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Patent Issued for JPEG Decoder Capable of Scaling and Scaling Method Using the Same

August 26, 2014



By a News Reporter-Staff News Editor at Journal of Technology -- From Alexandria, Virginia, VerticalNews journalists report that a patent by the inventors Shim, Jae Oh (Seoul, KR); Kim, Jogn Phil (Seongnam-si, KR), filed on November 3, 2010, was published online on August 12, 2014.

The patent's assignee for patent number 8805108 is Siliconfile Technologies, Inc. (Seoul, KR).

News editors obtained the following quote from the background information supplied by the inventors: "The present invention relates to a JPEG decoder capable of scaling and a scaling method using the same, and more particularly, to a JPEG decoder having a scaling function, which scales and outputs an image file through the use of an inverse discrete cosine transform (IDCT) circuit included in the decoder, without a separate circuit for scaling, while increasing a decoding speed, and a scaling method using the JPEG decoder.

"Joint Photography Experts Group (JPEG) is an international standard for compression of still color images. JPEG compresses image information through the use of various algorithms, including Discrete Cosine Transform (DCT), Quantization, Variable Length Coding, etc.

"Especially, JPEG is used in various fields, such as a digital camera, a mobile image sensor (CIS), etc., and recently, JPEG has been so widely used in a mobile field. When the conventional JPEG decoder for mobile is implemented with a general algorithm, the decoding speed is slow, which is not suitable for real-time output in mobile LCD displays.

"Also, since the mobile LCD displays do not generally require a high output resolution, the mobile LCD displays employ a scheme of outputting an image of a low resolution through scaling.

"For reference, although a high-resolution image provides a superior visual quality to that of a low-resolution image, it is necessary to use a low-resolution image in order to be matched with a bandwidth and other peripheral circuits.

"An image scaling method employs a scheme in which most of. the entire scene of an image before scaling is maintained while the size of the image is reduced. Although the scene of an original image is completely remained in an image after scaling, the scaled image is expressed in a lower resolution. Most of general scaling schemes scale an image in such a manner as to equalize pixels with an equal weighting in a specific image area, and then to discard a predetermined part of the entire pixels in the area.

"However, such a scaling scheme requires a separate functional block for scaling an image output from a JPEG decoder, thereby increasing the product size, and additionally increasing time required in a scaling block, which makes it impossible to output an image file in real time required, particularly in the mobile field."

As a supplement to the background information on this patent, VerticalNews correspondents also obtained the inventors' summary information for this patent: "Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and an object of the present invention is to provide a JPEG decoder having a scaling function, which can increase a decoding speed through the use of an inverse discrete cosine transform (IDCT) circuit included in the JPEG decoder, without using a separate block for scaling, and also can output an image with a desired resolution, and a scaling method using the JPEG decoder.

"In order to achieve the above object, according to one aspect of the present invention, there is provided a JPEG decoder having a scaling function, the JPEG decoder including an inverse discrete cosine transform block, wherein the JPEG decoder selectively performs an inverse discrete cosine transform on a part of pixel data of a macroblock through the inverse discrete cosine transform block and outputs a scaled image file.

"According to another aspect of the present invention, there is provided a scaling method of a JPEG decoder, the method including the steps of: (a) outputting encoded data as serial data through variable length decoding; (b) re-ordering the serial data in an 8.times.8 macroblock, which is a two-dimensional arrangement format; dequantizing and outputting pixel data of the 8.times.8 macroblock according to a scaling control signal; and (d) performing an inverse discrete cosine transform only on data of a pixel which is selected from among the dequantized 8.times.8 pixels according to the scaling control signal, and outputting an image file."

For additional information on this patent, see: Shim, Jae Oh; Kim, Jogn Phil. JPEG Decoder Capable of Scaling and Scaling Method Using the Same. U.S. Patent Number 8805108, filed November 3, 2010, and published online on August 12, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8805108.PN.&OS=PN/8805108RS=PN/8805108

Keywords for this news article include: Siliconfile Technologies Inc..

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Source: Journal of Technology


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