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公开(公告)号：CA1210170A
公开(公告)日：1986-08-19
申请号：CA436050
申请日：1983-09-02
Applicant: IBM
Inventor： JUDD IAN D , FARR ROBERT W E
Abstract: In order to compensate for image distortion introduced into a digitally-controlled raster-scan CRT by the finite video amplifier rise and fall times, the digital video drive waveform is subject to selective pulse stretching to extend where possible the duration of pels which represent critical features of the image. This is achieved by decoding means for examining each pel at least in relation to its two immediate neighbours on either side in order to detect predetermined relationships between the values of the pels, and retiming means for selectively advancing or delaying the transitions between consecutive pels of different value in accordance with the relationships so detected. In one embodiment, suitable for multibit or single bit video, the decoding means comprises means for comparing each pel with its immediate successor, a shift register for storing the result of each comparison together with the results of a plurality of immediately preceding comparisons, and a logic circuit connected to the shift register stages, and the retiming means comprises a delay path for the waveform having an output register and means responsive to the logic circuit for clocking the output register at a predetermined time in relation to non-selected transitions, earlier than the said predetermined time in relation to transitions selected for advancement, and later than the said predetermined time in relation to transitions selected for delay.
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Patent Agency Ranking
公开(公告)号：CA1122710A
公开(公告)日：1982-04-27
申请号：CA341987
申请日：1979-12-14
Applicant: IBM
Inventor： JUDD IAN D
Abstract: Data manipulation apparatus is described for converting raster-scanned data received for example from a scanner 2 at a first picture element (pel) resolution to a second lower pel resolution for display for example on a CRT terminal 4. The apparatus includes a scale-changing means 3 which operates on receipt of the image data from the scanner 2 to perform a scale-change operation on the pels, first in the image row direction and then in the image column direction. The row scale-change operation is performed by scale-change projector 5 which functions to replace sub-groups of pels in the input image rows by single pels at its output. The number of pels in the sub-groups are determined by the degree of compression required to convert to the lower pel resolution. The significance of the output bits replacing the sub-groups is determined in accordance with predetermined algorithms having regard to the significance of pels in a selected horizontal 'window' of pels which includes the sub-group of pels under consideration. The image data emerging from projector 5, consolidated in the row direction, is further processed by a second scale-change projector 6 which performs the column scale-changing operation. The projector 6 operates in a similar fashion to projector 5 except that in this case sub-groups of pels in the image column direction are replaced by single pels at its output. Again, the size of the sub-groups are determined by the degree of compression required to convert to the lower pel resolution. The significance of the output pels replacing the sub-groups is determined as in the previous step in accordance with predetermined algorithm having regard to the significance of pels in a selected vertical 'window' of pels which includes the sub-group of pels under consideration.
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公开(公告)号：CA1089988A
公开(公告)日：1980-11-18
申请号：CA290070
申请日：1977-11-02
Applicant: IBM
Inventor： EVANS JOHN M , JUDD IAN D , LOVIE RICHARD H , MINSHULL JOHN F
IPC: H04N5/262 , G06K9/54 , G06T3/00 , G06T9/20 , G06T11/20 , G09G5/36 , H04N1/411 , H03K13/02 , G06F3/05
Abstract: Graphical data on a document is raster scanned and the resulting bit pattern is processed to provide a processes-bit-pattern which represents single-pel-wide lines indicative of the shapes of objects scanned on the document. These single-pel-wide lines may represent the outlines of objects on the centre lines. The processed bit pattern is then passed to a line follower in which bits representing contiguous pels are detected and tested for linearity. When contiguous pels fall the linearity test, a new vector is started and the vector being tracked is terminated. Hardware for performing these operations is described. The resulting vector list is stored until needed for display etc. Optionally a display station can be used to correct faulty vectors or to encode alphanumeric data in a more convenient format than vector coding.
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公开(公告)号：GB2252020A
公开(公告)日：1992-07-22
申请号：GB9026336
申请日：1990-12-04
Applicant: IBM
Inventor： SHAH VINAY VELJI , JUDD IAN D , BEER REGINALD
Abstract: Described is a system and method of communicating between first and second nodes connected by a serial link wherein the data is transmitted between the nodes in the form of packets made up of multiple bit frames. Each packet that is correctly received by the second node is acknowledged by means of a pair of multibit frames. These frames may be interleaved among the frames making up any outgoing data packet that is being transmitted by the second node. The technique employed provides unambiguous acknowledgment of each data packet and if a data packet is received incorrectly, the packet is available in a buffer in the first node for resending.
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公开(公告)号：GB2250897A
公开(公告)日：1992-06-17
申请号：GB9026338
申请日：1990-12-04
Applicant: IBM
Inventor： SHAH VINAY VELJI , JUDD IAN D , GRAINGER BERNARD JOHN , COCKBURN GORDON JOHN
Abstract: Described is a method of error recovery in a data communication system of the kind comprising two nodes connected by a serial link and wherein data is transmitted between the nodes in the form of packets of a predefined format. Each node receives data over an inbound line and transmits data over an outbound line. When an error is detected, both notes enter a link check state, invoke a Link Error Recovery Procedure (ERP) and exchange status by means of Link Resets. Error recovery is performed separately for each line. Each node is responsible for recovering packets that were lost on its outbound line. In normal operation of the link, the transmitter does not reuse a packet buffer until it has received a response from the connected node indicating that the packet was correctly received. Therefore, when an error occurs, the affected packets are still available for retransmission.
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公开(公告)号：CA1160352A
公开(公告)日：1984-01-10
申请号：CA364796
申请日：1980-11-17
Applicant: IBM
Inventor： JUDD IAN D
Abstract: EQUIPMENT TO CORRECT ABERRATIONS OF A CATHODE-RAY BEAM Aberrations of an electron beam are corrected as the beam is scanned across the screen of a cathode-ray tube by deriving correction signals from stored digital values by means of the calculus of finite differences. The digital values, which are the initial differences of polynomial correction functions, are held in store 10 and summed in adder 20, the results being converted by digital-to-analogue converter 50 to analogue signals and supplied to the cathoderay tube. Provision is made for the reduction of error in the calculations by shifting higher order differences relative to lower order differences before addition. The circuitry may be implemented on a single chip. Preferably the inventtion is applied to the correction of misconvergence in a shadow mask tube. UK9-79-004
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