512 results about "Black level" patented technology

A display provides increased contrast and resolution via first LCD panel energized to generate an image and a second LCD panel configured to increase contrast of the image. The second panel is an LCD panel without color filters and is configured to increase contrast by decreasing black levels of dark portions of images (making them blacker or darker) using polarization rotation and filtration. Preferably, the second LCD panel is of higher resolution than the first LCD panel. The panels may be directly illuminated or edge lit, and may be globally or locally dimmed monochrome or multi primary lights that may also include individual control of color intensities for each image or frame displayed. The panels may be placed in any order, but preferably are arranged such that active layers in each panel are as close together as possible. Brightness is maintained by the combination of reusing polarization between the panels and by not going through more than one set of color filters. Improved contrast is a result of using multiple light modulators in series.

The challenge of the present invention is to suppress a variation in brightness of an image and make a reference value of a black level converge at an appropriate value in a short time. Acondition judgment circuit judges whether or not a frame of an amount of change in gains of a variable gain amplifier being equal to or greater than a threshold continues for a predefined frames or more. If a frame of an amount of change in the gains being equal to or greater than the threshold continues for the predefined frames, a black level value of the current frame is set for new black level reference. If not continues for the predetermined number, the previous black level reference value is retained in lieu of correcting the black level.

A solid state imager includes an arrangement for converting analog pixel values to digital form on an arrayed per-column basis. An N-bit counter supplies an N-bit DAC to produce an analog ramp output providing a ramp signal with a level that varies corresponding to the contents of the counter. Latches or equivalent digital storage elements are each associated with a respective column. A counter bus connects the counter to latch inputs of said latches, and comparators associated the columns gate the latches when the analog ramp equals the pixel value for that column. The contents of the latch elements are transferred sequentially to a video output bus to produce the digital video signal. There can be additionally black-level readout latch elements, for storing a digital value that corresponds to the dark or black video level, and a subtraction element subtracts the black level value from the pixel value to reduce fixed pattern noise. An additional array of buffer latches can be employed.

A semiconductor image sensor is provided that includes an on-chip temperature-sensitive element. The signal output of the temperature-sensitive element is used to determine a black level value for the image sensor and to calculate a color correction value to be applied to the signal output of the semiconductor image sensor. The signal output of the temperature-sensitive element may be determined by time-averaging a series of signal outputs from the temperature-sensitive element. The temperature-sensitive element signal output may also be determined by combining, e.g., averaging, the signal outputs of a plurality of on-chip temperature-sensitive elements.

A front projection screen (S) has a front shading sheet (5) facing a viewing side (A), and formed of a transparent material. The front shading sheet (5) has a front surface facing the viewing side (A), provided with a plurality of horizontal, parallel, minute ridges (8) having a triangular cross section and each having an upper side surface coated with a shading layer (9). A transparent filler layer (13) of a material having a refractive index nearly equal to that of the transparent material of the front shading sheet (5) is formed on the rear surface (4) of the front shading sheet (5), transparent glass beads (12) are embedded uniformly in a plane in the rear surface of the transparent filler layer (13), the rear surface of the transparent filler layer (13) is coated with a white, reflecting adhesive layer (11), and an opaque film (10) impermeable to light is applied to the rear surface of the reflecting adhesive layer (11). Horizontal end parts of an image displayed on the front projection screen (S) do not become dark, the front projection screen (S) has a large viewing angle, does not reflect an environmental image even in a light environment, and is capable of displaying a high-definition image having a high black level and a high contrast.

An image sensor and a pixel reading method used this image sensor, in which the accuracy of a black level can be increased by that an optical black region being the black level reference of signals is read every horizontal line at a local or random access mode, are provided. And also the structure of a camera system used this image sensor can be simplified is provided. The image sensor is a MOS type image sensor composed of a pixel array region and an optical black region disposed at the one end in the pixel array region. And the MOS type image sensor provides a mode selector that selects the local access or random access mode or a frame access mode. When the local access or random access mode is activated, the image sensor decides a pixel reading region in the pixel array region. The image sensor reads information of one or more pixels having a designated horizontal line address in the pixel reading region every horizontal line address. After this, the MOS type image sensor reads information of one or more pixels having the same designated horizontal line address in the optical black region.

A CMOS image sensor includes an image pixel array, a dark pixel array, data bit liens, reference bit lines, a driver, comparators, and analog-to-digital converter (“ADC”) circuits. The image pixel array generates analog image signals in response to incident light. The dark pixel array generates analog black reference signals for analog black level calibration of the analog image signals. In one embodiment, the data bit lines each coupled to a different column of image pixels of the image pixel array and the reference bit lines each coupled to a different column of black reference pixels within the dark pixel array. The driver is coupled to the reference bit lines to drive an analog black reference signal. The comparators each couple to one of the data bit lines and each coupled to an output of the driver and offset the analog image signals with the analog black reference signals in an analog domain. The ADC circuits each coupled to an output of a comparator.

A method and a system for the compensation of Fixed Pattern Noise (FPN) in digital images have been achieved. The FPN compensation is based on processing done during the production of said images. The fixed pattern noise is here defined as the fixed pattern seen in the individual pixel offsets. The fixed pattern noise is uncorrelated noise but it has a statistical distribution that can be scaled to fit all images. The general idea is to measure the distribution for each individual camera, compress it, and save it in the module. For each image that is then taken with the module the noise pattern can be retrieved and rescaled to fit the image. Covered pixels are employed to normalize the FPN data to the current frame. In order to minimize memory requirements a compression scheme has to be used. A method combining a quantization step with a non-lossy compression is used. The black level is corrected for as part of the operation.

A black clamp circuit for an image sensor utilizes a differential programmable gain amplifier and a feed-back loop to adjust a black level based on comparison to a reference black level. The gain (and therefore step size and range) of the feed-back loop constant for all programmable gain amplifier gain settings. The gain of the fee-back loop is kept constant by adjusting the values of programmable capacitors in the circuit.

To appropriately adjust luminance and a black level even when characteristics of an organic EL display element should be changed due to an environmental change or heat self-generation, to display a stable image. A current detector detects a level of a total panel current flowing in an organic EL panel. The detected level is subjected to A / D conversion before being supplied to an adder. Meanwhile, a video signal is supplied to a current calculator 24 to be converted into data corresponding to the level of a total panel current, before being supplied to the adder. The adder then compares an average total panel current level, estimated based on a video signal, and an actual total panel current level, to obtain a difference so that a black level for image data to be supplied to the panel is adjusted according to the difference.

A technique for providing a liquid crystal display device which has an excellent production yield but little orientation fault.A liquid crystal display device in which an orientation regulating member 108 including a trunk portion 108a and a branch portion 108b is formed between a seal member 112 and a liquid crystal 114 so that not only a mechanical strength is enhanced but also the liquid crystal molecules can be homogeneously arrayed to establish a satisfactory black level when no voltage is applied, thereby to improve the contrast.

Various techniques are provided herein for processing raw image data in front-end processing logic of an image signal processing system. In one embodiment, the front-end processing logic includes a statistics processing unit configured to process raw image data acquired by an image sensor to obtain one or more sets of statistics. The statistics processing unit may first correct defective pixels in the raw image data and then correct lens shading errors in the raw image data prior to extracting the statistics information. In certain embodiments, black level compensation may be applied between the defective pixel correction and lens shading correction steps, and inverse black level compensation may be applied between the lens shading correction step and the extraction of the statistics information. The acquired statistics information may be utilized by an image signal processing pipeline for converting the raw image data into a color (e.g., RGB) and / or luma (e.g., YCbCr) image.

The control inputs of reset switch elements 41 to 45 are commonly connected to a row reset line 51. In a line black clamp type, cathodes as reset ends of photodiodes (31) of optical black pixels 21 to 23 are commonly connected to a potential averaging line 30. In a frame black clamp type, potential averaging lines are connected similarly to respective pixel rows on the vertical scanning start side of an optical black pixel region, and the potential averaging lines may be commonly connected to each other to operate just like one pixel row. A first block includes a pixel array and a vertical scanning circuit, while a second block includes sample and hold circuits, a horizontal scanning circuit, an amplifier and an A / D converter 19. In a low power consumption mode, power supply to the second block is ceased in a light integration period of one frame with performing light integration in the pixel array, power supply to the first and second blocks is performed in a read-out period of one frame to read out integrated signals, and power supply to the first and second blocks is ceased in a power-off period of one frame.

There is provided a solid-state imaging device including: a plurality of aperture pixels configured to be used for capturing of an image; a plurality of first light-shielded pixels configured to be shielded from light for detection of an optical black level, a temperature dependence of a dark current in the first light-shielded pixels being larger than a temperature dependence of a dark current in the aperture pixels; and a plurality of second light-shielded pixels configured to be shielded from light for detection of an optical black level, a temperature dependence of a dark current in the second light-shielded pixels being smaller than a temperature dependence of a dark current in the aperture pixels.

A backlit display with improved dynamic range.

The present invention provides an image pickup device that can accurately adjust the black level value of the effective pixel area while correcting column noise contained in pixel signals of the effective pixel area. The image pickup device includes a solid-state image pickup element having a pixel part including an effective pixel area to be irradiated with light, a vertical light-shielded pixel area and a horizontal light-shielded pixel area where irradiation of light is shielded, a vertical scanning circuit, a horizontal scanning circuit, and an output circuit, a light-shielding section which shuts off light irradiated on the effective pixel area, a black level value detector which detects black level values of the vertical light-shielded pixel area, the horizontal light-shielded pixel area, and the effective pixel area shielded from light by the light-shielding section, based on pixel signals outputted from the output circuit of the solid state image pickup element, a comparator which compares the black level values, a noise component detector which detects a noise component, a noise corrector which corrects noise generated in the effective pixel area, based on the noise component detected by the noise component detector, and a controller which controls the noise component detector and the noise corrector, based on a comparison result of the comparator.

According to an embodiment, an image scanning device includes: a light source unit that emits light onto an original to be scanned; a photoelectric conversion unit that converts light from the original to an electric signal; a converting unit that converts the electric signal from the photoelectric conversion unit into digital image data; and a black correcting unit that performs black correction by correcting pixel-by-pixel black levels of pixels contained in pre-scanning digital image data obtained before the original is scanned based on a ratio of a dark-current black level of a pixel contained in ongoing-scanning digital image data obtained during scanning of the original to a dark-current black level of the pixel contained in the pre-scanning digital image data, and subtracting the corrected pixel-by-pixel black levels from the ongoing-scanning digital image data.

Apparatus and a method for improving image quality in an image sensor, where a black level of a photographed image is calibrated and luminance of an image signal is expanded within the allowable range of luminance through knee correction for the image signal in which the black level is calibrated. Interpolation for restoring a dead pixel may be achieved before gamma correction for image signal.

An imaging device includes photoelectric conversion elements arranged unidirectionally for each color of light to be received, and performing photoelectric conversion of reflected light from an approximately same position of an object for the each color sequentially pixel by pixel; and a black correction unit that corrects a black level of the object with respect to a pixel group including some photoelectric conversion elements in a way that an output result of the photoelectric conversion of reflected light by a photoelectric conversion element for a pixel, independent of the reflected light, is subtracted from another output result of photoelectric conversion of reflected light by the photoelectric conversion element for the same pixel.

A solid state imager converts analog pixel values to digital form on an arrayed per-column basis. An N-bit counter supplies an N-bit DAC to produce an analog ramp output with a level that varies corresponding to the contents of the counter. A ripple counter or equivalent is associated with each respective column. A clock supplies clock signals to the counter elements. A comparator in each column gates the counter element when the analog ramp equals the pixel value for that column. The contents of the counters are transferred sequentially to a video output bus to produce the digital video signal. Additional black-level readout counter elements can create and store a digital value that corresponds to a dark or black video level. A subtraction element subtracts the black level value from the pixel value to reduce fixed pattern noise. An additional array of buffer counter / latches can be employed. The ripple counters can be configured as counters to capture the digital video level, and then as shift registers to clock out the video levels to an output bus. The clock pulses for the DAC counter and for the ripple counters can be at the same or different rates.

A black clamp stabilization circuit for an image sensor utilizes a mixed-signal SoC block comprising sub-blocks to dynamically and precisely adjust the black level based on comparison to a reference black level. The black level adjustments include a first level regulation using digital control of an analog signal in a feedback loop that includes a programmable gain amplifier and high-resolution A / D converter. By applying the black clamping in the analog domain, dynamic range is extended. Additional black level regulation is subsequently performed in the digital domain to differentially eliminate line noise and column noise generated within the imaging System-on-Chip. By providing information between the sub-blocks, the algorithms can converge more quickly. The technique enables multiple signal paths to separately handle individual colors and to increase imaging data throughput.

An imaging sensor pixel array includes a semiconductor substrate, a plurality of active pixels and at least one black reference pixel. The plurality of active pixels are disposed in the semiconductor substrate for capturing an image. Each of the active pixels includes a first region for receiving light including a p-n junction for accumulating an image charge and active pixel circuitry coupled to the first region to readout the image charge. The black reference pixel is also disposed within the semiconductor substrate for generating a black level reference value. The black reference pixel includes a second region for receiving light without a p-n junction and black pixel circuitry coupled to the photodiode region without the p-n junction to readout a black level reference signal.

Brightness expression without solid white pattern is enabled, and video expression with an improved black level is achieved. A distortion module (5) reduces the luminance of a backlight source according to the histogram of the video signal so that the contrast may be a predetermined target one. A configuration design unit (13) sets the gain according to the luminance level (BLreduced) of the backlight source selected by the distortion module (5). When setting the gain, the luminance level (BLref) for reference of the backlight source preset according to the video feature value is referenced. If the video feature value meets a predetermined condition, the input video signal is always amplified with the gain. If not, depending on the relation between the BLreduced and the BLref, the input video signal is amplified or not.

An imaging system capable of black level calibration includes an imaging pixel array, at least one black reference pixel, and peripheral circuitry. The imaging pixel array includes a plurality of active pixels each coupled to capture image data. The black reference pixel is coupled to generate a black reference signal for calibrating the image data. Light transmitting layers are disposed on a first side of a pixel array die including the imaging system and cover at least the imaging pixel array and the black reference pixel. A light shielding layer is disposed on the first side of the pixel array die and covers a portion of the light transmitting layers and the black reference pixel without covering the imaging pixel array.

The present invention relates to an optical device for black level enhancement of a viewing display. Also disclosed are a system including the optical device and methods of improving black level of a viewing display, such as a plasma display panel, a liquid crystal display panel, an inorganic light emitting diode display panel, or an organic light emitting diode display panel.