KR970073157A - IMPROVED IMAGE CODING SYSTEM HAVING FUNCTIONS FOR CONTROLLING GENERATED AMOUNT OF CODED BIT STREEM - Google Patents

Abstract

The present invention calculates the complexity of an image to be currently coded based on a quantization error value between a current frame input for coding and a previous frame reconstructed in an encoding system including MC-DCT and quantization, To a video encoding system having a bit generation amount adjustment function capable of adaptively adjusting a bit generation amount after encoding by selectively removing a high frequency component of an input video signal using a two-dimensional low-pass filter according to the present invention. According to an aspect of the present invention, a quantization error value is calculated for each frame based on a pixel value difference signal between a current frame and a reconstructed previous frame, and averaged quantization error values of the calculated frame are used to calculate an average quantization error value Quantization error calculation means for calculating a quantization error; The average quantization error value of a plurality of calculated frames is referred to as a complexity of a current frame to be encoded through sign and means, and a predetermined plurality of filters for adaptively limiting a frequency passband bandwidth of a current frame input for encoding Control means for generating a filter coefficient determination signal corresponding to the calculated average quantization error value among the coefficient determination signals; And a filter coefficient determination unit that determines whether or not the current frame to be input is provided as a current frame signal for motion estimation and compensation to the encoding means without filtering or on a filter coefficient determined according to the filter coefficient determination signal generated in the plurality of filter coefficients Dimensional low-pass filtering that selectively applies a two-dimensional low-pass filtering to an input current frame signal and restricts a passband thereof to provide a frame signal from which a high-frequency component has been removed as a current frame signal for motion estimation and compensation, The amount of bits generated after encoding can be effectively adjusted without increasing the step size excessively at the time of quantization in the encoding means.

Description

IMPROVED IMAGE CODING SYSTEM HAVING FUNCTIONS FOR CONTROLLING GENERATED AMOUNT OF CODED BIT STREEM

Since this is a trivial issue, I did not include the contents of the text.

FIG. 1 is a block diagram of an image encoding system having a bit generation amount control function according to a preferred embodiment of the present invention. FIG. 4 is a diagram illustrating an example of a two-dimensional filtering process at a (3,3) Degree.

Claims (5)

And an error signal between predictive frames obtained through motion estimation and compensation of a current macroblock unit using the present frame and a reconstructed previous frame, through encoding means including discrete cosine transform, quantization, and entropy encoding, And generating a coded bit stream, wherein the quantization is a bit size adjustment function in which a step size is adjusted based on full state information of the bit stream stored in an output side buffer, the system comprising: A quantization error calculation unit for calculating a quantization error value for each frame based on the pixel value difference signal between the reconstructed previous frames and averaging the quantization error values of the calculated frame to calculate an average quantization error value for a plurality of predetermined frames Way; The average quantization error value of the calculated plurality of frames is referred to as a complexity of a frame to be currently encoded through the sign and the means and is set to a predetermined value for adaptively limiting the frequency passband bandwidth of the current frame inputted for encoding Control means for generating a filter coefficient determination signal corresponding to the calculated average quantization error value among the plurality of filter coefficient determination signals; And providing the input current frame as a current frame signal for motion estimation and compensation to the encoding means without filtering based on the generated filter coefficient determination signal, A low frequency component is removed from the input current frame signal by selectively applying two-dimensional low-pass filtering to the input current frame signal based on the determined filter coefficient, thereby limiting a passband of the frame signal to a current frame signal for motion estimation and compensation, Dimensional low-pass filtering means for generating a low-pass filtered low-pass filtering signal. 2. The method of claim 1, wherein the predetermined filter coefficient determination signal includes an average quantization error value of each of the calculated frames, an average error value for a plurality of frames transmitted per second obtained by averaging the average quantization error value of each frame, And a standard deviation of the average error value. ≪ Desc / Clms Page number 24 > 3. The method of claim 1 or 2, wherein each of the plurality of predetermined filter coefficient determination signals includes four filter coefficient determination signals having different integer values for selective bandwidth limitation of each block of the current frame signal Wherein the image coding system has a bit generation amount adjustment function. 4. The image encoding system according to claim 3, wherein each of the filter coefficients has a degree of 3x3. The image encoding system of claim 1, wherein the two-dimensional low-pass filtering for the current frame is performed in 8x8 block units. ※ Note: It is disclosed by the contents of the first application.