1
Akihiro Katayama, Hidefumi Ohsawa, Izuru Sunohara, Hiroshi Hosokawa, Masahiko Yoshimoto: Method and apparatus for image processing with fed-back error correction. Canon Kabushiki Kaisha, Fitzpatrick Cella Harper & Scinto, October 31, 1989: US04878125 (74 worldwide citation)

There is an image processing apparatus for digitally processing an image. This apparatus comprises: a binarization circuit to binarize image data by a predetermined threshold value; a processor to correct errors generated in binarization; a first detector to detect an edge direction of the image fro ...


2
Akihiro Katayama, Hidefumi Ohsawa, Shinichi Ishida, Masahiro Sakamoto, Yasuyuki Shinada: Image processing method and apparatus with error diffusion capability. Canon Kabushiki Kaisha, Fitzpatrick Cella Harper & Scinto, December 4, 1990: US04975786 (64 worldwide citation)

An image processing apparatus such as a digital printer or digital facsimile apparatus for half tone processing input image data has: an input device to input image data indicative of a concentration of an image; a discriminating circuit to discriminate whether the input image data is smaller than a ...


3
Hidefumi Ohsawa, Akihiro Katayama, Hiroshi Hosokawa, Izuru Sunohara, Masahiko Yoshimoto: Image processing apparatus with binarization-error dispersal. Canon Kabushiki Kaisha, Fitzpatrick Cella Harper & Scinto, October 24, 1989: US04876610 (61 worldwide citation)

An image processing apparatus for digitizing an analog image by dispersing the digitizing error to the surrounding areas. The characteristics or edge of the analog image are identified, and the error dispersing area is varied according to the result of identification, thus enabling reproduction of t ...


4
Miyuki Enokida, Hidefumi Ohsawa: Image processing method and apparatus for converting between data coded in different formats. Canon Kabushiki Kaisha, Fitzpatrick Cella Harper & Scinto, October 6, 1998: US05818537 (52 worldwide citation)

Image processing method and apparatus for converting between data encoded in different formats includes structure and steps for converting motion image data into first digital coded motion image data having a first encoding format and capable of being transmitted to a medium. The first digital coded ...


5
Akihiro Katayama, Hidefumi Ohsawa: Image processing method and apparatus for error-dispersion digitization without moire or spurious stripe formation. Canon Kabushiki Kaisha, Fitzpatrick Cella Harper & Scinto, April 16, 1991: US05008950 (48 worldwide citation)

There is provided an improvement on the error dispersion method for binary digitizing of an image, in which an area of plural pixels is digitzed, and the error into the digitizing is dispersed in a neighboring area of plural pixels. In the latter area the digitization is conducted according to the i ...


6
Naoto Kawamura, Yuji Nishigaki, Hidefumi Ohsawa: Image processing apparatus which converts m-bit image data to n-bit (n>m) image data. Canon Kabushiki Kaisha, Fitzpatrick Cella Harper & Scinto, May 15, 1990: US04926268 (44 worldwide citation)

An image processing apparatus of this invention includes a digital data output device for outputting bi-level image data, a bi-level processor for converting the bi-level image data into multi-level (e.g., 8-bit) image data, a multi-level processor for performing spatial filter processing with respe ...


7
Akihiro Katayama, Hidefumi Ohsawa: Image processing method and apparatus with conditional correction of error data. Canon Kabushiki Kaisha, Fitzpatrick Cella Harper & Scinto, September 18, 1990: US04958238 (43 worldwide citation)

There is provided an image processing apparatus which handles an image as a digital signal, comprising: an input device to input image data indicative of a concentration of an image; a binarization circuit to binarize the input image data; a positive/negative state detection circuit to detect whethe ...


8
Hidefumi Ohsawa: Selectively utilizing multiple encoding methods. Canon Kabushiki Kaisha, Fitzpatrick Cella Harper & Scinto, March 16, 1999: US05883976 (42 worldwide citation)

The invention is to exactly select an enconding method with satisfactory encoding efficiency, by comparing the final predicted code lengths for plural encoding methods, prior to the actual encoding operation. This object can be attained by an encoding device comprising generation means for generatin ...


9
Hidefumi Ohsawa: Image processing apparatus. Canon Kabushiki Kaisha, Fitzpatrick Cella Harper & Scinto, August 4, 1998: US05790195 (40 worldwide citation)

The invention provides an image processing apparatus comprising: an activity detecting unit for detecting an activity of input image data, a processing unit for space filter processing the input image data by controlling filter coefficients in accordance with the activity detected by the activity de ...


10
Akihiro Katayama, Hidefumi Ohsawa, Akiko Fukuhara: Image treatment method and apparatus with error dispersion and controllable quantization. Canon Kabushiki Kaisha, Fitzpatrick Cella Harper & Scinto, June 28, 1994: US05325448 (29 worldwide citation)

An image treatment apparatus comprising: an input device for inputting image data; a setting circuit serving as a reference when the image data is quantized in accordance with the image data input by the input device; a quantizing circuit for quantizing the image data; and a device for outputting an ...