Adaptive thresholding using loose gray scale template matching

#This invention relates to systems and methods for processing images using filters. More specifically, this invention relates to systems and methods for designing and implementing image processing filters using templates wherein the filters operate on gray-scale images and the templates identify gray-scale image features for the purposes of modification or for extracting some image statistic, and for the purposes of optimization for the human visual system, or compatibility with other system modules, such as, compression algorithms, recognition algorithms and those occurring in printing and display devices.

#The following patents and publications are hereby incorporated by reference for their teachings:

#“Method for design and implementations of an image resolution enhancement system that employs statistically generated lookup tables,” Loce et al., U.S. Pat. No. 5,696,845;

#The preferred embodiments and other aspects of the invention will become apparent from the following detailed description of the invention when read in conjunction with the accompanying drawings which are provided for the purpose of describing embodiments of the invention and not for limiting same, in which:

#FIG. 1 is a diagram illustrating a conventional template matching filter paradigm.

#FIG. 2A shows a flowchart of a conventional binary template matching arrangement;

#The term “bitmap” refers herein to a digital image quantized in a variety of forms, such as binary, 8 bits/pixel, or some intermediate number of bits/pixel, or some high resolution quantization state.

#The term “data” refers herein to physical signals that indicate or include information. When an item of data can indicate one of a number of possible alternatives, the item of data has one of a number of “values.” For example, a binary item of data, also referred to as a “bit,” has one of two values, interchangeably referred to as “1” and “0” or “ON” and “OFF” or “high” and “low.” A bit is an “inverse” of another bit if the two bits have different values. An N-bit item of data has one of 2N possible values.

#The term “data” includes data existing in any physical form, and includes data that are transitory or are being stored or transmitted. For example, data could exist as electrical, electromagnetic or other transmitted signals or as signals stored in electronic, magnetic, or other form. The terms image signal, video data, and pixel are interchangeably used herein to describe discrete digital signals that represent the active (on) or inactive (off) state of an element within a digital image. In addition, shaded or crosshatched portions of image bitmaps depicted herein are intended to represent black or active pixels (having a value of 1 in a binary representation) within the bitmaps. Such a representation is not intended to limit the present invention, but to simplify the description thereof. Accordingly, the present invention may be operated in the same manner by substituting white pixel states wherever black pixels are indicated, and vice versa.