A discoid optical correlator system having a plurality of reflective optical components, a source of electromagnetic radiation, such as visible light, and an output detector which are positioned around the rim region of a solid disk body to develop a symmetrically folded optical axis traversed by a beam of electromagnetic radiation so that an unknown object is optically detected and identified.

A method for correcting gradation of output data for reproducing a picture image, for use in a picture digital processing system wherein picture data is processed by using one or a plurality of lookup table memories aligned in series, wherein a variable number of lower bits of input data to be input to the lookup table memory, the number of the lower bits of the input data being varied depending on the input data and the input-output characteristics of the one lookup table memory or the total in...

Apparatus and method for converting image data of an image matrix to an image matrix having a different number of matrix points. Each new image pel has a gray scale determined by considering its position with respect to the nearest neighbors of an original image pel. A look up table is provided having a plurality of planes, each plane including a plurality of storage elements arranged in columns and rows. The storage elements contain the gray scale level of a new image pel. The look up table pla...

In a system for identifying hand-written characters, the read character is binary-coded with a high threshold value and a low threshold value, picture elements whose density levels are between the high and low threshold values are subjected to thinning, and the picture elements of the thinned character pattern having density levels lower than the high threshold level are redetermined as to black or white levels from the contrast of each picture element with respect to the surrounding picture ele...

A fully automatic method for rapidly and unambiguously interpreting fringe patterns, including those having branched fringes, is provided. The information from the fringe patterns processed by the method of the invention can be used in testing, surface characterization and inspection applications. Further processing of the information from the two-dimensional fringe patterns yields information from which the three-dimensional surface can be quantitatively reconstructed for further use such as fo...

An image processor converts a multiple gray-level image to a bi-tonal image using both error diffusion and ordered dither to enhance image quality. The error diffusion process is attenuated smoothly as the local area intensity approaches a light or dark maximum, while the ordered dither process is attenuated smoothly as the local area high spatial frequency content increases.

A method for compression of data used to describe an ideographic character, or a set of such characters such as Japanese, Chinese, Hebrew, Arabic or Tamil characters or a set of two-level images, on a computer screen. The computer screen is divided into an array of non-overlapping pixel sub-blocks, each J pixels wide by K pixels high, and a neighborhood of L adjacent pixels is defined for each target sub-block. The known pixel configuration (white versus black or off versus on) of the neighborho...

A method and apparatus for correlating two signals representing a live image and a reference image are disclosed. The reference signal is processed to provide a polarity bit and mask bit for each pixel position in the reference image. The processed video signal is stored in a memory 20 and used in a convolver and summer section 18 in which the polarity bits between the reference and live images are gated by gate 17 and are used in generating a correlation output from summer 23. However, the pola...

An image processing device capable of processing images containing poorly contrasted letters and/or bold letters in addition to well contrasted letters and pictures such that both resolutions of letters and tones of pictures can be preserved. The device may includes a circuit to distinguish two level images from non two level images according to image concentration related quantity, and a circuit to distinguish picture images out of non two level images according to another image concentration r...

An arrangement for checking or examining bank-notes or similar documents include a detector, such as a CCD array of, for example, 256 photocell devices. The documents are scanned by the photocell devices transversely of their longitudinal extent. The signals are digitized by an analogue/digital converter (2), such that the output of each photocell device is represented only by one digital bit. The analogue/digital converter (2) further defines horizontal and vertical edges of the documents and o...