Megachips Corporation

Sanyo Electric Co., Ltd.

Makoto Saitoh

Yuki Haraguchi

An image coding apparatus obtains a quantization parameter of a macroblock to be encoded. The quantization parameter is corrected by adding a correction value thereto. An encoding part encodes the macroblock by using the corrected quantization parameter. After the encoding, a quantization parameter correction part calculates the cumulative target amount of codes by accumulating the target amounts of codes set for the encoded macroblocks, respectively, and calculates the cumulative amount of generated codes by accumulating the respective amounts of generated codes of the encoded macroblocks. If the cumulative amount of generated codes is larger than the cumulative target amount of codes, the quantization parameter correction part increments the correction value. A new macroblock to be encoded is quantized more coarsely than the encoded macroblocks.

Image coding apparatus for correcting coarseness and encoding uncompressed data

A statistical value calculation part specifies macroblocks positioned around an object macroblock and calculates a minimum average value of activities of the macroblocks. When images of the macroblocks are flat and the minimum average value is smaller than an activity of the object macroblock, the minimum average value is set as an adjustment value. A correction factor determination part determines a correction factor on the basis of the adjustment value and a factor determination table. By multiplying a reference quantization step value by the correction factor, a quantization step value of the object macroblock is determined. Since the quantization step value reflects a distribution of the activities of the macroblocks, it is possible to suppress a local change of the quantization step value.

Image coding apparatus and image conversion apparatus

It is an object to provide a method of calculating a coding cost by which the magnitude relation of the amounts of generated codes can be estimated with high accuracy. A cost calculation part generates a differential block between a coding object block and a prediction block. Hadamard Transform is performed on the differential block to generate a frequency component block. A conversion factor matrix is generated with the information of a quantization matrix reflected thereon. A coding cost is calculated by multiplying components in the frequency component block individually by components in the conversion factor matrix and adding up the multiplied components. A mode selection part selects an optimum predictive coding method on the basis of the coding cost.

Encoder and image conversion apparatus

An image processing apparatus includes a CPU. In a camera mode, a TIFF file in which main image data is stored in such a manner as to satisfy a predetermined condition is recorded-by the CPU in a recording medium. When such the TIFF file is selected in a reproducing mode, the TIFF file itself is transferred from the recording medium to an SDRAM, and the main image data included in this TIFF file is subjected to a reproducing process by an ASIC. Herein, the predetermined condition includes a condition that a deviance amount between a head location of the TIFF file and a head location of the main image data is an integral multiple of '4', that is, the number of bytes storable in one address of the SDRAM.

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Osaka, Japan

Makoto Saitoh