Method and apparatus for encoding/decoding video signal by using edge-adaptive graph-based transform
AssigneesLG Electronics Inc., University of Southern California
InventorsYung-Hsuan Chao, Hilmi E. Egilmez, Antonio Ortega, Sehoon Yea, Bumshik Lee
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Abstract
The present invention provides a method for encoding a video signal based on an Edge Adaptive Graph-Based Transform (EA-GBT) including detecting a step edge or a ramp edge from a residual signal; generating a graph signal based on at least one of the step edge or the ramp edge; obtaining an EA-GBT coefficient by performing the EA-GBT for the graph signal; quantizing the EA-GBT coefficient; and entropy-encoding the quantized EA-GBT coefficient.
Claims10
A method for encoding a video signal based on an Edge Adaptive Graph-Based Transform (EA-GBT), comprising:
- detecting, by a processor, a step edge or a ramp edge from a residual signal;
- generating, by the processor, a graph signal based on at least one of the step edge or the ramp edge;
- obtaining, by the processor, an EA-GBT coefficient by performing the EA-GBT for the graph signal;
- quantizing, by the processor, the EA-GBT coefficient;
- and
- entropy-encoding, by the processor, the quantized EA-GBT coefficient,
- wherein the step of generating the graph signal includes:
- searching a center ramp pixel having a gradient greater than a threshold value;
- initializing a position of the center ramp pixel;
- searching the position of the center ramp pixel with five possible directions according to a priority;
- allocating a probability for each of direction information;
- and
- encoding the direction information with the allocated probability,
- wherein the direction information represents a direction of progress between two consecutive pixels.
A method for decoding a video signal based on an Edge Adaptive Graph-Based Transform (EA-GBT), comprising:
- extracting, by a processor, a residual signal, a position of a center ramp pixel and a mode index from the video signal;
- deriving, by the processor, the EA-GBT corresponding to the mode index based on the position of the center ramp pixel;
- performing, by the processor, an inverse transform for the residual signal based on the EA-GBT;
- and
- generating, by the processor, a reconstructed signal by adding the inverse-transformed residual signal and a prediction signal.
An apparatus for encoding a video signal based on an Edge Adaptive Graph-Based Transform (EA-GBT), comprising:
- a processor configured to:
- detect at least one of a step edge or a ramp edge from a residual signal;
- generate a graph signal based on at least one of the step edge or the ramp edge;
- obtain an EA-GBT coefficient by performing the EA-GBT for the graph signal;
- quantize the EA-GBT coefficient;
- and
- entropy-encode the quantized EA-GBT coefficient,
- wherein the processor is further configured to:
- search a center ramp pixel having a gradient greater than a threshold value;
- initialize a position of the center ramp pixel;
- search the position of the center ramp pixel with five possible directions according to a priority;
- allocate a probability for each of direction information;
- and
- encode the direction information with the allocated probability;
- wherein the direction information represents a direction of progress between two consecutive pixels.
An apparatus for decoding a video signal based on an Edge Adaptive Graph-Based Transform (EA-GBT), comprising:
- a processor configured to:
- extract a residual signal, a position of a center ramp pixel and a mode index from the video signal;
- derive the EA-GBT corresponding to the mode index based on the position of the center ramp pixel;
- perform an inverse transform for the residual signal based on the EA-GBT;
- and
- generate a reconstructed signal by adding the inverse-transformed residual signal and a prediction signal.
Dependencies are inferred from the claim text.