Invention Grant
US07899267B2 Dynamic range compensation by filter cascade 有权
通过滤波器级联的动态范围补偿

  • Patent Title: Dynamic range compensation by filter cascade
  • Patent Title (中): 通过滤波器级联的动态范围补偿
  • Application No.: US11752797
    Application Date: 2007-05-23
  • Publication No.: US07899267B2
    Publication Date: 2011-03-01
  • Inventor: Itsik Dvir
  • Applicant: Itsik Dvir
  • Applicant Address: US CA Sunnyvale
  • Assignee: Zoran Corporation
  • Current Assignee: Zoran Corporation
  • Current Assignee Address: US CA Sunnyvale
  • Agency: Perkins Coie LLP
  • Main IPC: G06K9/40
  • IPC: G06K9/40
Dynamic range compensation by filter cascade
Abstract:
A local method uses a cascade of multiple nonlinear edge preserving filters, and nonlinear pixel point operations, to calculate the pixel gain. Multiple low-pass filters are used, being applied to surrounding neighborhoods of the current pixel of narrow and of wide extent. The number of filter stages may be determined based on the image content. The coefficients used to combine a gray level image extracted from the input image with the ascending scale regions can be automatically extracted from high-pass filtered images of the ascending scale regions. Multiplying each color component of the input image by one or more pixel dependent gain or attenuation factors, using a nonlinear mapping function that can lighten shadow regions as well as darken bright regions, generates the output image.
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