Sanyo Electric Co., Ltd.

Victor Company of Japan, Limited

Yutaka Shimizu

Seiya Ota

Teruhiro Yamada

Hideaki Sasaki

Kazunori Chida

Shigeru Sawada

Mitoku Kamei

Teruo Hotta

Isao Tsukaune

Masanobu Koike

A video signal processing circuit includes an input processor configured to modify an input video signal in accordance with image magnification data and a buffer memory for storing the modified video signal. The processing unit also includes a write control unit configured to control a write function to the buffer memory by generating a write control signal in accordance with the image magnification data. The write control unit includes a calculating circuit configured to calculate image size data on the basis of the write control signal in response to a change in the image magnification data. The write control unit also includes an inhibition circuit configured to inhibit the write function to the buffer memory at least while the calculation circuit calculates the image size data. The processing unit further includes a read control unit for controlling reading from the buffer memory in accordance with the calculated image size data. A method of processing a video signal also is disclosed.

Video signal processing

A video signal processing circuit uses a buffer memory for reducing or expanding video signals in the generation of child images to be displayed within a display window. Image size data, stored in a header within the buffer memory, and a reduced video signal are prevented from representing different image reduction ratios which might otherwise occur when the reduction ratio is changed. At the time of changing the reduction ratio, image size data SIZ are calculated from a write enable signal based on reduction ratio data K, for a one-field period just after the change by an input video clock generator 22. The calculated image size data are written to a header together with a reduced video signal in a field memory 2, and a flag bit SP indicating the change in the reduction ratio is also written to the header for the one-field period just after the change. When data are read from the buffer memory, the flag bit SP is detected by a display video clock generator 23 to mute a video signal output when there is a likelihood of displaying distorted data. On the other hand, writing to the field memory 2 is inhibited for the one-field period just after the change in the image magnification data so that the muting period of the video signal output can be shortened.

Video signal processing circuit inhibiting display of distorted images

An input processing section reduces the content of an input video signal according to reduction ratio data, and the reduced video signal is stored in field memories. A display processing section reads a reduced video signal from the field memories to execute window display processing thereto according to video size SIZ data and video position data (X, Y). In this event, an input video clock generator, controlling a writing operation to the field memories, computes video size SIZ data from the reduction ratio data, and writes the SIZ data as a header, along with the reduced video signal, into the field memories via the input processing section. The SIZ data is read to be output to the display processing section and a display video clock generator for controlling reading.

Reduced video signal processing circuit

An input video signal is reduced according to size reduction ratio data K in an input processing section and written into alternate field memories. The written reduced video signal is alternately read from the field memories in a display processing section and processed for window displaying. Video reduction control sections are provided on the respective input and display sides, so that various signals, such as RHOLD, ADCANS, RACK signals, etc., are exchanged therebetween. When a size reduction ratio data K is changed, on the display side a read memory is fixed on a first field memory and size data is fixed, while on the write side video data is written into a second field memory, based on the new reduction ratio. After updating the size data on the display side, video data is read from the second field memory at the new reduction ratio. When reading and writing operations with respect to the second field memory are finished, fixing of the respective memories is released, whereby a signal processing operation returns to a normal operation.

Device for writing and reading of size reduced video on a video screen

An input video signal is written into alternate field memories M1 and M2, according to a timing clock from an input video clock generator. A display video signal is alternately read from those field memories, according to a timing clock from a display video clock generator. In switching a read memory, an address observation circuit judges whether or not a read/write address passes by a write/read address, referring to the condition of reading and writing operations. In this event, the circuit makes a judgement, based on the lag between a vertical synchronizing signals of an input video signal and of a display video signal, and a change of the lag with time. If it is judged that one address will pass by the other, the same read/write memory is again accessed for reading/writing. With this arrangement, there is provided a circuit having a relatively simple structure for preventing a match of read and write addresses.

Video signal processing device for writing and reading a video signal

A write clock signal and a write select signal are outputted from an input video clock generator, a read clock signal and a read select signal are outputted from a display video clock generator, either of first and second field memories is selected as the write memory or the read memory in compliance with the signal level of the respective select signal and writing is carried out in the selected write memory once a predetermined time has elapsed following inversion of the write select signal. When reading has commenced from the first and second buffer memory, a match is detected between the signal levels of the write select signal and the read select signal at each field or at each frame and writing and thus reading address passing is predicted.

Video signal processing circuit for monitoring address passing between

A 4:4:4 component video signal comprising a luminance signal Y and color-difference signals Cb and Cr is transformed to a 4:1:1 component coded video signal coded by a coding device, reducing processing is carried out after transformation and the result is written into the frame memory based on an enable signal. At this point, the pulse number of the enable signal ENy of the reduced luminance signal is counted, the differential between the horizontal pixel number when the reduced color-difference signals are decoded to the original 4:4:4 component video signal and the horizontal pixel number of the reduced luminance signal is determined, a dummy pulse of this differential is generated and the dummy pulse portion only of the writing address of the frame memory for the reduced luminance signal is shifted backwards. Reduced signals read out from the frame memory are outputted after being decoded to the original 4:4:4 component video signal by the decoding device.

Video signal processing circuit for reducing a video signal

The present invention relates to a cursor control device for controlling the display position of a cursor displayed on a display device. The cursor displayed on the display device is remotely controlled by a remote control transmitter. The remote control transmitter is provided with, for example, a light emitting element emitting light rays having a particular wavelength, for example, infrared rays. The position of the remote control transmitter is detected by an imaging device including a CCD. The position of the cursor on a display screen of the display device is controlled on the basis of the detected position of the remote control transmitter.

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Ota, Japan

Yutaka Shimizu