JP2008219830A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that, if each of imaging elements is driven for a storage time different for each imaging element of each color channel in order to equalize an output signal ratio for each color channel, color blurring may occur on the borderline of a moving object when imaging the moving object. <P>SOLUTION: Each of imaging elements is driven while differing a storage starting time and a storage ending time for each imaging element of each color channel, such that center times of storage periods of the respective channels with the different storage times are aligned. By thus driving the imaging element, blurring on the borderline of a moving object can be reduced when imaging the moving object. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an imaging apparatus using a solid-state imaging device.

  A technique for equalizing the output signal ratio for each color channel in a conventional imaging apparatus will be described. A general three-plate imaging device is shown in FIG. In FIG. 5, reference numeral 101 denotes an optical color separation unit that separates an optical image into, for example, green, red, and blue. 102a, 102b, and 102c are solid-state image sensors for green, red, and blue channels, respectively, and convert the color-separated optical images into electrical signals for the respective colors. Reference numeral 103 denotes a drive pulse generator that generates a pulse for driving the solid-state imaging device. Reference numerals 104a, 104b, and 104c are analog-digital converters for green, red, and blue channels, respectively, and convert electrical signals output from the solid-state imaging device into digital signals. A video signal processing unit 105 performs white balance correction, nonlinear processing, and the like on the signal converted into the digital signal, and outputs the video signal as a video signal.

  In a general imaging apparatus configured as described above, there is a difference in sensitivity between imaging elements for each color. For this reason, when the accumulation time of the image sensor for each color is driven equally, the signal ratio output from each image sensor will be different, and even if the accumulation time is optimal for an image sensor of a certain color channel, It is not always the optimum accumulation time for the color channel imaging device. For example, when the amount of light incident on the imaging device is large, the image sensor of a highly sensitive color channel may be saturated. In addition, when performing signal amplification in the video signal processing unit in order to achieve white balance, it is necessary to set a different amplification factor for each color channel, and the amplification factor increases for low-sensitivity color channel signals. Noise is also amplified, and the SN ratio is deteriorated.

As a prior art for solving this problem, one described in Patent Document 1 is known. In this prior art, the charge accumulation time of the solid-state imaging device of each color channel can be set and controlled independently. Therefore, the charge accumulation time for each individual color channel can be set to an optimum value. As shown in FIG. 6, the output signal ratio for each channel can be made equal by shortening the charge accumulation time of the generally sensitive green channel and lengthening the charge accumulation time of the generally less sensitive blue channel. . As a result, it is possible to prevent a charge accumulation amount saturation phenomenon and SN from deteriorating.
JP 2000-278704 A

  However, since the accumulation start time is different for each color channel in the above-described conventional technique, there is a problem that when the moving object is photographed, the color blurs at the boundary line of the object as shown in FIG. is there.

  The present invention solves the problems of the prior art by changing the accumulation start time and accumulation end time for each color channel and aligning the center position of the accumulation period.

  The imaging apparatus of the present invention stores an optical color separation unit that separates an optical image into green, red, and blue images, and stores the green, red, and blue images with different accumulation times and converts them into electrical signals. A solid-state imaging device that obtains green, red, and blue signals, and a drive pulse generator that generates driving pulses for driving the green, red, and blue solid-state imaging devices at different timings, respectively The drive pulse generator generates drive pulses such that the center positions of the accumulation times for the green, red, and blue images coincide.

  Further, the drive pulse generation unit makes the accumulation start time the earliest accumulation time and the latest accumulation end time for the least sensitive solid-state image sensor among the green, red, and blue solid-state image sensors. The red / blue solid-state image pickup device is driven at a timing that makes the accumulation start time for the most sensitive solid-state image pickup device the latest and the accumulation end time the earliest.

  In addition, a timing adjustment unit is provided for adjusting the timing of the output signals of the individual image pickup devices for green, red, and blue.

  The imaging apparatus of the present invention has a plurality of signal output paths, accumulates incident light for each output path with different accumulation times, and converts each into an electrical signal to obtain a signal for each output path. And a drive pulse generator for generating drive pulses for driving the solid-state imaging device at different timings for each path, wherein the drive pulse generator is a center position of each accumulation time for each path Drive pulses are generated such that the two coincide with each other.

  In addition, a timing adjustment unit for adjusting the timing of signal output for each path of the solid-state imaging device is provided.

  When the accumulation time of the solid-state imaging device is different for each color channel, the target when shooting moving objects by aligning the center position of the accumulation period for each channel by changing the accumulation start time and accumulation end time The blur of the color of the boundary line of the object can be reduced as compared with the prior art.

  Hereinafter, the best mode for carrying out the invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a configuration diagram illustrating an imaging apparatus according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes an optical color separation unit, which separates an optical image to be imaged into three colors of green, red, and blue. 2a, 2b, and 2c are solid-state image sensors for green, red, and blue channels, respectively, that convert the separated optical images into electrical signals. Reference numeral 3 denotes a drive pulse generator that generates a drive pulse for driving the solid-state imaging device. The drive pulse generator can send drive pulses to each solid-state image sensor independently so that the drive timing of each solid-state image sensor can be set individually. Reference numerals 4a, 4b, and 4c denote analog-digital converters that convert electrical signals output from the solid-state imaging device from analog signals to digital signals. Reference numerals 5a, 5b, and 5c denote timing adjustment units that align timings so that signals output from the respective solid-state imaging devices at different times can be processed at the same time by the subsequent video signal processing process unit. A video signal processing unit 6 performs signal processing such as signal level correction and nonlinear processing of each color channel, and outputs it as a video signal.

  Next, the operation of the image sensor in the present embodiment having the above configuration will be described. The relationship between the drive pulse of each image sensor and the accumulation timing is shown in FIG. As shown in this figure, the solid-state image sensor of the color channel with low sensitivity (here, the blue channel) has a higher storage start time than the other color channels, and the solid-state image sensor with high sensitivity of the color channel (here, green channel). The accumulation start time is delayed. As for the accumulation end time, the solid-state image sensor of the color channel with high sensitivity is advanced, and the solid-state image sensor of the color channel with low sensitivity is delayed. By setting such an operation timing, the center positions of the accumulation periods of the respective color channels are matched. When the moving object is imaged in this manner, as shown in FIG. 3, the area of the color blur per place is dispersed by dispersing the blur of the color of the boundary line of the object in the front and rear in the moving direction. The color blur becomes less noticeable and color bleeding can be reduced.

  In the above description, color separation is performed in three systems by optical color separation, and photoelectric conversion is performed using three solid-state imaging devices. However, this is not limited to three systems, and may be divided into two or more systems. .

(Embodiment 2)
FIG. 4 is a block diagram showing an imaging apparatus according to Embodiment 2 of the present invention. The operation and processing will be described below.

  In FIG. 4, 7 is a solid-state image sensor that converts an optical image into an electrical signal. The solid-state imaging device 7 has three signal output paths of green, red, and blue, and can be driven independently for each output path. The optical image entering the solid-state imaging device is color-separated by an optical filter, and the separated color is converted into an electrical signal for each path and output. Reference numerals 4a, 4b, and 4c denote analog-digital converters that convert electrical signals output from the solid-state imaging device from analog signals to digital signals. Reference numeral 8 denotes a drive pulse generator that generates a drive pulse for driving the solid-state imaging device. The drive pulse generator 8 can send drive pulses independently to each path so that the drive timing of each path of the solid-state imaging device can be set individually. Reference numerals 5a, 5b, and 5c denote timing adjustment units that correct the difference in accumulation end time of each color channel. Since the output time of the signal output from each color channel is different, this is corrected. A video signal processing unit 6 performs signal processing such as signal level correction and nonlinear processing of each color channel, and outputs it as a video signal.

  Next, the operation of the imaging apparatus according to the present embodiment having the above configuration will be described. As with the timing of the first embodiment shown in FIG. 2, the drive timing for each path is such that the accumulation start time of the color channel with low sensitivity is made earlier than the other color channels, while the accumulation start time of the color channel with high sensitivity is set. Will be late. As for the accumulation end time, the color channel with high sensitivity is advanced and the color channel with low sensitivity is delayed. By setting such an operation timing, the center positions of the accumulation periods of the respective color channels are matched. As a result, similar to the first embodiment, it is possible to reduce blurring of the color of the boundary line of the object when the moving object is imaged.

  In the above description, color separation is performed in three systems by optical color separation, and photoelectric conversion is performed using three solid-state imaging devices. However, this is not limited to three systems, and may be divided into two or more systems. .

  The image pickup apparatus according to the present invention is useful for improving the image quality of an image pickup apparatus in which the accumulation time of the solid-state image pickup element is different for each color channel.

1 is a configuration diagram of an imaging apparatus according to a first embodiment of the present invention. Charge accumulation timing chart of the imaging apparatus according to the first embodiment of the present invention Fig. 3 is an image diagram of a moving object in the imaging apparatus according to the first embodiment of the present invention. Configuration diagram of an imaging apparatus according to a second embodiment of the present invention Configuration diagram of conventional imaging device Charge accumulation timing diagram of conventional imaging device Image of moving object in conventional imaging device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical color separation part 2a-2c Solid-state image sensor 3 Drive pulse generation part 4a-4c Analog-digital converter 5a-5c Timing adjustment part 6 Video signal process part 7 Solid-state image sensor 8 Drive pulse generation part 101 Optical color separation part 102a-102c Solid-state image sensor 103 Drive pulse generator 104a to 104c Analog to digital converter 105 Video signal processor

Claims (5)

An optical color separation unit that separates the optical image into green, red, and blue images;
A solid-state imaging device that accumulates the green, red, and blue images with different accumulation times and converts them into electrical signals to obtain green, red, and blue signals, and
A drive pulse generator for generating a drive pulse for driving each of the solid-state image sensors for green, red, and blue at different timings,
The imaging apparatus according to claim 1, wherein the drive pulse generator generates a drive pulse such that the center positions of the accumulation times for the green, red, and blue images coincide with each other. The drive pulse generation unit makes the accumulation start time for the solid-state image sensor having the lowest sensitivity among the solid-state image sensors for green, red, and blue the earliest and the latest accumulation end time, so that the green, red, 2. The image pickup apparatus according to claim 1, wherein the image pickup apparatus is driven at a timing such that the accumulation start time for the most sensitive solid-state image pickup element among the blue solid-state image pickup elements is delayed and the accumulation end time is earliest. . The imaging apparatus according to claim 1, further comprising a timing adjustment unit configured to synchronize timings of output signals of the individual image sensors for green, red, and blue. A solid-state imaging device having a plurality of signal output paths, storing incident light for each output path with different storage times, and converting each into an electrical signal to obtain a signal for each output path;
A drive pulse generator for generating a drive pulse for driving the solid-state imaging device at different timing for each path;
The imaging apparatus according to claim 1, wherein the drive pulse generator generates a drive pulse such that the center positions of the accumulation times for the paths match. The imaging apparatus according to claim 4, further comprising a timing adjustment unit configured to synchronize a signal output timing for each path of the solid-state imaging device.

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