JP2010098436A - Imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging device that holds image quality by reducing difficulties in adjustment needed when an image signal is input fast and eliminating variance in input position depending upon an operation environment such as temperature. <P>SOLUTION: The imaging device includes an imaging element 102, a delay unit 104 which gives a plurality of delay amounts to an image signal input from the imaging element 102, and an input unit 105 which inputs the image signal delayed by the delay unit 104. Further, the imaging device includes a memory 109 which stores the position of a defect pixel of the imaging element 102 or the position of a test signal as an expected value, and a determination unit 106 which determines a suitable delay amount using the image signal input by the input unit 105 and the expected value stored in the memory 106. Furthermore, the imaging device includes a selection unit 107 which selects the suitable delay amount according to the determination result of the determination unit 106, a signal processing unit 108 which processes the image signal having been selected by the selection unit 107, and a reference signal generation unit 110 which generates a reference signal for synchronizing the signal processing unit 108 and imaging element 102 with each other. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging apparatus, and more particularly, to an imaging apparatus that is characterized by an automatic adjustment technique for capturing an image signal.

  In recent years, consumer video cameras (imaging devices) have improved in performance due to the increase in the number of pixels of input devices and the increase in capacity of recording media, and the environment in which high-definition moving images and still images can be easily handled has become widespread.

  This kind of product is equipped with a multi-pixel imaging device having 2 million pixels or more, records a high-definition still image in a memory, reads out a part of this high-definition image and records it as a moving image, and Video cameras capable of shooting both moving images have been developed (see, for example, Patent Document 1).

  Acquisition of high-definition images is performed at a bit rate of about 400 Mbps and is very fast. Therefore, timing adjustment at the image acquisition unit is very strict and important.

  FIG. 10 is a simplified block diagram of an imaging apparatus according to a conventional example.

  The imaging apparatus includes a lens 101, an imaging element 102, an A / D conversion unit 103, a capturing unit 105, and a signal processing unit 108.

  With such a circuit configuration, image signals of still images and moving images are captured and signal processing is performed on the video signals. An image signal and a signal synchronized with the image signal are input to the circuit, and the image signal is taken into the circuit at the timing of the synchronization signal.

In addition, the image sensor 102 includes defective pixels, that is, defective pixels. There are a plurality of factors for defective pixels of the image sensor 102. For example, there are defects in the light receiving element and defects in the transfer path for transferring signal charges. Furthermore, in recent years, a CMOS sensor is increasingly used as the image sensor 102, but there are a plurality of defect factors specific to the CMOS sensor.
JP-A-7-264517

  FIG. 11 is a diagram illustrating image signal capture timing in the imaging apparatus of FIG.

  As shown in FIG. 11, the image signal and the synchronization signal for capturing the image signal have a timing relationship in which the image signal must be captured within a predetermined interval.

  As demand for higher-definition still images and moving images is expected in the future, timing adjustment at the capturing unit 105 will become more severe and must be handled. It is a problem.

  Furthermore, since the image signal is affected by the delay of the transmission path, and the delay amount varies greatly depending on the usage environment such as temperature, there is a problem that the adjustment of the capture timing depending on the environment must be taken into consideration.

  An object of the present invention is to provide an imaging apparatus capable of reducing the difficulty of adjustment required when capturing an image signal at high speed, eliminating variations in the capturing position due to an operating environment such as temperature, and maintaining image quality. It is to provide.

  In order to achieve the above object, the imaging apparatus according to claim 1, the imaging device, a delay unit that gives a plurality of delay amounts to an image signal input from the imaging device, and the delay unit delayed by the delay unit. Capture means for capturing an image signal, storage means for storing the position of a defective pixel of the image sensor or the position of a test signal as an expected value, the image signal captured by the capture means, and stored in the storage means A determination unit that determines an appropriate delay amount using the expected value; a selection unit that selects the appropriate delay amount based on a determination result of the determination unit; and the image signal selected by the selection unit. Signal processing means for processing, and reference signal generation means for generating a reference signal for synchronizing the signal processing means and the image sensor are provided.

  According to the imaging apparatus of the present invention, it is possible to reduce the difficulty of adjustment required when capturing an image signal at high speed, and to maintain the image quality by eliminating variation in the capturing position due to the operating environment such as temperature. .

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram of an imaging apparatus according to the first embodiment of the present invention.

  In FIG. 1, a lens 101 inputs a subject image. The image sensor 102 converts the input from the lens 101 into an image signal. The A / D conversion unit 103 converts an analog signal from the image sensor 102 into a digital signal.

  The delay unit 104 gives various delay amounts to the image signal from the image sensor 102. The capturing unit 105 captures image signals having various delay amounts in the delay unit 104. The determination unit 106 determines appropriate capturing from image signals having different delay amounts captured by the capturing unit 105. The selection unit 107 selects an appropriate capture based on the result determined by the determination unit 106.

  The signal processing unit 108 processes the image signal selected by the selection unit 107. The memory 109 stores an expected value (expected value signal) used for determination by the determination unit 106. The reference signal generation unit 110 generates reference signals for the image sensor 102 and the determination unit 106.

(First operation example)
Next, a first operation example in the first embodiment will be described.

  In FIG. 1, a subject image is input from a lens 101 and converted into an image signal by an image sensor 102.

  FIG. 2 is a diagram showing a distribution image of defective pixels in the image sensor of FIG.

  A defective pixel 201 exists in the image sensor 102. An image signal from the image sensor 102 is converted into a digital signal by the A / D converter 103 as a signal of a certain level.

  FIG. 3 is a diagram illustrating the timing of an image signal having a delay difference in the imaging apparatus of FIG. FIG. 3 shows the image signal capture timing in the capture unit 105 of FIG.

  The image signal given various delays by the delay unit 104 has a delay difference as shown in FIG. The position of the defective pixel is known in advance, and the position is stored in the memory 109 as an expected value.

  The determination unit 106 determines the image signal captured by the capture unit 105 and the expected value stored in the memory 109, and uses the determination result for selection by the selection unit 107.

  FIG. 4 is a diagram illustrating the timing and expected value of an image signal having a delay difference in the imaging apparatus of FIG. FIG. 4 shows a determination method in the determination unit 106 of FIG.

  An image signal having a delay difference is captured by the capturing unit 105 at an arbitrary period, and the determination unit 106 performs a determination by comparing with an expected value to be captured at that time. The determination of the image signal and the expected value is performed in synchronization with the signal generated by the reference signal generation unit 110.

  In FIG. 4, if the image signal b is the position of the defective pixel, it is the delay amount 2, the delay amount 3, and the delay amount 4 that are correctly captured.

  FIG. 5 is a diagram illustrating a determination table at the time of determination in the determination unit of FIG.

  There are a plurality of defective pixels, and a determination result for each is obtained. In addition, the delay amount at each determination is not constant and varies.

  FIG. 6 is a diagram illustrating a determination table when determining a plurality of defective pixels in the determination unit of FIG.

  The determination unit 106 compares the expected values with the image signals b, e, h, j, o, s, and w at the plurality of defective pixel positions to determine whether they match, and the selection unit 107 stably expects Select the amount of delay that matches the value.

  In FIG. 6, since the delay amount 3 and the delay amount 4 stably match the expected value, the selection unit 107 selects them. Furthermore, since the delay amount and variation vary depending on changes in temperature and environment, the determination unit 106 and the selection unit 107 adaptively determine and select an appropriate delay amount each time.

  The period for driving the capturing unit 105 is a period for reading defective pixels.

(Second operation example)
Next, a second operation example in the first embodiment will be described.

  In FIG. 1, a subject image is input from a lens 101 and converted into an image signal by an image sensor 102. The image signal from the image sensor 102 is converted into a digital signal by the A / D converter 103 as a signal of a certain level.

  The image signal given various delays by the delay unit 104 has a delay difference as shown in FIG. The image signal includes an invalid image area and an effective image area, and the determination unit 106 determines an appropriate delay amount using the switching timing between the invalid image area and the effective image area.

  FIG. 7 is a diagram illustrating a boundary between an effective image and an invalid image in the image signal of the imaging apparatus of FIG.

  Since the level of the image signal is extremely different before and after the boundary, the determination unit 106 determines an appropriate delay amount using the signal level.

  At this time, there is no necessity to place an expected value in the memory 109. The switching timing of the effective image area and the invalid image area when the image signal input from the image sensor 102 generated by the reference signal generation unit 110 is captured by the capturing unit 105 can be used as an expected value.

  FIG. 8 is a diagram showing a determination table at the time of determination for one line of the image signal in the determination unit of FIG.

  The determination unit 106 compares the expected value with the expected value at the switching timing from the effective image region to the invalid image region for each of the plurality of lines, and determines whether or not they match, and the selection unit 107 stably matches the expected value. Select the amount of delay.

  In FIG. 8, since the delay amount 4 and the delay amount 5 stably match the expected value, the selection unit 107 selects them. As described above, the determination unit 106 and the selection unit 107 adaptively determine and select an appropriate delay amount using the boundary between the image signal region and the effective image region.

  The period for driving the capturing unit 105 is a period during which the image signal is switched from the effective image area to the invalid image area. Alternatively, the period during which the capturing unit 105 is driven is a period during which the image signal is switched from the invalid image area to the effective image area.

  FIG. 9 is a block diagram of an imaging apparatus according to the second embodiment of the present invention.

  The imaging apparatus according to the second embodiment shown in FIG. 9 is obtained by adding 111 to the configuration of the imaging apparatus according to the first embodiment shown in FIG.

(Operation example of the second embodiment)
In FIG. 9, a subject image is input from the lens 101 and converted into an image signal by the image sensor 102. The test signal generated by the test signal generator 111 is added to the image signal from the image sensor 102, and the test signal is mixed in the image signal.

  The image signal mixed with the test signal is converted into a digital signal by the A / D converter 103. The image signal mixed with the test signal having various delays by the delay unit 114 has a delay difference as shown in FIG.

  The test signal position is known in advance, and the position is stored in the memory 109 as an expected value. The determination unit 106 determines the image signal captured by the capture unit 105 and the expected value stored in the memory 109, and uses the determination result for selection by the selection unit 107.

  As described above, the determination method in the determination unit 106 is shown in FIG. An image signal having a delay difference is captured by the capturing unit 105 at an arbitrary period, and the determination unit 106 performs determination by comparing with an expected value signal to be captured at that time.

  The determination of the image signal and the expected value is performed in synchronization with the signal generated by the reference signal generation unit 110.

  In FIG. 4, assuming that the image signal b is the position of the test signal, it is the delay amount 2, the delay amount 3, and the delay amount 4 that are correctly captured.

  As described above, FIG. 5 shows a determination table at the time of capture. There are a plurality of test signals, and a determination result for each is obtained. In addition, the delay amount at each determination is not constant and varies.

  As described above, the determination result when determining a plurality of defective pixels is shown in FIG. The determination unit 106 checks whether the image signals b, e, h, j, o, s, and w at the plurality of test signal positions match the expected value, and determines whether or not they match. Select the amount of delay that matches the value.

  In FIG. 6, since the delay amount 3 stably matches the expected value, it is selected by the selection unit 107. Furthermore, since the delay amount and variation vary depending on changes in temperature and environment, the determination unit 106 and the selection unit 107 adaptively determine and select an appropriate delay amount each time.

  The period during which the capturing unit 105 is driven is a test signal input period.

1 is a block diagram of an imaging apparatus according to a first embodiment of the present invention. It is a figure which shows the distribution image of the defective pixel in the image pick-up element of FIG. FIG. 2 is a diagram illustrating timing of an image signal having a delay difference in the imaging apparatus of FIG. 1. FIG. 2 is a diagram illustrating the timing and expected value of an image signal having a delay difference in the imaging apparatus of FIG. 1. It is a figure which shows the determination table at the time of determination in the determination part of FIG. It is a figure which shows the determination table at the time of the determination with respect to several defective pixels in the determination part of FIG. It is a figure which shows the boundary of the effective image and invalid image in the image signal of the imaging device of FIG. It is a figure which shows the determination table at the time of determination with respect to 1 line of image signals in the determination part of FIG. It is a block diagram of the imaging device concerning a 2nd embodiment of the present invention. It is a simplified block diagram of the imaging device which concerns on a prior art example. It is a figure which shows the taking-in timing of the image signal in the imaging device of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Lens 102 Image pick-up element 103 A / D conversion part 104 Delay part 105 Acquisition part 106 Determination part 107 Selection part 108 Signal processing part 109 Memory 110 Reference signal generation part 111 Test signal generation part

Claims (5)

An image sensor;
Delay means for giving a plurality of delay amounts to the image signal input from the image sensor;
Capture means for capturing the image signal delayed by the delay means;
Storage means for storing the position of the defective pixel of the image sensor or the position of the test signal as an expected value;
A determination unit that determines an appropriate delay amount using the image signal captured by the capture unit and the expected value stored in the storage unit;
Selection means for selecting the appropriate delay amount from the determination result of the determination means;
Signal processing means for processing the image signal after being selected by the selection means;
A reference signal generating means for generating a reference signal for synchronizing the signal processing means and the image sensor;
An imaging apparatus comprising:   The imaging apparatus according to claim 1, wherein the period for driving the capturing unit is a period for reading the defective pixel.   The imaging apparatus according to claim 1, wherein the period during which the capturing unit is driven is a period during which the image signal is switched from an effective image area to an invalid image area.   The imaging apparatus according to claim 1, wherein the period during which the capturing unit is driven is a period during which the image signal is switched from an invalid image area to an effective image area.   The imaging apparatus according to claim 1, wherein the period for driving the capturing unit is an input period for the test signal.

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