US 11,949,867 B2
Image encoding apparatus, image decoding apparatus, control methods and non-transitory computer-readable storage medium
Masato Shima, Tokyo (JP)
Assigned to Canon Kabushiki Kaisha, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Jun. 14, 2021, as Appl. No. 17/346,849.
Application 17/346,849 is a continuation of application No. PCT/JP2019/044754, filed on Nov. 14, 2019.
Claims priority of application No. 2018-235910 (JP), filed on Dec. 17, 2018.
Prior Publication US 2021/0306633 A1, Sep. 30, 2021
Int. Cl. H04N 19/124 (2014.01); H04N 19/119 (2014.01); H04N 19/132 (2014.01); H04N 19/159 (2014.01); H04N 19/176 (2014.01); H04N 19/18 (2014.01)
CPC H04N 19/124 (2014.11) [H04N 19/119 (2014.11); H04N 19/132 (2014.11); H04N 19/159 (2014.11); H04N 19/176 (2014.11); H04N 19/18 (2014.11)] 22 Claims
OG exemplary drawing
 
1. An image decoding apparatus for decoding an image from encoded data, the apparatus comprising:
a decoding unit configured to decode data for a quantization matrix used for inverse quantizing processing which derives transform coefficients from quantized transform coefficients;
a deriving unit configured to derive a plurality of values corresponding to at least a part of elements in the quantization matrix by using the data, and derive the quantization matrix based on the plurality of values; and
an inverse quantizing unit configured to perform the inverse quantizing processing on an object block using the quantization matrix,
wherein, in a case where a width of the object block is 16 samples and a height of the object block is 8 samples, the deriving unit derives the quantization matrix by:
setting a first value among the plurality of values as a first element corresponding to DC component in the quantization matrix, wherein the first value is not set for a plurality of elements in the quantization matrix used for the inverse quantizing processing, and the first value is derived by using difference from a predetermined initial value;
setting a second value among the plurality of values as a second element adjacent to the first element on a right side of the first element, wherein the second value is not set for a plurality of elements in the quantization matrix used for the inverse quantizing processing, and the second value is derived by using difference from the first value; and
setting a third value among the plurality of values as a third element and a fourth element, wherein the third element is below the first element and the fourth element is below the second element, and
wherein the third element is adjacent to the first element and the fourth element is adjacent to the second element, and wherein the third value is derived by using difference from the second value.