Method for thresholding an image signal
January 24, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesPicture processing method Multi-resolution image signal processing apparatus and method Methods for converting a video signal into a black/white signal Filter for image pixels Filter for image pixels Apparatus and method for generating a dispersed dot half tone picture from a continuous tone picture Dynamic threshold device Picture processing method Method and equipment for processing gray scale facsimile signal Adaptive thresholder InventorApplicationNo. 301677 filed on 01/24/1989US Classes:358/465, Picture signal thresholding358/3.19, Stochastic or random dithering358/463, Noise elimination358/466, Variable thresholding technique382/210, Spatial filtering (e.g., holography)382/270Variable threshold, gain, or slice levelExaminersPrimary: Britton, Howard W.Assistant: Vu, Hien Attorney, Agent or FirmInternational ClassH04N 001/415AbstractThis invention relates to a method for converting a grayscale image to a bitonal image which provides improved tonal rendition with minimal loss of resolution. The invention attenuates the low spatial frequency component of the digital image and uses a similarly attenuated thresholder to convert the image to a bitonal image. When used with a dither type thresholder, this technique allows for simultaneous "continuous tone" and "line art" thresholding with minimal circuit complexity. | |
