JP4548163B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus, and more particularly to an imaging apparatus having a solid-state imaging device having a plurality of output units (channels: CH).

  In an image pickup apparatus equipped with a CCD (Charge Coupled Device) as a solid-state image pickup device, the number of pixels per line of the CCD increases due to the increase in the number of pixels accompanying the demand for higher resolution, while the image of one line from the CCD. Since the time for outputting a signal is defined by the television standard, the signal readout clock frequency generally increases in proportion to the number of pixels per line, and the subsequent signal processing circuit accordingly. As a result, the operating frequency of the circuit becomes higher, and restrictions on circuit design increase. In addition, it is necessary to carefully take measures against noise and radiation.

  Therefore, conventionally, as a means for avoiding these troubles, the imaging area of the solid-state imaging device is divided into right and left, and a signal output channel is provided independently to read out the imaging signals imaged in the divided imaging area. An imaging device including two data output units is known (see, for example, Patent Document 1).

  FIGS. 5A and 5B are configuration diagrams of examples of a conventional imaging apparatus including two data output units. In both drawings, the same components are denoted by the same reference numerals. The conventional imaging apparatus shown in FIG. 5A has divided imaging areas 1A and 1B in which the imaging area is divided into left and right, and horizontal optical devices provided at the vertical ends of the divided imaging areas 1A and 1B. Black level areas (OB areas) 2A and 2B, vertical OB areas 3 provided at the upper ends in the horizontal direction of the divided imaging areas 1A and 1B, and lower ends in the horizontal direction of the divided imaging areas 1A and 1B. Vertical OB area 4.

  The lower end vertical direction OB area 4 is connected to horizontal transfer paths (hereinafter referred to as horizontal transfer CCDs) 5A and 5B composed of CCDs, and the horizontal transfer CCDs 5A and 5B are connected to output amplifiers 6A and 6B. . From the output amplifiers 6A and 6B, video signals of channels (CH) 1 and 2 imaged in the imaging areas 1A and 1B are output.

  Each of the divided imaging areas 1A and 1B includes a vertical transfer path (hereinafter referred to as a vertical transfer CCD) composed of a large number of pixels arranged in a two-dimensional matrix and a CCD that transfers the output signal charge of each pixel in the vertical direction. Is arranged. The signal charges vertically transferred by the vertical transfer CCD are inputted to the horizontal transfer CCDs 5A and 5B, then horizontally transferred, further amplified by the output amplifiers 6A and 6B, and then outputted as video signals of CH1 and CH2, respectively. .

  Further, in the conventional imaging apparatus shown in FIG. 5B, a portion from the left end of the screen in the vertical direction OB area 4 to the center is connected to the horizontal transfer CCD 9A via the oblique shift region 8A, and the center of the vertical direction OB area 4 is The portion from the portion to the right end of the screen is connected to the horizontal transfer CCD 9B via the oblique shift region 8B, and the horizontal transfer direction is different from that of the conventional imaging device shown in FIG. That is, in the conventional imaging apparatus shown in FIG. 5A, the signal charges that are vertically transferred and input to the horizontal transfer CCDs 5A and 5B are respectively directed from the pixels at the left end of the screen and the right end of the screen toward the pixel at the center of the screen. Horizontally transferred and read from the output amplifiers 6A and 6B.

  On the other hand, in the conventional image pickup apparatus shown in FIG. 5B, the signal charges that are vertically transferred by the vertical transfer CCD and input to the horizontal transfer CCDs 9A and 9B through the oblique shift regions 8A and 8B, respectively, The data is horizontally transferred from the nearby pixels to the leftmost pixel direction of the screen, and from the pixels near the center of the screen to the rightmost pixel direction of the screen, and read from the output amplifiers 6A and 6B. The OB areas 2A, 2B, 3 and 4 are each composed of a plurality of pixels for each line. However, since the OB areas 2A, 2B, 3 and 4 are configured to block incident light, they output a signal level when there is no light. The video signals of CH1 and CH2 output from the output amplifiers 6A and 6B are synthesized by a processing circuit (not shown) at the subsequent stage.

JP 2003-046867 A

  However, the conventional imaging device shown in FIGS. 5A and 5B has a configuration in which the video signals of CH1 and CH2 are separately output from the two data output units. An output difference between CHs due to a horizontal transfer efficiency difference between the transfer CCDs 5A and 5B (or 9A and 9B), a gain difference between the output amplifiers 6A and 6B, etc. occurs. There is a problem that a saturation difference, a black level difference between CHs, and the like may also occur.

  The present invention has been made in view of the above points, and an object thereof is to provide an imaging apparatus including a plurality of data output units capable of performing correction between CHs of an output image.

In order to achieve the above object, the present invention provides a matrix in which each of a plurality of divided imaging areas obtained by dividing an imaging area into a plurality of horizontal directions generates a signal charge of a level corresponding to incident light. A plurality of arranged pixels and a vertical transfer path for transferring the signal charges of the plurality of pixels in the vertical direction, and separately transferring the signal charges transferred in the vertical direction by the vertical transfer paths of the plurality of divided imaging areas. In an image pickup apparatus having a plurality of channel output units having a plurality of horizontal transfer paths that are transferred in the horizontal direction and output as video signals of a plurality of channels, a plurality of vertical transfer paths provided for each of a plurality of divided imaging areas provided over a plurality of divided imaging area between the horizontal transfer path, at the same time input is vertically transferred by the respective signal charges of a plurality of pixels vertical transfer path of the plurality of divided imaging area Once, the number of stages to a predetermined the signal charges transferred in the horizontal direction by the vertical transfer path, and shift without dividing the signal charges of each pixel, and the direction of the horizontal shift of the number of predetermined A pixel distribution horizontal transfer unit having selectable pixel distribution horizontal transfer units, and a control unit that alternately switches and controls a predetermined number of horizontal shift directions of the pixel distribution horizontal transfer units at a predetermined cycle. , after the horizontal shift of the predetermined number of stages in the direction selected by the control means, characterized in that the vertical transfer signal charges of the pixels are simultaneously held to a plurality of horizontal transfer paths.

  In the present invention, the signal charges of a plurality of pixels in a plurality of divided imaging areas are each vertically transferred through a vertical transfer path and simultaneously input to a pixel distribution horizontal transfer unit. After the horizontal transfer in the selected horizontal direction, the signal charges of the pixels held in the pixel distribution horizontal transfer unit are simultaneously vertically transferred to a plurality of horizontal transfer paths, and the horizontal transfer direction is set at a predetermined cycle. Since the switching is alternately performed, in addition to the signal charges of the plurality of pixels in the corresponding divided imaging area, a part of the plurality of horizontal transfer paths described above includes a certain number of pixels in other adjacent divided imaging areas. Signal charges are also input, and these are transferred horizontally and output. As a result, a part of the monitor screen displaying the imaged video signal has the above-mentioned one of the divided imaging areas. Image portion from the pixels of the number of pixels is switched and displayed alternately at a predetermined period of the.

  According to the present invention, a pixel distribution horizontal transfer unit capable of selecting a horizontal transfer direction is provided between a vertical transfer path and a plurality of horizontal transfer paths in a plurality of divided imaging areas, and the pixel distribution horizontal transfer unit The horizontal transfer direction is alternately switched at a predetermined cycle, and the signal charge after the horizontal transfer is vertically transferred to a plurality of horizontal transfer paths, so that a part of the screen of the monitor that displays the captured video signal In the divided imaging areas, the image portions from the pixels having the predetermined number of pixels are alternately switched and displayed at the predetermined cycle, and the image portions are compared and detected, so that It is possible to accurately detect errors and horizontal transfer efficiency differences between horizontal transfer paths, output differences between channels, linearity differences, saturation differences, black level differences, etc., thereby correcting for these differences. It can be accurately performed.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of an embodiment of an imaging apparatus according to the present invention. In the figure, the same components as those in FIG. The embodiment shown in FIG. 1 is characterized in that a pixel distribution transfer unit (PSEL: pixel selection transfer unit) 11 is provided between the vertical OB area 4 and the horizontal transfer CCDs 6A and 6B.

  The pixel distribution horizontal transfer unit 11 first shifts the input signal charges by a predetermined number of stages in the horizontal direction. The shift direction (horizontal transfer direction) is a timing cycle (for example, set by a control unit (not shown)). , Line cycle, field cycle or frame cycle), and after shifting in the horizontal direction, the signal charges are transferred in the vertical direction and input to the horizontal transfer CCDs 5A and 5B.

  Note that the number of horizontal shift stages determined in the pixel distribution horizontal transfer unit 11 is, for example, in addition to the number of horizontal effective pixels in the divided imaging area 1A or 1B and the number of pixels in the horizontal OB area 2A or 2B, The number of steps including the horizontal movement.

Next, the operation of the present embodiment will be described with reference to FIG. In the figure, the same components as FIG. 1 are denoted by the same reference numerals. First, signal charges of a level corresponding to incident light obtained by photoelectric conversion of incident light in each of a large number of pixels arranged in a two-dimensional matrix in each of the divided imaging areas 1A and 1B in FIG. As shown in FIG. 2A, the data is output from the pixel and further vertically transferred by the vertical transfer CCD and input to the pixel distribution horizontal transfer unit 11.

  Here, in FIG. 2, for convenience of illustration, only two vertical transfer CCDs are shown in the divided imaging area 1A in FIG. 1 as indicated by 21A. Similarly, the vertical transfer CCD in the divided imaging area 1B in FIG. Only two transfer CCDs are shown as indicated by 21B. Further, the circles schematically indicate signal charges.

  When the signal charge vertically transferred by the vertical transfer CCDs 21A and 21B is input to the pixel distribution horizontal transfer unit 11 as shown in FIG. 2A, as shown by an arrow 22 in FIG. The signal charge is shifted (transferred horizontally) by a predetermined number of stages (to the CH1 side) in the direction (here, two stages are provided for convenience). As a result, a part of the signal charges from the pixels in the divided imaging area 1B, which are vertically transferred by the vertical transfer CCD 21B, move horizontally to the CH1 side from the center of the screen.

  When the horizontal transfer is completed, the pixel distribution horizontal transfer unit 11 performs vertical transfer as shown in FIG. 2C, and inputs the signal charges after the horizontal transfer to the horizontal transfer CCDs 5A and 5B. Here, as shown in FIG. 2C, the horizontal transfer CCD 5A has signal charges from the pixels in the divided imaging area 1B that are vertically transferred by the vertical transfer CCD 21B by the horizontal transfer of the pixel distribution horizontal transfer unit 11. (In this case, signal charges for two pixels from the center of the screen toward the right edge of the screen) are also input. On the other hand, only the signal charges from the pixels in the divided imaging area 1B are input to the horizontal transfer CCD 5B after being horizontally transferred several stages.

  Thereafter, the horizontal transfer CCD 5A horizontally transfers the input signal charge in the left direction as indicated by an arrow 23 in FIG. 2D, while the horizontal transfer CCD 5B as indicated by an arrow 24 in FIG. 2D. The input signal charge is horizontally transferred in the right direction. Hereinafter, signal charges output from the horizontal transfer CCDs 5A and 5B are output as video signals of CH1 and CH2 via the output amplifiers 6A and 6B of FIG.

  Thereafter, the operations shown in FIGS. 2A to 2D are repeated. However, the pixel distribution horizontal transfer unit 11 switches the horizontal transfer directions in several stages shown in FIG. 2B alternately at a set timing cycle (for example, a line cycle, a field cycle, or a frame cycle).

  Therefore, when the set timing period elapses, when the signal charge vertically transferred by the vertical transfer CCDs 21A and 21B is input to the pixel distribution horizontal transfer unit 11, as shown by the arrow 25 in FIG. The signal charge is shifted (transferred horizontally) by a predetermined number of stages (to the CH2 side) in the direction (here, two stages are provided for convenience). As a result, a part of the signal charges from the pixels in the divided imaging area 1A, which are vertically transferred by the vertical transfer CCD 21B, move horizontally to the CH2 side from the center of the screen. Thereafter, the operations shown in FIGS. 2C and 2D are performed.

  Accordingly, when the horizontal transfer direction switching period by the pixel distribution horizontal transfer unit 11 is set to one field, for example, if the captured image is displayed on the monitor, the odd-number field has the left side of the screen as shown in FIG. In each of the area 30A and the screen center area 31, an image of CH1 based on the video signal imaged in the divided imaging area 1A of FIG. 1 is displayed, and in the right area 30B of the screen, the divided imaging area 1B of FIG. A CH2 image based on the captured video signal is displayed.

  In the even field, as shown in FIG. 3B, the CH1 image based on the video signal imaged in the divided imaging area 1A is displayed in the screen left area 30A, and the screen center area 31 and the screen right area are displayed. In each of 30B, an image of CH2 by a video signal imaged in the divided imaging area 1B is displayed. That is, in the screen center region 31, the CH1 image and the CH2 image are alternately switched and displayed for each field. Note that the horizontal size of the screen center region 31 is determined by the number of horizontal transfer stages performed by the pixel distribution horizontal transfer unit 11.

  As a result, the same subject image is photographed between the left and right in the adjacent areas of CH1 and CH2, and by comparing the images in the odd field and the even field, the horizontal transfer efficiency difference between CH1 and CH2 described above. The gain difference and the like can be corrected with high accuracy. Here, the CH1 and CH2 video signals output from the output amplifiers 6A and 6B shown in FIG. 1 are, for example, a known CDS circuit that performs correlated double sampling, and an automatic gain control circuit that controls the amplitude constant ( AGC circuit) and an A / D converter that performs analog-digital conversion are separately and sequentially supplied to a digital signal processor (DSP) that performs signal processing such as signal synthesis.

  Therefore, at the time of shipment from the factory, a predetermined still image pattern is picked up by the image pickup apparatus of the present embodiment as a subject, and the image signal of the screen center region 31 shown in FIGS. By comparing and detecting each time, an error between CHs is detected, and the gain of the AGC circuit is controlled or corrected by the DSP so that the error becomes zero, so that correction between CHs can be performed with high accuracy. And can be done automatically.

  Next, another embodiment of the present invention will be described. FIG. 4 shows a configuration diagram of another embodiment of an imaging apparatus according to the present invention. In the figure, the same components as those in FIG. 5B are denoted by the same reference numerals, and the description thereof is omitted. The embodiment shown in FIG. 4 is characterized in that a pixel distribution transfer unit (PSEL) 12 is provided between the vertical OB area 4 and the oblique shift regions 8A and 8B of the imaging apparatus shown in FIG. 5B. is there.

  The pixel distribution horizontal transfer unit 12 performs the same operation as the pixel distribution horizontal transfer unit 11 shown in FIG. Thereby, this embodiment can also perform the correction | amendment between CH with sufficient precision by performing the operation | movement similar to FIG.

  Note that the present invention is not limited to the above-described embodiment, and a PSEL having a structure that moves in the horizontal direction may have another configuration having the same purpose, and is widely applied to an imaging apparatus including a plurality of output units. Applicable.

It is a block diagram of one embodiment of the present invention. It is operation | movement explanatory drawing of FIG. It is monitor display explanatory drawing of an example of the to-be-photographed image imaged by this invention apparatus. It is a block diagram of other embodiment of this invention. It is a block diagram of each example of the conventional imaging device.

Explanation of symbols

1A, 1B Divided imaging area 2A, 2B Horizontal optical black level area 3, 4 Vertical optical black level area 5A, 5B, 9A, 9B Horizontal transfer path (horizontal transfer CCD)
6A, 6B Output amplifier 8A, 8B Diagonal shift area 11, 12 Pixel distribution horizontal transfer unit (PSEL)
21A, 21B Vertical transfer path (vertical transfer CCD)

Claims (1)

Each of a plurality of divided imaging areas obtained by dividing the imaging area into a plurality of horizontal directions generates a signal charge of a level corresponding to incident light, and a plurality of pixels arranged in a matrix, A vertical transfer path for transferring the signal charges of the pixels in the vertical direction, and separately transferring the signal charges transferred in the vertical direction by the respective vertical transfer paths of the plurality of divided imaging areas in the horizontal direction. In an imaging device having a plurality of channels of output units having a plurality of horizontal transfer paths for outputting as video signals,
The plurality of pixels in the plurality of divided imaging areas provided across the plurality of divided imaging areas between the vertical transfer path and the plurality of horizontal transfer paths provided for each of the plurality of divided imaging areas. Signal charges are vertically transferred through the vertical transfer path and simultaneously input, the signal charges transferred through the vertical transfer path are divided into signal charges of the pixels by a predetermined number of stages in the horizontal direction. And a pixel distribution horizontal transfer unit that can select the horizontal shift direction of the predetermined number of stages without shifting,
Control means for alternately switching the horizontal shift direction of the predetermined number of stages of the pixel distribution horizontal transfer section at a predetermined cycle, and the pixel distribution horizontal transfer section is selected by the control means An image pickup apparatus, comprising: horizontally shifting the predetermined number of stages in a predetermined direction, and simultaneously vertically transferring the signal charges of the held pixels to the plurality of horizontal transfer paths.

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