Variable length coding method and variable length decoding method
View Patent ↗An image coding apparatus is provided with a unit operable to scan a two-dimensional array of quantized coefficients into scanned quantized coefficients, the scanning being performed from a low frequency component toward a high frequency component; a unit operable to convert the scanned quantized coefficients into a run value and a level value, the run value indicating the number of continuous quantized coefficients, each having a zero value, and the level value indicating a value of a quantized coefficient having a non-zero value; a unit operable to code the run value; and a unit operable to code the level value, wherein the coding of the run value is performed, from a high frequency component toward a low frequency component, in accordance with information that represents a total number of uncoded quantized coefficients which have not been coded.
1. A method for coding quantized coefficients of a block image, the method comprising:
scanning a two-dimensional array of quantized coefficients into scanned quantized coefficients, wherein said scanning is performed from a low frequency component toward a high frequency component;
converting the scanned quantized coefficients into a run value and a level value, the run value indicating the number of continuous quantized coefficients, each having a zero value, and the level value indicating a value of a quantized coefficient having a non-zero value;
coding the run value; and
coding the level value;
wherein the coding of the run value is performed, from a high frequency component toward a low frequency component, in accordance with information that represents a total number of uncoded quantized coefficients which have not been coded.
2. The coding method of claim 1 , wherein
the uncoded quantized coefficients are uncoded zero-value coefficients.
3. A coding apparatus for coding quantized coefficients of a block image, the apparatus comprising:
a unit operable to scan a two-dimensional array of quantized coefficients into scanned quantized coefficients, wherein said scanning is performed from a low frequency component toward a high frequency component;
a unit operable to convert the scanned quantized coefficients into a run value and a level value, the run value indicating the number of continuous quantized coefficients, each having a zero value, and the level value indicating a value of a quantized coefficient having a non-zero value;
a unit operable to code the run value; and
a unit operable to code the level value;
wherein the coding of the run value is performed, from a high frequency component toward a low frequency component, in accordance with information that represents a total number of uncoded quantized coefficients which have not been coded.