×

Image processing apparatus

  • US 6,819,717 B1
  • Filed: 05/03/2000
  • Issued: 11/16/2004
  • Est. Priority Date: 05/12/1999
  • Status: Expired due to Term
First Claim
Patent Images

1. An image processing apparatus which, for an input two-dimensional image constructed by arraying, in a matrix, a number of pixels each representing a luminance value at a corresponding position, adjusts a spatial frequency characteristic on the basis of a desired spatial frequency adjustment filter characteristic, and compresses the image, comprising:

  • a spatial filter for obtaining a new luminance value of each pixel of an input image on the basis of a first coefficient having a first filter characteristic which forms the desired spatial frequency adjustment filter characteristic in cooperation with a second filter characteristic, thereby generating a two-dimensional intermediate image which has the adjusted spatial frequency characteristic of the input image; and

    an orthogonal transform section for performing two-dimensional orthogonal transform for the intermediate image on the basis of a second coefficient which has the second filter characteristic, which forms the desired spatial frequency adjustment filter characteristic in cooperation with the first filter characteristic, and is used for two-dimensional orthogonal transform for compressing the intermediate image generated by said spatial filter, thereby generating image data which has the adjusted spatial frequency characteristic of the intermediate image and has undergone two-dimensional orthogonal transform for image compression, wherein said orthogonal transform section segments the intermediate image generated by said spatial filter into a plurality of second regions each constructed by N×

    N pixels (N is an integer;

    N≧

    2), and performs two-dimensional orthogonal transform in units of second regions using N×

    N second coefficients having the second filter characteristic, thereby generating the image data which has the adjusted spatial frequency characteristic of the intermediate image and has undergone two-dimensional orthogonal transform for image compression;

    wherein said orthogonal transform section is operative to segment the intermediate image generated by said spatial filter into a plurality of second regions each constructed by N×

    N pixels (N is an integer, N≧

    2), and to perform two-dimensional orthogonal transform in units of second regions using N×

    N second coefficients having the second filter characteristic, thereby generating the image data which has the adjusted spatial frequency characteristic of the intermediate image and has undergone two-dimensional orthogonal transform for image compression; and

    wherein as the second coefficients, N×

    N coefficients obtained by individually multiplying or adding N×

    N filter coefficients for adjusting the spatial frequency characteristic of the intermediate image and N×

    N transform coefficients used for two-dimensional orthogonal transform of the intermediate image are used.

View all claims
  • 3 Assignments
Timeline View
Assignment View
    ×
    ×