Showing papers on "Inter frame published in 1980"

Motion-compensated interframe coding system

Abstract: An interframe coding system provided for highly efficient transmission of coded television picture signal is improved by compensating prediction error of predicted picture motion in response to interframe correlation detected by shifting moving blocks in a direction opposite to a motion vector detected for predicting interframe picture motion in order to reduce an amount of coded signals to be transmitted, and further improved regarding the detection of motion vector by examining interframe correlation referred to accumulated logarithms of absolute values of interframe differential picture element signals, and still further improved regarding the compensation of predicted picture motion by changing a coding threshold level in response to picture motion and further by effecting more exact secondary prediction of picture motion. According to these improvements, an extremely high efficiency of transmission of precisely and correctly coded interframe picture signal can be attained.

Interframe television coding using gain and displacement compensation

Abstract: This paper presents algorithms for predicting luminance changes in successive television frames. The changes can result when objects in a TV scene move or when illumination varies. By a gradient search technique, which seeks to minimize a functional of the interframe prediction error, we estimate two parameters associated with these luminance changes — displacement and gain. Using the estimates of these parameters, we also develop, for interframe coding, adaptive predictors and a segmentor to determine which pels need to be transmitted. We describe several coder variations and compare them by computer simulations using three substantially different scene sequences. For these sequences, gain compensation with improved segmentation reduced the bit rate of a conditional replenishment encoder by 50.7, 11.1, and 39.3 percent. Displacement compensation reduced the bit rate by 61.0, 24.8, and 14.5 percent. Combined gain and displacement compensation reduced the bit rate by 63.4, 32.2, and 44.6 percent.

Video interframe transform coding technique

Abstract: The efficiency with which a video signal is encoded is increased by examining successive blocks of M picture elements to determine which K pels have frame differences which do not exceed a predetermined threshold. The values of these K pels are intentionally altered, and the pels are applied to a transform circuit which generates N≦M corresponding coefficient values. Only N-K of the coefficient values, and a code indicating the unchanged pel locations are then encoded for transmission. The decoder (and the feedback loop of the encoder) is arranged to recover the original picture using only the frame differences for pels which have changed significantly.

Technique for encoding pictorial information

Abstract: Pictorial information is encoded using an interframe prediction technique which accounts for spatial and/or temporal changes in illumination. In one embodiment (FIG. 3), the intensity value of each element of a picture is predicted using the intensity of the corresponding element in a previous frame and a recursively updated gain factor ρ which can account for both illumination changes as well as object movement. The prediction error and pel location is encoded only if the error exceeds a predetermined threshold. In a second embodiment (FIG. 3), additional predictions are made using displacement compensated prediction alone and in combination with gain adjustment. The best predictor is selected and the corresponding prediction error transmitted only if it is large.

Demodulator for quadrature modulated and digitalised colour TV signal - has filter for removing residual colour carrier when picture moves

Abstract: The circuit for demodulating a quadrature modulated and digitalised colour television signal has an inter frame comb filter with a delay section (1) having a delay time of at least one image element. This is between an adding stage (2) for the luminance channel and a subtracting stage (3) for the chrominance channel. An intraframe comb filter has a delay device (5) with a delay time of at least one line. A detector gives a switching signal for inter frame and intraframe demodulation when the image moves. This has a subtracting stage (6) for an intraframe comb filter for the luminance channel, which separates the residual colour carrier when the image moves. A bandpass (8) filters out this residual colour carrier. An envelope curve modulator has a gate pulse generator (9) for converting this residual colour carrier from inter frame to intraframe demodulation.