JP2005159621A - Color camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure of a low-cost, high-resolution color camera having a standard format output such as VGA, etc. <P>SOLUTION: The camera comprises an imaging device (imaging means 1) having more than a required number of pixels for its output format, forming 4 pixels of 2 rows × 2 columns: the pixel in the first row and the first column having an R-color filter, the pixel in the first row and the second column having a G-color filter, the pixel in the second row and the first column having the G-color filter, and the pixel in the second row and the second column having the B-color filter. This generates a set of RGB data in an output format of the VGA size. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a color camera used in an image processing apparatus or the like for determining good or defective products, and particularly relates to an RGB output device.

  In general, there are two structures of an imaging portion of a color camera having RGB output, a single plate type and a three plate type (for example, Patent Document 1). As shown in FIG. 5 (A), the single-plate type is such that each color filter of RGB is formed on each pixel of one image sensor, and only an R component of incident light is formed in a pixel on which an R filter is formed. In the pixel in which the G filter is formed, only the G component of the incident light is detected, and in the pixel in which the B filter is formed, only the B component of the light is detected. In the example shown in FIG. 5A, one pixel in which an R filter is formed, two pixels in which a G filter is formed, and one pixel in which a B filter is formed are configured as one set. The configuration is arranged in a matrix. In this type of image sensor, when pixel data of the G component or B component is necessary for the pixel in which the R filter is formed, it is created by complementing the data of the pixels arranged around the pixel. It was.

  On the other hand, as shown in FIG. 5 (B), the three-plate type includes an image pickup element in which an R color filter is formed on the surface, an image pickup element in which a G color filter is formed on the surface, and a B color filter on the surface. This is a method in which incident light is divided into three directions using three image sensors and three prisms of the formed image sensor and is made incident on each image sensor, and RGB components of light are detected by each image sensor.

  In the single-plate color camera shown in FIG. 5A, the number of pixels that can detect the R component or the B component is 1/4 of the total number of pixels of the image sensor, and the number of pixels that can detect the G component is the number of pixels that can be detected. Since it is 1/2 of the total number of pixels of the element, the resolution as a color image is 1/8 (= 1/2 · 1/4) of the total number of pixels.

In contrast, in a three-plate color camera, each image sensor detects only the component corresponding to the color filter provided on the surface, so the total number of pixels of the image sensor becomes the resolution as it is. However, the three-plate type color camera is more expensive than the single-plate type color camera because it requires an extra prism and two extra image sensors. The price of image sensors has been reduced due to rapid progress in semiconductor processes. However, it has been difficult to reduce the price of color cameras because the price of prisms is not as low as that of image sensors. In response to this situation, recently, with the advancement of semiconductor processes, inexpensive cameras using high-pixel image sensors (high-pixel cameras) have become widespread, and the resolution has been improved using these high-pixel image sensors. Many methods are adopted. However, high pixel cameras are not configured to output standard format image data such as conventional VGA, and the format is changed by changing the camera interface on the image processing device side according to the high pixel camera used. There was a need to do.
JP-A-8-114705

  The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a structure of a low-cost and high-resolution color camera having an output of a standard format such as VGA. is there.

  Accordingly, the color camera according to claim 1 includes an image pickup device having pixels equal to or more than the number of pixels necessary for the output format of the color camera, and pixels having R color filters in 4 pixels of 2 rows × 2 columns. And a pixel having a G color filter and a pixel having a B color filter are provided, and a set of RGB data in an output format is generated with the four pixels.

  The color camera according to claim 2 is the color camera according to claim 1, wherein the pixel in the first row and the first column is constituted by a pixel having an R color filter, and the first row and the second column. The pixel is composed of a pixel having a G color filter, the pixel in the second row and the first column is composed of a pixel having a G color filter, and the pixel in the first row and the second column is composed of a B color filter. 4 pixels of 2 rows × 2 columns are formed, and an image output in an output format of VGA size is performed.

  According to the present invention, a high-resolution color camera that outputs RGB data in a standard output format such as a VGA size is configured at a low price by using a high-pixel camera having more pixels than the number required for the output format. be able to. In addition, this makes it possible to achieve high resolution by exchanging only the camera for the already installed image processing apparatus.

  A color camera according to the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing a schematic structure of a color camera.

  In FIG. 1, reference numeral 1 denotes an image pickup means having a single-plate CMOS image pickup device having RGB color filters, and digital output so that digital pixel data as an image of an RGB color filter array is output. A circuit is provided. A and B are buffer memories each having a storage area of 1280 pixels × 2 lines, 2 is a memory write control circuit for storing pixel data output by the imaging means 1 in either of the buffer memories A and B, 3 Reads out the pixel data stored in the buffer memories A and B, and converts them into an output in a standard RGB format such as VGA. 4 is an output destination of the memory write control circuit 2 The switch circuit switches to the buffer memory A or the buffer memory B, and switches the image data read source read by the memory read control / RGB format circuit to the buffer memory A or the buffer memory B.

  FIG. 2A is a schematic diagram showing the arrangement of each pixel of the image pickup device provided in the image pickup means 1 of the present invention. The image pickup device includes an R color filter in four pixels of 2 rows × 2 columns. A pixel having a G color filter, and a pixel having a B color filter. Specifically, the first pixel in the first line (pixel in the first row and first column) is a pixel having an R color filter, and the second pixel in the first line (pixel in the first row and second column) ) Is a pixel having a G color filter, a second pixel in the second line (pixel in the second row and first column) is a pixel having a G color filter, and a second pixel in the first line (second row) The pixels in the second column) are composed of pixels having a B color filter, and one set of RGB data (one pixel data in the output format) is composed of these pixels, and a 640 × 480 VGA format When the output is performed, the set of the arrangement is arranged in a matrix of 640 horizontal rows × 480 vertical columns. Therefore, in the case of the VGA format, the imaging device of the imaging unit 1 is configured with 960 lines (480 × 2) in which 1280 pixels (640 × 2) are one line.

  FIG. 2B shows an arrangement of each pixel of a 640 × 480 VGA size image sensor. The image sensor of the present invention shown in FIG. 2A has double the number of pixels both vertically and horizontally compared to the VGA size image sensor shown in FIG. Further, the image pickup device of the present invention has all the RGB color filters in the region of one pixel of the image pickup device shown in FIG. 2B, and the resolution is doubled both vertically and horizontally. In this embodiment, the operation clock of the image pickup device of the image pickup means 1 of the present invention shown in FIG. 2A is operated at four times the clock of the image pickup device shown in FIG. That is, the output time of image data for one screen is the same for both.

  Next, the operation of the color camera of the present invention will be described based on the flowchart of FIG. First, the switch circuit 4 is switched to switch the output destination of the memory write control circuit 2 to the buffer memory A ((1) in FIG. 4). That is, the terminal SA connected to the buffer memory A is connected to the terminal SW connected to the output of the memory write control circuit 2. In this case, the terminal SB connected to the buffer memory B is configured to be connected to the terminal SR connected to the input of the memory read control / RGB format circuit 3. As a result, the pixel data output from the imaging unit 1 is written into the buffer memory A by the memory write control circuit 2 for two lines (the nth line and the (n + 1) th line). FIG. 3 is a schematic diagram showing the arrangement of the pixel data stored in the buffer memory A, in which pixel data for 1280 × 2 lines is stored.

  Thereafter, the switch circuit 4 is switched to switch the output destination of the memory write control circuit 2 to the buffer memory B. That is, the terminal SB connected to the buffer memory B is connected to the terminal SW connected to the output of the memory write control circuit 2. In this case, the terminal SA connected to the buffer memory A is connected to a terminal SR connected to the input of the memory read control / RGB format circuit 3. In this state, the pixel data for the next two lines ((n + 2) line, (n + 3) line) are written into the buffer memory B in the same manner as in the buffer memory A and the pixels stored in the buffer memory A Data is read by the memory read control / RGB format circuit 3.

  First, the first pixel (R) in the n-th line, the second pixel (G) in the n-th line, the first pixel (G) in the (n + 1) -th line, and the second pixel in the (n + 1) -th line are read out first. Four pixels of the pixel (B). ((2) in Fig. 4). Next, the memory read control / RGB format circuit 3 outputs R and B pixels of the read pixel data as they are as outputs Rout and Bout of the memory read control / RGB format circuit 3. The two pixels of G are configured to obtain an average of the two pixels and output the value as Gout ((3) in FIG. 4). As a result, a set of RGB data is output. Thereafter, the same operation is repeated up to the 1280th pixel of the nth line and the (n + 1) th line, and the process for one line is completed ((4) in FIG. 4).

  When the readout to the 1280th pixel of the nth line and the (n + 1) th line is completed, the switch circuit 4 is switched, and the output data of the imaging means 1 is transferred to the buffer memory A by the memory readout control circuit 2 for two lines. ((N + 4) line, (n + 5) line data) is written, and at the same time, the memory read control / RGB format circuit 3 stores the contents of the buffer memory B ((n + 2) line, (n + 3) line data) And outputs Rut, Bout, and Gout by the method described above. The above operation is repeated to output one screen.

  At this time, the outputs Rout, Bout, and Gout are performed in synchronization with an operation clock of a normal VGA format, and writing to the buffer memories A and B is performed by inputting four times the operation clock of the VGA format. The pixel data of the image pickup device A) is converted into high-resolution VGA format data.

1 is a block diagram illustrating a schematic configuration of a color camera according to an embodiment of the present invention. (A) is a schematic diagram showing the arrangement of each pixel of the imaging device provided in the imaging means 1 of the present invention, and (B) is a schematic diagram showing the arrangement of each pixel of the 640 × 480 VGA size imaging device. FIG. 3 is a schematic diagram showing an array of pixel data stored in a buffer memory A. FIG. It is a flowchart which shows operation | movement of the color camera of this invention. It is a structural diagram which shows the structure of the image pick-up element of the conventional color camera.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image pickup means 2 Memory write control circuit 3 Memory read control / RGB format circuit 4 Switch circuit A, B Buffer memory

Claims (2)

  An imaging device having pixels equal to or more than the number of pixels necessary for the output format of the color camera, and a pixel having an R color filter and a pixel having a G color filter in 4 pixels of 2 rows × 2 columns, And a pixel having a B color filter, and a set of RGB data in an output format is generated with the four pixels.   The pixel in the first row and the first column is constituted by a pixel having an R color filter, the pixel in the first row and the second column is constituted by a pixel having a G color filter, and the second row and the first column The pixel of the eye is composed of a pixel having a G color filter, the pixel of the first row and the second column is composed of a pixel having a B color filter, and 4 pixels of 2 rows × 2 columns are composed. 2. A color camera according to claim 1, wherein the image is output in an output format of VGA size.

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