Device and method for calculating a brightness signal
AssigneeHyundai Electronics Industries Co., Ltd.
InventorOh Bong Kwon
Life of this patent
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Abstract
The present invention relates to a digital image processing system, for example, video cameras, digital cameras, cathode ray tubes (CRT) etc. With reference to the calculation of the brightness signal, the main idea of the present invention is to carry out the calculations of it by using only the additions, the subtractions and the shifts, which require relatively short operation times, without the multiplications and divisions by substituting only the shift operations of the digits for them. Also, according to the present invention, high resolution is accomplished by a high speed process in calculating the brightness of an image signal. Also, it enables high speed digital image processing.
Claims11
A device for calculating a brightness signal comprising;
- a first storing means for storing the value of blue, red and green signals respectively, wherein the three signals are separated from a picture signal;
- a first adder for adding the value of the blue signal to the value of the red signal applied from said first storing means respectively;
- a first subtracter for subtracting the value of the green signal from the value of the red signal applied from said first storing means respectively;
- a first shifting means for doubling the output value of said first subtracting means;
- a delaying means for delaying the output of said first adder;
- a second adder for adding the output of said delaying means to the output of said first shifting means;
- a second shifting means for making the output of said second adder one eighth;
- a second storing means for storing the latest brightness signal;
- a third shifting means for making the output of said second storing means one fourth;
- a second subtracter for subtracting the output of said third shifting means from the output of said second shifting mean;
- and
- a third adder for adding the output of said second subtracter to the value of the green signal applied from said first storing means, wherein the third adder outputs the brightness and updates the content of said second storing means.
A method of calculating a brightness signal comprising:
- a first step of separating a color image signal into blue, red, and green signals, and of storing their values respectively;
- a second step of adding the value of the blue signal to the value of the red signal, and of subtracting the value of the green signal from the value of the red signal;
- a third step of doubling the subtracted value by using shift of the bits, and of delaying the added value for the shifting time of said subtracted value;
- a fourth step of adding the shifted value to the delayed value;
- a fifth step of making the result of the fourth step one eighth by using shift of the bits, and of making a latest brightness signal one fourth by using shift of the bits;
- a sixth step of subtracting one fourth of said latest brightness signal from one eighth of said result of said fourth step;
- and
- a seventh step of adding the result of said sixth step to the value of the green signal stored in the first step, and of outputting its result, wherein its result updates said latest brightness signal.
Dependencies are inferred from the claim text.