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Shading compensation device, shading compensation value calculation device and imaging device

a compensation value and shading compensation technology, applied in the direction of picture signal generators, solid-state device signal generators, television systems, etc., can solve the problems of not being able to solve the problems, and the white balance is also affected, and achieve the effect of high accuracy

Inactive Publication Date: 2006-05-11
FUJIFILM HLDG CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides a shading compensation device, shading compensation value calculation device, and imaging device that can compensate for shading that differs for each color. The device includes a compensation table storage component that stores compensation values for each color, a relative position calculation component that calculates the relative position of a pixel in an image signal with respect to the compensation table, and a shading compensation value interpolation component that interpolates shading compensation values for the relative position of a pixel. The device can thus compensate for shading that differs for each color by calculating the shading compensation values based on the relative position of the pixel and the compensation values in the compensation table. The device can be used in imaging devices such as cameras and monitors to improve image quality.

Problems solved by technology

Hence, when shading amounts for respective colors are different, a problem arises in that colors differ between locations of a screen, and white balance is also affected.
However, consideration has not been extended to differences in shading amounts for respective colors in any of the technologies recited in JP-A No. 5-83622, JP-A No. 6-273171 and JP-A No. 6-319042, and it has not been possible to solve the problems described above.

Method used

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  • Shading compensation device, shading compensation value calculation device and imaging device
  • Shading compensation device, shading compensation value calculation device and imaging device
  • Shading compensation device, shading compensation value calculation device and imaging device

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first embodiment

[0051]FIG. 1 is a block diagram showing structure of an imaging device relating to a first embodiment of the present invention. The imaging device is provided with a CCD image sensor 11, an analog front end / timing generator (AFE / TG) 12, a processing system 20 and an SDRAM 30. The CCD image sensor 11 takes images of a subject. The AFE / TG 12 performs predetermined analog signal processing on image signals which have been generated by the CCD image sensor 11 and generates synchronous signals, the processing system 20 performs predetermined digital signal processing, and the SDRAM 30 stores image data.

[0052] The CCD image sensor 11 generates image signals constituted of three primary colors in accordance with imaged light from the subject, and feeds these image signals to the AFE / TG 12. The AFE / TG 12 applies correlated double sampling processing and analog / digital conversion to the image signals supplied from the CCD image sensor 11. The AFE / TG 12 also generates vertically synchronized...

second embodiment

[0077] Next, a second embodiment of the present invention will be described. Here, portions that are the same as in the first embodiment are assigned the same reference numerals, and detailed descriptions thereof are omitted.

[0078]FIG. 8 is a block diagram showing structure of an imaging device relating to the second embodiment. The imaging device relating to the second embodiments calculates red and blue shading compensation values, and is provided with a processing system 20A with a structure which differs from the first embodiment.

[0079] In addition to the various structures of the processing system 20 shown in FIG. 1, the processing system 20A is further provided with an auto white balance (AWB) adjustment section 25 and a memory control section 26. The AWB adjustment section 25 both implements automatic white balance adjustment and calculates shading compensation values. The memory control section 26 writes image data to the SDRAM 30 after the white balance adjustment.

[0080]...

third embodiment

[0093] Next, a third embodiment of the present invention will be described. Here, portions that are the same as in the second embodiment are assigned the same reference numerals, and detailed descriptions thereof are omitted.

[0094] The imaging device relating to the third embodiment calculates, as well as shading compensation values for R and B, shading compensation values for G Here, the imaging device relating to the present embodiment has a similar structure to the second embodiment, but a portion of the shading compensation value generation routine of the AWB adjustment section 25 is different.

[0095] Specifically, after performing the processing from step S1 to step S4 shown in FIG. 9, the AWB adjustment section 25 may perform the following calculations, so as to find shading compensation values RHji, GHji and BHji.

RHji=Gcenter / Rji

GHji=Gcenter / Gji

BHji=Gcenter / B′ji

[0096]FIG. 14 is a diagram showing levels of R, G and B data after white balance adjustment. Although not to th...

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PUM

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Abstract

A shading compensation device which compensates for shading which differs for respective colors. A pixel counter counts co-ordinate positions of image data which is supplied from a black level correction section. A relative position calculation section compares the image data with compensation value tables and calculates relative co-ordinate positions of pixels which are objects of processing. A compensation value interpolation section refers to the compensation value tables, which are stored for the respective colors in a compensation value table memory, and interpolates shading compensation values for the relative co-ordinate positions calculated by the relative position calculation section. A multiplier multiplies the image data which is the objects of processing with the new shading compensation values obtained by the interpolation processing. Thus, shading-compensated image data is generated.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims priority under 35 USC 119 from Japanese Patent Application No. 2004-323820, the disclosure of which is incorporated by reference herein. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a shading compensation device, a shading compensation value calculation device and an imaging device, and relates to, for example, an excellent shading compensation device, shading compensation value calculation device and imaging device which are employed at a time of compensating for shading of an image signal which is outputted from a high-pixel count image capture device. [0004] 2. Description of the Related Art [0005] In an image generated by a CCD image sensor, because of effects such as variations in transparency of a lens and the like, a so-called shading effect occurs, in which a central portion of the image is brighter than a peripheral portion. Accordingly, various tech...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): H04N1/40
CPCH04N1/401H04N5/3572H04N9/045H04N9/646H04N25/61H04N23/843
Inventor FUNAMOTO, KENJI
Owner FUJIFILM HLDG CORP