Image coding device and method thereof and image decoding device and method thereof
AssigneeSony Corporation
InventorsTakahiro Fukuhara, Seiji Kimura
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Abstract
A predetermined area of input image data (100) is read and stored into a memory section (1). As soon as data is stored in the data read memory section (1), wavelet conversion filtering is performed on the image area, in the horizontal or vertical direction, by a wavelet conversion section (5). The wavelet conversion section (5) comprises a fixed-point type wavelet conversion section (3) and an integer type wavelet conversion section (4). Data from the data read memory section (1) is switched and controlled by a switching section (2), and supplied to either the fixed-point wavelet conversion section (3) or the integer type wavelet conversion section (4).
Claims2
An image decoding device into which a coded bit stream generated by a coding device comprising integer type wavelet conversion means and/or fixed-point type wavelet conversion means is inputted, the image decoding device comprising:
- wavelet reverse conversion means;
- gain adjustment means for a high-band component coefficient;
- a bit-shifter;
- and
- means for detecting whether wavelet conversion performed by the coding device is of an integer type or a fixed-point type, from the inputted coded bit stream,
- wherein if the wavelet conversion is of the integer type, a decoded image is outputted without performing gain adjustment of the high-band component coefficient or a bit shift after the wavelet reverse conversion, or if the wavelet conversion is of the fixed-point type, the gain adjustment of the high-band component coefficient and the bit shift after the wavelet reverse conversion are carried out, to output a decoded image.
An image decoding method in which a coded bit stream generated by a coding device comprising integer type wavelet conversion means and/or fixed-point type wavelet conversion means is inputted and wavelet reverse conversion is performed, comprising the steps of:
- detecting whether wavelet conversion performed by the coding device is of an integer type or a fixed-point type, from the inputted coded bit stream;
- and
- outputting a decoded image without performing gain adjustment of a high-band component coefficient or a bit shift after wavelet reverse conversion when the wavelet conversion is detected to be of the integer type by the detecting step, or performing the gain adjustment of the high-band component coefficient and the bit shift after the wavelet reverse conversion to output a decoded image, when the wavelet conversion is detected to be of the fixed-point type by the detecting step.
Dependencies are inferred from the claim text.