Abstract: Communications between a Host Computing System and a number of remote terminals is enhanced by a data compression method which modifies the data compression method of Lempel and Ziv by addition of new character and new string extensions to improve the compression ratio, and deletion of a least recently used routine to limit the encoding tables to a fixed size to significantly improve data transmission efficiency.

Abstract: An architecture for the implementation of an information utility for accessing information and executing transactions on an interactive basis between Videotex databases and individual end user terminals, some or all of which may be remotely located with respect to each other. The utility may be associated with a Videotex Application Network (VAN) and includes a combination of distributed, semiautonomous Operations Nodes (ONs), each characterized by (1) one or more affiliated users, (2) the inclusion of some form of database, and (3) one or more customized application programs, and each is also capable of "standalone" operation. Each database comprises pages of control information and displayable data. Each node comprises a directory of databases at other nodes.

Abstract: A method for suppressing the perception of flicker in interlaced video images, includes the steps of: testing, each pixel in an image, for an intensity value below a first predetermined threshold; modifying, for each tested pixel, an intensity value representation for each nearest neighbor pixel along a first axis of said interlaced image having an intensity value exceeding a second predetermined threshold, if the intensity value of the tested pixel is below the first predetermined threshold; displaying, on a video display device, an interlaced image generated by the steps of testing and modifying, having a suppressed perception of flicker.

Abstract: A system for formatting electronic binary image data, which may be in compressed raster form, into transposed or rotated raster form for storage or output, such as on a printing device, is disclosed wherein the image data is first assembled in a buffer in the form of vectors of run ends representing successive raster scan lines of an original image to be reproduced. The elements of an intermediate buffer are initialized to zero and the data is entered into the intermediate buffer by using each run end to set a bit in the intermediate buffer, with the bits being set in the buffer elements in correspondence with the respective raster positions of the run ends. The elements of the intermediate buffer containing the entered electronic data are then combined, such as by EXCLUSIVE-ORing, to create transposed or rotated raster data, which may stored or input to a suitable output device, such as a printer or display.

Abstract: A system and method for electronically segmenting character components on character-containing documents involving first scanning a document and quantizing the image information obtained by the scanning into two levels, e.g., black and white, by 1 and 0 bits, and from the quantized information, m-bit OR groups are generated by sequentially ORing every m-th bit in a first direction of the quantized image, where m is an integer equal to or greater than two. The black (character) bits in each of the m-bit OR groups are counted and processed using the steps of: sequentially calculating sums of n consecutive count values by shifting one by one the count values obtained by the counting along a second direction perpendicular to the first direction; and then, segmenting character components by comparing the sums with a predetermined threshold value.

Abstract: In contrast to existing light addressed light valves for projection displays which use a homogeneous CdS or Se photoconductive layer as the control element for a liquid crystal cell, a silicon photo-diode array is disclosed which makes an effective control element capable of applying a spatially varying AC voltage across a liquid crystal light valve. Writing may be done with a miniature CRT in an optical or electron excitation mode. It is shown that for a video mode the ratio of diode capacitance to liquid crystal cell capacitance associated with the diode, and the frequency of the applied square wave voltage, define the buildup or decay time of the liquid crystal cell voltage. Thus, the frequency of the applied AC voltage can be used to control sensitivity and transient response and there is no lag. The dynamic range of the cell voltage is shown to depend on the ratio of diode capacitance to liquid crystal cell capacitance.

Abstract: An area fill technique for graphic images is disclosed wherein the contour lines constituting an image are given in a series of line segments or a series of vectors, and horizontal line segments are ignored. Each line segment other than the horizontal ones is specified by the coordinate addresses for the start and end points in one direction, that is, from top to bottom or from bottom to top. Each is then converted into approximate pixels in the X-Y coordinate system, and stored in a random access work memory. The pixels of each line segment are stored in the work memory according to a rule whereby each line segment is represented by one pixel per horizontal line, and is written by taking exclusive OR of its pixels, excluding the start point, with read pixel data at corresponding coordinate addresses in the work memory.

Abstract: An intense electrical discharge along the axis of a capillary having condensed phase (liquid or solid) walls produces a controlled transient plasma temperature of 10 million degrees Kelvin or more. In order to reach such a temperature, the capillary is formed with a suitably small diameter and a sufficiently large aspect ratio and the electrical discharge must have a suitably short risetime and a sufficient high intensity. In the preferred embodiment, the capillary walls comprise thermonuclear fusible material, the plasma temperature reaches at least 60 million degrees Kelvin, and the density-time product is sufficient to produce a useful thermonuclear fusion reaction. The ultra-high temperature capillary discharge can be used as a pulsed source of nuclear and/or x-ray radiation or as a pulsed nuclear fusion reactor.

Abstract: A multiprocessing system is presented for dynamically partitioning a storage module into a global storage efficiently accessible by a number of processors connected to a network, and local storage efficiently accessible by individual processors, including the interleaving of storage references output by a processor, under the control of that processor, and dynamically directing the storage references to first or second portions of the storage module.

Abstract: For recognizing a three-dimensional object from its two-dimensional image which was produced e.g. by a TV camera, a Hough transform representation is generated of the image and specific configurations or structures of the cluster points which constitute the Hough transform representation are determined. The information about these specific configurations is compared to similar information stored for the Hough representation of known object models. By thus relating portions of the image to portions of one or several object models, vertices of the image which are present at line or edge intersections, are related to vertices of the known object model(s). This knowledge about the correspondence of model and object vertex points allows the exact fitting of vertices and thus recognition of the unknown object and its relative orientation.

Abstract: A method for encoding and decoding digital image data, includes the steps of: testing the data for a vertical relationship between adjacent lines of the image; generating directly a reference code word representative of the vertical relationship for each successful test; generating by table lookup a run code word for a stream of data bits of common value for each unsuccessful test whereby a data element representing a number of bits in a code word is stored at a predetermined offset from a table entry for the code word; merging the vertical reference code words and the run code words generated by the above steps to form an encoded data stream; testing the encoded data stream for a reference code; decoding directly the vertical relationship from the reference code for each successful test; decoding by table lookup a run of bits of common value by serial examination of said encoded data stream for each unsuccessful test; and storing data decoded by the above steps in a predetermined relationship.

Abstract: A binary image is reduced in size by a method including the steps of: storing the image in bit sequence; dividing the image into transposable blocks; transposing by look up table, for each block having any nonzero data, each group of 6 bits along a first axis to a group of 5 bits; transposing by look up table, for each block having any nonzero data, each group of 6 bits along a second axis to a group of 5 bits; storing said transposed blocks.

Abstract: A system or scheme for automatic detection of and recovery from transmission errors in the asynchronous communication mode at the data link level with complete transparency at the higher levels is disclosed wherein the transmissions are in the form of a sequence of data packets, and an improved combination of end-of-text (ETX) bytes along with checksums is used in each data packet to detect errors. The ETX character is dynamically selected for each packet after the data comprising the packet has been assembled. This character is coded differently from the remaining character codes in its respective packet and is made the second byte thereof following the start-of-text byte (STX). The third byte in each packet is made the complement of the preceding ETX byte, the latter of which is also made the last byte in the packet. Thus, the second and last bytes in each packet are identical, and different from all the other bytes, and the third byte is their complement.

Abstract: Video images are corrected for shading effects by generating a histogram of picture element (pel) gray scale intensity values and calculating the median and the black and white extremes thereof. A range of permitted background gray scale values is empirically selected such as by calculating the distance between the median and the closest color extreme and setting the range as twice that distance centered at the median. A background image is then created by sampling the intensity values of the original image pels and using a look-up table to remap the image. In one embodiment, pel intensity values are compared with the median value and only corrections lying within the range are carried out. In another embodiment the original image pels are remapped from 8 bits to 5 bits with all values outside the permitted range set to that of the nearest color extreme.

Abstract: An electronic processing system for reproducing mixed images, i.e., original images having areas of continuous tone and areas of text, in such a manner that both areas are of balanced, good quality in the reproduction. The image to be reproduced is (1) divided into non-overlapping 4.times.4 blocks of pixels or picture elements, and, (2) each block is classified as either of TEXT or IMAGE, based on the values of the 16 pixels within it. The classification is improved by (3) eliminating short runs of blocks with the same classification. The pixel values are then adjusted by appropriately (4) thresholding those in the TEXT blocks and, (5) averaging those in the IMAGE blocks. The IMAGE block values are quantized to one of 17 levels using an improved error diffusing process and then mapped onto a 4.times.4 pattern preparatory to (6) merging the binary images for the TEXT and IMAGE areas.

Abstract: To achieve high speed line-thinning, an electronic picture to be processed is divided into sections, and the scanning for line-thinning is performed for each section. If no point removal is performed in the scanning of a section, the line-thinning is completed for that section. When points are removed in the scanning, incomplete areas that require further line-thinning are determined based on positions where the points are removed. In the next scanning, scanning for line-thinning is not performed for all of the sections, but is done for areas within sections that contain the incomplete areas. These areas are smaller than the sections and are variably determined according to the size of their incomplete area. Thus, the area to be scanned is reduced and dynamically controlled. It is because the incomplete areas become smaller and smaller as the scanning is repeated, that the area variably determined according to the size of the incomplete area also becomes smaller.

Abstract: A method and apparatus for converting an image in run representation form into a raster image which is rotated by some multiple of 90.degree. from the orientation of the original image is disclosed wherein the original image data which is stored in run end or run length form may be divided and stored in discontiguous blocks. In implementing a 90.degree. rotation, the image data is conceptually divided into vertical strips, each of which is independently rotated to create a horizontal strip of the output image. The rotation process is carried out by firstly converting the run representation image data to raster form, dividing the data in each row among a number of intermediate buffers, each of which contains the data from one vertical strip of the original image. The contents of each buffer are rotated and rearranged in an available buffer to form a horizontal strip of the rotated image ready for raster readout. Similarly, a convenient method of rotating the input image 180.degree.

Abstract: A system is described for thresholding graphics images to reduce the information content for transmission and reproduction and which uses a particular image data thresholding technique that may be used to obtain display images with a number of intensity levels. Firstly, an histogram of the image to be encoded is generated and analyzed to determine essential parameters. In particular, the background color of the image is determined by summing the histogram elements to find the median of the distribution, that is, the point at which the half sum of total pixels is reached. The extrema of the histogram are calculated and the skew is determined from the position of the median with respect thereto. If the difference between the median and the black extreme is less than half the difference between the median and the white extreme then the background of the image is deemed to be black, otherwise, the image will be defined as having a white background.