JP2007281816A - Camera apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera apparatus capable of extending a dynamic range of an image so as to prevent white jump and black crash from taking place over a whole object included in a photographing range. <P>SOLUTION: The camera apparatus is characterized to include: a plurality of image signals generating means 50 including an imaging lens 10 and an imaging element 51 for forming an optical image of an object through the imaging lens 10, generating image signals with at least two kinds of different luminance levels on the basis of the optical image formed by the imaging element 51 and outputting the respective image signals; a threshold value setting section for setting a threshold value; a partial image signal extract section for extracting image signal parts to be selected from each image signal as partial image signals respectively on the basis of the setting threshold value; and a composite image signal generating section for composing the extracted partial image signals into one composite image signal corresponding to the whole optical image of the object. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a camera apparatus that captures a subject, and more particularly, to a camera apparatus that expands the dynamic range of an image that can be captured.
“Expanding the dynamic range of an image” here does not simply mean increasing the absolute value difference between the maximum luminance and the minimum luminance that can be photographed, but the luminance difference between each luminance portion ( It means to enlarge the absolute value difference between the maximum luminance and the minimum luminance in a state where the contrast) appears clearly.

  An imaging element that converts an optical image into an image signal by forming an optical image has a contrast storage capacity (dynamic range) unique to the photoelectric conversion element. For example, when the exposure amount for the photoelectric conversion element exceeds a predetermined value, the charge accumulated in the photoelectric conversion element becomes saturated. That is, it becomes impossible to accumulate more charge. Therefore, even if the luminance is different in the high luminance part, it is output as the same luminance. On the other hand, as the exposure amount on the photoelectric conversion element decreases, noise included in the electrical signal output from the photoelectric conversion element increases. Therefore, when the subject is substantially uniformly bright or dark, the optimum exposure amount for the photoelectric conversion element is set by adjusting the shutter speed and the aperture value.

  FIG. 15 is a block diagram showing the overall configuration of a conventional camera device. The camera device 501 forms an optical image with the imaging lens 510 that captures light from a subject, a diaphragm 560 that adjusts the amount of light to be captured, and the light captured from the imaging lens 510 and converts the optical image into an image signal. Image sensor 550, image processing means 520 that executes various image processing on the image signal from image sensor 550 to create image information, monitor 540 that displays the created image information, and created image information And a storage device 580 for storing. That is, the diaphragm 560 is provided in the optical path between the imaging lens 510 and the imaging element 550. Therefore, the exposure amount for the photoelectric conversion element is controlled by adjusting the aperture value of the aperture 560.

In addition, by using an image sensor capable of non-destructive readout or high-speed readout that performs readout without losing charges accumulated in the photoelectric conversion element, readout is performed at least once during the exposure period, and as a result, the amount of transmitted light is reduced. An imaging light amount control device to be controlled is disclosed (for example, see Patent Document 1).
JP-A-5-122614

  However, there are cases where an appropriate image cannot be obtained only by controlling the amount of light. For example, when shooting a subject part exposed to sunlight and a subject part that becomes a shadow at the same time, if the exposure amount is limited so that the charge of the photoelectric conversion element for the subject part exposed to sunlight is not saturated, the subject part that becomes a shadow Since the exposure amount of the photoelectric conversion element is insufficient, the image of the shadowed subject portion becomes inappropriate (blackout phenomenon) or noise increases. On the other hand, if the exposure amount is increased to such an extent that a sufficient exposure amount can be obtained for the photoelectric conversion element for the shadowed subject portion, the charge of the photoelectric conversion element for the subject portion exposed to sunlight will be saturated, so that the subject will be exposed to sunlight The image of the part became inappropriate (overexposed phenomenon). As described above, in the conventional camera device, it has been impossible to simultaneously photograph a subject portion exposed to sunlight and a subject portion that becomes a shadow.

  Therefore, an object of the present invention is to provide a camera device capable of expanding the dynamic range of an image so that overexposure and blackout do not occur over the entire subject included in the shooting range.

  The camera device of the present invention made to solve the above problems includes an imaging lens and an imaging element on which an optical image of a subject is formed by the imaging lens, and an optical image formed on the imaging element. Based on a plurality of image signal generating means for generating image signals of at least two different luminance levels and outputting the respective image signals, a threshold value setting unit for setting a threshold value, and each threshold value based on the set threshold value. A partial image signal extraction unit for extracting each image signal portion to be selected from the image signal as a partial image signal, and one synthesized image signal corresponding to the entire optical image of the subject is synthesized based on the extracted partial image signal. And a composite image signal creating unit.

  According to the camera device of the present invention, since a plurality of image signals having different luminance levels are generated based on the optical image formed on the image sensor, the luminance that does not cause blackout or overexposure from each image signal is generated. Since the level part is extracted and the image signals of the extracted luminance levels are combined into one composite image signal, the image is not overexposed to prevent overexposure or blackout over the entire subject included in the shooting range. The dynamic range can be expanded.

(Means and effects for solving other problems)
In the above invention, the imaging device of the plurality of image signal generating means includes a plurality of photoelectric conversion elements arranged in a row direction and a column direction, and a light transmittance before the plurality of photoelectric conversion elements. At least two different optical filters may be regularly arranged so that optical filters having different light transmittances are adjacent to each other.
According to the camera device of the present invention, for example, in the case where a subject part exposed to sunlight and a subject part that becomes a shadow are simultaneously photographed, the subject part exposed to sunlight is provided with an optical filter having a low light transmittance. Extracted from the image signal output from the element, and the subject part that becomes a shadow is extracted from the image signal output from the image sensor provided with an optical filter having a high light transmittance. It is possible to appropriately capture an image of a subject part that becomes a shadow. Further, since at least two types of image signals having different luminance levels can be obtained as image signals without subject time lag, one composite image signal without subject time lag can be obtained.

Further, in the above invention, the multiple image signal generating means includes at least two image sensors and a light beam dividing means for dividing the light flux from the imaging lens into different light quantities and forming an optical image on each of the image sensors. It may be made to become.
According to the camera device of the present invention, for example, when shooting a subject part exposed to sunlight and a subject part that becomes a shadow at the same time, the subject part exposed to sunlight is output from an imaging device that receives a small amount of light. Extracted from the image signal, and the subject portion that becomes a shadow is extracted from the image signal that is output from the image sensor that receives a large amount of light, so that both the subject portion exposed to sunlight and the subject portion that becomes a shadow are appropriately imaged. be able to. Further, since at least two types of image signals having different luminance levels can be obtained as image signals without subject time lag, one composite image signal without subject time lag can be obtained.

In the above invention, the light beam splitting means may be constituted by a plurality of prisms and a reflective ND filter interposed at a joint portion between the prisms.
Thereby, the light beam can be divided into a desired division ratio with a simple structure of a combination of a prism and an ND filter.

Further, in the above invention, the plurality of image signal generating means splits at least two image sensors having different light sensitivities and a light flux from the imaging lens and forms an optical image on each of the image sensors. You may make it consist of.
According to the camera device of the present invention, for example, when simultaneously photographing a subject part exposed to sunlight and a subject part that becomes a shadow, an image signal output from an image sensor with low light sensitivity for the subject part exposed to sunlight. Further, since the subject portion that becomes a shadow is extracted from the image signal output from the image sensor with high light sensitivity, both the subject portion exposed to sunlight and the subject portion that becomes a shadow can be appropriately imaged. Further, since at least two types of image signals having different luminance levels can be obtained as image signals without subject time lag, one composite image signal without subject time lag can be obtained.
Here, the “photosensitivity of the image sensor” refers to the ease of charge accumulation in the image sensor. For example, an image sensor that does not accumulate charge when a large amount of light is not incident is called an image sensor with low photosensitivity, while an image sensor that accumulates charge even when a small amount of light is incident is an image sensor with high photosensitivity. It is called an image sensor.

In the above invention, the multiple image signal generating means includes at least two image sensors, the same number of light quantity adjusting means, and the same number of image pickup lenses, and each image pickup lens is parallel to each other from the subject with respect to one image sensor. Each light quantity adjusting means is arranged between one image pickup lens and one image pickup element, and each light quantity adjusting means makes a different light quantity incident thereon. It may be.
According to the camera device of the present invention, for example, when shooting a subject part exposed to sunlight and a subject part that becomes a shadow at the same time, the subject part exposed to sunlight is output from an imaging device that receives a small amount of light. Extracted from the image signal, and the subject portion that becomes a shadow is extracted from the image signal that is output from the image sensor that receives a large amount of light, so that both the subject portion exposed to sunlight and the subject portion that becomes a shadow are appropriately imaged. be able to. Further, since at least two types of image signals having different luminance levels can be obtained as image signals without subject time lag, one composite image signal without subject time lag can be obtained.

In the above invention, the light amount adjusting means may be a diaphragm having an aperture and / or an optical filter.
In the above invention, the multiple image signal generating means may include an amplifying means for amplifying light taken from the imaging lens. For example, a microchannel plate type image indenter may be provided as the amplification means.

Furthermore, in the above invention, the plurality of image signal generating means includes a microchannel plate type image indenter, and the image sensor of the plurality of image signal generating means has a plurality of photoelectric conversion elements arranged in a row direction and a column direction. In addition, at least two types of optical filters having different spectral characteristics are adjacent to each other between the microchannel plate type image indentifier and the plurality of photoelectric conversion elements. It may be arranged regularly.
According to the camera device of the present invention, in the microchannel plate type image indentifier, the optical image formed on the phosphor screen is obtained by amplifying the number of photoelectrons of the optical image formed on the photocathode. Since the transmittance of the number of photoelectrons differs depending on each spectral characteristic, it is possible to obtain at least two kinds of image signals having different luminance levels by transmitting through at least two kinds of color filters having different spectral characteristics.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment, It cannot be overemphasized that various aspects are included in the range which does not deviate from the meaning of this invention.

<First embodiment>
FIG. 1 is a block structure diagram showing the overall configuration of a camera apparatus according to an embodiment of the present invention. In this embodiment, optical filters having different transmittances are applied to adjacent pixels. That is, the camera device 1 generates three types of image signals with different luminance levels, outputs the respective image signals, a multiple image signal generation unit 50, an AD converter 70, a processing system 11, and a composite image signal. And a monitor 40 for display.

  The multiple image signal generation unit 50 is captured from the imaging lens 10 that captures light from the subject, a light amount adjustment unit 60 (aperture) that adjusts the amount of captured light, an optical filter unit 52 that limits the amount of transmitted light, and the imaging lens 10. An optical image is formed by light, and the imaging element 51 converts the optical image into an image signal. At this time, the multiple image signal generation unit 50 includes the imaging lens 10, the light amount adjustment unit 60, the optical filter unit 52, and the imaging element 51 in order from the closest to the subject. FIG. 2 is a diagram illustrating a configuration of the image sensor 51 according to the first embodiment, and FIG. 3 is a diagram illustrating a configuration of the optical filter unit 52 according to the first embodiment.

  As shown in FIG. 2, the image sensor 51 forms a matrix in which m photoelectric conversion elements 53 are regularly arranged in the row direction and n in the column direction. The photoelectric conversion elements 53 are of the same type. At this time, since one photoelectric conversion element 53 becomes one pixel, it has m × n pixels. Note that m and n are natural numbers. Examples of the image pickup device include a general one having an n-type semiconductor substrate, a p-well layer, a light receiving portion, a charge transfer portion, a polysilicon electrode, a metal light shielding layer, and a flat film, and a photodiode and a CCD element group. The thing etc. which have are mentioned.

  As shown in FIG. 3, the optical filter unit 52 constitutes a matrix in which m optical filters 54 are arranged in the row direction and n optical filters 54 are arranged in the column direction. That is, one optical filter 54 is provided corresponding to one photoelectric conversion element 53. The optical filter 54 is composed of three types (that is, three relative ratios) having different light transmittances of 1, a light transmittance of 1/2, and a light transmittance of 1/4. At this time, the optical filter with 1 light transmittance, the optical filter with 1/2 light transmittance, and the optical filter with 1/4 light transmittance are arranged regularly. For example, an optical filter having a light transmittance of 1, a light filter having a light transmittance of 1/2, and an optical filter having a light transmittance of 1/4 are sequentially arranged in the row direction, and arranged in the column direction. Also, the optical filter having the light transmittance of 1, the optical filter having the light transmittance of 1/2, and the optical filter having the light transmittance of 1/4 are sequentially arranged. Therefore, an optical filter having the same light transmittance is provided in about 1/3 of the total number of photoelectric conversion elements forming the pixel.

  Here, a photoelectric conversion element provided with an optical filter having a light transmittance of 1 (hereinafter also referred to as element 1FP), a photoelectric conversion element provided with an optical filter having a light transmittance of 1/2 (hereinafter referred to as element 1FP). The relationship between the charge accumulation amount and the exposure time of a photoelectric conversion element (hereinafter also referred to as element 1 / 4FP) provided with an optical filter having a 1/4 light transmittance is also described. FIG. 4 is a graph showing the relationship between the charge accumulation amount and the exposure time when the same light is irradiated to the element 1FP, the element 1 / 2FP, and the element 1 / 4FP. As shown in FIG. 4, even when the exposure time is the same, different charge accumulation amounts are obtained. That is, when the subject is photographed, three types of electrical signals (output signals from the photoelectric conversion elements) having different luminance levels can be obtained. Note that the maximum charge accumulation amount (saturated state) of the photoelectric conversion element is M.

The AD converter 70 converts the electrical signal (analog signal) output from the photoelectric conversion element 53 into an electrical information signal (digital signal). An image signal is generated based on the electrical information signal.
The processing system 11 includes an image processing unit 20 that executes various image processes and a storage device 80 that stores a composite image signal described later.

  The image processing means 20 synthesizes one composite image signal based on the extracted partial image signal, and a partial image signal extraction unit 23 that extracts an image signal portion to be selected from each image signal as a partial image signal. A composite image signal creating unit 21, a threshold setting unit 22, a signal reading unit 24, and a signal processing unit 25. These are constituted by a CPU.

  The threshold setting unit 22 performs control for setting a threshold and the like in advance. For example, after the electrical information signal information of the element 1FP reaches the threshold A, the electrical information signal output from 1 / 2FS is extracted, and after the electrical information signal information of the element 1 / 2FP reaches the threshold A Sets a threshold A so that the electrical information signal output from the element 1 / 4FP can be extracted. Note that the value of the threshold A may be given as an initial setting value, or may be set from an input device (for example, a keyboard) not shown.

  The signal readout unit 24 has the same light transmittance of (m × n) / 3 so that the electrical information signal output from the photoelectric conversion element provided with the optical filter having the same light transmittance becomes one image signal. Each of the photoelectric conversion elements provided with the optical filter is controlled to read out electrical information signals. That is, three kinds of images are obtained by three kinds of electric information signals, that is, an electric information signal output from the element 1FP, an electric information signal output from the element 1 / 2FP, and an electric information signal output from the element 1 / 4FP. Form a signal.

  The partial image signal extraction unit 23 performs control to extract an image signal portion to be selected from each image signal as a partial image signal based on the set threshold A. That is, for the image signal of the element 1FP, the information of the electrical information signal equal to or less than the threshold A is extracted as the partial image signal, and for the 1 / 2FS image signal, the information of the electrical information signal equal to or greater than A / 2 and equal to or less than A is partially extracted. It is extracted as an image signal (the ratio between the element 1FP and the element 1 / 2FP is twice, so the switching value is A / 2 which is the reciprocal ratio thereof). For the 1 / 4FS image signal, A / 2 The information of the electrical information signal is extracted as a partial image signal (since the ratio of the element 1 / 2FP and the element 1 / 4FP is twice, the switching value is set to A / 2 which is the reciprocal ratio thereof).

The signal processing unit 25 performs control to compress the partial image signal.
The composite image signal creating unit 21 performs control to synthesize three types of partial image signals having different luminance levels into one composite image signal.

  Here, an example of a synthesis method for synthesizing three types of image signals into one synthesized image signal will be described. FIG. 5 is a flowchart for explaining an example of a synthesis method for synthesizing three types of image signals into one synthesized image signal, and FIG. 6 is a synthesis for synthesizing three types of image signals into one synthesized image signal. It is a figure for demonstrating an example of a method. In addition, the vertical axis | shaft of the graph of FIG. 6 shows the information of an electrical information signal, and a horizontal axis shows a position.

  First, in the process of step S101, the signal readout unit 24 reads out an electrical information signal for each photoelectric conversion element provided with (m × n) / 3 optical filters having the same light transmittance. That is, three kinds of images are obtained by three kinds of electric information signals, that is, an electric information signal output from the element 1FP, an electric information signal output from the element 1 / 2FP, and an electric information signal output from the element 1 / 4FP. A signal is formed (see FIG. 6A).

  Next, in the process of step S <b> 102, the partial image signal extraction unit 23 extracts partial image signals from the respective image signals based on the threshold A. That is, for the image signal of the element 1FP, the information of the electrical information signal below the threshold A is extracted as a partial image signal, and for the image signal of the element 1 / 2FP, the information of the electrical information signal of A / 2 or more and A or less is extracted. Extracted as a partial image signal, and for the image signal of the element 1 / 4FP, information of an electrical information signal of A / 2 or more is extracted as a partial image signal (see FIG. 6B).

  Next, in the process of step S103, the signal processing unit 25 compresses the partial image signal of the element 1FP and the partial image signal of 1 / 2FS. That is, for the partial image signal of 1FS, the information of the partial image signal is compressed to 1/4 (the ratio of the element 1FP and the element 1 / 2FP is four times, so the reciprocal ratio thereof is 1/4. For the partial image signal of the element 1 / 2FP, the information of the partial image signal is compressed by half (since the ratio of the element 1FP and the element 1 / 2FP is twice, the reciprocal ratio thereof) (Refer to FIG. 6C).

  Next, in the process of step S104, the composite image signal creation unit 21 performs the partial image signal compressed by the element 1FP, the partial image signal compressed by the element 1 / 2FP, and the partial image of the element 1 / 4FP. By synthesizing the signals, one synthesized image signal is obtained (see FIG. 6D). One composite image signal obtained in this way is transferred to the storage device 80 and output to the monitor 40.

  As described above, according to the camera device of the first embodiment, for example, when shooting a subject part exposed to sunlight and a subject part that becomes a shadow at the same time, the element part FP is used for the subject part exposed to sunlight. Is extracted from an image signal output from the element 1 / 2FP, an intermediate subject portion is extracted from an image signal output from the element 1 / 2FP, and a shadowed subject portion is extracted from an image signal output from the element 1FP. Therefore, by combining these parts by part, it is possible to appropriately capture both the subject part exposed to sunlight and the subject part that becomes a shadow. Furthermore, since three types of image signals with different luminance levels can be obtained as image signals without subject time lag, one composite image signal without subject time lag can be obtained.

  Note that the arrangement of the optical filter having the light transmittance of 1, the optical filter having the light transmittance of 1/2, and the optical filter having the light transmittance of 1/4 is not limited to the arrangement shown in FIG. Furthermore, the type of light transmittance of the optical filter is not limited to 1, 1/2, 1/4. Further, the light transmittance is not limited to three, and it is sufficient that there are at least two.

  The above description has been made on the assumption that the image is a black and white image. However, the basic structure is the same when applied to a color image. In this case, a color filter unit is further attached. That is, the multi-image signal generation unit is configured to include a light amount adjustment unit, a color filter unit 55, an optical filter unit, and an image sensor in order from the closest to the subject. FIG. 7 is a diagram illustrating a configuration of an example of the color filter unit. At this time, the color filter unit 55 forms a matrix in which m / 3 color filters 56 are arranged in the row direction and n / 3 color filters 56 are arranged in the column direction, as shown in FIG. That is, one color filter 56 is provided corresponding to nine photoelectric conversion elements 53. The color filter 56 includes three types having different spectral characteristics that transmit green (G), spectral characteristics that transmit blue (B), and spectral characteristics that transmit red (R). At this time, the color filter with spectral characteristics that transmits green (G), the color filter with spectral characteristics that transmits blue (B), and the color filter with spectral characteristics that transmits red (R) are arranged regularly. ing. For example, in order in the row direction, the color filter having a spectral characteristic that transmits green (G), the color filter having a spectral characteristic that transmits blue (B), and the color filter that has a spectral characteristic that transmits red (R) are repeatedly arranged. In addition, color filters having spectral characteristics that transmit green (G), blue (B), and red (R) are also arranged in order in the column direction.

<Second Embodiment>
FIG. 8 is a block structure diagram showing the overall configuration of the camera device of the second embodiment. In this embodiment, the light beam from the subject is divided into three types of light beams having different light amounts, and a special prism type three-plate camera is used for dividing the light beam. That is, the camera device 101 according to the present embodiment generates three types of image signals having different luminance levels and outputs the respective image signals, an AD converter 170, a processing system 111, And a monitor 140 for displaying a composite image signal.

  The multiple image signal generation unit 150 captures from the imaging lens 110 that captures light from the subject, a light amount adjustment unit 160 that adjusts the amount of captured light, a light beam splitting unit 130 that divides the light into three types of light beams, and an imaging lens 110. An optical image is formed by the emitted light, and the image pickup device 151a, 151b, 151c is configured to convert the optical image into an image signal.

  The light beam splitting unit 130 splits incident light into three types of light beams having different light amounts. For example, the incident light is divided at a ratio of 12/16, 3/16, and 1/16, except for the loss due to reflection or the like. Then, a 12/16 light beam is guided to the image sensor 151a, a 3/16 light beam is guided to the image sensor 151b, and a 1/16 light beam is guided to the image sensor 151c. Specifically, a special prism type three-plate camera using a reflective ND filter as shown in FIG. 9 can be used as the light beam splitting unit. That is, in the case of a prism type three-plate camera, in general, a light beam incident through an imaging lens is divided (wavelength division) into three primary colors (R, G, and B) by a prism, and reaches each of three different imaging devices. Designed to be. On the other hand, in the present embodiment, the intensities (light quantities) of the light beams reaching the three image sensors are made different. Therefore, instead of the dichroic filter used for splitting the three primary colors at the joint of the prism, a reflective ND filter is used to divide the luminous flux into three types of light.

The image sensors 151a, 151b, and 151c are each composed of a photoelectric conversion element group, similarly to the image sensor 51 described with reference to FIG. 2 in the first embodiment.
Therefore, the photoelectric conversion element of the imaging element 151a (hereinafter also referred to as element 12 / 16PP), the photoelectric conversion element of the imaging element 151b (hereinafter also referred to as element 3 / 16PP), and the photoelectric conversion element of the imaging element 151c (hereinafter referred to as “element 12 / 16PP”). The element 1 / 16PP) has different charge accumulation amounts even in the same exposure time when the same light enters the imaging lens 110. That is, when one subject is photographed, three types of electrical signals having different luminance levels can be obtained.

The AD converter 170 converts an electrical signal (analog signal) output from the photoelectric conversion element into an electrical information signal (digital signal). By gathering the electrical information signals, an image signal is generated.
The processing system 111 includes an image processing unit 120 that executes various image processes and a storage device 180 that stores a composite image signal.

  The image processing unit 120 synthesizes one composite image signal based on the extracted partial image signal, and a partial image signal extraction unit 123 that extracts each image signal portion to be selected from each image signal as a partial image signal. A composite image signal creating unit 121, a threshold setting unit 122, a signal reading unit 124, and a signal processing unit 125. These are constituted by a CPU.

  The threshold value setting unit 122 performs control for setting a threshold value and the like in advance. For example, after the electrical information signal information from the element 12 / 16PP reaches the threshold value A, the electrical information signal output from the element 3 / 16PP is extracted, and the electrical information signal information from the element 3 / 16PP is the threshold value. After reaching A, the threshold A is set so that the electrical information signal output from the element 1 / 16PP can be extracted. Note that the value of the threshold A may be given as an initial set value, or may be set from an input device (not shown).

  The signal reading unit 124 forms an image signal for each of the image sensors 151a, 151b, and 151c so that the electrical information signal output from the photoelectric conversion element of the same image sensor becomes one image signal. That is, there are three types of electrical information signals: an electrical information signal output from the element 12 / 16PP, an electrical information signal output from the element 3 / 16PP, and an electrical information signal output from the element 1 / 16PP. The image signal is formed.

  The partial image signal extraction unit 123 performs control to extract an image signal portion to be selected from each image signal based on the set threshold A as a partial image signal. That is, for the image signal of the element 12 / 16PP, the information of the electrical information signal below the threshold A is extracted as a partial image signal, and for the image signal of the element 3 / 16PP, the electrical information of A / 4 or more and A or less. The signal information is extracted as a partial image signal (the ratio between the element 12 / 16PP and the element 3 / 16PP is four times, and the switching value is set to A / 4 which is the reciprocal ratio thereof). As for the image signal, information of an electrical information signal of A / 3 or more is extracted as a partial image signal (the ratio of 3 / 16PP to 1 / 16PP is 3 times, so that the switching value is the reciprocal ratio A / 3).

The signal processing unit 125 performs control to bias the partial image signal.
The composite image signal creation unit 121 performs control to synthesize three types of partial image signals having different luminance levels into one composite image signal.
Here, an example of a synthesis method for synthesizing three types of image signals into one synthesized image signal will be described.

  First, the signal reading unit 124 forms an image signal for each of the image sensors 151a, 151b, and 151c. That is, there are three types of electrical information signals: an electrical information signal output from the element 12 / 16PP, an electrical information signal output from the element 3 / 16PP, and an electrical information signal output from the element 1 / 16PP. The image signal is formed.

  Next, the partial image signal extraction unit 123 extracts partial image signals from the respective image signals based on the threshold A. That is, for the image signal of the element 12 / 16PP, the information of the electrical information signal below the threshold A is extracted as a partial image signal, and for the image signal of the element 3 / 16PP, the electrical information signal of A / 4 or more and A or less is extracted. Information is extracted as a partial image signal, and for an image signal of the element 1 / 16PP, information of an electrical information signal of A / 3 or more is extracted as a partial image signal.

  Next, the signal reading unit 124 applies a negative bias process to the information of the partial image signal of the element 12 / 16PP, and applies a positive bias process to the information of the partial image signal of the element 1 / 16PP.

  Next, the composite image signal creation unit 121 performs composite processing of the partial image signal subjected to the bias processing of the element 12 / 16PP, the partial image signal of the element 3 / 16PP, and the partial image signal subjected to the bias processing of the element 1 / 16PP. Thus, one composite image signal is obtained. One composite image signal obtained in this way is transferred to the storage device 180 and output to the monitor 140. Although one composite image signal is different from information of one photographed subject, it is output to the monitor 140 so that a subject portion exposed to sunlight and a subject portion that becomes a shadow can be visually recognized. become.

  As described above, according to the camera device of the second embodiment, for example, when photographing a subject part exposed to sunlight and a subject part that becomes a shadow at the same time, the element 1 / 16PP is applied to the subject part exposed to sunlight. Is extracted from the image signal output from the image signal, the intermediate subject portion is extracted from the image signal output from the element 3 / 16PP, and the subject portion which is a shadow is output from the element 12 / 16PP. Therefore, it is possible to appropriately capture both the subject portion exposed to sunlight and the subject portion that becomes a shadow. Furthermore, since three types of image signals with different luminance levels can be obtained as image signals without subject time lag, one composite image signal without subject time lag can be obtained.

In this embodiment as well, the type of light quantity of the divided light beam is not limited to 12/16 light quantity, 3/16 light quantity, and 1/16 light quantity. Furthermore, the light quantity of the light beam to be divided is not limited to three types, and it is sufficient that there are at least two types.
Moreover, it is good also as a structure which has a color filter part in front of three image sensors.

<Third embodiment>
FIG. 10 is a block structure diagram showing the overall configuration of the camera apparatus of the third embodiment. In the present embodiment, the light flux from the subject is divided and three image sensors having different light sensitivities are used. In other words, in the present embodiment, the camera device 201 generates image signals of three different luminance levels and outputs the respective image signals, an AD converter 270, and a processing system 211. And a monitor 240 for displaying the composite image signal.

  The multiple image signal generation unit 250 is captured from the imaging lens 210 that captures light from the subject, a light amount adjustment unit 260 that adjusts the amount of light to be captured, a light beam splitting unit 230 that divides the light into three light beams having the same light amount, and the imaging lens 210. An optical image is formed by the reflected light, and the image pickup device 251a, 251b, 251c is configured to convert the optical image into an image signal.

  The light beam splitting unit 230 splits incident light into three light beams having the same light amount (or no large light amount difference). Then, the first light beam is guided to the image sensor A251a, the second light beam is guided to the image sensor B251b, and the third light beam is guided to the image sensor C251c.

The image sensor A251a is composed of a photoelectric conversion element group in the same manner as the image sensor 51 described with reference to FIG. 2 in the first embodiment.
The image sensor B251b is the same as the image sensor A251a described above except that the image sensor B251b is changed to one having a light sensitivity lower than that of the image sensor A251a.
Further, the image sensor C251c is the same as the image sensor B251b described above except that the image sensor C251c is changed to one having a light sensitivity lower than that of the image sensor B251b. The difference in light sensitivity of the image sensor can be realized by changing the type of the image sensor. It can also be realized by integrally attaching filters with different transmittances and masks with different apertures in front of the image sensors 251a, 251b, and 251c.

  Therefore, the photoelectric conversion element of the image sensor 251a (hereinafter also referred to as a high sensitivity element SP1), the photoelectric conversion element of the image sensor 251b (hereinafter also referred to as a medium sensitivity element SP2), and the photoelectric conversion element of the image sensor 251c (hereinafter, referred to as “high sensitivity element SP1”). The low-sensitivity element SP3) has different charge accumulation amounts even in the same exposure time when the same light enters the imaging lens 210. That is, when one subject is photographed, three types of electrical signals having different luminance levels can be obtained.

The AD converter 270 is the same as the AD converter 170 as described above.
The processing system 211 is the same as the processing system 111 as described above. Therefore, the synthesis method for synthesizing the three types of image signals into one synthesized image signal is the same as the synthesis method described above.

  As described above, according to the camera device of the third embodiment, for example, in the case where a subject part exposed to sunlight and a subject part that becomes a shadow are simultaneously photographed, the subject part exposed to sunlight is low sensitive element SP3. Is extracted from the image signal output from the medium sensitivity element SP2, the middle subject portion is extracted from the image signal output from the medium sensitivity element SP2, and the shadow subject portion is extracted from the image signal output from the high sensitivity element SP1. Since extraction is performed, it is possible to appropriately capture both the subject portion exposed to sunlight and the subject portion that becomes a shadow. Furthermore, since three types of image signals with different luminance levels can be obtained as image signals without subject time lag, one composite image signal without subject time lag can be obtained.

In addition, it is good also as a structure which has a color filter part in front of three image sensors.
Further, the type of light quantity of the divided light beam is not limited to one divided into three, and may be, for example, 12/16 light quantity, 3/16 light quantity, and 1/16 light quantity. That is, you may use together 2nd embodiment and 3rd embodiment.

<Fourth embodiment>
FIG. 11 is a block structure diagram showing the overall configuration of the camera device of the fourth embodiment. In the present embodiment, three image sensors are used, and an optical image is formed using an independent imaging lens for each image sensor. That is, the camera device 301 generates image signals of three different brightness levels, outputs the respective image signals, a multiple image signal generation unit 350, an AD converter 370, a processing system 311, and a composite image signal. And a monitor 340 for displaying.

The multiple image signal generation unit 350 captures light from the three imaging lenses 310a, 310b, and 310c that capture light from the subject, three light amount adjustment units 360a, 360b, and 360c that adjust the captured light amount, and the imaging lenses 310a, 310b, and 310c. An optical image is formed by the emitted light, and is configured by three imaging elements 351a, 351b, and 351c that convert the optical image into an image signal.
In addition, each of the imaging lenses 310a, 310b, and 310c is disposed so as to form an image of mutually parallel light beams from the subject on one imaging element 351a, 351b, and 351c, respectively. When there is a distance to the subject, the three lenses and the image sensor need only be arranged in parallel. Furthermore, each light quantity adjustment part 360a, 360b, 360c is arrange | positioned between one imaging lens 310a, 310b, 310c and one imaging element 351a, 351b, 351c, respectively.
Note that the imaging elements 351a, 351b, and 351c each include a photoelectric conversion element group, similarly to the imaging element 51 described with reference to FIG. 2 in the first embodiment.

  The light amount adjustment units 360a, 360b, and 360c are diaphragms each having an opening for making the F number different. The area of the opening of the light amount adjusting unit B360b is smaller than the area of the opening of the light amount adjusting unit 360aA, and the area of the opening of the light amount adjusting unit C360c is smaller than the area of the opening of the light amount adjusting unit B360b. .

  Therefore, the photoelectric conversion element (hereinafter also referred to as a large aperture element HP) of the image sensor 351a, the photoelectric conversion element of the image sensor 351b (hereinafter also referred to as a medium aperture element HP), and the photoelectric conversion element ( Hereinafter, when the same light is incident on the imaging lenses 310a, 310b, and 310c, the small aperture element HP has different charge accumulation amounts even in the same exposure time. That is, when one subject is photographed, three types of electrical signals having different luminance levels can be obtained.

The AD converter 370 is the same as the AD converter 170 as described above.
The processing system 311 is the same as the processing system 111 as described above. Therefore, the synthesis method for synthesizing the three types of image signals into one synthesized image signal is the same as the synthesis method described above.

As described above, according to the camera device of the fourth embodiment, for example, when photographing a subject part exposed to sunlight and a subject part that becomes a shadow at the same time, a small aperture element is used for the subject part exposed to sunlight. Extracted from the image signal output from the HP, the intermediate subject portion is extracted from the image signal output from the medium aperture element HP, and the shadow subject portion is output from the large aperture element HP. Therefore, it is possible to appropriately capture both the subject portion exposed to sunlight and the subject portion that becomes a shadow. Furthermore, since three types of image signals with different luminance levels can be obtained as image signals without subject time lag, one composite image signal without subject time lag can be obtained.
In the camera device of the fourth embodiment, since light is taken in by the three imaging lenses as described above, it is preferable to make the light beams parallel, and therefore it is preferable to use it for photographing a distant subject.

In addition, it is good also as a structure which has a color filter part in front of three image sensors.
In addition, the light amount adjusting units 360a, 360b, and 360c are configured to be aperture stops having openings, but instead, an optical filter having a light transmittance of 1, an optical filter having a light transmittance of 1/2, For example, an optical filter having a light transmittance of 4 may be provided.
The image sensors used for the image sensors 351a, 351b, and 351c may be configured as image sensors having different light sensitivities. At this time, each of the light amount adjustment units 360a, 360b, and 360c may include a diaphragm having an opening having the same area.

<Fifth embodiment>
FIG. 12 is a block structure diagram showing the overall configuration of the camera device of the fifth embodiment. In the present embodiment, unlike the previous embodiments, the night vision function is provided by amplifying light taken from the imaging lens. The camera device 401 generates three types of image signals having different luminance levels, and displays a plurality of image signal generation units 450 that output the respective image signals, an AD converter 470, a processing system 411, and a composite image signal. And a monitor 440.

  The multiple image signal generation unit 450 includes an imaging lens 410 that captures light from a subject, a light amount adjustment unit 460 that adjusts the amount of light to be captured, and a microchannel that receives the light captured from the imaging lens 410 and converts the light into an optical image. A plate type image indentifier (hereinafter also referred to as MCP type II) 457, a coupling mechanism 458, an optical filter unit 452 for limiting the amount of transmitted light, and an MCP type I.I. An optical image output from I.457 is formed, and the imaging device 451 converts the optical image into an image signal. At this time, the multiple image signal generation unit 450 sequentially includes the imaging lens 410, the light amount adjustment unit 460, the MCP type I.D. I. 457, a coupling mechanism 458, an optical filter portion 452, and an image sensor 451.

  FIG. 13 shows the MCP type I.D. It is a structural diagram which shows an example of I. MCP type I.M. I. Reference numeral 457 denotes an incident fiber glass 457a that receives incident light, a photocathode 457b, a microchannel plate 457c that converts incident light into photoelectrons and increases the number of photoelectrons, and a microchannel, in order from the side closer to the imaging lens 410. A fluorescent screen 457d for converting photoelectrons output from the plate 457c into an optical image.

  As a result, the MCP type I.D. I. In 457, the light incident on the incident fiber glass 457a from the imaging lens 410 is formed as an optical image on the photoelectric surface 457b. The microchannel plate 457c converts this optical image into photoelectrons. Further, the microchannel plate 457c transfers photoelectrons while causing an electron collision by applying a pulse voltage. At this time, an avalanche phenomenon in which a large number of secondary electrons are emitted repeatedly occurs. As a result, the number of photoelectrons is multiplied. The photoelectrons transferred by multiplication are returned to the optical image and output again when they hit the phosphor screen 457d. That is, the optical image formed on the fluorescent screen 457d is obtained by amplifying the number of photoelectrons of the optical image formed on the photoelectric surface 457b.

The coupling mechanism 458 guides the optical enhancement imaged on the fluorescent screen to the image sensor 451, and for example, a lens system or an optical fiber is used.
The image sensor 451 forms a matrix in which m photoelectric conversion elements are arranged in the row direction and n photoelectric conversion elements are arranged in the column direction. The photoelectric conversion elements are of the same type. At this time, since one photoelectric conversion element becomes one pixel, it has m × n pixels. Note that m and n are natural numbers.

  The optical filter unit 452 constitutes a matrix in which m optical filters are arranged in the row direction and n optical filters are arranged in the column direction. That is, one optical filter is provided corresponding to one photoelectric conversion element. In addition, the optical filter 454 is configured by three types having different light transmittances of 1, a light transmittance of 1/2, and a light transmittance of 1/4 as in the first embodiment. At this time, the optical filter with 1 light transmittance, the optical filter with 1/2 light transmittance, and the optical filter with 1/4 light transmittance are arranged regularly. For example, an optical filter having a light transmittance of 1, a light filter having a light transmittance of 1/2, and an optical filter having a light transmittance of 1/4 are sequentially arranged in the row direction, and arranged in the column direction. Also, the optical filter having the light transmittance of 1, the optical filter having the light transmittance of 1/2, and the optical filter having the light transmittance of 1/4 are sequentially arranged.

  Accordingly, a photoelectric conversion element provided with an optical filter having a light transmittance of 1 (hereinafter also referred to as element 1FP), a photoelectric conversion element provided with an optical filter having a light transmittance of 1/2 (hereinafter referred to as element 1 / 2FP). And a photoelectric conversion element provided with an optical filter having a light transmittance of 1/4 (hereinafter also referred to as element 1 / 4FP) has the same exposure when the same light enters the imaging lens 410. Even in time, the amount of charge accumulation differs. That is, when one subject is photographed, three types of electrical signals having different luminance levels can be obtained.

The AD converter 470 converts an electrical signal (analog signal) output from the photoelectric conversion element into an electrical information signal (digital signal). An image signal is generated based on the electrical information signal.
The processing system 411 includes an image processing unit 420 that executes various image processes, and a storage device 480 that stores a composite image signal.

  The image processing unit 420 synthesizes one composite image signal based on the extracted partial image signal, and a partial image signal extraction unit 423 that extracts each image signal portion to be selected from each image signal as a partial image signal. A composite image signal generation unit 421, a threshold setting unit 422, a signal reading unit 424, and a signal processing unit 425. These are constituted by a CPU.

  The threshold setting unit 422 performs control for setting a threshold and the like in advance. For example, thresholds B and C are set such that information on electrical information signals not less than threshold C and not more than threshold B can be extracted. The threshold values B and C may be given as initial setting values, or appropriate values may be set from an input device (for example, a keyboard) (not shown).

  In the signal reading unit 424, an electrical information signal generated based on an output from a photoelectric conversion element provided with an optical filter having the same light transmittance among the photoelectric conversion elements constituting the imaging element 451 is converted into one image signal. Thus, control is performed to read out electrical information signals for each photoelectric conversion element provided with (m × n) / 3 optical filters having the same light transmittance. That is, three kinds of images are obtained by three kinds of electric information signals, that is, an electric information signal output from the element 1FP, an electric information signal output from the element 1 / 2FP, and an electric information signal output from the element 1 / 4FP. Form a signal.

  The partial image signal extraction unit 423 performs control to extract an image signal portion to be selected from each image signal as a partial image signal based on the set threshold values B and C. That is, for the image signal of the element 1FP, the information of the electrical information signal not less than the threshold C and not more than the threshold B is extracted as a partial image signal, and for the image signal of the element 1 / 2FP, the electrical information signal not less than the threshold C and not more than the threshold B. Is extracted as a partial image signal, and for an image signal of the element 1 / 4FP, information on an electrical information signal not less than the threshold C and not more than the threshold B is extracted as a partial image signal.

The signal processing unit 425 performs control to compress and bias the partial image signal.
The composite image signal generation unit 421 performs control to combine three types of partial image signals having different luminance levels into one composite image signal.

  Here, an example of a synthesis method for synthesizing three types of image signals into one synthesized image signal will be described. FIG. 14 is a diagram for describing an example of a combining method for combining three types of image signals into one combined image signal. Note that the vertical axis of the graph of FIG. 14 indicates the luminance level of the image signal created based on the electrical information signal, and the horizontal axis indicates the position.

  First, an electrical information signal is read by the signal reading unit 424 for each photoelectric conversion element provided with (m × n) / 3 optical filters having the same light transmittance. That is, three kinds of images are obtained by three kinds of electric information signals, that is, an electric information signal output from the element 1FP, an electric information signal output from the element 1 / 2F, and an electric information signal output from the element 1 / 4FP. A signal is formed (see FIG. 14A).

  Next, the partial image signal extraction unit 423 extracts partial image signals from the respective image signals based on the threshold values B and C, respectively. That is, for the image signal of the element 1FP, the image signal of the element 1 / 2FP, and the image signal of the element 1 / 4FP, the information of the electrical information signal that is greater than or equal to the threshold C and less than or equal to the threshold B is extracted as a partial image signal (FIG. 14 ( b)).

Next, the signal processing unit 425 compresses the partial image signal of the element 1FP, the partial image signal of the element 1 / 2FP, and the partial image signal of the element 1 / 4FP (see FIG. 14C).
Further, the signal processing unit 425 applies a negative bias process to the information of the partial image signal compressed by the element 1FP, and applies a positive bias process to the information of the partial image signal subjected to the 1 / 4FS compression process. The brightness level between the partial image signals is adjusted (see FIG. 14D).

  Next, the composite image signal creating unit 21 converts the biased partial image signal of the element 1FP, the compressed partial image signal of the element 1 / 2FP, and the biased partial image signal of the element 1 / 4FP. By performing the synthesis process, one synthesized image signal is obtained (see FIG. 14E). One composite image signal obtained in this way is transferred to the storage device 480 and output to the monitor 440. Note that one composite image signal is different from information of one photographed subject, but is output to the monitor 440 so that a subject portion exposed to sunlight and a subject portion that becomes a shadow can be visually recognized. become.

  As described above, according to the camera device of the fifth embodiment, for example, when shooting a subject part such as a streetlight and another subject part simultaneously in a dark place such as at night, The subject portion is extracted from the image signal output from the element 1 / 4FP, the other subject portions are extracted from the image signal output from the element 1 / 2FP, and the other subject portion is extracted from the element 1FP. Therefore, the subject portion such as a streetlight and other subject portions can be appropriately imaged. Furthermore, since three types of image signals with different luminance levels can be obtained as image signals without subject time lag, one composite image signal without subject time lag can be obtained.

  The type of light transmittance of the optical filter is not limited to 1, 1/2, 1/4. Further, the light transmittance is not limited to three types, and at least two types are sufficient.

Further, instead of the optical filter unit, a color filter unit may be used. That is, the MCP type I.D. I. 457, the optical image formed on the phosphor screen is MCP type I.D. I. Depending on the type of phosphor screen used for 457 (for example, P-43 and P-53), the characteristics of the fluorescence wavelength are different, and the multiplication factor is different corresponding to the wavelengths of red, blue, and green (usually Green fluorescence is strongest). Therefore, when one subject is photographed, three types of image signals having different luminance levels can be obtained.
At this time, the color filter unit forms, for example, a matrix in which m color filters are arranged in the row direction and n color filters are arranged in the column direction. That is, one color filter is provided corresponding to one photoelectric conversion element. The color filter is composed of three types having different spectral characteristics that transmit green (G), spectral characteristics that transmit blue (B), and spectral characteristics that transmit red (R). At this time, the color filter with spectral characteristics that transmits green (G), the color filter with spectral characteristics that transmits blue (B), and the color filter with spectral characteristics that transmits red (R) are arranged regularly. So that
As a result, image signals with different luminance levels can be generated for each of the three types of color filters, and the same output as when an optical filter is attached can be obtained. Color filters are used in various fields, are available at low cost, and have stable performance, so that they can be easily manufactured and cost can be reduced by substituting for optical filters.

  The present invention can be used for a camera device capable of expanding the dynamic range of an image.

It is a block structure figure showing the whole camera device composition of a first embodiment. It is a figure which shows the structure of the image pick-up element which concerns on 1st embodiment. It is a figure which shows the structure of the optical filter part which concerns on 1st embodiment. It is a graph which shows the relationship between each charge accumulation amount and exposure time when the same light is irradiated to the element 1FP, the element 1 / 2FP, and the element 1 / 4FP. It is a flowchart for demonstrating an example of the synthetic | combination method which synthesize | combines three types of image signals into one synthetic | combination image signal. It is a figure for demonstrating an example of the synthetic | combination method which synthesize | combines three types of image signals into one synthetic | combination image signal. It is a figure which shows the structure of an example of a color filter part. It is a block structure figure showing the whole camera device composition of a second embodiment. It is a structural diagram showing an example of a special prism type three-plate camera using a reflection type ND filter. It is a block structure figure which shows the whole structure of the camera apparatus of 3rd embodiment. It is a block structure figure which shows the whole structure of the camera apparatus of 4th embodiment. It is a block structure figure which shows the whole structure of the camera apparatus of 5th embodiment. MCP type I.M. It is a structural diagram showing an example of I. It is a figure for demonstrating an example of the synthetic | combination method which synthesize | combines three types of image signals into one synthetic | combination image signal. It is a block block diagram which shows the whole structure of the conventional camera apparatus.

Explanation of symbols

1, 101, 201, 301, 401: Camera devices 10, 110, 210, 310, 410: Imaging lenses 20, 120, 220, 320, 420: Processing systems 40, 140, 240, 340, 440: Monitors 50, 150 , 250, 350, 450: multiple image signal generators 51, 151, 251, 351, 451: imaging device 52, 452: optical filter units 70, 170, 270, 370, 470: AD converters 80, 180, 280, 380 480: Storage device

Claims (9)

An image pickup lens and an image pickup element on which an optical image of a subject is formed by the image pickup lens are generated, and image signals having at least two different brightness levels are generated based on the optical image formed on the image pickup element. A plurality of image signal generating means for outputting the respective image signals;
A threshold setting unit for setting a threshold;
A partial image signal extraction unit that extracts, as a partial image signal, an image signal portion to be selected from each image signal based on the set threshold value;
What is claimed is: 1. A camera device, comprising: a combined image signal creating unit configured to combine one combined image signal corresponding to an entire optical image of a subject based on an extracted partial image signal. The image pickup device of the plurality of image signal generating means includes a plurality of photoelectric conversion elements arranged in a row direction and a column direction,
The at least two types of optical filters having different light transmittances are regularly arranged in front of the plurality of photoelectric conversion elements so that the optical filters having different light transmittances are adjacent to each other. Item 2. The camera device according to Item 1. The multiple image signal generation means includes at least two image sensors,
The camera apparatus according to claim 1, further comprising: a light beam splitting unit that splits a light beam from the imaging lens into different light amounts and forms an optical image on each image sensor. The beam splitting means includes a plurality of prisms,
The camera apparatus according to claim 3, wherein the camera apparatus includes a reflective ND filter interposed at a joint portion between the prisms. The multiple image signal generating means includes at least two image sensors having different light sensitivities,
The camera apparatus according to claim 1, further comprising: a light beam splitting unit that splits a light beam from the imaging lens and forms an optical image on each imaging element. The multiple image signal generating means comprises at least two image sensors, the same number of light quantity adjusting means and the same number of imaging lenses,
Each imaging lens is arranged to form an image of light beams parallel to each other from a subject on one imaging element,
Each light quantity adjusting means is arranged between one imaging lens and one imaging element,
2. The camera apparatus according to claim 1, wherein each of the light amount adjusting units makes a different amount of light incident thereon. The camera apparatus according to claim 6, wherein the light amount adjusting unit is a diaphragm having an aperture and / or an optical filter. The camera apparatus according to claim 1, wherein the plurality of image signal generation means includes amplification means for amplifying light taken from the imaging lens. The multiple image signal generating means comprises a microchannel plate type image indenter,
The image pickup device of the plurality of image signal generating means includes a plurality of photoelectric conversion elements arranged in a row direction and a column direction,
Between the microchannel plate-type image indentifier and the plurality of photoelectric conversion elements, at least two types of optical filters having different spectral characteristics are regularly arranged so that optical filters having different spectral characteristics are adjacent to each other. The camera apparatus according to claim 1, wherein:

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