Prefilter Control Scheme for Low bitrate TV Distribution

Abstract

In IP-based TV distribution, coding degradation is sometimes evident in critical scenes because the bit rate for compression is rather low. Prefiltering is an effective countermeasure since it replaces the coding noise with the degradation more difficult to detect visually, though it has the drawback that excessive smoothing might occur. This paper proposes a scene-adaptive method to control a prefilter separate from the encoder. By calculating block-wise motion-compensated predictive error variances and correlation coefficients, it estimates the coding noise as well as the potential improvement by prefiltering each frame, realizing a control scheme which performs prefiltering only when effective.

Application of Fast Non-Local Means Algorithm for Noise Reduction Using Separable Color Channels in Light Microscopy Images

“…Moreover, in the biomedical field where cells and tissues with complex structures and functions are analyzed, the presence of noise is fatal [ 33 , 34 ]. Although various conventional algorithms have been developed to reduce and solve noise problems, these processes have deteriorated the sharpness and resolution of LM images [ 35 , 36 , 37 ].…”

New adaptive filters as perceptual preprocessing for rate-quality performance optimization of video coding

“…Even when the video sequences are not altered by the presence of noise, which is a common situation in video professional applications, adaptive low-pass filters are still useful to help the encoding stage at low bitrates by reducing the high-frequency content before the quantization stage [22] [23]. However, the adaptive filters suffer from smoothing effect which is annoying for high quality applications.…”

A Spatial Regularization Approach for Vector Quantization

“…However, one drawback is the lack of spatial regularity of the quantized image. Spatially smooth properties may be useful in low-rate compression when using advanced coding algorithms (e.g based on run length, differential or multiresolution techniques), especially in the context of medical and low bit-rate video compression applications like compression of confocal laser scanning microscopy image sequences [7] or mobile television [8]. It may also be of interest for quantizing images featuring noise.…”