Abstract: Provided is a load driving device controlling a drive of a load including a driver for periodically turning on/off a current according to a switching clock signal and supplying a average driving current to the load. Further provided is a dimming controller for controlling the driver to turn on/off the drive of the load based on a dimming step. Also provided is a controller for controlling at least one of the driver and the dimming controller so as to make a step interval of the dimming step and a switching clock period of the switching clock signal the same. A load driving device is provided that is capable of stably controlling the dimming of a drive of a load, by improving a linear response characteristic of a driving current according to a dimming control.

Abstract: The present invention relates to a display apparatus comprising a light emitting element supplying light, and a switch to switch on and off power, which is supplied to the light emitting element. A comparing unit compares a predetermined first reference voltage and an output voltage which is proportional to a current applied to the light emitting element. A controller compares a comparison voltage output, which is a comparison result of the comparing unit and a predetermined second reference voltage, in order to control the switch to be switched on and off. Accordingly, the present invention provides a display apparatus and control method which precisely controls a size of a current applied to a light emitting element.

Abstract: A highly efficient lighting system, a scrolling unit, and a projection system adopting the highly efficient lighting system and the scrolling unit are provided. The scrolling unit has at least one lens cell. From the viewpoint of light incident upon the at least one lens cell, the rotation of the at least one lens cell is converted into a rectilinear motion of a lens array, such that incident light is scrolled. The projection system includes a light source, an optical splitter, at least one scrolling unit, and a light valve. The optical splitter splits light emitted from the light source according to wavelenght. The at least one scrolling unit has at least one lens cell. The lens cell has an incident side and an emitting side and divides incident light into light beams. The rotation of the lens cell causes a rectilinear motion of the light beams, thereby scrolling incident light.

Abstract: A brightness control apparatus comprising a probability density function (PDF) calculator to calculate a PDF based on pixel values of respective pixels of an input image signal, a first setter to set an upper limit value and a lower limit value with respect to the pixel values that are equal to or smaller than a predetermined level in the PDF, and a brightness value controller to calculate a cumulative distribution function for the PDF controlled by the upper and lower limit values set by the first setter, and calculating brightness levels corresponding to the input image signal based on the calculated cumulative distribution function. The brightness control apparatus controls the brightness of an image signal so as to prevent it from becoming unnecessarily bright or dark when compensating the brightness of an image signal, while also preventing degradation of contrast.

Abstract: Disclosed is a plasma display panel. The plasma display panel comprises a lower substrate and an upper substrate, which are spaced apart by a predetermined distance from each other to define a plurality of discharge cells therebetween; a plurality of barrier ribs disposed between the lower substrate and the upper substrate; a plurality of address electrodes formed in parallel with one another on an upper surface of the lower substrate; a plurality of discharge electrodes formed in a direction crossing the address electrodes on a lower surface of the upper substrate; and a fluorescent layer formed on an inner wall of the discharge cells, wherein the upper substrate comprises a plurality of light guides, which are formed in parallel with the plurality of address electrodes to focus and output visible light generated from the discharge cells by a discharge, the light guides having a light incident surface.

Abstract: A spiral lens disk and a projection system adopting the same are provided. The spiral lens disk has spirally arranged cylinder lens cells and scrolls incident light by converting the rotation of the cylinder lens cells into rectilinear motion of a cylinder lens array. The projection system includes at least one spiral lens disk such that color scrolling is achieved using a single component to form a color image. Due to a reduction in the number of components, a light, low-price projection system can be obtained, and a single-panel projection system with high light efficiency can also be obtained.

Abstract: An image enhancing apparatus and method in which a PDF calculation unit calculates a probability density function according to a distribution of a luminance value with respect to each pixel of an input image. An average brightness calculation unit calculates average brightness of the input image based on the probability density function and an overflow threshold adaptive to the average brightness is calculated. A BUBO unit calculates a probability density function of which a distribution is adjusted, based on the overflow threshold and a predetermined underflow threshold and a cumulative distribution function is calculated with respect to the adjusted probability density function. A CDF compensating unit compensates for an influence that the BUBO unit has on the cumulative distribution function and a mapping unit uses the compensated cumulative distribution function as a mapping function, and adjusts and outputs the luminance value with respect to each pixel of the input image.

Abstract: A brightness control apparatus comprising a probability density function (PDF) calculator to calculate a PDF based on pixel values of respective pixels of an input image signal, a first setter to set an upper limit value and a lower limit value with respect to the pixel values that are equal to or smaller than a predetermined level in the PDF, and a brightness value controller to calculate a cumulative distribution function for the PDF controlled by the upper and lower limit values set by the first setter, and calculating brightness levels corresponding to the input image signal based on the calculated cumulative distribution function. The brightness control apparatus controls the brightness of an image signal so as to prevent it from becoming unnecessarily bright or dark when compensating the brightness of an image signal, while also preventing degradation of contrast.

Abstract: Disclosed is a brightness control apparatus and method capable of adaptively compensating brightness values based on an average brightness of an image signal. The adaptive brightness control apparatus comprises a probability density function (PDF) calculation unit calculating a PDF based on a distribution of pixel values of pixels of an input image signal, a compensation value calculation unit for calculating an average value of the pixel values of the respective pixels, and calculating a function having a predetermined slope according to a range of the average brightness value, and a pixel value compensation unit for re-establishing the distribution of the pixel values based on the calculated function.

Abstract: A contrast compensation apparatus and a method thereof utilize a simplified hardware structure and a low contrast distortion. The contrast compensation apparatus includes a pixel value detection unit to detect a distribution of pixel values of respective pixels of an input image signal, a pixel value limit unit having pre-set luminance limit values and re-configuring the distribution of the pixel values of the respective pixels based on the pre-set luminance limit values, and a mapping unit to set luminance for the respective pixels based on a cumulative distribution function with respect to the re-configured pixel values. When certain portions of an image are rendered very bright or dark, the phenomenon in which the entire image becomes abruptly bright or dark is reduced. Further, the contrast compensation apparatus uses the minimum number of multipliers, adders, and subtractors only, thus having an advantage of simplified structure and using less electric power.

Abstract: A quantization error compensation includes a dividing unit to divide an input current image signal into a first high-frequency signal and a low-frequency signal; a changing unit to replace bits of the first high-frequency signal with a predetermined signal to output a second high-frequency signal; an adding unit to add the low-frequency signal and the second high-frequency signal to create a composite signal; a quantization unit to cut n number of bits of the composite signal and to output the cut composite signal and the n number of bit signal; an equalizing unit to output a brightness equalizing value of the cut composite signal; a calculating unit to calculate a compensation value using the n number of the bit signal and a difference between brightness equalizing values with respect to a current and next brightness levels; and a compensation unit to add the compensation and the current brightness equalizing values.

Abstract: A spiral lens disk and a projection system adopting the same are provided. The spiral lens disk has spirally arranged cylinder lens cells and scrolls incident light by converting the rotation of the cylinder lens cells into rectilinear motion of a cylinder lens array. The projection system includes at least one spiral lens disk such that color scrolling is achieved using a single component to form a color image. Due to a reduction in the number of components, a light, low-price projection system can be obtained, and a single-panel projection system with high light efficiency can also be obtained.

Abstract: A progressive image signal compression coding method and apparatus are provided. If a progressive image signal composed of frames is input in units of fields, the input signal is compression-coded such that one field is compression-coded using only data from itself, and the other field is compression-coded using differential data between the previous field and that field without consideration of a motion vector, based on the characteristics of the input progressive image signal composed of frames. In such a manner, the amount of output data of the second field can be considerably reduced, so that the amount of output data of the first field increases.

Abstract: A 3-dimensional image is generated from an input 2-dimensional image based upon illuminative characteristics of the input image by filtering the 2-dimensional input image with filters of different orientations, outputting base shading images corresponding to the filters, extracting positive pixel values for each base shading image, calculating a difference between the pixel values of the input image and the extracted positive pixel values, calculating a median value of the calculated difference, selecting the filter to output a base shading image of smallest median, outputting a shading image by filtering the input image with the selected filter, combining the input image with the shading image and outputting the 3-dimensional image based upon the combined image. A previously selected filter for a preceding image can be considered when selecting a filter for a current image, enabling generation of 3-dimensional moving pictures.

Abstract: A histogram equalization apparatus for contrast enhancement of a moving image includes a CDF calculator for counting the number of pixels having a gray level from the minimum to the maximum or less with respect to an input image in a frame unit to calculate a cumulative distribution function (CDF) value of each gray level, and a look-up table for updating histogram-equalized level corresponding to each gray level of the input moving image in a frame unit based on the CDF value of each gray level, and outputting a corresponding histogram-equalized level according to a level of the input moving image. Therefore, the histogram equalization apparatus can perform real-time histogram equalization on a moving image with a simple hardware, without using a frame memory, a probability density function (PDF) calculator and dividers for a cumulative density function (CDF) calculation.

Abstract: A vertical filter circuit providing a PIP function, which can be used for constructing a sub-screen when the input signal of a main screen is a double-scanned signal or a HDTV signal, compresses the vertical lines of the sub-screen into two-thirds of the original image. Preferably, the vertical filter includes an array of logical elements, a one line memory, two switches for signal routing and a control signal generator operating selected ones of the logical elements and the switches responsive to the horizontal and vertical sync signals.

Abstract: An interleave detector between a horizontal synchronous signal and a chrominance subcarrier signal comprises a 1H delay part, an adder, a squarer, a low pass filter and a comparator for achieving a high quality of image. The interleave detector detects the interleave between the horizontal synchronous signal and the chrominance subcarrier signal of a composite video signal in such a manner that a burst signal of the composite video signal is 1H delayed and added to the original signal thereof for squaring the added output so as to extract the phase error by filtering the squared output through the low pass filter.

Abstract: A circuit for composing a still sub picture video image for a picture-in-picture (PIP) video display displaying a main picture and a sub picture in an area of the main picture includes a write address generator for storing in a memory the sub picture data of every second line of an input video image field so as to vertically compress the input image field data, along with a read address generator which reads-out the data stored at odd-numbered memory addresses in step with the horizontal sync signal of the first field of the main picture signal to compose a first video field of the sub picture display and which also reads out the data stored at even-numbered memory addresses in step with the horizontal sync signal of the second field of the main picture signal to compose a second video field of the sub picture display, enabling a sub picture consisting of first and second sub picture image fields but composed from the data of only a single input image field to be displayed in step with the corresponding first