Abstract: A system and method for detecting local motion between image frames are presented. Each image frame may include a plurality of pixels. A first image frame and a second image frame may be received. Values of a first plurality of pixels at first pixel locations of the first image frame may be read. Values of a second plurality of pixels at second pixel locations of the second image frame may be read. The first pixel locations of the first image frame may correspond to the second pixel locations of the second image frame. A first delta function, based on differences between pixel values between the first and second image frames, may be calculated to produce a first output. The first output may be compared to a first one or more thresholds. It may be determined whether local motion has occurred in the second image frame based on said comparing.

Abstract: In various embodiments, temporal filtering may be used to reduce noise over time in a series of video frames. A temporal filter may use previous filtered frames to reduce the noise in a current frame. For example, a temporal filter may filter noise in still parts of an image more strongly than in moving parts of the image. In some embodiments, a temporal filter requiring less processing power may include a method for detecting motion between a set of pixels and applying the temporal filter based on the detected motion. For example, if substantial motion is not detected, the temporal filter for the block of pixels may be stronger (i.e., reduce more noise) than the temporal filter applied to a block of pixels for which substantial motion has been detected.

Abstract: A system and method for detecting local motion between image frames are presented. Each image frame may include a plurality of pixels. A first image frame and a second image frame may be received. Values of a first plurality of pixels at first pixel locations of the first image frame may be read. Values of a second plurality of pixels at second pixel locations of the second image frame may be read. The first pixel locations of the first image frame may correspond to the second pixel locations of the second image frame. A first delta function, based on differences between pixel values between the first and second image frames, may be calculated to produce a first output. The first output may be compared to a first one or more thresholds. It may be determined whether local motion has occurred in the second image frame based on said comparing.

Abstract: In some embodiments, images for the video conference may be white balanced. White balancing may include dividing at least a subset of an image's pixels into multiple ranges according to their luminance and chrominance values. For example, at least a portion of the pixels in an image may be sorted into different groups (i.e., by incrementing counters respective to each group) according to the luminance and chrominance values of the pixels. If enough pixels are found to be in a particular group, a portion or all of the image may be adjusted by a ratio corresponding to that particular group. For example, blue and red analog gains (corresponding to the selected pixels) may be modified by a corresponding ratio to bring red and blue accumulations closer to green accumulations.

Abstract: In various embodiments, multiple participants (at endpoints) may connect through a video conferencing system. A screen may display other participants in the conference call. For example, multiple participants may be displayed in respective portions of the screen. In some embodiments, each of the participants may use video conferencing systems that support different resolutions. In some embodiments, a transcoder may resolution transcode signals to allow the conference call participants to be displayed on each participant's respective screen at up to the highest possible resolution supported by the respective screen. For example, low resolution video conferencing systems may be displayed on a high definition screen of a high resolution system at the low resolution of the low resolution video conferencing system while another image on the same high definition screen from a different, higher resolution video conferencing system, may be displayed at the higher resolution.

Abstract: Various embodiments of a dual-sensor video camera are disclosed. The dual-sensor video camera includes a color filter array (CFA) sensor, which has a low-pass filter. The dual-sensor video camera also includes a panchromatic sensor. A beam splitter directs an incoming light beam to both sensors. An output image is produced based on image information from the two sensors. The output image includes luminance information based on the image information from the panchromatic sensor and chrominance information based on the image information from the CFA sensor.

Abstract: In some embodiments, images for the video conference may be white balanced and/or exposure controlled. White balancing may include dividing an image's pixels into multiple ranges according to their luminance and chrominance values. In some embodiments, blue and red analog gains may be modified to bring red and blue accumulations closer to green accumulations. In some embodiments, luminance values for an image may be adjusted by increasing or decreasing exposure. The decision whether to increase or decrease the exposure may be made by looking at statistics for luminance values of skin colored regions if there are sufficient skin colored regions on the image. Otherwise, luminance values for the entire image may be analyzed to determine whether to increase or decrease exposure.

Abstract: Various embodiments of a dual-sensor video camera are disclosed. The dual-sensor video camera includes a color filter array (CFA) sensor, which has a low-pass filter. The dual-sensor video camera also includes a panchromatic sensor. A beam splitter directs an incoming light beam to both sensors. An output image is produced based on image information from the two sensors. The output image includes luminance information based on the image information from the panchromatic sensor and chrominance information based on the image information from the CFA sensor.

Abstract: A sound or music synthesizer includes a reverberation simulator having a substantially reduced volatile storage, random access memory, or buffer size in comparison to conventional reverberation simulators by decimating the sound signal prior to applying the sound signal to a reverberator and then interpolating the sound signal generated by the reverberator to restore the sample frequency. The substantial reduction in buffer size enables the usage of the reverberator in low-cost, reduced size and single-chip environments.

Abstract: A variable sample rate approximation technique is used for coding and recreating musical signals in a wavetable synthesizer. Many sounds inherently include one large fast transfer of energy followed by vibrations that dampen over time so that the bandwidth requirement of a musical sound is reduced with passing time. Using the variable sample rate approximation technique, musical sounds are classified into two categories, sustaining sounds and percussive sounds. A sustaining instrument creates a noisy stimulus then sustains the sound created by the noisy stimulus. A percussive instrument is also a noisy source and generates a sound signal having high frequencies that decay rapidly while sustaining instruments sustain at all frequencies nearly equally. The sustaining and percussive instruments have substantially different waveform characteristics but present similar conditions with respect to memory reduction.

Abstract: The present invention relates to a tone signal generator. The tone signal generator includes first tone signal generation means for producing a dual-tone, multi-frequency ("DTMF") audio signal; second tone signal means for producing a plurality of non-DTMF audio signals; storage means for storing data that represents at least one channel of an output audio tone signal; and selection means for selectively loading the DTMF signal into the storage means and for selectively accumulating the non-DTMF signals into the storage means so as to generate the output tone signal.

Abstract: A frequency modulation (FM) tone signal generator for generating a FM tone signal is disclosed. The tone signal generator includes a waveform generator having a plurality of wave tables, a selector and an enveloper. The waveform generator furnishes a waveform signal in response to a phase angle address signal. Each wave table stores a different waveform. The selector selects one of the wave tables in response to a plurality of selection signals such that the selected wave table largely provides the waveform signal upon being addressed largely by the phase angle address signal. Selection of the selected wave table varies with each selection signal. The enveloper impresses an envelope signal on the waveform signal. The envelope signal is used as a carrier or modulator for generating the FM tone signal.

Abstract: A frequency modulation (FM) tone signal generator for generating a FM tone signal is disclosed. The tone signal generator includes a waveform generator having a plurality of wave tables, a selector and an enveloper. The waveform generator furnishes a waveform signal in response to a phase angle address signal. Each wave table stores a different waveform. The selector selects one of the wave tables in response to a plurality of selection signals such that the selected wave table largely provides the waveform signal upon being addressed largely by the phase angle address signal. Selection of the selected wave table varies with each selection signal. The enveloper impresses an envelope signal on the waveform signal. The envelope signal is used as a carrier or modulator for generating the FM tone signal.