81results about How to "Reduce pattern noise" patented technology

An imaging method and system that flexibly accesses light sensor elements and processes imaging signals. The imaging system comprises an array of pixel sensor cells, an array controller and a readout control circuit.

A backside illuminated imaging device performs imaging by illuminating light from a back side of a p substrate to generate electric charges in the substrate based on the light and reading out the electric charges from a front side of the substrate. The device includes n layers located in the substrate and on an identical plane near a front side surface of the substrate and accumulating the electric charges; n+ layers between the respective n layers and the front side of the substrate, the n+ layers having an exposed surface exposed on the front side surface of the substrate and functioning as overflow drains for discharging unnecessary electric charges accumulated in the n layers; p+ layers between the respective n+ layers and the n layers and functioning as overflow barriers of the overflow drains; and an electrode connected to the exposed surface of each of the n+ layers.

A pixel comprises a photo-sensitive element for generating charges in response to incident radiation and a sense node. A transfer gate is positioned between the photo-sensitive element and the sense node for controlling transfer of charges to the sense node. A reset switch is connected to the sense node for resetting the sense node to a predetermined voltage. A first buffer amplifier has an input connected to the sense node. A sample stage is connected to the output of the first buffer amplifier and is operable to sample a value of the sense node. A second buffer amplifier has an input connected to the sample stage. Control circuitry operates the reset switch and causes the sample stage to sample the sense node while the photo-sensitive element is being exposed to radiation. An array of pixels is synchronously exposed to radiation. Sampled values for a first exposure period can be read while the photo-sensitive element is exposed for a second exposure period.

An imaging method and system that flexibly accesses light sensor elements and processes imaging signals. The imaging system comprises an array of pixel sensor cells, an array controller and a readout control circuit. The imaging system provides color interpolation.

A method or a device that reduces fixed pattern noise in an image captured by a digital image device and adjusts the reduction based on the level of FPN, preferably on an area-by-area basis or on a pixel-by-pixel basis.

Systems and methods provide scene-based non-uniformity correction for infrared images, in accordance with one or more embodiments. For example in one embodiment, a method of processing infrared images includes storing a template frame comprising a first plurality of pixel data of an infrared image; receiving an input frame comprising a second plurality of pixel data of an infrared image; determining frame-to-frame motion between at least some of the first and second plurality of pixel data; warping the template frame based on the determining of the frame-to-frame motion; comparing the first plurality of pixel data to the second plurality of pixel data to determine irradiance differences based on the determining; propagating pixel offset information for scene based non uniformity correction terms, based on the determining of the frame-to-frame motion, for at least some of the scene based non uniformity correction terms to other ones of the scene based non uniformity correction terms; updating the scene based non uniformity correction terms based on the comparing and the propagating; applying the scene based non uniformity correction terms to the second plurality of pixel data to reduce fixed pattern noise; and providing an output infrared image after the applying.

An imaging method and system that flexibly accesses light sensor elements and processes imaging signals. The imaging system comprises an array of pixel sensor cells, an array controller and a readout control circuit. The imaging system provides color compensation.

The present invention is to allow an XY-address scanning-type imaging device such as a CMOS imaging device to detect a fluorescent flicker correctly and accurately and reduce a fluorescent flicker component surely and sufficiently. The RGB primary color signals arising from A/D conversion of the RGB primary color signals obtained from an imaging element are clamped. Subsequently, for the clamped RGB primary color signals, the following processes are executed: correction of the gains of reading-out channels; reduction of fixed pattern noise; correction of the data of defective pixels; noise reduction; lens shading correction; and gain adjustment for exposure adjustment. Thereafter, for the resultant signals, a flicker detection and reduction unit 60 detects and reduces a flicker component. Furthermore, white balance adjustment is implemented for the RGB primary color signals for which the flicker has been reduced, and then defective pixels in the imaging element are detected from the RGB primary color signals for which the white balance adjustment has been executed.

A method of sensing radiation in a pixel includes applying a transfer clock signal, applying a pixel reset clock signal, and applying a pixel reset voltage. The applying a transfer clock signal applies the transfer clock signal to a gate electrode of a transfer gate transistor. The applying a pixel reset clock signal applies the pixel reset clock signal to a gate electrode of the pixel reset transistor. The applying a pixel reset voltage applies the pixel reset voltage to a drain of the pixel reset transistor. The method further includes switching the transfer clock signal to a high state, switching the pixel reset clock signal to a high state, switching the pixel reset voltage to a low state, switching the pixel reset voltage to a high state, and switching the pixel reset clock signal to a low state at a beginning of an integration cycle.

A method for controlling the exposure of an active pixel array electronic still camera includes the steps of: integrating photocurrent in each pixel during an integration time period; collecting overflow charge from all pixels in the array during the integration time period; developing an overflow signal as a function of the overflow charge; and terminating the integration time period when the overflow signal exceeds a preset threshold level selected to represent a desired reference exposure level. Apparatus for performing the method of the present invention includes circuitry for integrating photocurrent in each pixel during a integration time period; circuitry for diverting and detecting overflow charge from all pixels in the array during the integration time period; circuitry for developing an overflow signal as a function of the overflow charge; and circuitry for terminating said integration time period when the overflow signal exceeds a preset threshold level selected to represent a desired reference exposure level.

An image sensor and offset-able reference voltage generator thereof are provided. The image sensor comprises a plurality of pixels, an offset-able reference voltage generator and a pixel sampling circuit. The pixel senses light from an image and generate an image signal. The offset-able reference voltage generator provides a reference voltage having a voltage offset. The pixel sampling circuit is coupled to the pixels and the offset-able reference voltage generator to sample the image signal and generate a pixel signal according to the reference voltage. The voltage offset of the reference voltage is able to compensate for the offset voltage in the process of generating the pixel signals.

A pixel includes five transistors, a photodetector and a storage node. A first transistor is coupled between the photodetector and the storage node. A second transistor includes a second transistor source and a second transistor drain. The second transistor source is coupled to the storage node. The second transistor drain is coupled to an output drain voltage. A third transistor includes a third transistor drain. The third transistor is coupled between the photodetector and a pixel reset voltage. The third transistor drain is coupled to the pixel reset voltage. The pixel reset voltage is different than the output drain voltage.

Improved data acquisition systems and methods that enable large numbers of data samples to be accumulated rapidly with low noise are described. In one aspect, a data acquisition system includes an accumulator that has two or more parallel accumulation paths and is configured to accumulate corresponding data samples across a transient sequence through different accumulation paths.

An image pickup device includes pixels each including a photoelectric conversion unit and a transfer switch for transferring a photoelectric conversion signal generated by the photoelectric conversion unit, and a driver for applying a pulse to the transfer switch a plurality of times when the signal generated by the photoelectric conversion unit is transferred via the transfer switch.

Effective sensitivity of a photodetector of an image sensor is controlled by partitioning signal charge from incident photons, thus producing a manageable yield and a consequently higher, photon shot noise limited, signal to noise ratio than in the prior art, when imaging high flux rates of energetic photons or particles, such as produced by x-ray generators. The invention may be applied, for example, to an image sensor with a photosensitive layer coupled to a charge collection/readout structure, e.g. photoconductor or scintillator on CMOS array, or to an intrinsically sensitive charge collection/readout structure, e.g. deep active layer CMOS. A radiation sensor pixel structure 10 for use in the invention includes a photodetector 11, a transfer gate 131 for controlling charge collection from the photodetector and a dump drain 12 controlled by a dump gate 121, arranged for selectively dumping charge to the dump drain means and collecting charge from the photodetector means, in a duty cycle 31, for varying effective sensitivity of the pixel structure. An image sensor containing such pixel structures may selectively be operated in an integration mode or a photon counting mode. Preferably the image sensor has imaging pixels and control circuitry arranged on a same semiconductor die, such as a CMOS semiconductor die.

A self-adjusting adaptive input circuit with minimal excess noise and a linear charge-handling capacity exceeding 10⁹ electrons to enable high-quality imaging at long wavelength infrared backgrounds and video frame rates is disclosed. An integration capacitor stores a charge produced from a photodetector. A self-adjusting current source skims a current during integration on the integration capacitor. The gate voltage of a skimming transistor is set via a programming transistor in order to set the skim level.

An image sensor has a stacked pixel arrangement including both rolling and global shutter readout circuits wherein each pixel includes an adjustable transfer transistor gate voltage level for modifying electric charge within a photodiode during exposure depending on incident light intensity. The sensor also has a row decoder circuit providing readout signals to each row of the imaging cells during both a readout interval and during a calibration interval for each row. The row decoder may employ one of several of its features to provide a self-knee point calibration following an image signal readout in order to minimize photo conversion variations that lead to fixed pattern noise and to enhance dynamic range.

Provided is a pneumatic tire which achieves both reduction of pattern noise and improvement in driving stability on a dry road surface. The pneumatic tire according to the present invention is designed to be mounted in such a way that a designated side of the tire faces to the outside of a vehicle, and is characterized in that: multiple block elements arrayed in a circumferential direction of the tire are formed in each of regions sectioned by an equator of the tire in a tread portion of the tire, the regions on inner and outer sides; the number of pitches of the block elements on the vehicle inner side is set to 60 to 80; the number of pitch variations of the block elements on the vehicle inner side is set to at least 4; the number of pitches of block elements on the vehicle outer side is set to 50 to 70; the number of pitch variations of the block elements on the vehicle outer side is set to at least 4; the number of pitches of the block elements on the vehicle inner side is set larger than the number of pitches of the block elements on the vehicle outer side; and a ratio of an average pitch length of the block elements on the vehicle outer side to an average pitch length of the block elements on the vehicle inner side is set in a range of 1.05 to 1.20.

In one aspect of the present invention, a light sensor is provided in the active pixel sensor cell for sensing incident radiation. The voltage corresponding to the photon-generated or other radiation-generated charge in the active pixel sensor cell is stored on a storage node via a sample-and-hold capacitor. Additional elements, such as source-follower transistors, may reside between the sensing element and the sample-and-hold capacitor. The signal is read via a readout source-follower (RSF) transistor. The readout source-follower drain is connected to the row select switch while its drain is connected to the output node on the column output bus. This configuration couples the storage node to the gate-source capacitance of the readout source-follower transistor. This allows the voltage on the storage node to increase proportionally to the increase in voltage on the readout node when the row select is closed and thus enables the drain current to flow through the RSF to the column output bus.

A pixel cell that utilizes a JFET transistor, instead of a CMOS transistor, linked to each pixel's photosensor as an anti-blooming and/or transfer transistor to provide an overflow path for electrons during charge integration. Using a JFET transistor reduces charge uncertainty and fixed pattern noise in the imaging system.