Abstract: A brightness control apparatus comprising a probability density function (PDF) calculator to calculate a PDF based on pixel values of respective pixels of an input image signal, a first setter to set an upper limit value and a lower limit value with respect to the pixel values that are equal to or smaller than a predetermined level in the PDF, and a brightness value controller to calculate a cumulative distribution function for the PDF controlled by the upper and lower limit values set by the first setter, and calculating brightness levels corresponding to the input image signal based on the calculated cumulative distribution function. The brightness control apparatus controls the brightness of an image signal so as to prevent it from becoming unnecessarily bright or dark when compensating the brightness of an image signal, while also preventing degradation of contrast.

Abstract: A saturation-adaptive image enhancement apparatus and method enhances image quality by calculating a saturation level pixel by pixel of an input image and adjusts the saturation of the pixels according to the calculated saturation level.

Abstract: An image enhancing apparatus and method in which a PDF calculation unit calculates a probability density function according to a distribution of a luminance value with respect to each pixel of an input image. An average brightness calculation unit calculates average brightness of the input image based on the probability density function and an overflow threshold adaptive to the average brightness is calculated. A BUBO unit calculates a probability density function of which a distribution is adjusted, based on the overflow threshold and a predetermined underflow threshold and a cumulative distribution function is calculated with respect to the adjusted probability density function. A CDF compensating unit compensates for an influence that the BUBO unit has on the cumulative distribution function and a mapping unit uses the compensated cumulative distribution function as a mapping function, and adjusts and outputs the luminance value with respect to each pixel of the input image.

Abstract: A brightness control apparatus comprising a probability density function (PDF) calculator to calculate a PDF based on pixel values of respective pixels of an input image signal, a first setter to set an upper limit value and a lower limit value with respect to the pixel values that are equal to or smaller than a predetermined level in the PDF, and a brightness value controller to calculate a cumulative distribution function for the PDF controlled by the upper and lower limit values set by the first setter, and calculating brightness levels corresponding to the input image signal based on the calculated cumulative distribution function. The brightness control apparatus controls the brightness of an image signal so as to prevent it from becoming unnecessarily bright or dark when compensating the brightness of an image signal, while also preventing degradation of contrast.

Abstract: Disclosed is a brightness control apparatus and method capable of adaptively compensating brightness values based on an average brightness of an image signal. The adaptive brightness control apparatus comprises a probability density function (PDF) calculation unit calculating a PDF based on a distribution of pixel values of pixels of an input image signal, a compensation value calculation unit for calculating an average value of the pixel values of the respective pixels, and calculating a function having a predetermined slope according to a range of the average brightness value, and a pixel value compensation unit for re-establishing the distribution of the pixel values based on the calculated function.

Abstract: A contrast compensation apparatus and a method thereof utilize a simplified hardware structure and a low contrast distortion. The contrast compensation apparatus includes a pixel value detection unit to detect a distribution of pixel values of respective pixels of an input image signal, a pixel value limit unit having pre-set luminance limit values and re-configuring the distribution of the pixel values of the respective pixels based on the pre-set luminance limit values, and a mapping unit to set luminance for the respective pixels based on a cumulative distribution function with respect to the re-configured pixel values. When certain portions of an image are rendered very bright or dark, the phenomenon in which the entire image becomes abruptly bright or dark is reduced. Further, the contrast compensation apparatus uses the minimum number of multipliers, adders, and subtractors only, thus having an advantage of simplified structure and using less electric power.

Abstract: A quantization error compensation includes a dividing unit to divide an input current image signal into a first high-frequency signal and a low-frequency signal; a changing unit to replace bits of the first high-frequency signal with a predetermined signal to output a second high-frequency signal; an adding unit to add the low-frequency signal and the second high-frequency signal to create a composite signal; a quantization unit to cut n number of bits of the composite signal and to output the cut composite signal and the n number of bit signal; an equalizing unit to output a brightness equalizing value of the cut composite signal; a calculating unit to calculate a compensation value using the n number of the bit signal and a difference between brightness equalizing values with respect to a current and next brightness levels; and a compensation unit to add the compensation and the current brightness equalizing values.

Abstract: An apparatus for color compensation includes a chroma deflection generation unit to calculate a chroma deflection based on an input chroma signal and a predetermined first reference value, a hue deflection generation unit to calculate a hue deflection based on an input hue signal and a predetermined second reference value, a chroma deflection function generation unit to calculate a luminance deflection based on an input luminance signal and a predetermined third value, and a tone mapping function generation unit to output the chroma signal, hue signal and luminance signal after individually compensating these signals based on the chroma deflection, hue deflection and luminance deflection. According to the present invention, when color is distorted due to transmission flaws, the color can be compensated to be an appropriate color.

Abstract: An apparatus and method to enhance a contrast includes a first operation part, a second operation part, and a mapping part. The first operation part calculates an average and a standard deviation of an input image. The second operation part calculates an average and a standard deviation of a target image based on the average and the standard deviation of the input image. The mapping part converts a pixel value of the input image by a mapping function generated by receiving the averages and the standard deviations of the input image and the target image from the first operation part and the second operation part, respectively, and outputs a pixel value of an output image.