Abstract The present invention provides color conversion apparatus that prevents overflow in color reproduction, changes in hue, and the deterioration of gradation to improve image quality. The present color conversion apparatus inputs to itself luminance and color difference signals, sets a reference value not less than the maximum level of the luminance signal, converts the luminance and color difference signals into primary color signals, detects the maximum value of the primary color signals for each pixel, lowers the levels of the color difference signals if the maximum value is over the reference value to locate the amplitude of the primary color signals not greater than the reference value. Further, the present color conversion apparatus inputs to itself luminance and color difference signals, sets a reference value not greater than the minimum level of the luminance signal, converts the luminance and color difference signals into primary color signals, detects the minimum value of the primary color signals for each pixel, lowers the amplitudes of the color difference signals if the minimum value is under the reference value to locate the amplitude of the primary color signals not less than the reference value.
A color conversion apparatus comprising: a primary color conversion means that converts a video signal consisting of a luminance signal and two color difference signals into primary color signals, a maximum value detecting means that selects and outputs the maximum value of the outputs of said primary color conversion means for each pixel, a reference value setting means that sets an admissible maximum level of said primary color signals, a factor determining means that determines, depending on said luminance signal, a correction factor that restricts the output of said maximum value detecting means to a value not greater than the output of said reference value setting means, and a multiplying means that multiplies said two color difference signals by said correction factor, said color conversion apparatus outputting the outputs of said multiplying means as new color difference signals.
Claim 2
Dependent Claim
138 words
A color conversion apparatus comprising: a primary color conversion means that converts a video signal consisting of a luminance signal and two color difference signals into primary color signals, a maximum value detecting means that selects and outputs the maximum value of the outputs of said primary color conversion means for each pixel, a reference value setting means that sets an admissible maximum level of said primary color signals, a factor determining means that determines, depending on said luminance signal, a correction factor that restricts the output of said maximum value detecting means to a value not greater than the output of said reference value setting means, and a multiplying means that multiplies said two color difference signals by said correction factor, said color conversion apparatus outputting the outputs of said multiplying means as new color difference signals.