Samsung Electronics Co., Ltd.

Bom-Yun Kim

Jong-seon Kim

Hwa-hyun Cho

Shi-hwa Lee

Je-Kook Kim

Young-wook Jang

Tae-hyeon Sim

Dong-yul Lee

Sang-Jo Lee

Jin-Feng Zhan

A device for data compression includes a domain transformer unit, a classifying unit, a variable length encoder, a fixed length encoder and a memory unit. The domain transformer unit transforms time-domain data into frequency-domain data. The classifying unit determines an encoding type of the frequency-domain data based on occurrence probability of the frequency-domain data. The variable length encoder encodes first frequency-domain data that are determined to be encoded by variable length coding. The fixed length encoder encodes second frequency-domain data that are determined to be encoded by fixed length coding. The memory unit stores the encoded first and second frequency-domain data by relocating the encoded first and second frequency-domain data such that the encoded first frequency-domain data are placed adjacently and the encoded second frequency-domain data are placed adjacently. Therefore, the time for decoding the corresponding data may be reduced.

Devices and methods for data compression and decompression

A contrast control apparatus includes a memory for storing input image signals within one frame and an image reducing unit for selecting at least one image signal of the input image signals. An accumulation value calculating unit calculates accumulation values for predetermined sampling gray values with respect to the selected image signal. An image characteristic decision unit determines at least one characteristic of the selected image based on the accumulation values. A contrast control function calculating unit calculates a contrast control function based on the characteristic of the selected image. A contrast controller controls contrast of the image signals stored in the memory according to the contrast control function.

Contrast control apparatus and method

A method of changing a pixel color includes determining whether a chrominance of a pixel is in a preference chrominance area, where the preference chrominance area is defined as a conic section in a two-dimensional chrominance plane and an eccentricity of the conic section is not greater than 1, and changing the chrominance of the pixel to a preference chrominance to generate a preference pixel when the chrominance of the pixel is in the preference chrominance area. Therefore, the method may set a preference chrominance area in a simple manner, and hardware for setting the preference chrominance area may be easily implemented.

Method and apparatus for changing a pixel color

A variable-length decoder includes a bitstream interface unit and a decoding unit. The bitstream interface unit generates a decoding bitstream for a current decoding process based on an unused decoding bitstream and an input bitstream. The unused bitstream includes unused bits of a previous decoding bitstream. The decoding unit decodes the decoding bitstream to generate a plurality of symbols per clock cycle and provides a next unused bitstream for a next decoding process to the bitstream interface unit.

Variable-length decoder, video decoder and image display system having the same, and variable-length decoding method

Method and apparatus for controlling the light power of an optical disk system, and optical disk system having the same are provided. The optical disk system includes a microcontroller for controlling the operation of the optical disk system, a light power adjusting apparatus for generating a light quantity control signal for controlling the quantity of light emitted from the optical disk, and an optical pickup device for adjusting the quantity of light emitted from the optical disk in response to the light quantity control signal. The method includes the steps of converting E and F beam signals used for generating a tracking error signal into the form of voltage and synthesizing the converted E and F beam signals to obtain a tracking sum signal; maintaining the light power of the light emitting diode when the level of the tracking sum signal is the same as that of a reference signal; decreasing the light power of the light emitting diode, corresponding to the difference between the tracking sum signal and the reference signal, when the level of the travel sum signal is higher than that of the reference signal; and increasing the light power of the light emitting diode, corresponding to the difference between the tracking sum signal and the reference signal, when the level of the travel sum signal is lower than that of the reference signal. The progress of the method returns back to the stop of obtaining a tracking sum signal after increasing or decreasing the light power. Accordingly, the quantity of light reflected from the an optical disk can be constantly maintained.

Method and apparatus for controlling light power of optical disk system, and optical disk system having the same

A control apparatus and method for controlling a velocity of a spindle motor included in an optical disk reproducing system to prevent a forward or backward overrun of a spindle motor are disclosed. A widest signal detector of the apparatus detects the widest pulse width of an eight-to-fourteen modulation (EFM) signal according to a main clock signal and generates a first status signal representing a status of the pulse width of the detected signal according to a frame clock signal, which is divided by a first predetermined number j. A narrowest signal detector of the apparatus generates a second status signal representing a status of the narrowest pulse width of the first status signals according to the frame clock signal divided by a second predetermined number k, where k is greater than j. An overrun controller increases or decreases or holds a previously counted result according to the frame clock signal divided by the second predetermined number and the second status signal. The overrun controller compares the currently counted result with overrun upper limit and lower limit values and generates first and second flag signals braking the rotation of the spindle motor according to the compared result.

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Seoul, South Korea

Bom-Yun Kim