Image compression/decompression based on mathematical transform, reduction/expansion, and image sharpening
Patent 5703965 Issued on December 30, 1997. Estimated Expiration Date: 
June 6, 2015. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
June 6, 2015. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesFilter-subtract-decimate hierarchical pyramid signal analyzing and synthesizing technique Method of compressing image signals Image processing apparatus Sub-band coding of images with low computational complexity Method and device for spatial filtering of digital images decoded by transformation of block Quantization step size adjusting circuit using edge detections Patent #: 5491761 InventorsApplicationNo. 486172 filed on 06/06/1995US Classes:382/232, IMAGE COMPRESSION OR CODING382/266, Edge or contour enhancement382/299, Raising or lowering the image resolution (e.g., subpixel accuracy)382/300InterpolationExaminersPrimary: Boudreau, Leo H.Assistant: Tran, Phuoc Attorney, Agent or FirmInternational ClassesG06K 009/36G06K 009/46 AbstractAn image represented in a first image array of pixels is first decimated in two dimensions before being compressed by a predefined compression algorithm such as JPEG. Another possible predefined compression algorithm can involve a wavelet technique. The compressed, reduced image is then transmitted over the limited bandwidth transmission medium, and the transmitted image is decompressed using an algorithm which is an inverse of the predefined compression algorithm (such as reverse JPEG). The decompressed, reduced image is then interpolated back to its original array size. Edges (contours) in the image are then sharpened to enhance the perceptual quality of the reconstructed image. Specific sharpening techniques are described.Other References
Field of SearchIMAGE COMPRESSION OR CODINGContour or chain coding (e.g., Bezier) Discrete cosine or sine transform Compression of color images Pattern boundary and edge measurements Edge or contour enhancement Minimize discontinuities in dot-matrix image data (i.e., connecting or merging the dots) Minimize discontinuities at boundaries of image blocks (i.e., reducing blocking effects or effects of wrap-around) Minimize jaggedness in edges (e.g., anti-aliasing) Highpass filter (i.e., for sharpening or enhancing details) Lowpass filter (i.e., for blurring or smoothing) Raising or lowering the image resolution (e.g., subpixel accuracy) Interpolation | |
