发明名称 |
Method of and apparatus for converting image signal representing image having gradation |
摘要 |
An original image is divided into a plurality of pixel blocks each consisting of a plurality of pixels. A density histogram represented by an electric signal is obtained for each pixel block. Respective pixel blocks are analyzed to find adjacent pixel blocks which are uniform and continuous in density. If the pixel blocks thus found are continuous in density with the reference pixel blocks located at the corner of the original image, the pixel blocks are regarded as those representing the background portion of the original image. The numbers of pixels in the density histogram is corrected for each background pixel block, and highlight and shadow points for determining a gradation curve is determined. The gradation curve is set in a signal-converter to convert an image signal representative of the original image.
|
申请公布号 |
US5680477(A) |
申请公布日期 |
1997.10.21 |
申请号 |
US19920953536 |
申请日期 |
1992.09.28 |
申请人 |
DAINIPPON SCREEN MFG. CO., LTD. |
发明人 |
ASADA, SHINJI |
分类号 |
H04N1/407;(IPC1-7):G06T5/40 |
主分类号 |
H04N1/407 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|