KR970073133A - IMPROVED IMAGE CODING SYSTEM HAVING FUNCTIONS FOR CONTROLLING GENERATED AMOUNT OF CODED BIT STREEM - Google Patents

Abstract

The present invention relates to a method and an apparatus for coding and decoding a motion vector of a current frame based on a temporal complexity between a previous image and an input image predicted based on a motion compensation error value in an encoding system including an MC-DCT quantization, A complexity of an image to be encoded is calculated and a high frequency component of an input image signal is selectively removed using a two-dimensional discrete Fourier transform according to a result of the calculation, thereby adjusting a bit generation amount The present invention proposes a method for calculating a spatial complexity value for each of the previous frames reconstructed for motion estimation compensation and then averaging the spatial complexity values of each of the calculated previous frames, Calculate the average spatial complexity value for a frame A motion compensation error value is calculated by adding each pixel value to each error signal in a block unit for each mat, and a motion compensation error value of each calculated macroblock is averaged to calculate a motion average A spatial complexity calculation means for calculating an error value and calculating a final complexity value based on the calculated average spatial complexity value and the motion average error value; And the calculated final complexity value is referred to as a complexity of a current frame to be encoded through a coding means having DCT, quantization, and entropy coding, and the predetermined complexity value is set in advance for adaptively limiting a frequency passband bandwidth of a current frame input for encoding Control means for generating a bandwidth determination signal corresponding to the calculated final complexity value among the plurality of bandwidth determination signals; And transforming the video signal in the spatial domain for the input current frame signal into two-dimensional DCT transform coefficients in the frequency domain of the M × N block unit using the two-dimensional discrete Fourier transform, Dimensional DFT transform coefficient blocks based on the transformed 2D DFT transform coefficient block, limits the high-frequency passband of each transformed 2D DFT transform coefficient block to a determined bandwidth, and quantizes each quantized DFT block And a frequency selection unit for performing inverse discrete Fourier transform on each of the input signals and restoring the original signal before coding and providing the restored bandwidth limited frame signal as a current frame signal for motion estimation and compensation to the coding unit, The amount of bits generated after encoding without increasing the step size excessively during quantization in the means As it can be adjusted.

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.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an image encoding system having a bit generation amount adjustment function according to a preferred embodiment of the present invention; FIG.

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, Wherein the step size is adjusted based on the fullness state information of the bitstream stored in an output side buffer, the system comprising: Calculates a spatial complexity value for each of the previous frames reconstructed for the previous frame, and then averages the joint complexity values of the previous frames calculated for each of the previous frames to calculate a homogeneous space complexity value for a predetermined plurality of previous frames, For each macroblock unit Calculating a motion compensation error value by adding each pixel value, and then calculating a motion average error value for a predetermined plurality of previous frames by averaging motion compensation error values of the respective calculated macroblocks, A spatial complexity calculation means for calculating a final complexity value based on a value and a motion average error value; The final complexity value is referred to as a complexity of a current frame to be encoded through the encoding means, and a predetermined plurality of bandwidth determination signals for adaptively limiting a frequency passband bandwidth of the current frame, Control means for generating a bandwidth determination signal corresponding to the calculated final complexity value; And transforming the video signal in the spatial domain of the input current frame signal into two-dimensional DCT transform coefficients in the frequency domain of M × N block units using two-dimensional discrete Fourier transform, Determining a high-frequency passband for the transformed two-dimensional DCT transform coefficient blocks based on a bandwidth determination signal, restricting a high-frequency passband of each transformed two-dimensional DFT transform coefficient block to the determined bandwidth, And restoring the restored original signal to the original frame signal by performing an inverse discrete Fourier transform on each of the limited quantized DFT blocks and outputting the restored original frame signal as a current frame signal for motion estimation and compensation, And a frequency selection means for selecting a frequency with which a bit is to be generated The coding system. The method of claim 1, wherein the predetermined bandwidth determination signal includes a first average value of a plurality of frames transmitted per second obtained by averaging an average spatial complexity value of each frame, A first standard deviation of the first average error value, a motion average error value of each of the calculated frames, and a motion average error value of each frame obtained by averaging the error value, the first standard deviation of the first average error value, An average error value, and a second standard deviation of the second average error value. The method of claim 1 or 2, wherein the predetermined plurality of bandwidth determination signals include four bandwidth determination signals having different integer values for selective bandwidth limitation of each of the two-dimensional DFT conversion coefficient blocks Wherein the bit rate control function is a feature of the image encoding system. 2. The apparatus as claimed in claim 1, wherein the frequency selecting unit converts the video signal of the spatial domain of the current frame signal into two-dimensional DFT transform coefficients of 8x8 block units. Encoding system. The apparatus as claimed in claim 1 or 4, wherein the frequency selecting means maps the high frequency components below the generated bandwidth determining signal to each of the converted two-dimensional DFT transform coefficient blocks to a zero value Wherein the bit rate control function is a feature of the image encoding system. ※ Note: It is disclosed by the contents of the first application.