JPH0259896A - Image pickup device and display device - Google Patents

Abstract

PURPOSE:To discriminate between an object which is irradiated with infrared rays from an infrared-ray source and a self-emission type infrared-ray source by providing a light source which emits infrared rays which contain a modulated signal of high frequency, its power source, and an image pickup camera which has sensitivity to infrared rays and performs signal processing by picture elements. CONSTITUTION:The object 3 is lighted with the light from the infrared-ray source 1 which is turned on with a current containing a signal modulated by a power source circuit 2 and an infrared-ray intensity distribution image which is formed with reflected light from the object 3, light containing infrared rays generated by the object 3, and light containing infrared rays from other light sources is picked up by the image pickup camera 8 and inputted to a detection part 9. The detection part 9 detects a signal corresponding to the modulated signal of the infrared-ray illumination light from the infrared-ray source 1 in the input signal and a processing part 10 forms an image with the detection signal. Consequently, the reflected light of the infrared rays emitted by the infrared-ray source 1 and direct light from the self-emission type infrared-ray source can be discriminated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application of the Invention The present invention relates to an imaging device and a display device used, for example, in a nighttime crime prevention system or a forward monitoring system for driving a car at night.

BACKGROUND ART FIG. 4 shows a configuration diagram of a conventional illumination device, imaging device, and display device. In FIG. 4, 1 is an infrared light source, 2 is a power supply circuit, 3 is an object to be illuminated, 4 is a scanning television camera, and 5 is a display. The scanning television camera 4 is sensitive to infrared rays, and for example, an image sensor that is highly sensitive to infrared rays is used, or a camera that uses an image sensor that is sensitive to visible light and infrared rays only uses infrared rays. Equipped with an optical filter that transmits light. The imaging device 6 includes an infrared light source 1 , a power supply circuit 2 , a scanning television camera 4 , and a display 5 . In the imaging device 6 and display device 7 configured in this way, the object 3 is illuminated with infrared rays from the infrared light source 1 supplied with current from the power supply circuit 2, and the image thereof is captured by the scanning television camera 4.
, and display the image on display 6.

The light from the infrared light source 1 needs to have a sufficient amount of infrared rays and a high uniformity of illuminance so that the object 3 illuminated by it can be easily photographed by the scanning television camera 4. For this reason, the infrared light source 1 consists of a high-pressure discharge lamp whose emitted light contains a large amount of infrared rays by adjusting the composition of the enclosed substance, and an optical system to effectively utilize the emitted infrared rays. It consists of

Since infrared rays are invisible to the human eye, if the object 3 is a person or there is a person near the object 3, it is necessary to prevent the person from feeling glare from the visible light from the infrared light source 1. can. Furthermore, you can prevent the other person from knowing that you are being photographed.

In recent years, in order to reliably obtain various information such as signs and traffic lights without relying solely on the movement of the driver's line of sight, it has been considered to install the above-mentioned imaging device and display device in automobiles.

In this case, since infrared rays can pass through even in foggy weather conditions, the detection rate of obstacles is superior to that achieved by visual inspection, which increases safety.

Problems to be Solved by the Invention In the conventional imaging devices and display devices configured as described above, an object illuminated with infrared rays from the infrared light source 1 and a self-luminous infrared light source such as a signal light or a light emitting display The problem was that it was not possible to distinguish between the two.

In addition, the current frequency generally supplied from the power supply circuit 2 is
It is 50 or 60Hz. In the high-pressure discharge lamp constituting the infrared light source 1, when discharge is performed symmetrically in positive and negative directions per current cycle, the modulation frequency of the infrared rays is 100 or 120 Hz, which is twice the frequency of the current supplied from the power supply circuit 2. Generally, the frame frequency of the scanning television camera 4 is 60Hz, so when the object 3 illuminated by the infrared light source 1 configured in this way is photographed, a bright and dark striped pattern appears in the image, and the object appears on the display 5. There was a problem that object 8 was difficult to find. Also,
In the infrared light source 1, when discharge is not performed symmetrically in positive and negative directions per current cycle, the frequency of visible light emitted from the infrared light WA1 is 50 or 60 Hz, the same as the current frequency. The modulation frequency of light at the limit at which humans perceive flickering in light is about 100 Hz, so if the light emitted from the infrared light source 1 includes visible light, the human as the illuminated object 3 or , object 3
People near the camera sometimes felt flickering.

Furthermore, in the above-described configuration, the scanning television camera 4 is simply placed in place of the human eye, and the information obtained therefrom still needs to be picked up by the human looking at the image. For example, in the case of vehicle imaging devices and display devices, human pattern recognition has been relied upon to extract oncoming vehicles, pedestrians, obstacles, etc. from the image information.

If this pattern recognition is performed using a computer, it is currently not practical because the recognition rate is low, the required time is long, and the system is expensive and complicated.

Means for Solving the Problems A light source that emits infrared rays having a high-frequency modulation signal, a power source that supplies power to the light source, and an imaging camera that is sensitive to the infrared rays and is capable of signal processing for each pixel. An imaging device is constructed from the following.

By extracting the modulation frequency component of the infrared light source for each active pixel, the shape of the object illuminated by the infrared illumination light can be extracted.

Embodiment A first embodiment of the present invention is shown in FIG. 1. In FIG. 1, 8 is an imaging camera, 9 is a detection section, 10 is a processing section, and 11
is an imaging device. The power supply circuit 2 is a high frequency power supply such as an electronic circuit ballast that can easily modulate current. Power circuit 2
By setting the frequency of the current supplied from
Among the illumination light emitted from the infrared light source 1, visible light does not flicker. The modulation frequency of the infrared rays emitted from the infrared light source 1 is twice the frequency f of the current supplied from the power supply circuit 2 (2f).

The detection unit 9 is connected to the imaging camera 4 and detects a signal in a band centered on the frequency 2r from among the output signals from the imaging camera. The processing section 10 is connected to the detection section 9 and extracts information on the band from the signal detected by the detection section 9. The imaging camera 8 is sensitive to infrared rays and can detect high frequency modulation for each pixel. In the imaging camera 8, for example, a camera that outputs a signal with an intensity corresponding to the amount of incident infrared rays in parallel for each pixel that can detect a high-frequency modulation signal, or a camera that outputs a signal with an intensity corresponding to the amount of incident infrared rays in parallel, or Arrange modulation elements etc.
High-frequency modulation is detected for each pixel by changing the amount of incident light at a certain frequency.

In this way, in the device 10 composed of the infrared light source 1, the imaging camera 8, and the display 5, the power supply circuit 2
The object 3 is illuminated by light from an infrared light source 1 which is activated by a current having a signal modulated by . The imaging camera 8 captures an infrared intensity distribution image formed by the reflected light from the object 3 due to the infrared illumination light from the infrared light source 1, the light containing infrared rays generated from the object 3, and the light containing infrared rays from other light sources. An image signal from the imaging camera 8 corresponding to the infrared intensity distribution image is input to the detection unit 9. The detection section 9 detects a signal corresponding to the modulation signal of the infrared illumination light from the infrared light source 1 from among the input signals, and outputs the detection signal to the processing section 10 . In the processing section 10, an image is formed from the detection signal from the detection section 10, necessary information is extracted, and the image and information are displayed on the display 5.

In general, the modulation frequency of infrared rays emitted from self-luminous infrared light sources, such as signal lights whose light sources are incandescent bulbs or discharge lamps powered by commercial power, and emissive displays that have the same 60Hz refresh rate as televisions, has a low modulation frequency (120Hz). below). Therefore, by setting the modulation frequency of the infrared rays emitted from the infrared light source 1 sufficiently high, the detection unit 9 can detect the reflected light and self-emission of the infrared rays emitted from the infrared light source 1 from among the image signals from the imaging camera 8. can be distinguished from direct light from type infrared light sources. Further, since the infrared illumination light from the infrared light source 1 is a modulated signal, it can be easily distinguished from signals in other frequency bands among the image signals of the imaging camera 8, so that noise in the infrared image can be reduced. Power circuit 2
The oscillation frequency r'I! : Since it is used as a modulation signal, a special modulation circuit can be eliminated and the configuration can be simplified.

FIG. 2 shows the configuration of a second embodiment of the present invention.

In FIG. 2, the difference from the first embodiment is that the detection unit 14
and the processing section 10. The detection unit 14 includes a detection unit a12 that detects a signal in a band centered on a frequency 2f that is twice the frequency f of the current supplied from the power supply circuit 2 from among the output signals from the imaging camera 8, and a detection unit a12 that detects a signal in a band centered on a frequency 2f that is twice the frequency f of the current supplied from the power supply circuit 2; Low band (
The processing unit 10 extracts information included in both bands. In addition to the effect of the first embodiment of being able to extract the reflected light from the infrared illumination light from the infrared light source 1, the imaging device 11 configured as described above has the effect of being able to extract the reflected light from the infrared illumination light from the infrared light source 1. In the environment, there are self-luminous infrared light sources such as signal lights and luminescent displays that have a modulation frequency lower than the modulation frequency of the infrared illumination light, and in the natural world such as animals and humans where the emitted infrared light is hardly modulated. Infrared light sources can be easily extracted from image information. In particular, when the light source 1 is a vehicle headlamp, animals such as dogs and cats, pedestrians, etc. can be easily and clearly identified, improving driving safety.

The configuration of the third embodiment of the present invention is similar to the configuration of the second embodiment shown in FIG. The difference is that the detection unit 14t,
A detection unit a12 detects signals in a band centered on a frequency 2f that is twice the frequency of the current supplied from the power supply circuit 2 from among the output signals from the imaging camera 4, and detects particularly strong signals. It is composed of a detection section c15.

In the processing section 10, the signals detected by both the detection sections 12 and 15 are combined into one image.

The infrared light source 1 is
When photographing infrared illumination light from an imaging device of the same type existing in the range illuminated by infrared illumination light from the have the same frequency modulation, but the intensity of the direct light is stronger. Therefore, the detection unit 12
By combining the signals from 1 and 15, the existence of the same type of imaging device can be known more clearly.

In particular, when the infrared light source 1 is used as a vehicle headlamp, infrared rays are transmitted even under weather conditions such as fog, making it possible to clearly identify the presence of an oncoming vehicle, thereby increasing driving safety.

Further, as shown in FIG. 3, the display 5 is a color display, and the image information corresponding to the signal from the detection section a12 in the second embodiment and the detection section b13 and the third detection section in the second embodiment are displayed. The detection unit of the imaging device according to the present invention can be combined with the image information corresponding to the signal from the detection unit 15 in the embodiment in the processing unit 10, and by specifying the respective colors to be different colors and displaying them on the display 5. It is possible to configure a display device that can display image information extracted by 12, 13, and 15 more clearly without using a complicated pattern recognition device. In order to avoid confusion, the chromaticity of the image information from each processing unit is set to be a color that is outside the range indicated by MacAdam's deviation ellipse indicating the color discrimination range. Furthermore, even if the display 5 is a monochrome display, the processing section 10 can change the brightness of the image information from each detection section on the display, or cause information from a specific detection section to flicker. The same effect can be obtained. In particular, when the infrared light source 1 is a vehicle headlamp, the shape of the eighth object illuminated by the illumination light from the infrared light source 1 is the detection part a.
The image information from 12, the presence of humans and animals, and the display contents of the self-luminous display correspond to the image information from the detection unit b13, and the presence of an oncoming vehicle corresponds to the image information from the detection unit c15, which are necessary for driving. Since important information is displayed in an easy-to-understand and emphasized manner, driving safety is further improved.

In the third embodiment, the imaging camera 8 is connected to the infrared light source 1.
By also providing a device sensitive to infrared rays of a wavelength different from that emitted from the infrared light source 1, it is possible to display image information representing the object 3 illuminated by the infrared light source 1, the presence of Ozeki/animals, and a self-luminous display. It is possible to more clearly separate and extract the image information representing the displayed content.

When the infrared light source 1 is used as a vehicle headlamp, a part of the light containing infrared rays emitted from the vehicle light source is separated by a light transmission means, and a part of the light including the infrared rays emitted from the vehicle light source is separated from a light transmitting device such as a windshield that is a component of the vehicle. By allowing light to enter the window from an end surface other than the window surface, infrared rays are propagated by repeated reflections within the windshield, and the infrared rays are radiated from the entire surface of the windshield. When a vehicle equipped with a vehicle headlight configured in this manner is observed as an oncoming vehicle, the imaging device 11 according to the second embodiment and/or the third embodiment detects not only the headlight but also the window. Since the image information includes the oncoming vehicle, the shape of the oncoming vehicle becomes clearer, improving the recognition rate. Furthermore, since condensation on the window surface that occurs during humid seasons and frost that adheres to the window surface during cold mornings is melted and evaporated by infrared rays, it can also function as a defroster.

Note that in the second and third embodiments, the detection unit 14 is replaced by the detection unit a12. Detection unit b13. Although it is divided into the detection section c15, the same thing may be done with one electronic circuit. Further, although the number of the processing section 10 is one, the same effect may be obtained even if each detection section is provided.

Further, in this embodiment, the light emitted from the infrared light source 1 is light that includes visible light, but it may be only infrared light that does not include visible light. Further, although the infrared light emitted from the infrared light source 1 is modulated by an electronic circuit type ballast, it is also possible to use an electro-optic light modulator such as PLZT, or by mechanical means such as a mechanical chopper. It doesn't matter.

Effects of the Invention It is possible to distinguish between an object illuminated with modulated infrared rays from an infrared light source and a self-luminous infrared light source.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a first embodiment of an imaging device according to the present invention, FIG. 2 is a block diagram of a second embodiment and a third embodiment of an imaging device according to the present invention, and FIG. 3 is a display device. FIG. 4 is a block diagram of a conventional display device. 1... Light source, 2... Power supply circuit, 8... Target object, 8
... Imaging camera, 5... Display, 9... Detecting section, 10... Processing section, 11... Imaging device. Name of agent: Patent attorney Shigetaka Awano (1 person) Figure 61, q

Claims (11)

[Claims] (1) Consisting of a light source that emits infrared rays with a high-frequency modulation signal, a power source that supplies power to the light source, and an imaging camera that is sensitive to the infrared rays and is capable of signal processing for each pixel. imaging device. (2) The imaging device according to claim 1, wherein the light source is a high-pressure discharge lamp and the power source is an electronic circuit ballast. (3) A patent that includes a detection unit that detects a modulated signal of infrared rays emitted from a light source among signals related to infrared intensity distribution output from an imaging camera, and a processing unit that is connected to the detection unit and extracts necessary information. An imaging device according to claim 1 or 2. (4) A patent claim comprising: a detection unit that detects signals in a low frequency band including direct current among signals related to infrared intensity distribution output from an imaging camera; and a processing unit connected to the detection unit and extracting required information. 2. The imaging device according to item 2. (5) A patent claim comprising: a detection unit that detects a strong signal among signals related to infrared intensity distribution output from an imaging camera; and a processing unit connected to the detection unit and enhancing the signal from the detection unit. The imaging device according to scope 2. (6) The imaging device according to claim 3, further comprising a second imaging camera that is sensitive to infrared rays having a different wavelength from the infrared rays. (7) The imaging device according to claim 2, 3, 4, 5, or 6, wherein the light source is a vehicle headlamp. (8) A vehicle light source that emits light including infrared rays, and a light transmission means that guides the light and guides the light from an end surface other than the window surface to a light-transmitting window that is a component of the vehicle. An imaging device according to claim 7. (9) A display device characterized in that image information corresponding to an infrared modulated signal emitted from a light source and image information corresponding to signals other than the above are displayed in different colors. (10) Claim 9 in which the light source is a vehicle headlamp
Display device as described in section. (11) A vehicle light source that emits light including infrared rays, and a light transmission means that guides the light and guides the light from an end surface other than the window surface to a light-transmitting window that is a component of the vehicle. A display device according to claim 10.