Appeal No. 1998-1895 Page 2
Application No. 08/425,990
images. Compression methods have been described by the Joint
Photographic Experts Group (JPEG) for still images and the
Motion Picture Experts Group (MPEG) for moving images. The
JPEG method involves a discrete cosine transform, followed by
quantization and variable-length encoding. The MPEG method
involves detecting motion vectors. Both methods require
extensive computation, with the detection of motion vectors
being particularly demanding.
The appellant's invention encodes a digitized image by
detecting edges in the image, encoding the position and
sharpness of the detected edges, filtering the image by a low-
pass filter to generate a low-frequency image, and encoding
the low-frequency image. A digitized image encoded in this
way is reconstructed by generating a horizontal edge image and
a vertical edge image from the encoded edge position and
sharpness, synthesizing a pair of high-frequency images by
filtering the horizontal and vertical edge images with an edge
synthesis filter, decoding the low-frequency image, and
performing an inverse wavelet transform on the decoded low -
frequency image and the high frequency images. Synthesizing
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