Abstract: The invention relates to a system in which given search keys are evaluated, segment by segment, to search through tree-structured tables for finding an output information corresponding to the longest matching prefix. For at least one of the segments, only selected bits of the search key segment are used as index for accessing an associated table where test values are stored which are to be compared to the respective search key segment. The bits to be selected are determined by an index mask, reflecting the distribution of the valid test values in the table entries (and valid search key segment values). This allows table compression for minimizing storage requirements and search time. A procedure is disclosed for generating an optimum index mask in response to the set of valid test values.

Abstract: Method and system for selecting and accessing multimedia information/services located on a user workstation or on a server by touching finger items that are electronically illuminated over the surface of a hard-copy document or any other physical surface. The system includes: an opto-touch foil, placed over (or under) a portion of the document, used to highlight hyperlinked items over the surface of the physical document and to read coordinates of these hyperlinked items; and a user workstation for accessing the information/service associated with the hyperlinked items. Hyperlinked items are illuminated by the luminous signal for identifying and selecting hyperlinked items. When a user selects an item, the workstation receives a signal indicating the position of this selected item. The user workstation identifies, locates and accesses the information/service associated with the position of the selected item.

Abstract: The present invention provides methods and apparatus to distinguish and/or separate an object from a background. The methods use backgrounds of known and/or advantageous texture. In an embodiment, a measure of image texture, namely the spatial frequency is used to distinguish and/or separate an object from its background. The use of image texture overcomes limitations of chroma keying used as a processing technique in photography for object-background separation. This is useful in the separation of image pixels belonging to the object of interest from image pixels belonging to the background.

Abstract: A pulse Doppler, laser radar as described which includes master laser whose output Fo is shifted in frequency by dF(t) during its amplification. The dF(t) frequency shift is compensated by providing a modulator which modulates the master laser output frequency Fo with a local oscillator signal Fl. A first mixer is provided which combines the shifted master laser frequency signal and the local oscillator modulated, master laser output so as to eliminate the master laser frequency Fo from the combined signals. A second mixer is provided for combining the reflected, Doppler shifted laser signal with the local oscillator modulated, master laser output signal Fo+Fl to eliminate the master laser output frequency Fo from the combined signal. Additional detection circuitry is provided to determine the difference in frequencies of the combined signals from the first and second mixers so as to isolate the Doppler shift signal from the amplifier-induced shift dF(t).

Abstract: A pulse train in the presence of random noise and other pulse trains is identified by controlling pixels in a raster display in accordance with incoming signals; using the raster display to modulate a laser beam with the pulses; Fourier-transforming the modulated beam, then performing a Cartesian to polar coordinate transformation on the Fourier-transformed beam; inverse Fourier transforming the coordinate-transformed beam, and passing the result through a line spatial filter and focusing the filtered beam on a one-dimensional detector array.