Abstract: In an image enhancement method and circuit, a luminance signal is extracted from input color signals. Histogram equalization is performed using a cumulative density function of the extracted luminance signal which is input in a screen unit. A transform function is controlled to map a mean level of the extracted luminance signal to itself, so that an adjusted luminance signal is output. The color signals are varied according to the variation of the luminance signals to output compensated color signals. Thus, image contrast is enhanced, and an undistorted color signal is provided at the same time. In order to reduce the hardware of the circuit, an interpolated cumulative density function is obtained by interpolating a quantized cumulative density function of an input luminance image and is used as a transform function. The transform function is controlled to map a mean level of the input luminance image to itself.

Abstract: A data compression system 200, method, and apparatus 214 employs an encoder 210 optimized to decorrelate and make independent from the original signal 202, the quantization noise produced during signal compression. The proposed system 200, method, and apparatus 214 supports high degrees of signal compression, which in turn leads to lower computational complexity and improved performance. Because the quantization noise produced during signal compression is made independent from and non-orthogonal (i.e., uncorrelated) to the original signal 202, enhanced filtering is achievable, which in turn leads to improvements in the signal-to-noise ratio (SNR) of the decoder 220.