JPH02298184A - Adaptive frame interpolation system for inter-frame prediction decoder with movement compensation - Google Patents

Abstract

PURPOSE:To prevent deterioration in picture quality caused in the case of interpolation through the use of an erroneous moving vector by using selectively a method of interpolation to an interleaved frame through the use of a moving vector based on a predetermined criterion and the method of interpolation with other method not using a moving vector. CONSTITUTION:A means 105 which uses a predicted error signal 107 in a moving vector block from an inter-frame prediction decoding section 102 with moving compensation for each moving vector detection block, calculates an evaluation from a moving vector evaluation section 103 based on the predetermined evaluation function, compares the result of calculation with a predetermined threshold level and interpolates the interleaved frame through the use of the moving vector, and a means 104 interpolating the frame through the use of preceding and succeeding frames of the interleaved frame are used selectively to move Jarkieness due to frame interleaving while deterioration in the picture quality due to the interpolation of the moving vector caused due to inaccurate moving vector is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an adaptive frame interpolation method for a motion compensated interframe predictive decoding device for television signals.

[Prior Art] Conventionally, in interframe predictive coding and decoding systems, the amount of information to be transmitted on the receiving side increases due to, for example, intense movement, and due to transmission speed limitations, frames are thinned out to reduce the amount of information. On the receiving side, encoding control was performed to repeatedly display the previous frame for frames that were not sent.

[Problems to be Solved by the Invention] As described above, the above-described conventional interframe predictive coding and decoding system has the drawback that jerkiness occurs due to frame thinning.

An object of the present invention is to provide an adaptive frame interpolation method for a motion-compensated interframe predictive decoding device that eliminates the above drawbacks and does not cause jerkiness.

[Means for Solving the Problems] According to the present invention, encoded data obtained by encoding a television signal in a motion compensated interframe predictive encoding device having a frame thinning mode is received, and the encoded data is decoded. In an interframe predictive decoding device with motion compensation, a thinned frame is interpolated using a motion vector and a decoded signal based on a predetermined criterion, or
An adaptive frame interpolation method for a motion compensated interframe predictive decoding device is obtained, which is characterized in that it switches whether or not to interpolate the thinned frame using only the decoded signal.

[Example code] Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a basic block diagram of an embodiment of the present invention.

As shown in FIG. 1, the prediction setting signal 107 and motion vector signal 109 from the motion compensated bone interframe predictive coding device 101 are input to the decoding unit 102 of the motion compensated interframe predictive decoding device 100, and are inputted to the decoding side. In , the motion vector evaluation unit 103 evaluates the accuracy of the motion vector 109 using the prediction error signal 107 according to a certain evaluation criterion, and based on the result, linear interpolation 104 using the frame before or after the 8 thinned out frames is performed. This is used to switch whether to perform the motion vector interpolation 105 using the motion vector or the motion vector interpolation 105 using the motion vector.

FIG. 2 is a block diagram of an example of the motion compensated bone interframe predictive coding device 101 in one embodiment of the present invention shown in FIG.
FIG. 3 is a block diagram of the interframe predictive decoding device 100. However, in this embodiment, a case will be described in which frames are thinned out every other frame by encoding control.

The interframe predictive coding device shown in FIG. 2 is composed of a general interframe predictive coding loop and a motion vector detection circuit. Image signal 108 input from input terminal 1
is input to the subtracter 4 through the delay circuit 12 and also to the motion vector detection circuit 8. The motion vector detection circuit 8 uses the input image signal 108 and the image signal 908 of one frame before, which is the output of the frame memory 9, to calculate the difference within a block of a certain size, which is a vector detection unit, and calculates the difference between the blocks. This circuit finds a block in which the sum of absolute values of frame difference values within is the minimum, and outputs this as a motion vector signal 810. However, due to the frame thinning signal 203.

The output is set to O during frame thinning.

The encoding control circuit 2 outputs a frame thinning signal 203 indicating whether or not frame thinning is to be performed based on the occupancy state signal 102 of the buffer memory on the sending side. Here, the frame thinning signal 203 has a thinning frame interval of 1
．． The encoded frame interval is defined as 0.

The quantizer 5 uses the frame thinning signal 203 to
Normal quantization is performed for frames to be encoded, and the quantization output is set to 0 for frames to be thinned out.
This is the circuit.

The frame memory 9 is a variable memory and has a function of varying the read address using the motion vector signal 810, and outputs the previous frame signal 908 whose read address is not modified by the motion vector signal 810. The previous frame signal 904 whose read address has been modified by the above is output. Delay circuits 12 and 13 compensate for delays caused by motion vector detection circuit 8.

The frame thinning signal 203 is sent from the output terminal 3, the prediction error signal 506 from the output terminal 6, and the single motion vector signal 810 from the output terminal 10 to the interframe decoding device shown in FIG.

FIG. 3 is a block diagram of an interframe predictive decoding device. Prediction error signal 2122 is input to the interframe decoding loop through input terminal 21. At this time, the motion vector signal 3323 input to the frame memory A23 is input through the input terminal 33. Therefore, normal decoding is performed in this decoding loop, and the previous frame data is output as a decoded signal 2224 for one thinned-out frame.

The prediction error signal 2122 is input to the absolute value sum calculation circuit 32, and a motion vector signal 3323 corresponding to the error signal 2122 is evaluated.

The absolute value sum calculation circuit 32 has a function of calculating the sum of the absolute values of the error signals within one block, and this result is compared with a predetermined threshold value TI (by the comparator 31, and if it is larger than TH), If it is less than O, TH, it is set to 1 and a motion vector evaluation signal 3130 is output.

Further, the motion vector evaluation signal 3130 and the frame thinning signal 3430 are ANDed, and the interpolation switching signal 3
027 is obtained.

The frame memory B25 is a variable memory for interpolating thinned frames. The read address of the frame memory B25 is modified by the interpolation vector signal 2827 or the O vector selected by the interpolation switching signal 3027 via the switch 27.

That is, for the decoded signal 2224 in which the previous frame data is output in one thinned-out frame section, a decoded signal subjected to motion vector interpolation using the interpolation vector signal 2827 is output in accordance with the interpolation switching signal 3027. , or the 0 vector is selected, and an output signal obtained by delaying the previous frame data by one frame is output.

Further, in the figure, a two-frame delay circuit 29 and a frame delay memory 24 are used to set the timing between an interpolation switching signal 3027 and a decoded signal 2224.

As explained above, according to the present embodiment, an evaluation value is calculated for each motion vector detection block based on a predetermined evaluation function using the prediction error signal in the motion vector block, and this calculation result and Compare with a predetermined threshold value.

An adaptive frame interpolation method for an interframe predictive decoding device with motion compensation is obtained, which is characterized in that the magnitude relationship is used as a determination criterion.

In this way, in this embodiment, the certainty of a motion vector is determined by using an evaluation function using a prediction error signal for a frame that has been thinned out by one, and as a result, the certainty of a motion vector is determined by using a frame that has been thinned out by one. By switching between interpolation means and frame interpolation means using frames before and after a thinned frame, jerkiness caused by frame thinning can be suppressed while suppressing image quality deterioration caused by motion vector interpolation caused by motion vector inaccuracy. I can do it.

[Effects of the Invention] According to the present invention, interpolation is performed using a method of interpolating using a motion vector and another method that does not use a motion vector for frames that have been thinned out by one based on a predetermined criterion. This method has the effect of suppressing jerkiness and improving image quality without causing the image quality deterioration that would occur if the wrong motion vector was used for interpolation.

[Brief explanation of drawings]

FIG. 1 is a basic block diagram of an embodiment of the present invention. 2 and 3 are block diagrams showing details of the main parts in FIG. 1. 100: Motion compensated interframe predictive decoding device. 101... Motion compensated interframe predictive coding device, 10
2... Motion compensated interframe predictive decoding unit, 103...
・Motion vector evaluation unit, 104...Linear interpolation, 105・
・・Motion vector interpolation, 1, 11, 21.33.34・・
・Input terminal, 3, 6, 10.26... Output terminal, 2・
...Encoding control circuit, 5...Quantizer, 4...Subtractor. 7.22... Adder, 9... Frame memory, 8.
...Motion vector detection circuit, 12.13...Delay circuit,
24...Frame delay memory, 23...Frame memory A. 25...Frame memory B, 32...Absolute value sum calculation circuit, 31...Comparator, 29...2 frame delay circuit. 30...AND circuit, 28...multiplier, 27...
Changeover switch.

Claims (1)

[Claims] (1) In a motion compensated interframe predictive decoding device that receives encoded data obtained by encoding a television signal by a motion compensated interframe predictive encoder having a frame thinning mode, and decodes the encoded data, With motion compensation, the apparatus switches between interpolating a thinned frame using a motion vector and a decoded signal, or interpolating the thinned frame using only a decoded signal, based on a predetermined criterion. Adaptive frame interpolation method for interframe predictive decoding device.