Patent application number | Description | Published |
20090295965 | METHOD AND CIRCUIT FOR DRIVING ACTIVE PIXELS IN A CMOS IMAGER DEVICE - One embodiment of the present invention describes a pixel circuit that comprises at least one photodiode, a first transistor coupled between the photodiode and a floating diffusion node, a second transistor coupled between the floating diffusion node and a modifiable driving voltage signal, and a third transistor having a gate coupled to the floating diffusion node, a source coupled to a signal output, and a drain coupled to a constant voltage. Another embodiment of the present invention provides a method for driving the pixel circuit, which comprises resetting the photodiode and the floating diffusion node, exposing the photodiode to light to accumulate charges, selecting the pixel circuit by switching the driving voltage signal from a first voltage level to a second voltage level, retrieving a reference voltage from the selected pixel circuit, and retrieving an image signal from the selected pixel circuit corresponding to the accumulated charges. | 12-03-2009 |
20110058073 | Signal Chain of an Imaging System - A signal chain of an imaging system is disclosed. The system includes three circuit stages. The first circuit stage includes a programmable gain amplifier (PGA) and a black level compensation (BLC) circuit that form a BLC loop. The second circuit stage includes an analog-to-digital converter (ADC), where a dark signal offset is added at an input of the ADC. The third circuit stage includes a digital gain circuit and a digital loop that makes a final output of the imaging system settle on a target level in the BLC mode. | 03-10-2011 |
20110090238 | BLACK LEVEL CALIBRATION METHOD AND SYSTEM - Black level calibration methods and systems are generally disclosed. According to one embodiment of the present invention, a method of calibrating a black level signal in a frame includes performing an iteration of averaging a first set of digital values corresponding to a first set of adjusted black level signals associated with a first set of black pixels of the frame, determining whether an average value based on the first set of digital values has reached a target black level, determining a calibration offset based on a difference between the average value and the target black level and an accumulator step, converting the calibration offset to an analog signal, generating a calibration signal based on the analog signal for a second set of black pixels of the frame, and repeating the iteration for the frame until a predetermined condition is determined to have been met. | 04-21-2011 |
20110141291 | MULTI-PHASE BLACK LEVEL CALIBRATION METHOD AND SYSTEM - Multi-phase black level calibration (BLC) methods and systems are generally disclosed. According to one embodiment of the present invention, an image sensor comprises a pixel sensor array, a timing generator, and a front-end processing block. The front-end processing block also includes a first summing junction, a first BLC block, and a second BLC block. According to a first timing signal from the timing generator, the first BLC block is configured to iteratively generate a first calibration signal in a first phase based on a first set of adjusted black level signals associated with a first set of black pixels, a changing accumulator step, and a predetermined condition associated with a first target black level. According to a second timing signal from the timing generator, the second BLC block is configured to generate a second calibration signal for a second summing junction to apply to an image signal associated with one or more active pixels in the frame in a second phase. | 06-16-2011 |
20140124648 | ULTRA LOW READOUT NOISE ARCHITECTURE - A method to read out pixels includes reading a first pixel by resetting a first photodetector, integrating the first photodetector after resetting the first photodetector, resetting a first floating diffusion node coupled to the first photodetector and a second floating diffusion node coupled to a second photodetector, transferring charge from the first photodetector to the first floating diffusion node, comparing a first signal at the first floating diffusion node and a second signal at the second floating diffusion node and generating a first signal to latch a first counter value when the first signal is less than the second signal, incrementing the first signal and decrementing the second signal, and comparing the first signal and the second signal and generating a second signal to latch a second counter value when the first signal is greater than the second signal, wherein the difference between the second counter value and the first counter value indicates a first pixel level. | 05-08-2014 |
Patent application number | Description | Published |
20110085086 | METHOD FOR ADAPTIVE NOISE REDUCTION AND APPARATUS THEREOF - An adaptive noise reduction method is for reducing chroma noise of pixels within a frame, wherein each pixel has a chroma value and a luma value. The adaptive noise reduction method includes: de-noising the chroma values of the pixels, without de-noising the luma values of the pixels. | 04-14-2011 |
20110085729 | DE-NOISING METHOD AND RELATED APPARATUS FOR IMAGE SENSOR - A de-noising method includes: comparing a pixel value of a target pixel with pixel values of a plurality of nearby pixels, wherein each of the target pixel and the nearby pixels corresponds to a specific color component; for each nearby pixel of the nearby pixels, checking if a difference between the pixel value of the target pixel and a pixel value of a nearby pixel of the nearby pixels is smaller than a specific noise threshold value, and when the difference between the pixel value of the target pixel and the pixel value of the nearby pixel is smaller than the specific noise threshold value, setting the nearby pixel as a similar nearby pixel; and updating the pixel value of the target pixel according to the pixel value of the target pixel and a pixel value of each similar nearby pixel. | 04-14-2011 |
20110085730 | METHOD FOR PIXEL COLOR CORRECTION AND PIXEL COLOR CORRECTING APPARATUS THEREOF - A method for pixel color correction includes the steps of determining a gray degree of a designated pixel; generating an adjusted color correction matrix according to the gray degree of the designated pixel; and applying the adjusted color correction matrix to the designated pixel to correct color errors of the designated pixel. The gray degree is generated according to a ratio of the chrominance information to the luminance information. A weighted sum of a reference color correction matrix and a unity matrix is calculated to generate the adjusted color correction matrix, and weighting factors of the reference color correction matrix and the unity matrix are determined by the gray degree, wherein the unity matrix is a fundamental matrix without color correction. | 04-14-2011 |
20140270572 | SIGNAL PROCESSING APPARATUS AND METHOD FOR DETECTING/CORRECTING ECLIPSE PHENOMENON, AND RELATED CORRELATED DOUBLE SAMPLING APPARATUS - A correlated double sampling apparatus includes a first processing unit and a second processing unit. The first processing unit is arranged for receiving a reset signal, a data signal, and a predetermined signal; obtaining a reset level of the reset signal and a first data level of the data signal in a first operation mode; and obtaining a second data level of the data signal, and comparing the second data level with the predetermined signal to generate a detection result in a second operation mode. The second processing unit is arranged for storing the reset level and the first data level in the first operation mode, and selectively correcting an output signal according to the detection result in the second operation mode, wherein the output signal is determined according to a level difference between the reset level and the first data level. | 09-18-2014 |
Patent application number | Description | Published |
20090251572 | EFFICIENT WIDE-RANGE AND HIGH-RESOLUTION BLACK LEVEL AND OFFSET CALIBRATION SYSTEM - A black level calibration (BLC) system is disclosed. A readout chain receives and amplifies dark signal, and generates corresponding digital output. A level integrator performs integration of calibration levels in multiple steps according to the digital output, thereby achieving wide calibration range. | 10-08-2009 |
20100141571 | Image Sensor with Integrated Light Meter for Controlling Display Brightness - The present invention is directed to an image sensor with an integrated light meter that can be used to automatically adjust the display brightness based on ambient light in the environment. According to one embodiment, an automatic exposure (AE) control loop estimates the ambient light when the image sensor is imaging, and the image sensor measures the ambient light when the image sensor is not imaging. | 06-10-2010 |
20100282946 | Low Noise Pixel Readout Circuit with High Conversion Gain - A pixel circuit of a CMOS image sensor is disclosed. At least two transfer transistors are configured to transfer integrated light signals of corresponding photodetectors to a first node. A reset transistor is configured to reset the first node to a predetermined reset voltage of a second node, and a source follower is configured to buffer the integrated light signals. In one embodiment, a capacitor is further connected between the first node and the second node to minimize influence of the effective capacitance including capacitance of a floating diffusion region and parasitic capacitance due to the photodetector and the transfer transistor. | 11-11-2010 |
20110164146 | Adaptive Frame Rate Control System and Method for an Image Sensor - An adaptive frame rate control system and method for an image sensor includes an amplifier which amplifies a sensor output signal of the image sensor with a gain. An automatic exposure gain (AEG) controller determines a product of exposure time and the gain (EGP) based on incident light intensity, and controls a timing controller and the amplifier, to adjust the exposure time and the gain of the image sensor such that the amplified sensor output signal may approximately approach a sensor target signal, where the change of the exposure time is preferred over the change of the gain. | 07-07-2011 |