Regularized dequantization for DCT-based transform coding

We present a new dequantization technique for discrete cosine transform (DCT) based encoding. For the lack of better dequantization methods, the currently existing image compression standards states simply to multiply the received quantized DCT coefficients by the quantization matrix. Therefore, for each DCT coefficient, the quantization noise as large as half quantizer step size may be introduced (in the DCT domain). Our proposed technique, through regularization, dequantizes the quantized DCT coefficients so that the resulting decoded image will be visually more pleasing. Through simulation studies, we show improvements in the visual characteristics and also in terms of the peak-signal-to-noise-ratio (PSNR).