Sony RDR-GX7 Technical Notes - Page 26

RDR-GX7 Technical Notes Chapter 4-4 High quality image & sound s Motion Adaptive Block Noise Reduction Block Noise Reduction is used to effectively reduce both noise and block noise, which are characteristics of MPEG processing. The RDR-GX7 is equipped with a Block Noise Reduction circuit, which detects higher harmonic block noise and works effectively in both horizontal and vertical directions in order to minimize the appearance of block noise borders. It operates in tandem with the Field Noise Reduction circuitry (explained later), in a motion adaptive manner to minimize detection errors, while automatically applying block noise reduction to video images in which block noise is easily generated. The Theory of Motion Adaptive Block Noise Compensation Block diagram Video input Video output Block noise detection Compensator output MC residual movement vector Detecting the degree of encoding difficulty Operation theory Block noise Compensation Amplitude Block border Block border Before compensation After compensation s Motion Adaptive Field Noise Reduction The most noticeable drawback of MPEG playback is video background noise. Conventional digital noise reduction (DNR) has the negative effects of residual images and loss of detail, so it is not a thoroughly effective approach. The RDR-GX7, however, employs Motion Adaptive Field Noise Reduction which precisely detects movement and extracts the noise through Hadamard transform, to achieve a highly efficient reduction of noise components. In addition, there are virtually no adverse effects to either movement or detail, making this a much more thorough and effective approach to noise reduction than conventional methods. The Theory of Motion Adaptive Field Noise Reduction Block diagram Video input Inverse Hadamard transform Limiter Hadamard transform Motion compensation Noise detection Operation theory Field one Field two Noise Video output Field memory Output Movement compensation Subtraction, Hadamard limiter processing Subtraction Blocks are analyzed and movement vectors are calculated Region of blocks with movement is zero vector blocks only are moved, and subtraction processing is performed. Representational Diagram of Motion Detection by Block Matching Vertical search area Horizontal search area Compensation pixels 4 pixels 16 pixels (-8 , -4) Search area -1 to -4 -1 to -8 (0 , 0) (+7, +3) +1 to +7 +1 to +3 26