| US 7,599,564 B2 | ||
| Jpeg-compressed file creating method | ||
| Shigeo Ando, Tokyo (Japan); Yasuo Maeda, Tokyo (Japan); Mitsunobu Yoshinaga, Tokyo (Japan); Kanae Ikeda, Tokyo (Japan); Satoshi Minami, Tokyo (Japan); Kyosuke Yoshimoto, Tokyo (Japan); and Aki Kimura, Tokyo (Japan) | ||
| Assigned to Mitsubishi Electric Corporation, Tokyo (Japan) | ||
| Appl. No. 10/548,439 PCT Filed Mar. 12, 2004, PCT No. PCT/JP2004/003344 § 371(c)(1), (2), (4) Date Aug. 08, 2006, PCT Pub. No. WO2004/082260, PCT Pub. Date Sep. 23, 2004. |
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| Claims priority of application No. 2003-067891 (JP), filed on Mar. 13, 2003. | ||
| Prior Publication US 2007/0036451 A1, Feb. 15, 2007 | ||
| Int. Cl. G06K 9/36 (2006.01) | ||
| U.S. Cl. 382—232 | 8 Claims |
| 1. A JPEG-compression-file generation method for generating a JPEG compression file from image data, using a second quantization
table obtained based on a quantization data coefficient value and on a first quantization table as a reference, the method
comprising:
(a) a step of deriving using a computer, from the image data before JPEG compression, image feature value;
(b) a step of deriving using a computer the quantization data coefficient value by, with respect to a relational expression,
which includes the quantization data coefficient value and the image feature value, for expressing the file size of a JPEG
compression file, designating a desired file size as the file size of the JPEG compression file, and
the step (a) comprises:
(a-1) a step of dividing the image data into a plurality of unit blocks;
(a-2) a step of calculating for each of the unit blocks a pixel-value difference between pixels in predetermined positions;
and
(a-3) a step of deriving the image feature value by summing each pixel-value difference calculated in the step (a-2); and
the step (a-2) comprises:
(a-2-1) a step of deriving a first of the image feature values using a pixel-value difference between two pixels at a first
distance range; and
(a-2-2) a step of deriving a second of the image feature values using a pixel-value difference between two pixels at a second
distance range.
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