element, 8: transparent substrate, 9: transparent electrode film, 10: dielectric multilayer film, 11: transparent substrate, 12: transparent electrode film, 13: dielectric multilayer film, 14: liquid crystal layer, 15: Head amplifier circuit, 16: video processing circuit, 17: A / D conversion circuit, 18: frame memory circuit, 19: difference circuit,
20: Absolute value circuit, 21: D / A conversion circuit, 22: Amplifier circuit, 23: Optical bandpass filter, 24: Polarizing film, 30: Wavelength selection type liquid crystal camera device, 31: Wavelength selection optical system, 31a: Wavelength selection optical system, 31b: wavelength selection optical system, 31c: wavelength selection optical system, 32: short wavelength side image processing unit, 33: short wavelength side difference image extraction unit, 34: long wavelength side image processing unit, 35: long Wavelength side difference image extraction unit, 36: video synthesis unit, 37: liquid crystal filter, 38: lens, 39:
Incident surface, 40: second emission surface, 41: reflection / transmission surface, 42:
First emission surface, 43: Total reflection surface, 44: Beam splitter, 45: Optical bandpass filter, 46: Short wavelength side image sensor, 47: Optical bandpass filter, 48: Long wavelength side image sensor, 49: Head amplifier circuit, 50: video processing circuit, 51: A / D conversion circuit, 52: frame memory circuit, 53: difference circuit, 54: absolute value circuit, 55: D
/ A conversion circuit, 56: amplification circuit, 57: head amplifier circuit, 58: video processing circuit, 59: A / D conversion circuit, 6
0: frame memory circuit, 61: difference circuit, 62: absolute value circuit, 63: D / A conversion circuit, 64: amplification circuit, 6
5: adder circuit, 66: amplifier circuit, 67: prism type band pass filter, 68: front surface, 69: prism, 70:
Front surface, 71: rear surface, 72: inclined surface, 73: inclined surface, 74: prism, 75: optical low-pass filter, 76: emission surface, 77: optical high-pass filter, 78: emission surface, 7
9: optical low-pass filter, 80: incident surface, 81: prism type low-pass filter, 82: optical low-pass filter, 83: optical high-pass filter, 84: front surface, 8
5: prism, 86: front, 87: rear, 88: slope,
89: slope, 90: prism, 91: optical low-pass filter, 92: incident surface, 93: exit surface, 94: total reflection surface, 95: exit surface, 96: prism type low-pass filter, 97: optical band-pass filter , 98: optical bandpass filter, 99: front surface, 100: prism, 1
01: front surface, 102: rear surface, 103: inclined surface, 104: inclined surface, 105: prism, 106: optical low-pass filter, 107: incident surface, 108: exit surface, 109: total reflection surface, 110: exit surface, 111: Wavelength selective liquid crystal camera device, 112: full color wavelength selective optical system, 112a: full color wavelength selective optical system, 112b: full color wavelength selective optical system, 113: R color image processing unit, 114: R color difference image extraction unit, 115: G Color image processing unit, 116: G color difference image extracting unit, 117: B color image processing unit, 118: B color difference image extracting unit, 119: encoder circuit, 120: liquid crystal filter, 121: lens, 123: dichroic prism, 124: R color image sensor, 125: G color image sensor, 1
26: B color image sensor, 127: head amplifier circuit, 12
8: video processing circuit, 129: A / D conversion circuit, 130:
Frame memory circuit, 131: difference circuit, 132: absolute value circuit, 133: D / A conversion circuit, 134: amplification circuit,
135: head amplifier circuit, 136: video processing circuit, 1
37: A / D conversion circuit, 138: frame memory circuit,
139: difference circuit, 140: absolute value circuit, 141: D /
A conversion circuit, 142: amplification circuit, 143: head amplifier circuit, 144: video processing circuit, 145: A / D conversion circuit, 146: frame memory circuit, 147: difference circuit,
148: absolute value circuit, 149: D / A conversion circuit, 15
0: amplifying circuit, 151: optical bandpass filter, 1
52: polarizing film, 153: sea surface, 154: helicopter, 155: helicopter, 156: optical axis, 157: light beam, 158: light beam, 159: sea surface

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/225 H04N 5/225 Z 5C065 // G03B 11/00 G03B 11/00 H04N 5/238 H04N 5 / 238 Z F term (for reference) 2H048 AA06 AA12 AA15 AA18 GA05 GA12 GA15 GA51 GA61 2H083 AA15 AA27 2H088 EA33 EA49 HA11 JA19 2H091 FA05X FA08X FA26X LA11 MA10 5C022 AA01 AB68 AC42 AC51 AC54 AC07 5G01 EE01A01

Claims (26)

[Claims] 1. A wavelength-selective liquid crystal camera device for converting a light image obtained by a photographing operation into a light image for each wavelength region and extracting a specific subject image, having an optical band-pass filter function, and A liquid crystal filter whose center wavelength can be changed by a voltage, an image sensor that photoelectrically converts an optical image in a wavelength range selected by the liquid crystal filter to generate a video signal, and a wavelength output from the image sensor. An image calculation unit that calculates a signal level difference between two different images and generates a video signal based on an absolute value of the difference, and a wavelength selection type liquid crystal camera device. 2. The wavelength-selective liquid crystal camera device according to claim 1, wherein the imaging element is a CCD, a MOS, a CPD, a SIT, or an A / D.
Solid-state imaging device using silicon such as MI or GaAs
s, a solid-state imaging device using a material exhibiting high sensitivity in the infrared region such as InGaAs, or a solid-state imaging device using a material exhibiting high sensitivity in ultraviolet light or short-wavelength visible light such as amorphous selenium, or plan bicon, sachicon, Vidicon,
A wavelength-selective liquid crystal camera device, comprising one of an image pickup tube such as a caricon and a harpicone. 3. The wavelength-selective liquid crystal camera device according to claim 1, wherein the image calculation unit selects a video signal of each wavelength range output from the imaging device in units of frames in advance. A frame memory circuit that captures and stores a video signal in a set wavelength range; a video signal in a wavelength range stored in the frame memory circuit; and the image sensor having a wavelength range corresponding to the video signal. A difference circuit that calculates a level difference between the video signal output from the pixel unit and a frame signal for each pixel having the same spatial coordinate; an absolute value circuit that calculates an absolute value of the level difference output from the difference circuit; 1. A wavelength-selective liquid crystal camera device comprising: 4. The wavelength-selective liquid crystal camera device according to claim 1, wherein the liquid crystal filter includes a transparent electrode formed in a film shape and a dielectric multilayer formed in a film shape. It has a structure in which a film, a layered liquid crystal layer, a dielectric multilayer film formed in a film shape, and a transparent electrode formed in a film shape are sandwiched between two transparent substrates formed in a plate shape. -A wavelength-selective liquid crystal camera device having the same function as a Perot interferometer. 5. The liquid crystal camera device according to claim 1, wherein a burst-like AC voltage synchronized with a vertical signal of a television signal is applied to said liquid crystal filter, and said liquid crystal filter is turned on. A wavelength-selective liquid crystal camera device, wherein a refractive index of a liquid crystal layer to be formed is changed to shift a center wavelength of transmission characteristics of the liquid crystal filter. 6. The wavelength-selective liquid crystal camera device according to claim 1, wherein a full width at half maximum (Full width at half maximum) of said image sensor is provided in front of said image sensor.
an optical band-pass filter having a full width at half maximum greater than width at half maximum), and the optical band-pass filter limits a wavelength range of an optical image incident on the image pickup device. Type LCD camera device. 7. The wavelength-selective liquid crystal camera device according to claim 1, wherein a polarizing film or a polarizing plate is disposed in front of the imaging device, and the liquid crystal is formed by the polarizing film or the polarizing plate. A wavelength-selective liquid crystal camera device, wherein a light having a specific polarization plane is selected from the light constituting the light image of each wavelength range selected by the filter, and is incident on the image sensor. 8. The wavelength-selective liquid crystal camera device according to claim 1, wherein the video signal generated by the image calculation unit is guided to a determination circuit, and the video signal is preset by the determination circuit. A wavelength-selective liquid crystal camera device, wherein a threshold value is compared with the level of the video signal to determine the presence or absence of a specific subject image. 9. A wavelength-selective liquid crystal camera device for converting a light image obtained by a photographing operation into a light image for each wavelength region and extracting a specific subject image, having an optical bandpass filter function and A liquid crystal filter whose center wavelength can be changed by a voltage; and, among the light images of each wavelength range selected by the liquid crystal filter, a light image of each wavelength range included on the short wavelength side is photoelectrically converted to form a short wavelength side image. A signal level difference is calculated for each pixel having the same spatial coordinate for each pixel of the short wavelength side image signal output from the short wavelength side image sensor that generates a signal and each short wavelength side video signal output from this short wavelength side image sensor, and this difference is calculated. A short-wavelength-side image calculation unit that generates a short-wavelength-side video signal based on the absolute value of the light image, and an optical image of each wavelength band included on the long-wavelength side among the optical images of each wavelength band selected by the liquid crystal filter. Photoelectrically converts The signal level difference is calculated for each pixel having the same spatial coordinate for the long wavelength side image sensor that generates the wavelength side video signal and for each pixel of each long wavelength side video signal output from the long wavelength side image sensor. A long-wavelength-side image calculation unit that generates a long-wavelength-side video signal based on the absolute value of the difference; and a long-wavelength-side video signal output from the long-wavelength-side image calculation unit and the short-wavelength-side image calculation unit. A video signal synthesizing unit for synthesizing the output short-wavelength-side video signal to generate a synthesized video signal. 10. The wavelength-selective liquid crystal camera device according to claim 9, wherein the image pickup device is a CCD, a MOS, a CPD, a SIT, or an A / D.
Solid-state imaging device using silicon such as MI or GaAs
s, a solid-state imaging device using a material exhibiting high sensitivity in the infrared region such as InGaAs, or a solid-state imaging device using a material exhibiting high sensitivity in ultraviolet light or short-wavelength visible light such as amorphous selenium, or plan bicon, sachicon, Vidicon,
A wavelength-selective liquid crystal camera device, comprising one of an image pickup tube such as a caricon and a harpicone. 11. The wavelength-selective liquid crystal camera device according to claim 9, wherein the short-wavelength-side image calculation unit outputs a short-wavelength image to the short-wavelength side output from the short-wavelength-side image sensor in frame units. A frame memory circuit that captures and stores a video signal of a preset wavelength range among video signals of each included wavelength range, a video signal of a wavelength range stored in the frame memory circuit, and the video signal And a difference circuit that calculates a level difference between a video signal output from the short-wavelength-side imaging device in frame units for each pixel having the same spatial coordinate and has a wavelength range corresponding to An absolute value circuit that calculates an absolute value of a level difference to be performed, the long-wavelength-side image calculation unit includes: Movie Among the image signals, a frame memory circuit that captures and stores a video signal in a preset wavelength range, a video signal in a wavelength range stored in the frame memory circuit, and a wavelength range corresponding to the video signal. A difference circuit for calculating, for each pixel having the same spatial coordinate, a level difference between the video signal output from the long-wavelength-side image sensor and the video signal in frame units; and an absolute value of the level difference output from the difference circuit. And an absolute value circuit for calculating a value. 12. The wavelength-selective liquid crystal camera device according to claim 9, wherein the liquid crystal filter includes a transparent electrode formed in a film shape and a dielectric multilayer formed in a film shape. It has a structure in which a film, a layered liquid crystal layer, a dielectric multilayer film formed in a film shape, and a transparent electrode formed in a film shape are sandwiched between two transparent substrates formed in a plate shape. -A wavelength-selective liquid crystal camera device having the same function as a Perot interferometer. 13. A liquid crystal camera device according to claim 9, wherein a burst-like AC voltage synchronized with a vertical signal of a television signal is applied to said liquid crystal filter. A wavelength-selective liquid crystal camera device, wherein a refractive index of a liquid crystal layer to be formed is changed to shift a center wavelength of transmission characteristics of the liquid crystal filter. 14. The wavelength-selective liquid crystal camera device according to claim 9, wherein the full-width at half maximum of the short-wavelength imaging element is provided in front of the short-wavelength imaging element and the long-wavelength imaging element. (Full width
and at least one optical bandpass filter having a full width at half maximum that is wider than the full width at half maximum of the image pickup device at the half wavelength and the long wavelength side image pickup device. A wavelength-selective liquid crystal camera device, wherein a wavelength range of an optical image incident on a side image sensor is limited. 15. The wavelength-selective liquid crystal camera device according to claim 9, wherein one or more polarizing films or one or more polarizing films are provided in front of the short-wavelength imaging device and the long-wavelength imaging device. Arranging the above polarizing plate, by this polarizing film or polarizing plate, of each light constituting the light image of each wavelength band selected by the liquid crystal filter, to select light having a specific polarization plane, A wavelength-selective liquid crystal camera device, wherein the light is incident on the short-wavelength image sensor and the long-wavelength image sensor. 16. The wavelength-selective liquid crystal camera device according to claim 9, wherein the synthesized video signal generated by the video signal synthesizing unit is guided to a determination circuit, and is set in advance by the determination circuit. A wavelength selection type liquid crystal camera device, wherein the presence / absence of a specific subject image is determined by comparing the threshold value and the level of the composite video signal. 17. A wavelength-selective liquid crystal camera device for converting a light image obtained by a photographing operation into a light image for each wavelength region and extracting a specific subject image, having an optical band-pass filter function, A liquid crystal filter whose center wavelength can be changed by a voltage; and an optical image of each wavelength region selected by the liquid crystal filter is separated into a red (R) region, a green (G) region, and a blue (B) region to perform photoelectric conversion. R image signal, G image signal, B image signal
A color image sensor for generating a color image signal; and R, G, and G pixels for each of the R, G, and B video signals output from the color image sensor.
A signal level difference is calculated for each pixel having the same spatial coordinates for each of the colors B and B, and an R color video signal, a G color video signal and a B color video signal are generated based on the absolute value of the difference. A color image calculation unit that performs R and R image signal output from the color image calculation unit;
A color video signal synthesizing unit for synthesizing a color video signal and a B color video signal to generate a synthesized color video signal; 18. The wavelength-selective liquid crystal camera device according to claim 17, wherein the color imaging device is a CCD, a MOS, a CPD, an SI,
High sensitivity in ultraviolet light or short wavelength visible light, such as solid-state imaging device using silicon such as T, AMI, or material having high sensitivity in infrared region such as GaAs, InGaAs, or amorphous selenium. A wavelength-selective liquid crystal camera device, comprising: a solid-state imaging device using a material; or an imaging tube such as a plumbicon, a sachicon, a vidicon, a carnicon, a harpicon, or the like. 19. The wavelength-selective liquid crystal camera device according to claim 17, wherein the color image calculation unit is configured to control the color image sensor from the color image sensor.
A frame that captures and stores a video signal in a wavelength range that is preset for each of R, G, and B among video signals in each wavelength range that is output in frame units for each of the colors G, B, and B. A memory circuit, a video signal in a wavelength range for each of R, G, and B colors stored in the frame memory circuit; and an R color from the image sensor having a wavelength range corresponding to the video signal.
A difference circuit for calculating a level difference between a video signal output in a frame unit for each of G and B colors for each pixel having the same spatial coordinates, and calculating an absolute value of the level difference output from the difference circuit A wavelength selection type liquid crystal camera device, comprising: 20. The wavelength-selective liquid crystal camera device according to claim 17, wherein the liquid crystal filter includes a transparent electrode formed in a film shape and a dielectric multilayer formed in a film shape. It has a structure in which a film, a layered liquid crystal layer, a dielectric multilayer film formed in a film shape, and a transparent electrode formed in a film shape are sandwiched between a transparent substrate formed in a plate shape, and Fabry-Perot interference A wavelength-selective liquid crystal camera device having the same function as a meter. 21. The wavelength selective liquid crystal camera device according to claim 17, wherein a burst-like AC voltage synchronized with a vertical signal of a television signal is applied to said liquid crystal filter. A wavelength-selective liquid crystal camera device, wherein a refractive index of a liquid crystal layer to be formed is changed to shift a center wavelength of transmission characteristics of the liquid crystal filter. 22. The wavelength-selective liquid crystal camera device according to claim 17, wherein a full width at half maximum (Full) for each of R, G, and B of the color imaging device is provided in front of the color imaging device. width at Half Max
imum) one or more optical band-pass filters having a wider full width at half maximum than the optical band-pass filter, and the wavelength band of a light image incident on the color image sensor is limited by the optical band-pass filters. Wavelength-selectable liquid crystal camera device. 23. The wavelength-selective liquid crystal camera device according to claim 17, wherein one or more polarizing films or one or more polarizing plates are arranged in front of the color image sensor. By a polarizing film or a polarizing plate, among the respective lights constituting the light image of each wavelength range selected by the liquid crystal filter, a light having a specific polarization plane is selected and incident on the color imaging device. Characteristic wavelength selective liquid crystal camera device. 24. The wavelength-selective liquid crystal camera device according to claim 17, wherein the synthesized color video signal generated by the color video signal synthesis unit is guided to a determination circuit, and is set in advance by the determination circuit. A predetermined threshold value is compared with the level of the composite video signal to determine the presence or absence of a specific subject image. 25. The wavelength-selective liquid crystal camera device according to claim 1, further comprising: an optical shutter disposed in front of the wavelength-selective liquid crystal camera device; A wavelength-selective liquid crystal camera device intermittently supplying a light image to the selective liquid crystal camera device. 26. The wavelength-selective liquid crystal camera device according to claim 25, wherein the optical shutter is a nematic liquid crystal, a cholesteric liquid crystal, a smectic liquid crystal, LiNbO ₃ , LiTaO ₃ , K
A wavelength-selective liquid crystal camera device comprising any one of electro-optical materials such as DP, DKDP, PZT, and GaAs, or a combination thereof.