Including Frame Or Field Delays (e.g., Motion Adaptive) Patents (Class 348/669)
  • Patent number: 6995804
    Abstract: An apparatus for separating color and luminance signals from a composite video signal in consideration of the existence and degree of a motion of the video image. The apparatus includes an output section, a first filter, a second filter, a third filter, a motion detector, a motion estimator, a color selector and a luminance selector. The color and luminance selectors select and output the color and the luminance signal from the output signals of the filters in accordance with the existence and degree of the motion.
    Type: Grant
    Filed: May 8, 2002
    Date of Patent: February 7, 2006
    Assignee: LG Electronics Inc.
    Inventors: Sun Kyu Kwon, Yeong-Ho Ha
  • Publication number: 20040189875
    Abstract: In one embodiment, a method for processing a video signal includes: (1) receiving and storing luminance and chrominance information for each pixel in a first portion of the signal; (2) receiving luminance and chrominance information for each pixel in a second portion of the signal; (3) determining an estimated motion vector for each particular pixel of the second portion by comparing the luminance and chrominance information of the particular pixel to the stored luminance and chrominance information for one or more pixels in a search area of the first portion to determine a pixel in the search area that most closely matches the particular pixel and determining the estimated motion vector according to the particular pixel and the most closely matching pixel; (4) using the estimated motion vector to access the chrominance information for the most closely matching pixel; (5) using a three-dimensional comb filter to filter the chrominance information for the particular pixel and for the most closely matching pixe
    Type: Application
    Filed: March 31, 2003
    Publication date: September 30, 2004
    Applicant: Texas Instruments Incorporated
    Inventors: Fan Zhai, Karl H. Renner
  • Patent number: 6774954
    Abstract: An apparatus and method for a three-dimensional luminance/chrominance (Y/C) seperation comb filter bank. The method and system consider the effect of motions in the temporal domain as the effect of edges in the spatial domain. The method and system apply a temporal filter to the section rule of edge location detection in the spatial domain. With this applications, the three-dimension comb filter bank can separate Y and C from each other freely without motion consideration. The method and system do not simply exploit the topology in the pixel phases. Rather, the method and system consider the Y/C comb filter to operate from the spectral viewpoint. Temporal filtering function is increased to better utilize the memory buffers of the three-dimensional filter. In so doing, balanced usage among the horizontal, vertical and temporal filter functions is achieved using the method and system.
    Type: Grant
    Filed: June 28, 2001
    Date of Patent: August 10, 2004
    Assignee: NDSP Corporation
    Inventor: Jooho Lee
  • Patent number: 6674488
    Abstract: A luminance (Y) and a color difference (C) signal separator switches filters according to an image and separates a Y signal and a C signal included in a composite color picture signal to eliminate a degradation which would otherwise be involved at a transition point because of the characteristics of the filters. A first weighting circuit calculates the weighted average of the C signals extracted from the composite signal by a comb filter and a three-line comb filter. A second weighting circuit calculates the weighted average of the C signals extracted by the three-line comb filter and a two-line comb filter. When the motion level of the image exceeds a predetermined threshold, a selector selects, as the final C signal, the signal output from the second weighting circuit. When the motion level is equal to or lower than the predetermined threshold, the selector selects, as the final C signal, the signal output from the first weighting circuit.
    Type: Grant
    Filed: July 26, 2000
    Date of Patent: January 6, 2004
    Assignee: Oki Electric Industry Co., Ltd.
    Inventor: Yasunori Satoh
  • Patent number: 6667776
    Abstract: A video signal processor, having an input receiving unit for selectively receiving either of a baseband video signal and a composite video signal are selectively input as an input video signal thereto, a 1H delay unit for delaying the selected input video signal by one line period (1H), an inter-line non-correlation component extractor for extracting inter-line non-correlation components between the input video signal and the 1H delay signal from the 1H delay unit, an inter-frame non-correlation component remover for removing inter-frame non-correlation components from the selected input video signal, a first subtractor responsive to the selection of the baseband video signal for subtracting the inter-line non-correlation component from the baseband video signal processed the inter-frame non-correlation component removal at the inter-frame non-correlation component removing means to result noise-reduced baseband video signals, a second subtractor responsive to the selection of the composite video signal the i
    Type: Grant
    Filed: June 9, 1998
    Date of Patent: December 23, 2003
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Sumiyoshi, Naoki Mazda, Hitoshi Kawabata, Seiichi Tanaka, Kazumasa Ikeda
  • Patent number: 6584226
    Abstract: Methods and apparatus for processing video data that is divided into frames are presented. In one aspect, this relates to a method for processing video data that is divided into frames. The video data includes a current frame, which has an associated current macroblock, and an adjacent frame, which also has an associated macroblock. The method for processing video data involves obtaining an uncompressed current block that is a part of the current macroblock and an adjacent block that is part of the adjacent macroblock, and calculating a distance between the uncompressed current block and the adjacent block. It is determined whether the distance between the uncompressed current block and the adjacent block is acceptable. If the distance is unacceptable, then the motion between the uncompressed current block and the adjacent block is estimated, and the uncompressed current block is adaptively compressed.
    Type: Grant
    Filed: March 14, 1997
    Date of Patent: June 24, 2003
    Assignee: Microsoft Corporation
    Inventors: Navin Chaddha, Albert Wang, Sanjeev Mehrotra
  • Publication number: 20020167591
    Abstract: An apparatus for separating color and. luminance signals from a composite video signal in consideration of the existence and degree of a motion of the video image. The apparatus includes an output section, a first filter, a second filter, a third filter, a motion detector, a motion estimator, a color selector and a luminance selector. The color and luminance selectors select and output the color and the luminance signal from the output signals of the filters in accordance with the existence and degree of the motion.
    Type: Application
    Filed: May 8, 2002
    Publication date: November 14, 2002
    Inventors: Sun Kyu Kwon, Yeong-Ho Ha
  • Patent number: 6462790
    Abstract: A digital comb filter for decoding composite video signals into a luminance and a chrominance component. A Fast Fourier Transform (FFT) circuit or a band split filter circuit is used to determine important characteristics of an input video signal without demodulating the video signal. The circuits produce a signature signal by which each of the video lines can be correlated. Signature signals on various surrounding video lines that are of opposite subcarrier phase with the current line are compared to determine similarity and appropriate weighting coefficients for the surrounding lines. If none of the surrounding lines are similar, the comb reverts to a band split filter to form chrominance. A noise measure circuit determines an error signal input used to adjust the weighting coefficients as the noise level increases or decreases. Multiplexer combines high pass and low pass taps of a band split filter into a single data stream.
    Type: Grant
    Filed: August 11, 2000
    Date of Patent: October 8, 2002
    Assignee: Fortel DTV, Inc.
    Inventors: Virgil L. Lowe, John W. Curtis
  • Patent number: 6300985
    Abstract: A composite video decoder that separates digitized composite video signals into luminance and chrominance, demodulates the chrominance signal to its R-Y and B-Y components, removes time base errors, synchronizes the output to the station reference signal and converts three parallel digital signals to a serial digital output signal. A three dimensional digital comb filter, an interpolation circuit for time base correction, a sync error detector circuit, a noise measurement circuit and a means of using the noise measurement level to adapt the other circuits for best operation at various noise levels of the video input signal provide high quality translation from a composite video input to a serial digital interface output (SDI). A digital line recursive filter is used to extract the horizontal synchronizing signal whether the signal is clean or masked by a very high noise level riding on the video signal.
    Type: Grant
    Filed: March 13, 2000
    Date of Patent: October 9, 2001
    Assignee: Fortel DTV
    Inventors: Virgil L. Lowe, John W. Curtis
  • Patent number: 6288754
    Abstract: A video composite signal is thinned by sub-Nyquist sampling signal to reduce a capacity of a memory, a carrier chrominance signal is separated from the thinned video composite signal by an inter-frame YC separation circuit 13, the first separated carrier chrominance signal is interpolated by horizontal interpolation circuit 25 to reproduce the lost data due to thinning, the interpolation data is compensated by an adding circuit 29 in accordance with a high frequency component in a second separated carrier chrominance signal separated without thinning detected by an intra-field YC separation circuit 16 and high frequency component extraction circuit 28 when an edge is present in the separated carrier chrominance signal from the inter-frame YC separation circuit 13, which is detected by an edge detection circuit 26, the first separated carrier chrominance signal is outputted at the timing corresponding to the sub-Nyquist sampling signal, the interpolation data is outputted at an interpolation timing when the ed
    Type: Grant
    Filed: February 19, 1998
    Date of Patent: September 11, 2001
    Assignee: Victor Company of Japan, Ltd.
    Inventor: Kazuki Ito
  • Patent number: 6278495
    Abstract: A digital comb filter for decoding composite video signals into a luminance and a chrominance component. A Fast Fourier Transform (FFT) circuit or a band split filter circuit is used to determine important characteristics of an input video signal without demodulating the video signal. The circuits produce a signature signal by which each of the video lines can be correlated. Signature signals on various surrounding video lines that are of opposite subcarrier phase with the current line are compared to determine similarity and appropriate weighting coefficients for the surrounding lines. If none of the surrounding lines are similar, the comb reverts to a band split filter to form chrominance. A noise measure circuit determines an error signal input used to adjust the weighting coefficients as the noise level increases or decreases. Multiplexer combines high pass and low pass taps of a band split filter into a single data stream. Line delays delay the current video signal to form two additional lines of video.
    Type: Grant
    Filed: March 13, 2000
    Date of Patent: August 21, 2001
    Assignee: Fortel DTV, Inc
    Inventors: Virgil L. Lowe, John W. Curtis
  • Patent number: 5929938
    Abstract: A circuit for separating composite video signals into luminance and chrominance signals in response to motion of a displayed image. A motion detecting section detects motion of an image to be displayed on a television screen according to input composite video signals in order to generate motion sensing signals corresponding to motion of the image. A first comb-filtering section adaptively comb-filters input composite video signals in a vertical direction according correlation among three continuous horizontal scanning lines to separate input composite video signals into first comb-filtered chrominance signals and first comb-filtered luminance signals. A second comb-filtering section adaptively comb-filters input composite video signals in the time direction in response to a correlation between frames in order to separate the input composite video signals into the second comb-filtered chrominance signals and the second comb-filtered luminance signals.
    Type: Grant
    Filed: March 31, 1997
    Date of Patent: July 27, 1999
    Assignee: Daewoo Electronics Co., Ltd.
    Inventor: Hyun-Duk Cho
  • Patent number: 5835162
    Abstract: Upon NTSC broadcasting, switches are respectively electrically connected to the N sides and a three-dimensional comb filter is made up of memories, a subtracter, etc., whereby a carrier chrominance signal is separated from a video signal in accordance with a frame-to-frame process. In this case, the video signal is divided into two signals, which are in turn written into the memories. Upon EDTV2 broadcasting, the switches are respectively electrically connected to the E sides and a three-dimensional comb filter is made up of the memory and the subtracter, whereby a composite signal obtained by combining a carrier chrominance signal and a horizontal resolution supplementary signal is separated from the video signal. The switch is electrically connected to the E side and a three-dimensional comb filter is made up of the memory, a subtracter, etc., whereby a horizontal resolution supplementary signal is separated from a composite signal in accordance with a field-to-field process.
    Type: Grant
    Filed: July 19, 1996
    Date of Patent: November 10, 1998
    Assignee: Sony Corporation
    Inventors: Satoshi Inoue, Minoru Urushihara
  • Patent number: 5786872
    Abstract: An apparatus and method in which a difference between lines in an input composite video signal is calculated. The difference is compared with a specified threshold to detect chrominance correlation. A difference between lines in a composite video signal which is delayed for a one-frame period is calculated. The difference is compared with the specified threshold to detect chrominance correlation. The difference between these chrominance correlations is calculated and is used as a motion detection signal. When this frame difference is smaller than a specified threshold, the motion detection signal is forcibly set to 0.
    Type: Grant
    Filed: July 22, 1996
    Date of Patent: July 28, 1998
    Assignee: Sony Corporation
    Inventors: Shinichirou Miyazaki, Masaharu Tokuhara
  • Patent number: 5589888
    Abstract: Two field memories for supplying a composite video signal of a previous frame to a motion detector are provided in performing a three dimensional Y/C separation. An output of the field memory connected to an input terminal is connected to a two dimensional Y/C separator by a switching circuit when there is a request for a function employing a field memory. When there is no such request, the input terminal is connected to the two dimensional Y/C separator. When there is a request for a still reproducing function employing a field memory, the function is realized by using the field memory employed in a three dimensional Y/C separation.
    Type: Grant
    Filed: July 20, 1995
    Date of Patent: December 31, 1996
    Assignee: NEC Corporation
    Inventor: Kiyoshi Iwasaki
  • Patent number: 5585861
    Abstract: A luminance (Y) and chrominance (C) signals separating filter includes a motion detecting circuit which partially detects a movement of an image utilizing a correlation between frames; an inter-frame YC separating circuit which performs a separation utilizing the inter-frame correlation when the motion detecting circuit detects a still image, and outputs intra-frame YC separated C signals and intra-frame YC separated Y signals; an intra-frame YC separating circuit which partially detects a correlation between fields or between frames and a correlation in a field when the motion detecting circuit detects a moving image, performs a separation utilizing the correlations, and outputs intra-frame YC separated C signals and intra-frame YC separated Y signals; a C signal mixing circuit which mixes the inter-frame YC separated C signals and the intra-frame YC separated C signals in accordance with an output of the motion detecting circuit and outputs motion adaptive YC separated C signals; and a Y signal mixing circu
    Type: Grant
    Filed: November 9, 1994
    Date of Patent: December 17, 1996
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Junko Taniguchi, Noriyuki Yamaguchi, Takuji Kurashita, Mitsuru Ishizuka, Masaharu Yao
  • Patent number: 5579401
    Abstract: Feature grouping of moving rigid bodies in an image is accomplished by processing a sequence of two-dimensional orthogonal projection of a three-dimensional scene containing a plurality of such independently-moving rigid bodies.
    Type: Grant
    Filed: September 7, 1995
    Date of Patent: November 26, 1996
    Assignee: NEC Research Institute, Inc.
    Inventor: C. William Gear
  • Patent number: 5541669
    Abstract: A filter is used for separating luminance and color signals from a composite color television signal in which the frequency of the color signal is multiplexed over the high-frequency region of the luminance signal. When a picture is detected with respect to its motion under frame correlation and if that motion is relatively small, the separation of luminance and color signals is performed based on the interframe correlation. If the motion is relatively large, the separation of luminance and color signals is made based on the interfield correlation. The luminance and color signal separation based on the interfield correlation is attained from a correlation with signals in a field spaced forwardly away from the subject field by one field. This is accomplished by selecting a calculation having the highest correlation in calculations for an objective sample point and a plurality of sample points located about the objective sample point.
    Type: Grant
    Filed: February 13, 1995
    Date of Patent: July 30, 1996
    Assignee: Mitsubishi Denki Kabushiki Denki
    Inventors: Noriyuki Yamaguchi, Takuji Kurashita, Mitsuru Ishizuka, Junko Taniguchi, Masaharu Yao
  • Patent number: 5502509
    Abstract: Motion-adaptive chrominance-luminance separation of a composite video signal is accomplished by comb-filtering the video signal on the time axis, bandpass-filtering the video signal on at least one spatial axis selected according to spatial correlation detected in the video signal, and combining the two filtered results in proportion to motion detected in the video signal. Motion is detected in part by obtaining a one-frame difference signal that has been filtered to eliminate chrominance information; here too the filtering is performed on at least one spatial axis selected according to spatial correlation. Selecting the spatial filtering axes according to spatial correlation enables chrominance and luminance to be separated effectively without unnecessary information loss.
    Type: Grant
    Filed: June 21, 1994
    Date of Patent: March 26, 1996
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takuji Kurashita, Noriyuki Yamaguchi, Mitsuru Ishizuka, Junko Kijima, Hitoshi Hasegawa, Masaharu Yao
  • Patent number: 5500686
    Abstract: A filter for motion adaptive Y/C separation, which is capable of obtaining image of high resolution and little picture quality degradation in the case where an image is switched from static one to motion one or vice-versa, is provided with a filter for extracting Y signal outputting Y signal and a filter for extracting C signal outputting C signal, by detecting whether image is motion one or static one by a motion detecting unit, and when motion image is detected, by detecting partially interframe correlation or correlation in three fields, and according to the detection result, by adaptively switching a plurality of processings for extracting intraframe Y signal and a plurality of processings for extracting intraframe C signal.
    Type: Grant
    Filed: June 7, 1994
    Date of Patent: March 19, 1996
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Noriyuki Yamaguchi, Takuji Kurashita, Mitsuru Ishizuka, Junko Kijima, Masaharu Yao
  • Patent number: 5475445
    Abstract: A filter is used for separating luminance and color signals from a composite color television signal in which the frequency of the color signal is multiplexed over the high-frequency region of the luminance signal. When a picture is detected with respect to its motion under frame correlation, and if that motion is relatively small, the separation of luminance and color signals is performed based on interframe correlation. If the motion is relatively large, the separation of luminance and color signals is made based on interfield correlation. The luminance and color signal separation based on the interfield correlation is attained from a correlation with signals in fields spaced forwardly and rearwardly away from the subject field by one field. This is accomplished by selecting a calculation having the highest among a plurality of calculations for an objective sample point and a plurality of sample points located about the objective sample point.
    Type: Grant
    Filed: July 25, 1994
    Date of Patent: December 12, 1995
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Noriyuki Yamaguchi, Takuji Kurashita, Mitsuru Ishizuka, Junko Taniguchi, Masaharu Yao
  • Patent number: 5473389
    Abstract: A Y/C separating filter apparatus for outputting a carrier chrominance signal and a luminance signal from a color video signal supplied thereto comprises first and second three-dimensional filters for subtracting the color video signal and signals of one or two- frame period-advanced or delayed signals from each other to obtain first and second carrier chrominance signals, a selector circuit for selecting the first and second carrier chrominance signals and an average third carrier chrominance signal to obtain the carrier chrominance signal, and a judging circuit for judging first and second correlations between the color video signal and first or second frame period-advanced or delayed signals, wherein the selector circuit is selected in response to a judged result of the judging circuit, the selector circuit selects the first carrier chrominance signal when the first correlation is higher than the second correlation, the selector circuit selects the second carrier chrominance signal when the second correlat
    Type: Grant
    Filed: November 8, 1993
    Date of Patent: December 5, 1995
    Assignee: Sony Corporation
    Inventors: Toru Eto, Tadao Fujita
  • Patent number: 5457501
    Abstract: A quadrature modulated luminance/color signal separating device applied in a color television receiver. The most suitable luminance/color signal separation is performed by determining sizes of interference components in gross, fine, and superfine structures, thereby solving cross-color, cross-luminance and deterioration of resolution generated in fixed luminance/color signal separation. According to the present device, a control signal properly corresponding to a composite video signal can be generated using a control signal generated in a spectrum distribution adaptive system, and consistency of control signal can be kept by introducing a concept of IIR filter into the control signal. Also, luminance/color signal separation suitable for human visual characteristic can be done, and the luminance/color separating function in a 2-dimensional region can be improved by interference elimination function.
    Type: Grant
    Filed: April 21, 1993
    Date of Patent: October 10, 1995
    Assignee: Goldstar Co., Ltd.
    Inventor: Sung H. Hong
  • Patent number: 5412434
    Abstract: A luminance (Y) and chrominance (C) signals separating filter includes a movement detecting circuit which partially detects a movement of an image utilizing a correlation between frames; an inter-frame YC separating circuit which performs a separation utilizing the inter-frame correlation when the movement detecting circuit detects a still image, and outputs intra-frame YC separated C signals and intra-frame YC separated Y signals; an intra-frame YC separating circuit which partially detects a correlation between fields or between frames and a correlation in a field when the movement detecting circuit detects a moving image, performs a separation utilizing the correlations, and outputs intra-frame YC separated C signals and intra-frame YC separated Y signals; a C signal mixing circuit which mixes the inter-frame YC separated C signals and the intra-frame YC separated C signals in accordance with an output of the movement detecting circuit and outputs movement adaptive YC separated C signals; and a Y signal mi
    Type: Grant
    Filed: March 12, 1992
    Date of Patent: May 2, 1995
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Junko Taniguchi, Noriyuki Yamaguchi, Takuji Kurashita, Mitsuru Ishizuka, Masaharu Yao
  • Patent number: 5386249
    Abstract: In each of various motion detectors operative on composite video signal comprising chrominance component signals as well as a luminance component signal, the chrominance component signals are suppressed with a filter that removes only diagonal high frequencies in the spatial-frequency domain. These diagonal high frequencies in the spatial-frequency domain include the chrominance signal components of the composite video signal if it is in accordance with an appropriate standard, such as that employed by broadcasters in the United States of America. Motion detection is improved by reason of including more of the spatial high-frequency components.
    Type: Grant
    Filed: January 22, 1992
    Date of Patent: January 31, 1995
    Assignee: SamSung Electronics Co., Ltd.
    Inventors: Christopher H. Strolle, Jung W. Ko
  • Patent number: 5373329
    Abstract: A method of detecting a digital color picture movement signal precisely and economically for three-dimensional processing for the purpose of improving TV and VTR picture quality comprises the steps of detecting the differential between the brightness signals of an input digital color picture signal and the preceding picture delayed one frame period, of detecting in the input signal brightness signal components having frequencies in the vicinity of the color subcarrier frequency, and of allowing the passage of the brightness signal having components in the higher frequency range of the color subcarrier frequency.
    Type: Grant
    Filed: February 10, 1992
    Date of Patent: December 13, 1994
    Assignee: NEC Corporation
    Inventor: Shigeo Niitsu
  • Patent number: 5365281
    Abstract: A motion signal detection circuit adapted to a video recording/reproducing apparatus having a frequency unfolding circuit for unfolding a luminance signal of a high frequency component included in the luminance signal of a low frequency component into an original frequency band, comprising a prefilter for eliminating the folding carrier and sidebands thereof included in the video signal unfolded by the frequency unfolding circuit, a comb filter for filtering the output of the prefilter to detect a motion signal, an error compensation circuit for compensating the errors included in the motion signal output from the comb filter.
    Type: Grant
    Filed: June 26, 1992
    Date of Patent: November 15, 1994
    Assignee: SamSung Electronics, Co., Ltd.
    Inventors: Jung-Wan Ko, Christopher H. Strolle
  • Patent number: 5345276
    Abstract: A composite video signal is separated into a luminance signal and a color signal according to spectrum distributions thereof.
    Type: Grant
    Filed: November 24, 1992
    Date of Patent: September 6, 1994
    Assignee: Gold Star Co., Ltd.
    Inventor: Sung H. Hong
  • Patent number: 5339113
    Abstract: In a three-dimensional YC separating circuit including an intra-field YC separating circuit and an inter-frame YC separating circuit, when an NTSC composite video signal is nonstandard and is used for a static image part of an image, a low pass filtering is performed upon a C signal of the inter-frame YC separating circuit, and the low pass filtered C signal is added to a C signal of the intra-field YC separating circuit. Then, a Y signal is obtained by subtracting the combination of the two C signals from the NTSC composite video signal.
    Type: Grant
    Filed: September 24, 1993
    Date of Patent: August 16, 1994
    Assignee: NEC Corporation
    Inventor: Kiyoshi Iwasaki
  • Patent number: 5333054
    Abstract: A video signal processing apparatus capable of improving a signal to noise ratio of a video signal by providing for a first luminance/chrominance separation circuit for still pictures and a second luminance/chrominance separation circuit for moving pictures. Color disturbances on the screen can be avoided by switching between a parallel configuration and a serial configuration of the first and second separation circuits without generating differences in signal delay times.
    Type: Grant
    Filed: December 9, 1992
    Date of Patent: July 26, 1994
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Seiichi Tanaka, Masahiko Mawatari
  • Patent number: 5325186
    Abstract: A filter for separating a color signal and a luminance signal from a composite color television signal in which the frequency of said color signal is multiplexed in a high-frequency region of the luminance signal. In response to the movement of a picture, an appropriate filter is selected from a filter utilizing interframe correlation, a filter utilizing interfield correlation and a filter utilizing the infield correlation. A plurality of filters utilizing filed correlation are prepared and a color signal and a luminance signal are separated by the processing of a principal pixel, which is an object of processing, and pixels different from each other. A filter is selected in accordance with the correlation state between the principal pixel and the pixels therearound.
    Type: Grant
    Filed: September 4, 1992
    Date of Patent: June 28, 1994
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Mitsuru Ishizuka, Noriyuki Yamaguchi