发明授权
US5394250A Image processing capable of handling multi-level image data without
deterioration of image quality in highlight areas
失效
图像处理能够处理多级图像数据,而不会在亮点区域中降低图像质量
- 专利标题: Image processing capable of handling multi-level image data without deterioration of image quality in highlight areas
- 专利标题(中): 图像处理能够处理多级图像数据,而不会在亮点区域中降低图像质量
-
申请号: US955265申请日: 1992-10-01
-
公开(公告)号: US5394250A公开(公告)日: 1995-02-28
- 发明人: Seita Shono
- 申请人: Seita Shono
- 申请人地址: JPX Tokyo
- 专利权人: Canon Kabushiki Kaisha
- 当前专利权人: Canon Kabushiki Kaisha
- 当前专利权人地址: JPX Tokyo
- 优先权: JPX3-256187 19910310; JPX4-000119 19920601; JPX4-000120 19920601; JPX4-000121 19920601
- 主分类号: H04N1/405
- IPC分类号: H04N1/405 ; H04N1/40
摘要:
An image processing apparatus, which stochastically binary-converts lower-bit data of a pixel of interest to improve image quality in a highlight portion, as well as in a low-density portion, is provided. In an image processing apparatus for quantizing multi-value image data to binary data, multi-value image data of a pixel of interest is divided into upper- and lower-bit data by a calculator (24). The lower-bit data is binary-converted by a comparator (25) using a normalized uniform random number generated by a random number generator (26) as a threshold value. The binary-converted data is added to the upper-bit data of the image signal of the pixel of interest by an adder (22), and the sum data is binary-converted by a comparator (18) using one of a plurality of weighted average values of a plurality of pixels near the pixel of interest, which values are calculated by a calculator (600), on the basis of binary data of pixels, which have already been binary-converted before the pixel of interest. At this time, the density is preserved by distributing a density error generated upon binary conversion to non-binary-converted pixels near the pixel of interest by a circuit including a subtracter (17), an adder (22), and the like.
公开/授权文献
- US4216385A AC/DC Power supply device 公开/授权日:1980-08-05