Abstract: A frequency-modulation halftone screen and method that enable the use of relatively large frequency-modulation halftone dots, which have desirable reprographic characteristics, in combination with high resolution rendering of text, graphics, and boundary information in general.

Abstract: An apparatus produces an encoded and compressed digital data stream from an original input digital data stream using a forward discrete wavelet transform and a tree encoding method. The input digital data stream may be a stream of video image data values in digital form. The apparatus is also capable of producing a decoded and decompressed digital data stream closely resembling the originally input digital data stream from an encoded and compressed digital data stream using a corresponding tree decoding method and a corresponding inverse discrete wavelet transform. A dual convolver is disclosed which performs both boundary and nonboundary filtering for forward transform discrete wavelet processing and which also performs filtering of corresponding inverse transform discrete wavelet processes. A portion of the dual convolver is also usable to filter an incoming stream of digital video image data values before forward discrete wavelet processing.

Abstract: A neural network architecture is provided for optical character recognition from an input image in which the target character may be rotated in the image plane. The architecture includes hidden units whose inputs receive image information from portions of the image which are rotationally distributed. That is, the local link between input units and the hidden units is adequate for rotation of the character in the image. Therefore, regardless of the orientation of the image, it is right side up, or approximately so, with respect to one of the hidden units. The hidden units have corresponding inputs with corresponding weight factors, i.e., symmetric weight sharing. Thus, regardless of the orientation of the image, one of the hidden units will produce a high output value indicative of an upright character. Alternatively, a single hidden unit has groups of inputs, each group having a corresponding set of weight factors. The groups are coupled to input units for rotationally distributed portions of the image.

Abstract: The invention provides methods and apparatus for processing an image to identify the position of a linear pattern--for example, a line or a cross-hair comprising a plurality of intersecting lines. The system performs a first processing step for generating a projection of the image along axes aligned with an expected position of the linear patterns. A second processing step performs a mirror symmetry filtering on the projection to bring out a single peak corresponding to the center of the linear pattern. To further isolate that peak, the system performs a further filtering operation to remove peaks of lesser slope angle, so that only a highly sloped spike corresponding to the linear pattern will remain. The position of the center that peak corresponds to the center of the linear pattern in the original input signal.

Abstract: A method of performing an inverse discrete cosine transform (IDCT) capable of reducing the amount of calculation while satisfying bit accuracy required by international standards. The IDCT method comprises the steps of defining each column of scalars X.sub.ij (where, i,j=0,1,2, . . . , N-1) and Y.sub.ij as a vector X.sub.i ={X.sub.i0, X.sub.i1, . . . , X.sub.i(N-1) } and a vector Y.sub.i ={Y.sub.i0, Y.sub.i1, . . . , Y.sub.i(N-1) }, respectively, storing values of ##EQU1## in a scalar register, storing values of X.sub.i ={X.sub.i0, X.sub.i1, . . . , X.sub.i(N-1) } in a vector register, obtaining Y.sub.i ={Y.sub.i0, Y.sub.i1, . . . , Y.sub.

Abstract: A character string correction system corrects a spelling error in a character string input through the keyboard, OCT, etc. An error pattern representing frequent occurrences of errors is preliminarily set and stored in the memory, etc. A processor reads an input character string character by character, and compares the read character with the error pattern. If the input character string matches an error pattern, it is assumed that an error exists. The input character is replaced with one of the alternative characters. Using the input character string or the character string corrected with an alternative character, a dictionary (TRIE table) is searched. If a corresponding word is detected in the dictionary, the word is output as one of the recognition results.

Abstract: The present invention relates to a combined approach of image and template correlation, and vector correlation wherein edge detection and pattern searching are joined in a single operation to provide great flexibility without requiring extensive computational facilities. A template is devised from a sparse set of coordinate points that model only the important edges of an object to be located within an image. Different templates are dynamically reconstructed as an estimation of the object location within the image becomes more precise.

Abstract: A skin pattern image is filtered by convolution calculation on a real plane or product calculation on a Fourier transformed plane with each of two-dimensional filters prepared according to kinds of features to be extracted of the skin pattern image. Image intensity of each subregion of each filtered data is calculated. Feature of each subregion is represented by a feature parameter corresponding to a filter that gives a highest value of the image intensity of the subregion. An initial pattern of features thus obtained is smoothed to minimize an evaluation function. A filtered skin pattern image having pixel values of each subregion smoothed by a set of filters prepared for extracting a kind of features is further filtered by another set of filters for extracting another kind of features.

Abstract: An encoded symbol reading device capable of reading and decoding a tessellated symbol. A detector detects an optical image formed by the encoded symbol and outputs a signal corresponding to the optical image. The signal is compared with threshold values and a 1-bit data value is output. The 1-bit data values are converted into an n-bit data value which is stored in a memory. The threshold values are also stored in memory and are obtained by detecting an optical image formed by a surface having a predetermined color.

Abstract: A bitstream quality analysis system includes a demultiplexer, a bitstream quality analyzer, and a graphical user interface. The demultiplexer receives a bitstream and separates from the bitstream at least one elementary bitstream that includes a video elementary bitstream. The bitstream quality analyzer receives the video elementary bitstream from the demultiplexer and parses the video elementary bitstream to extract parameters characterizing the video elementary bitstream. The bitstream quality analyzer provides the extracted parameters to the graphical user interface, which displays the extracted parameters characterizing the video elementary bitstream. A user can monitor the video elementary bitstream at varying levels of detail, and can perform varying levels of quality analysis on the video elementary bitstream.

Abstract: An improved circuit for compensating a pattern recognition type edge for a video signal processor which is capable of preventing a undershooting and an overshooting by recognizing a pattern of a luminance signal which is converted into a digital form when compensating an edge of a luminance signal, by substituting a sample value at incline start or end portions and at decline start or end portions of a pattern with the previous sample value or the next sample value, by generating a plurality of luminance signals having a different delay time by sequentially delaying a luminance signal which is converted into a digital form as many as the number of samples, by subtracting a luminance signal which is delayed by the previous process from the luminance signal which is delayed by each process, by recognizing a pattern of an edge of luminance signal by logically operating a difference signal and a reference signal after computing a plurality of difference signals, and by selecting a signal among luminance signals h

Abstract: The objects of this invention are accomplished by combinging the inverse DCT of an appropriate size with scaling on the resulting reconstructed image. In particular, if the data is stored as DCT values of blocks of size P.times.Q and an output image is to be scaled by a factor of R in one dimension and S in the second dimension, then the process is performed in two stages. First a scaling of factor K1/P in the first dimension and a scaling of factor L1/Q in the second dimension are done by inverse transforming with 2-dimensional DCTs of size K1.times.L1. A factor .sqroot.(K1/P).times..sqroot.(L1/Q) is absorbed into a dequantization process prior to the inverse transorm process. Then a scaling of factor K2/K3 in the first dimension and a scaling of factor L2/L3 in the second dimension is done in the spatial domain. The integers K1, K2, K3, L1, L2, L3 are chosen so the (K1K2/K3)=R, (L1L2/L3)=S, (K1/P).gtoreq.R, (L1/Q).gtoreq.S, and the ratios (K2/K3) and (L1/L2) are close to 1.

Abstract: Fast, low-overhead implementations of a powerful, reliable image matching engine based on the Hausdorff distance are disclosed. In one such implementation, a method is provided in which a processor receives two inputs. The first input is a pattern to be recognized in an image; the second, a digital image in which the pattern is to be recognized. The digital image is preprocessed with the processor using various morphological dilation operations so as to produce a set of preprocessed digital images. Thereafter, the processor performs a hierarchical search for the pattern in the digital image. The hierarchical search is performed over a search space, and includes a series of decisions, each decision indicating whether a portion of the search space can be eliminated from the search. Each decision is made by performing a plurality of comparisons between the pattern and the preprocessed digital images of the set and analyzing the results of these comparisons.

Abstract: A thick group of cells classifier. Image data acquired from an automated microscope from a cytological specimen is processed by a computer system. The computer applies filters at different stages. Obvious artifacts are eliminated from analysis early in the processing. The first stage of processing is image segmentation where objects of interest are identified. The next stage of processing is feature calculation where properties of each segmented thick group object are calculated. The final step is object classification where every segmented thick group object is classified as being abnormal or as belonging to a cellular or non-cellular artifact.

Abstract: A method and apparatus for storing and retrieving images of documents, e.g. checks.

Abstract: The present invention provides a marker detection and thinning process for a photocopier which is executed during a single scan of a document and does not require a prescan of the document. The system realtime analyzes pixel image data, which is stored in a memory during the scanning process, to detect a marker line of a predetermined color and to thin the marker line. This analysis begins with image data stored in the memory that corresponds to a first pixel. The first pixel is associated with the scanline being presently scanned. It is determined if the image data of the first pixel represents a color that is equivalent to the predetermined color. Marker data is then stored in a buffer at a location corresponding to the first pixel if it is determined that the image data of the first pixel represents a color that is equivalent to a predetermined marker color. The data, stored in the buffer at a second pixel location, is analyzed.

Abstract: A method for mosaicing medical images, particularly volumes acquired by a 3D ultrasound device. The method relies on an image-based technique that transforms a target volume to align with a reference volume. The transformation is composed of a coarse rigid transformation and a fine elastic warp. The fine transformation assumes that the two volumes are close enough for the mapping between them to be expressed in terms of their gradient values.

Abstract: An image, eg of an advertising or promotional nature, is depicted in an inverse perspective form on a playing field (10) for a sporting event. The playing field is imaged by means of a video camera (12) whose line of sight (14) corresponds to the line of sight used in transforming the image to its inverse perspective form, and the output of the camera then broadcast or diffused in a television broadcasting or diffusion service.

Abstract: Preferably using frame vectors, a reference memory (13) keeps feature vectors of a set as a tree comprising a root node, leaf nodes farthest from the root node, and intermediate nodes with the frame vectors assigned respectively to the leaf nodes. A calculator (17) calculates cluster distances between each feature vector of an input pattern and a subset assigned among the set to each daughter node of a mother node which is first the root node. From the intermediate nodes with the mother node successively selected along each branch of the tree, a selector (19) selects at least one daughter node that gives a shortest possible cluster distance.

Abstract: The character reader device of the present invention is capable of reading as read data characters written in a portion corresponding to a given read field on a manuscript; detecting a reject character in the read data; generating a pattern image corresponding to the reject character; displaying the read data, the reject character, and the pattern image; computing the position of a display area for the read data; deciding whether or not the computed display area is overlapped with the display area for the pattern image; shifting the pattern image to the area which is the outside of the display area for the read data if overlapped; and displaying it on the latter area.