Patent ID: 8014049

Claim:
A method for automatic color correction, using an analog-to-digital converter (ADC) to receive an analog image signal, adjusting an offset and/or gain of the ADC, so as to correct the color of the analog image signal and output a digital image signal, the method for automatic color correction comprising: receiving a test image signal, wherein the test image signal comprises a pixel with a first color level; initializing a first gray-level range and the offset of the ADC, wherein the first gray-level range starts from a gray-level value corresponding to the first color level; dividing the first gray-level range into a plurality of subsections of a first section by a plurality of section adders, at least including a first subsection of the first section and a second subsection of the first section, wherein the range of the first subsection of the first section starts from the gray-level value corresponding to the blackest level, each subsection of the first section has a gray-level amount, and the gray-level amount is the number of pixels having gray-level values falling within the subsection of the first section; measuring the test image signal through the ADC, so as to obtain the gray-level amount for each of the subsections of the first section; reducing the first gray-level range according to the distribution of the gray-level amounts for the subsections of the first section, so as to reduce the range of each of the subsections of the first section, the total range of the subsections of the first section received by the section adders being reduced; determining whether the gray-level amount for the first subsection of the first section reaches a first threshold value or not and adjusting the offset of the ADC only according to the gray-level amount for the first subsection of the first section after reducing the first gray-level range; and when the gray-level amount for the first subsection of the first section has not reached the first threshold value, adjusting the offset of the ADC and measuring the test image signal through the adjusted ADC, and repeating the adjusting and measuring steps until the gray-level amount for the first subsection of the first section reaches the first threshold value.