JP2003250085A - Ccd camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a CCD camera capable of obtaining an easy to see image with uniform lightness and obtaining an easy to see image without white skip and black decay in particular. <P>SOLUTION: An electrochromic device (ECD) panel 30 formed by separately arranging e.g. a plurality of transmission ECDs on a plane is placed on an incident light side of a CCD imaging element 2. The ECD panel 30 decreases the light transmittance of the ECD (not shown) in an area corresponding to a part with an extremely high object illuminance in an imaging area by the CCD imaging element 2 and increases the light transmittance of the ECD (not shown) in an area corresponding to a part with an extremely low object illuminance in the imaging area by the CCD imaging element 2. Thus, the object image without the parts having the extremely low and high object illuminance can be made incident onto the CCD imaging element 2 so as to obtain an easy to see image without white skip and black decay. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CCD camera, and more specifically, it is possible to obtain an easy-to-see image with uniform brightness over the entire image, and particularly to obtain an easily-viewable image without whiteout phenomenon or blackout phenomenon. CCD improved to allow
It's about the camera.

[0002]

2. Description of the Related Art A CCD camera, which is generally used as a digital camera or a video camera, has a CCD through an imaging lens.
(Charge Coupled Device) In order to automatically adjust the brightness of the subject incident on the image pickup device, an iris control circuit for controlling an auto iris arranged between the imaging lens and the CCD image pickup device is usually provided. ing.
In addition, an automatic gain adjustment circuit (AGC circuit) for the image signal output from the CCD image pickup device is also provided (Japanese Patent Laid-Open No. H06-69242).
-105194).

In this type of CCD camera, when the illuminance of the subject is sufficient, the iris control circuit automatically controls the auto iris to adjust the brightness of the subject. The adjusting circuit (AGC circuit) automatically operates to obtain a clear image signal.

[0004]

However, there is a limit to the adjustment of the object illuminance by the auto iris,
If there is an extremely high subject illuminance (extremely bright part) due to sunlight or its reflected light from the glass or metal, etc. within the imaging area of the CCD image sensor, the auto iris function will work, but the extremely bright part Depending on the peak value, area ratio, and position (depending on the setting unique to the camera), the so-called whiteout phenomenon occurs in extremely bright areas, making the image very difficult to see. Also, due to the peak value, area ratio, and position of the extremely bright portion, a so-called black drop phenomenon occurs in the portion where the subject illuminance is low (relatively dark portion), and the image becomes very difficult to see. Further, smear (a phenomenon that occurs because the charge of the photodiode overflows to the transfer line) occurs in a portion where the amount of light is large.

Therefore, according to the present invention, it is possible to obtain an image in which the entire image has uniform brightness and is easy to see, and in particular, it is possible to obtain an easy-to-see image without the phenomenon of whiteout or blackout.
It is an object to provide a camera.

[0006]

As means for solving the above problems, a CCD camera according to the present invention divides a plurality of transmissive electrochromic devices (ECD) in a plane on the incident light side of a CCD image pickup device. A CCD camera provided with an ECD panel formed by arranging, a means for setting a plurality of image pickup areas by dividing the entire image pickup area in a CCD image pickup element corresponding to each ECD area, and brightness of each image pickup area. And a means for controlling the voltage applied to each ECD corresponding to the brightness of each imaging area to control the transmittance of each corresponding ECD area. In this way, by controlling the transmittance of each ECD area corresponding to each image pickup area according to the brightness of each image pickup area in the CCD image pickup element, the CC
The amount of incident light incident on each image pickup area in the D image pickup device can be made uniform (averaged), and as a result, an image with uniform brightness and easy to see can be obtained. Moreover, it is possible to contribute to the smear countermeasure by averaging the light amount. Further, the function can be improved as compared with the conventional mechanical auto iris mechanism. For example, by reducing the transmittance only in a portion where the subject illuminance is extremely high, it is possible to easily obtain an easy-to-see image without a whiteout phenomenon or a blackout phenomenon. Further, by reducing the transmittance of a portion where the subject illuminance is extremely high, it is possible to improve the maximum subject illuminance that can be seen without overexposure.

In the CCD camera of the present invention, the CC
When the image pickup area in the D image pickup element is divided into n × m in the vertical and horizontal directions and set, it becomes easy to set the image pickup area and detect the brightness of the image pickup area. In addition, the ECD panel,
When the CCD image pickup device is divided into n × m in the vertical and horizontal directions so as to correspond to the entire image pickup area, the ECD array panel can be manufactured more easily than other divided arrangement modes.

In the CCD camera of the present invention, the means for detecting the brightness of each image pickup area calculates or extracts the brightness of each image pickup area based on the luminance signal of the image signal output from the CCD image pickup device. If it is a means, CC
Since the brightness signal of the image signal output from the D image pickup device can be used, the brightness of each image pickup area can be easily calculated or extracted by software processing (arithmetic processing), and a means for detecting other brightness Need not be provided separately.

In the CCD camera of the present invention, when a transmissive electrochromic device (ECD) is arranged on the front side of the imaging lens of the CCD camera at a right angle to the optical axis, a commercially available CCD camera (imaging lens and CCD imaging The CC according to the present invention can be easily and cost-effectively provided by only disposing an ECD panel or the like outside a module having at least an element).
A D camera can be manufactured.

In the CCD camera of the present invention, the light that does not pass through the ECD is the back side of the ECD (the side from which the transmitted light exits).
In the case of a structure that does not wrap around, only light whose transmittance is controlled via the ECD can enter the CCD image sensor. In particular, when the ECD is arranged on the front side of the imaging lens of the CCD camera as described above, light that does not pass through the ECD is likely to enter the back side of the ECD.
It is preferable that the outer peripheral portion from the outside of the transmissive area of the ECD panel to the incident surface of the CCD image sensor is shielded from light.

The CCD camera of the present invention is particularly suitable for use as a vehicle-mounted camera for displaying on a vehicle-mounted monitor. This is because it is possible to adjust the amount of light incident on the CCD image sensor without having a mechanical drive part such as a mechanical iris structure, so it is suitable for use in an in-vehicle camera used in a severe environment with many vibrations. Is. Further, it is suitable for an on-vehicle camera that needs to be automatically displayed in an environment where the brightness changes extremely. Furthermore, it is suitable for vehicle-mounted cameras that do not require high image quality as high as digital cameras and video cameras.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a CCD camera according to the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 shows a CC according to an embodiment of the present invention.
It is a perspective view showing a schematic structure of a D camera. As shown in FIG. 1, a CCD camera according to an exemplary embodiment of the present invention has a CC
A transmission type ECD panel 30 is installed on the incident light side of the D image pickup device 2. Here, as shown in FIG. 2, the transmissive ECD panel 30 is an ECD in which a plurality of transmissive electrochromic elements (ECDs) 32 are formed in a transmissive region 31 in a plane by dividing the transmissive electrochromic device (ECD) 32 in a horizontal m × vertical n direction. An array panel,
Each of the ECDs 32 is connected to the external wiring 33 shown in FIG. 1 through an extraction electrode (not shown) in the peripheral portion of the ECD panel which is connected to a counter electrode (not shown). As shown in FIG. 3, the entire image pickup area 21 of the CCD image pickup device 2 is divided into n × m in the vertical and horizontal directions to set a plurality of image pickup areas 22, and each of the n × m divided image pickup areas 22 is shown in FIG. It corresponds to each ECD 32 arranged in n × m division as shown in FIG. Specifically, the means for setting the image pickup area in the CCD image pickup element can set the image pickup area 22 by setting a plurality of pixel data in the CCD image pickup element in the vertical and horizontal directions to be collectively processed. In addition, the brightness of each imaging area can be determined by performing data processing (for example, arithmetic processing such as calculation of an average value or extraction of a value at the center of the imaging area or software processing) on a plurality of set pixel data in each set imaging area 22. Data (for example, brightness data) is obtained. Setting of these imaging areas and acquisition of data of each imaging area are performed by the CP shown in FIG.
It can be done by U40. In the CPU 40, the brightness data (luminance data, etc.) of each imaging area is arithmetically processed and converted into a corresponding applied voltage to each ECD. The transmittance of each ECD is controlled by feeding back the obtained ECD applied voltage value to each corresponding ECD via the external wiring 33. In the buffer 50, each ECD is operated by adjusting the data transfer speed and time.

The CC according to the present invention configured as described above
In the D camera, by controlling the transmittance of each ECD, the light incident on the CCD image sensor is averaged, and it is possible to obtain an image in which the entire image has uniform brightness and is easy to see. Although the specific mode of control is not particularly limited, for example, each EC
When the transmittance of D32 can be controlled by changing it in the range of 80% to 30%, for example, the initial transmittance of each ECD32 is 80%.
% (Transparency / zero initial voltage) and when an extremely bright imaging area 22 is detected, it is possible to reduce only the ECD transmittance of the location corresponding to that imaging area and eliminate the extremely bright area. is there. Also, for example, each ECD3
The initial transmittance of 2 is 50 to 70% (almost transparent, initial voltage;
When the image pickup area 22 which is relatively extremely dark is detected, the transmittance of the ECD of the portion corresponding to the image pickup area is increased by 10 to 30%, and the relatively extremely dark portion is detected. It is possible to eliminate it. Also, for example,
The initial transmittance of each ECD 32 is set to 50% (initial voltage; predetermined voltage for the whole), the brightness of each imaging area 22 is detected, and the transmittance of each ECD at a location corresponding to each imaging area is set to the set brightness. To approach the level, or
It is possible to control so that the brightness level is the same as that of the entire other imaging area or the surrounding imaging areas. If an extremely bright imaging area or a relatively extremely dark imaging area is not detected, the transmittances of all ECDs 32 are uniformly changed according to the changing conditions of the incident light quantity such as the weather and the outdoors / indoors. As a result, the same function as that of the conventional mechanical auto iris mechanism can be achieved. In addition, the CC of the present invention
By adding a conventional mechanical auto iris mechanism to the D camera, if it does not detect an extremely bright imaging area or a relatively extremely dark imaging area, the weather, outdoors, etc.
It is also possible to adopt a configuration in which a conventional mechanical auto-iris mechanism is actuated to automatically adjust the brightness of a subject in accordance with a change situation of the amount of incident light such as indoors. In addition, in FIG.
Although the imaging lens is not shown, the position of the imaging lens is
It can be arranged between the CCD image pickup device 2 and the transmission type ECD panel 30, and in this case, the ECD panel or the like is arranged outside a commercially available CCD camera (a module having at least an imaging lens and a CCD image pickup device). Just set it up,
The CCD camera according to the present invention can be realized easily and at low cost. Further, in the case where the CCD image pickup device 2 and the transmission type ECD panel 30 are arranged in close contact or close to each other,
It is also possible to provide an imaging lens on the incident light side of the transmissive ECD panel 30.

In the application of the vehicle-mounted camera for displaying on the vehicle-mounted monitor, the image quality as high as that of a digital camera or a video camera is not required, so that each ECD 32 arranged in n × m division shown in FIG. 2 and FIG. Each of the n × m divided image pickup areas 22 shown in (3) does not cause a big problem even if the area is set to be relatively large (the number is small). This facilitates data processing by the CPU, and
The D panel can be easily manufactured and can be manufactured at low cost. From this point of view, it is preferable that the n × m division number is a division number that provides a sufficient display quality level for the vehicle-mounted monitor.

(Second Embodiment) FIG. 4 is a system configuration diagram of a CCD camera according to an embodiment of the present invention. As shown in FIG. 4, the CCD camera according to the embodiment of the present invention is a CCD in which an electrochromic device (ECD) panel 30 is arranged on the front side of the imaging lens 1 at right angles to the optical axis.
A camera, which is the ECD panel 30 and the imaging lens 1
Color images the subject by receiving light via C
CD (Charge Coupled Device) image sensor 2 and this C
A DSP (Digi) that processes a digital image signal input from the CD image sensor 2 via the sampling circuit 3, the AGC circuit 4, and the A / D (analog / digital) converter 5.
tal signal processor), and a CPU 40 that processes a brightness signal obtained through the AGC circuit 4, the brightness signal processing circuit 8 and the like and performs various settings and controls.

The ECD panel 30 is divided into a plurality of areas over the entire image pickup area 21 of the CCD image pickup device 2. That is, as shown in FIG. 2, the ECD panel 30 has vertical n rows and horizontal m over the entire rectangular area 21.
It is divided into a matrix of rows, and the light transmittance can be controlled for each imaging area 32. The image forming lens 1 has a function of forming an image of a subject on the exposed surface of the CCD image pickup device 2. The CCD image pickup device 2 outputs the subject image formed on the exposure surface by the image forming lens 1 as a color image signal. On the exposed surface of the CCD image pickup device 4, color filters such as complementary color filters are provided for each pixel, and Mg, G, C corresponding to each pixel are provided.
Color image signals of y and Ye are sequentially output. The DSP described later has a dimming generator 7,
The CCD image pickup device 2 is driven and controlled via the CCD driver circuit 6. In addition, the EC which is not transmitted through the transmissive region of the ECD panel 30 is prevented from entering the back side of the ECD.
A structure is provided in which the light shielding portion 12 that shields the outer peripheral portion from the outside of the transmissive area of the D panel 30 to the incident surface of the CCD image pickup element 2 is provided. The sampling circuit 3 removes horizontal transfer pulse components, noise, etc. from the color image signal output from the CCD image pickup device 2 and outputs the image signal to the AGC circuit 4. The AGC circuit 4 adjusts the gain of the color image signal so that the illuminance of the subject becomes equal to or higher than the minimum illuminance of the subject.

The CPU 40 processes the brightness signal obtained from the CCD image pickup device 2 through the sampling circuit 3, the AGC circuit 4, the brightness signal processing circuit 8 and the like, and performs various settings and controls. The CPU 40 includes, for example, an image pickup area setting / image pickup area brightness detection circuit 41, an ECD voltage control circuit 42, and an ECD voltage signal output circuit 43.

The A / D converter 5 converts an analog color image signal output from the CCD image pickup device 2 into a corresponding digital color image signal and outputs the color image signal.

The DSP is a circuit for processing a digital image signal input from the A / D converter 5, and is a luminance signal processing circuit 8, a color signal processing circuit 9, various signal processing / control circuits 10, an image signal output circuit 11, etc. Is equipped with.

The color image signal output from the A / D converter 5 is separated into a luminance signal Y and a color difference signal C and input to the luminance signal processing circuit 8 and the color signal processing circuit 9, respectively. The luminance signal processing circuit 8 limits the band of the inputted luminance signal Y by the LPF, and executes luminance signal processing such as setup and blanking addition. Further, the color signal processing circuit 9 receives the input color difference signal C
To generate a color signal. The luminance signal processing circuit 8, the color signal processing circuit 9, and the AGC circuit 4 are respectively controlled by various signal processing / control circuits 10. Then, the image signal output unit 11 inputs signals from the luminance signal processing circuit 8 and the color signal processing circuit 9,
A color image signal composed of a YC signal is output as an analog signal A and an 8-bit or 16-bit digital signal D.

Next, the operation of the CCD camera having the above structure according to the embodiment of the present invention will be described. In the CCD camera according to the embodiment of the present invention, the EC
The subject image received through the D panel 30 and the imaging lens 1 is color-photographed by the CCD image pickup device 2, and the image signal output from the CCD image pickup device 2 is sampled by the sampling circuit 3.
It is input to the CPU 40 via the AGC circuit 4 and the like. CP
In the image pickup area setting / image pickup area brightness detection circuit 41 in U40, for example, the input image signal (CC
The image pickup area 22 can be set by setting data processing for each of a plurality of image pickup areas 22 divided into n × m in the vertical and horizontal directions shown in FIG. Also,
For example, by performing data processing (for example, arithmetic processing such as calculation of an average value or extraction of a value at the center of the imaging area or software processing) on a plurality of set pixel data in each set imaging area 22, Data (for example, brightness data) is obtained. It is possible to process the setting of the image pickup area with a pulse from the timing generator 7 and detect the brightness of the image pickup area from the digital data from the luminance signal processing circuit 8. Specifically, the location can be specified by counting the horizontal / vertical synchronization pulses in order to set an arbitrary image pickup area, and the divided image pickup area (virtual window) can be set by software processing. In this case, the brightness can be detected by, for example, averaging the luminance signals in each imaging area (virtual window). In the ECD voltage control circuit 42, the obtained brightness data (luminance data etc.) of each imaging area is processed to be converted into a corresponding applied voltage to each ECD. EC
The D voltage signal output circuit 43 outputs an ECD voltage signal to each corresponding ECD based on the obtained each ECD applied voltage value. As a result, each E in the ECD panel 30 is
The transmittance of the CD is controlled. Note that each ECD can be statically driven or dynamically driven. After the transmittance of each ECD is controlled, each ECD is transmitted, and C
The amount of incident light incident on the CD image sensor 2 is made uniform (averaged), the image signal output from the CCD image sensor 2 is input to the DPS via the A / D converter 5, and the entire image has uniform brightness. Is displayed as an easy-to-see image.

[0022]

As described above, the CC according to the present invention
With the D camera, it is possible to obtain an easy-to-see image with uniform brightness over the entire image, and particularly to obtain an easily-viewable image without a whiteout phenomenon or a blackout phenomenon.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of a CCD camera according to an embodiment of the present invention.

FIG. 2 is a schematic view showing an ECD panel formed by dividing and arranging ECDs in a horizontal m × vertical n pattern.

FIG. 3 shows a lateral image of the entire image pickup area of the CCD image pickup device by m ×
It is a schematic diagram which shows the state which divided into vertical n and set several imaging area.

FIG. 4 is a system configuration diagram of a CCD camera according to an embodiment of the present invention.

[Explanation of symbols]

1: imaging lens 2: CCD imaging device 3: sampling circuit 4: AGC circuit 5: A / D converter 6: CCD driver circuit 7: timing generator 8: luminance signal processing circuit 9: color signal processing circuit 10: various signal processing -Control circuit 11: Image signal output circuit 12: Light-shielding portion 30: ECD panel 32: ECDs 22 formed by dividing and arranged: Imaging area 40 set by dividing: CPU 41: Setting of imaging area-Brightness of imaging area Detection circuit 42: ECD voltage control circuit 43: ECD voltage signal output circuit 50: Buffer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Eiho Sato             748 Hyodayu, Fujieda City, Shizuoka Prefecture             Kamikaido Fujieda Office F-term (reference) 5C022 AB14 AC42 AC55 AC69                 5C024 CX03 CX13 GY01 HX13 HX18                       HX23

Claims (7)

[Claims] 1. A CCD camera having an ECD panel formed by dividing a plurality of transmissive electrochromic devices (ECDs) in a plane on the incident light side of a CCD image pickup device, wherein each ECD area is provided in each ECD area. Correspondingly, a means for dividing the entire image pickup area in the CCD image pickup device to set a plurality of image pickup areas, a means for detecting the brightness of each image pickup area, and a corresponding ECD corresponding to the brightness of each image pickup area 2. A CCD camera according to claim 1, further comprising means for controlling an applied voltage to control the transmittance of each corresponding ECD area. 2. An image pickup area of the CCD image pickup device is divided into n × m vertically and horizontally, and the EC is set.
2. The CCD camera according to claim 1, wherein the D panel is formed by arranging the ECDs in n × m divisions in the vertical and horizontal directions so as to correspond to the entire image pickup area of the CCD image pickup device. 3. The means for detecting the brightness of each imaging area is means for calculating or extracting the brightness of each imaging area based on the brightness signal of the image signal output from the CCD imaging device. The CCD camera according to claim 1 or 2, which is characterized. 4. A transmissive electrochromic device (ECD) on the front side of an imaging lens of a CCD camera at right angles to the optical axis.
The CCD camera according to claim 1, wherein the CCD camera is provided. 5. A structure in which light that does not pass through the ECD does not go around to the back side of the ECD.
The CCD camera according to any one of 4 above. 6. The CCD camera according to claim 1, which is a vehicle-mounted camera for displaying on a vehicle-mounted monitor. 7. The CCD camera according to claim 1, having no mechanical iris structure.