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公开(公告)号：JP2000029449A
公开(公告)日：2000-01-28
申请号：JP17468599
申请日：1999-06-21
Applicant: TEXAS INSTRUMENTS INC
Inventor： OHARA KAZUHIRO , SEXTON WILLIAM J , TAKEDA AKIRA , SEXTRO GARY
Abstract: PROBLEM TO BE SOLVED: To obtain a method for selectively scaling a part of image data based on the intensity level of histogram image data, and a device therefor. SOLUTION: Image data are made appropriate when relatively many image pixels have a high intensity level as the intensity of dark pixels is decreased by black level extension and the image data are made appropriate when relatively many image pixels have a low intensity level as the intensity of light pixels is increased by white level extension. A histogram comparator 402 compares each pixel intensity with a threshold value, and when an appropriate number of pixels in each frame coincides with the threshold reference, the level extention is increased. A field accumulator 404 decides whether the image data are to be scaled or not, every time when the frame coincides with the extension reference determined by the histogram comparator 402, the level extension is increased and every time when the frame does not coincide therewith, it is decreased. The accumulated value is used for a level extender 406 to scale at least a part of input data.
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公开(公告)号：DE69908713D1
公开(公告)日：2003-07-17
申请号：DE69908713
申请日：1999-06-17
Applicant: TEXAS INSTRUMENTS INC
Inventor： OHARA KAZUHIRO , SEXTON WILLIAM J , TAKEDA AKIRA , SEXTRO GARY
Abstract: A method and apparatus for selectively scaling portions of image data based on the intensity levels of historical image data. The selective scaling, or level expansion, provides improved images by increasing or decreasing the intensity of a portion of image pixels. Black level expansion reduces the intensity of dark pixels and is appropriate when a relatively large number of the image pixels have a high intensity level. White level expansion increases the intensity of bright pixels and is appropriate when a relatively large number of image pixels have a low intensity level. Level expansion is implemented by using histogram comparators 402 to compare the intensity of each pixel with a threshold, typically on a frame-by-frame basis. When an adequate number of pixels in each frame meet the threshold criteria, the level expansion is increased. Field accumulator 404 is used to determine whether and by how much the image data is scaled. Field accumulator 404 increments each time a frame meets the expansion criteria, as determined by the histogram comparators 402, and decrements each time a frame does not meet the expansion criteria. The value accumulated by the field accumulator 404 is used by level expander 406 to scale at least a portion of the input data.
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公开(公告)号：DE69908713T2
公开(公告)日：2004-05-13
申请号：DE69908713
申请日：1999-06-17
Applicant: TEXAS INSTRUMENTS INC
Inventor： OHARA KAZUHIRO , SEXTON WILLIAM J , TAKEDA AKIRA , SEXTRO GARY
Abstract: A method and apparatus for selectively scaling portions of image data based on the intensity levels of historical image data. The selective scaling, or level expansion, provides improved images by increasing or decreasing the intensity of a portion of image pixels. Black level expansion reduces the intensity of dark pixels and is appropriate when a relatively large number of the image pixels have a high intensity level. White level expansion increases the intensity of bright pixels and is appropriate when a relatively large number of image pixels have a low intensity level. Level expansion is implemented by using histogram comparators 402 to compare the intensity of each pixel with a threshold, typically on a frame-by-frame basis. When an adequate number of pixels in each frame meet the threshold criteria, the level expansion is increased. Field accumulator 404 is used to determine whether and by how much the image data is scaled. Field accumulator 404 increments each time a frame meets the expansion criteria, as determined by the histogram comparators 402, and decrements each time a frame does not meet the expansion criteria. The value accumulated by the field accumulator 404 is used by level expander 406 to scale at least a portion of the input data.
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