| 摘要 |
PURPOSE: A low illumination contrast compensation device of CCD(Charge Coupled Device) is provided to control contrast and brightness of image easily only with control of a selection signal without relation to change of environment by automatically compensating for contrast of image data taken according to each selection signal in low illumination. CONSTITUTION: A lens(10) controls photo quantity and focus of an image taken by controlling an iris. A CCD unit(20) transforms the photo signal imaged through the lens(10) into an electric signal. A sampling and A/D(analog/digital) converting unit(30) removes a noise component of the image data transformed in the CCD unit(20) and converts it into a digital signal after sampling. An image signal processing unit(40) processes the output signal of the sampling and A/D converting unit(30) to an appointed level. A low illumination contrast compensation unit(50) compares brightness data with a critical value of an established brightness level and adjusts a gain value to compensate for according to the comparison result, and determines compensation for contrast of the image data output from the image signal processing unit(40) in low illumination according to each selection signal. An automatic exposure control unit(80) controls each unit(10-50) and receives in feedback the compensated brightness data of the low illumination contrast compensation unit(50) and outputs a compensated control signal to each unit(10-50). A video encoder(60) transforms the compensated image data of the low illumination contrast compensation unit(50) into an image format matching type of a display unit(70).
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