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Patent Issued for Image Signal Processor and Method

February 26, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- According to news reporting originating from Alexandria, Virginia, by VerticalNews journalists, a patent by the inventor Park, Hye-joung (Yongin-si, KR), filed on January 17, 2008, was published online on February 11, 2014.

The assignee for this patent, patent number 8648965, is Samsung Electronics Co., Ltd. (Suwon-si, KR).

Reporters obtained the following quote from the background information supplied by the inventors: "Apparatuses and methods consistent with the present invention relate to an image signal processing, and more particularly, to image signal processing in which an input analog image signal is converted into a digital image signal compliant with a system standard.

"An analog image signal is generally classified into a composite video blanking and Sync (CVBS) signal, a super (S) signal, and a component signal. The CVBS signal combines a luminance (Y) signal and a chrominance (C) signal and is transmitted according to one of a Phase Alternation by Line System (PAL), a National Television System Committee (NTSC), and Sequential Color with Memory (SECAM).

"FIG. 1 is a view illustrating a waveform of a related art CVBS signal.

"The waveform illustrated in FIG. 1 represents a horizontal line of one frame of an NTSC image signal. The horizontal line comprises a horizontal synchronization signal (H-SYNC), a color burst signal (COLOR BURST), and a color signal (COLOR) corresponding to values of pixels of one horizontal line.

"The COLOR BURST is a reference signal added for a demodulation of a color when a color image signal is transmitted, and is often referred to as a 'color subcarrier reference signal.' The COLOR BURST is transmitted in a horizontal blanking period where there is no COLOR, and is used at a replay side to demodulate the COLOR based on the waveform.

"In NTSC, amplitude of a normal COLOR BURST without a distortion is 40 IRE (140 IRE=1 V as that of the H-SYNT), and a period of a normal COLOR BURST is approximately 3.58 MHz.

"Most of the image signal processors execute an automatic chroma gain control (ACC) using a COLOR BURST to compensate distortion of an image signal when the size of the image signal is distorted in transmission and reception. That is, the size of a COLOR is adjusted to that of a reference COLOR corresponding a COLOR BURST.

"Amplitude of a COLOR BURST in a normal image signal is 40 IRE, but amplitude of COLOR BURST in a distorted image signal is lower or higher than 40 IRE. If the amplitude of the COLOR BURST is lower than a reference level, the amplitude of the COLOR is amplified to meet the reference level of the COLOR corresponding to the amplitude of the normal COLOR BURST. On the other hand, if the amplitude of the COLOR BURST is higher than a reference level, the amplitude of the COLOR is attenuated to attain to the reference level of the COLOR corresponding to the amplitude of the normal COLOR BURST.

"When the size of a COLOR is lower or higher than that of a reference COLOR, the process of ACC includes multiplying the size of the COLOR by a difference between the size of the COLOR and the size of the reference COLOR to compensate the distorted COLOR. The ACC gain is the multiplier of the multiplication. The multiplication is reiterated by feedback until the ACC gain converges into 1. Accordingly, if a difference is large between the size of a COLOR of an input CVBS signal and the size of a reference COLOR, the ACC takes long amount of time. As a result, transient phenomenon appears on a screen, or a brightness varies slow, and an image quality is deteriorated."

In addition to obtaining background information on this patent, VerticalNews editors also obtained the inventor's summary information for this patent: "Exemplary embodiments of the present invention address at least the above problems and/or disadvantages and other disadvantages not described above. Also, the present invention is not required to overcome the disadvantages described above, and an exemplary embodiment of the present invention may not overcome any of the problems described above.

"The present invention provides an image signal processor which adjusts a variable rate of ACC gain according to distortion of an input color signal, and so compensates rapidly the size of the color signal to enhance an image quality, and a method for processing an image signal thereof.

"According to an exemplary aspect of the present invention, there is provided an image signal processor, comprising a controller which changes an adjustment reference for adjusting gain to compensate the size of an input color signal according to the size of the input color signal; and a decoder which decodes the compensated input color signal.

"The controller may comprise a detector which detects the size of the input color signal; a comparator which compares the size of the input color signal detected by the detector with the size of a predetermined reference color signal; a filter which changes the adjustment reference according to a result of the comparator, and changes the gain to compensate the size of the input color signal; and a compensator which compensates the size of the input color signal according to the gain changed by the filter.

"The filter may comprise an adjustor which adjusts the adjustment reference according to the result of the comparison; and a determiner which determines the gain according to the adjustment reference.

"The controller may change the adjustment reference of each of horizontal lines.

"If a difference between the size of the input color signal and the size of the reference color signal is large, the controller may increase the adjustment reference.

"If a difference between the size of the input color signal and the size of the reference color signal is small, the controller may decrease the adjustment reference.

"The controller may change the adjustment reference by varying multiples of a reciprocal of a result of dividing the size of the input color signal by the size of the reference color signal.

"According to an exemplary aspect of the present invention, there is provided a method for processing an image signal, comprising changing an adjustment reference for adjusting gain compensating the size of an input color signal according to the size of the input color signal, and compensating the size of the input color signal; and decoding the compensated input color signal.

"The compensating may comprise detecting the size of the input color signal; comparing the size of the input color signal detected by the detector with the size of a predetermined reference color signal; changing the adjustment reference, and changing the gain to compensate the size of the input color signal according to a result of the comparator; and compensating the size of the input color signal according to the changed gain.

"The changing the gain may comprise adjusting the adjustment reference according to the result of the comparison; and determining the gain according to the adjustment reference.

"The compensating may change the adjustment reference of each of horizontal lines.

"If a difference between the size of the input color signal and the size of the reference color signal is large, the compensating may increase the adjustment reference.

"If a difference between the size of the input color signal and the size of the reference color signal is small, the compensating may decrease the adjustment reference.

"The compensating may change the adjustment reference by varying multiples of a reciprocal of a result of dividing the size of the input color signal by the size of the reference color signal.

"According to another exemplary aspect of the present invention, there is provided an image signal apparatus, comprising a controller which changes an adjustment reference for adjusting gain to compensate the size of an input color signal according to the size of the input color signal; and a decoder which decodes the compensated input color signal."

For more information, see this patent: Park, Hye-joung. Image Signal Processor and Method. U.S. Patent Number 8648965, filed January 17, 2008, and published online on February 11, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=43&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=2128&f=G&l=50&co1=AND&d=PTXT&s1=20140211.PD.&OS=ISD/20140211&RS=ISD/20140211

Keywords for this news article include: Signal Processing, Samsung Electronics Co. Ltd..

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Source: Electronics Newsweekly


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