Abstract: An automatic door system includes a motor which drives a door to open and close. A CPU operating in accordance with a signal from an encoder operatively coupled to the motor detects the position of the door and prepares and applies a control signal based on the detected door position to a motor drive unit. The motor drive unit alternately drives and brakes the motor. The CPU calculates the speed of the door at a particular door position on the basis of the signal from the encoder and operates to make the door speed equal to the aimed speed for the current door position.

Abstract: Host multiple-byte character generator processing of guest keyboard events is blocked during applications sharing. A guest keyboard driver generates guest keyboard events which may be processed by any guest multiple-byte character generator. The guest events are transmitted to a host for use in shared applications. A patch instruction is written over a host storage queue which causes a jump to a patch subroutine when an attempt is made to deposit host keyboard events in the storage queue. Host keyboard events are marked by the patch subroutine and the marked host events are deposited in a shadow queue which is disposed in parallel with the host storage queue. Guest events also are deposited in the shadow queue. Untranslated host and single-byte character guest events, are stored in the host storage queue. When a shared application requires data from the host storage queue, the outgoing event is examined for origin, such as by examining the shadow queue.

Abstract: A door panel is actuated when an actuator sensor disposed near the door panel senses an object approaching the door panel. When a safety sensor mounted on the door panel senses an object while the door panel is opening, the door panel is stopped. When a safety sensor mounted on the door panel senses an object while the door panel is closing, the door panel is opened. Each of the sensors includes a light-emitting unit, a light-receiving unit and a control unit, and the sensor can detect for itself failure in any of the light-emitting unit, the light-receiving unit and the control unit.

Abstract: A power supply apparatus includes a housing containing therein a component which generates heat when operating, a fan for cooling the heat-generating component, and a driving unit for driving the fan. The housing also contains therein a temperature detector for detecting the temperature in the housing and providing a detected-temperature representing signal. In response to the detected-temperature representing signal, a control unit provides the driving unit with a control signal to change the rotation speed of the fan.

Abstract: An intelligent start for a block-matching search is employed. Motion vectors which have been calculated for immediately adjacent blocks in the same image and for corresponding blocks in previous images are used. If the region upon which motion estimation is being performed is uniform and there is no disturbance motion estimation may be very fast. If there are many discontinuities, for example edges, then a more extensive search is required. To do this, possible candidate vectors are searched and a comparison measure is obtained for each. From these the best match is determined . A local fine search is then performed. The best motion vector can usually be found by examining only a few well-chosen candidate vectors. This greatly improves the efficiency of the search.

Abstract: Blocks of video frames are classified for encoding, for example, as empty blocks, inter blocks, or Intra blocks. This block classification is based on (at least) one statistical measure for each block. The classification is based on a comparison of the statistical measure for each block to a threshold value, but the threshold value can change, for example, from block to block or from frame to frame. In a preferred embodiment, the threshold values change as quantization (Q) level changes. In embodiments in which more than one statistical measure is used for block classification of each block, the more than one corresponding threshold values change as Q level changes.

Abstract: A current level of a virtual transmission buffer is maintained and used to select video frames for compression. The current level is compared to a threshold to determine whether to compress the current frame. The threshold is dynamically maintained between an upper "full" level and a lower "clear" level. If the current level exceeds the full level, the video compression processing is changed to a decline mode in which the threshold is gradually decremented towards the clear level. In addition, if the current level exceeds a "watch" level for too long, then the video compression processing is also switched to the decline mode. The present invention allows the virtual buffer to absorb variability in compressed frame size from frame to frame without resulting in undesired latency.

Abstract: Video signals are encoded and decoded using a set of quantization tables that is generated from a base matrix and a scale matrix, which are both explicitly encoded into the encoded video bitstream. The sets of quantization tables may be changed as often as needed as long as the new base and scale matrices are explicitly encoding into the bitstream.

Abstract: A computer-implemented method and apparatus for encoding pictures of a sequence of pictures. According to a preferred embodiment, an encoding system determines a relatively fixed background of the sequence of pictures, and transmits the background to a decoding system. Foreground objects of a current picture are separated from the background, and motion compensation encoding of the foreground objects is performed with respect to at least one previous picture. The encoded foreground objects are then transmitted to the decoding system.

Abstract: Video signals are encoded by dividing a current video frame into regions and generating a local complexity measure and a local quantization level for each region, where the local quantization level is selected using the local complexity measure, a previous complexity measure corresponding to a previous video frame, and a previous quantization level corresponding to the previous video frame. The complexity measures are generated using the DCT coefficients for each region. The region is encoded using the local quantization level to generate an encoded bit stream corresponding to the current video frame.

Abstract: Digital video data is transmitted by sending significant pixel data differences, column by column, within the same frame rather than differences between corresponding pixel data of adjacent frames; a "no change" signal is transmitted when a difference between corresponding pixel data of adjacent frames is not significant (i.e. less than a fixed minimum threshold value). This method eliminates the necessity of storing a previous frame's data at the receiver while computing the subsequent frame's data. The technique also eliminates "bleed-through" artifacts sometimes experienced in the prior art during scene transitions.

Abstract: Information for forming a predicted image having at least two blocks sharing a common border is evaluated to determine whether a discontinuity exists at the common border. If it is determined that a discontinuity exists at the border, the predicted image is filtered in the vicinity of the border.

Abstract: A prediction block is generated using a first region of a first reference frame and a second region of a second reference frame. A current block of a current frame is compared to the prediction block, where the comparison is based on a set of match points from the current block and a corresponding set of match points from the prediction block. The current block is processed based on the comparison of the current block to the prediction block. For each match point of the prediction block, a table index is generated from a pixel of the first region and either a pixel of the second region or an offset value, and a corresponding entry is retrieved from a lookup table using the table index. The comparison of the current block to the prediction block is based on the lookup-table entries for the prediction block. In a preferred embodiment, prediction blocks are generated for motion-estimation processing for bi-directionally predicted (B) frames of certain video encoding standards such as the H.263 standard.

Abstract: A method, apparatus, and storage medium for receiving, with a callee of a data conferencing system, a data conferencing call from a caller of the data conferencing system. An answering machine answers the call if the callee does not answer the call. A pre-recorded callee greeting is displayed to the caller to notify the caller that the callee is not answering the call, and the caller is prompted to leave a message.

Abstract: Histograms are generated for one or more of the image components. Each histogram is clipped at each end to exclude outlying values and to identify initial minimum and maximum values. Conservatism terms are included in each of the initial minimum and maximum values to generated final minimum and maximum values that are used as thresholds to define the color range used in chroma-key processing. In one embodiment, the first frame of a video sequence is designated as a chroma-key frame that is analyzed to determine the chroma-key color range.

Abstract: Input signals in floating-point format are converted into output signals in integer format while handling saturation cases appropriately. Saturation exists when the value of an input signal is outside the output range. Saturation cases are detected by invoking an integer comparison instruction using signals in floating-point format as inputs to tile integer comparison instruction. When implemented in software on processors such as the Intel.RTM. Pentium.TM. processor, using an integer comparison instruction to compare signals in floating-point format provides more efficient signal conversion than conventional schemes that use a floating-point comparison instruction to compare floating-point signals.

Abstract: A heterogeneous multimedia stream has interleaved samples of two or more different substream types. For example, a heterogeneous video stream may have interleaved intra, predicted, and bi-directional frames. In addition to a global bit bank, a different bit bank is maintained for each different frame type. A global quantization level is selected for each frame based on the global bit bank and the bit bank for the corresponding frame type. The frames are encoded using the selected global quantization levels. In a preferred embodiment, the number of bits available for encoding frames differs based on the frame type. In addition, any unused bits from encoding the current frame are shifted from the bit bank corresponding to the current frame type to a bit bank of a different frame type.

Abstract: An odd pixel and an even pixel of a row of an image are selected in accordance with digital differential accumulator processing. An odd-pixel weight factor and an even-pixel weight factor are selected in accordance with the digital differential accumulator processing. A weighted odd-pixel image signal is generated by multiplying an image signal corresponding to the odd pixel by the odd-pixel weight factor and a weighted even-pixel image signal is generated by multiplying an image signal corresponding to the even pixel by the even-pixel weight factor. A horizontally scaled image signal is generated by adding the weighted odd-pixel signal and the weighted even-pixel image signal.

Abstract: A method, apparatus, and storage medium for encoding data. According to one embodiment, the data is encrypted with a variable encryption technique, and the encryption is varied to prevent oversaturation of a processor. According to another embodiment, a method, apparatus, and storage medium for decoding data. Encrypted data is received and decrypted, wherein the encrypted data has been generated by encrypting the data with a variable encryption technique, wherein the encryption is varied to prevent oversaturation of a processor.