Abstract: A radiation image pickup device includes: an image pickup section having a plurality of pixels and generating an electric signal according to incident radiation, the plurality of pixels each including a photoelectric conversion element and one or a plurality of transistors of a predetermined amplifier circuit; and a correction section subjecting signal data of the electric signal obtained in the image pickup section to predetermined correction process. The correction section makes a comparison between measurement data obtained by measuring an input-output characteristic of the amplifier circuit in each of the plurality of pixels and initial data on the input-output characteristic, and performs the correction process by the pixel individually, by using a result of the comparison.

Abstract: A solid-state imaging device having within a pixel region where pixels containing photoelectric conversion device are two-dimensionally arranged, a plurality of noise extracting pixels for outputting a noise signal not depending on incident light amount provided in an effective pixel region from which image signal associated with object image is outputted, disposed in a manner scattered into two dimensions so that, taking N×N (N being an integer of 2 or more) pixels within the effective pixel region as unit block, at least one is provided in each row and in each column within that unit block.

Abstract: Systems and methods for processing raw image data are provided. One example of such a system may include memory to store image data in raw format from a digital imaging device and an image signal processor to process the image data. The image signal processor may include data conversion logic and a raw image processing pipeline. The data conversion logic may convert the image data into a signed format to preserve negative noise from the digital imaging device. The raw image processing pipeline may at least partly process the image data in the signed format. The raw image processing pipeline may also include, among other things, black level compensation logic, fixed pattern noise reduction logic, temporal filtering logic, defective pixel correction logic, spatial noise filtering logic, lens shading correction logic, and highlight recovery logic.

Abstract: A CMOS image sensor includes a pixel array including a plurality of unit pixels with individual rows of unit pixels being coupled to respective row control signal lines, and a buffer including plural row control signal drivers. Each driver is coupled to a respective one of the row control signal lines and is configured to provide a row control signal pulse to a respective row control signal line in response to an input pulse when the row control signal line is in an active state and to bias the row control signal line at a ground voltage when the respective row control signal line is in an inactive state. Each driver has a first drive capability when the row control signal line is in the active state and a second drive capability greater than the first drive capability when the row control signal line is in an inactive state.

Abstract: According to one embodiment, an image sensor module including a plurality of image sensors and a common signal line. The common signal line is commonly electrically connected to the plurality of image sensors. To the common signal line, image signals are output sequentially from the plurality of image sensors. The image sensor module feeds back a feedback signal from a first image sensor to a predetermined image sensor. The first image sensor is an image sensor which lastly outputs the image signal among the plurality of image sensors. The predetermined image sensor is an image sensor which outputs an offset signal to the common signal among the plurality of image sensors. The feedback signal indicates a completion of an output of image signal to the common signal line. The predetermined image sensor outputs the offset signal to the common signal line in response to the feedback signal.

Abstract: A solid-state imaging device includes a first substrate, a second substrate, connection units that electrically connect the first substrate aid the second substrate, pixels in the first substrate, the pixel including a photoelectric conversion element that converts incident lights to signal charges and accumulates the signal charges, and the pixel outputting pixel signals in accordance with the signal charges, signal lines that supply the second substrate with the pixel signals via the connection units, signal integration units in the second substrate that integrate the pixel signals supplied via the signal lines, and that produce an integrated signal, and signal output units that output the integrated signal.

Abstract: A method for estimating a fly screen effect of an image capture unit is described, having a plurality of image sensors for providing an item of light intensity information. The method includes a step of determining an image property of an item of image information, based on a plurality of items of light intensity information and on a plurality of parameters, each of the plurality of parameters being associated with each of the plurality of image sensors. This method also includes a step of ascertaining a plurality of parameter values for the plurality of parameters, in which the image property is at least made to approximate an ideal image property, the plurality of parameters representing the fly screen effect in a model of the image capture unit.

Abstract: According to one embodiment, a second determining unit performs defect determination according to an illumination light component, which is a component of illumination light irradiated onto an object, of pixel values of a plurality of adjacent pixels. A third determining unit performs defect determination according to a reflectivity component, which is a component based on a unique reflectivity of the object, of the pixel values of the plurality of adjacent pixels.

Abstract: Grain noise and scratches are applied to an input image as random noise to generate a combined image. When applying grain noise clipped from two-dimensional noise data to the input image, each time clipping is performed, a positional difference from a last clipping position is evaluated. When the positional difference is determined to be small, a current clipping position is changed. When applying scratches clipped from noise data of a plurality of patterns to an input image, when a condition for successively applying scratches for a predetermined time period is selected, a positional difference from a last pasting position is evaluated. When the positional difference is determined to be large, the application of scratches is invalidated.

Abstract: A Charge-Coupled Device (CCD) image sensor includes a linear array of photodetectors. The photodetectors in the linear array are arranged into distinct sub-arrays with each sub-array including two or more photodetectors. An output channel is connected to each sub-array of photodetectors. Each output channel includes a horizontal CCD shift register and an output structure connected to an end of the horizontal CCD shift register in a linear arrangement with respect to each other. Each successive output channel is disposed on an alternate side of the linear array. Every other output channel is disposed on an alternate side of the linear array. One or more dark reference pixels can be connected to one or more additional shift register elements in the horizontal CCD shift registers.

Abstract: 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.

Abstract: An image correcting apparatus and method are disclosed to correct a smear vertical line on an image captured by a camera. The method for correcting an image comprising: detecting image data corresponding to a vertical line of a specific image and having hue values greater than a hue reference value; and correcting the detected image data.

Abstract: Examples of systems and methods to provide estimates of dark current for pixels of a photosensor as a function of the temperature of the sensor and the gain applied to the photosensor are described. In various implementations, the dark current estimated for each pixel can depend at least partly on a global scale factor and a global bias that depend on temperature and gain and a temperature-independent and gain-independent offset value for each pixel. The scale, bias, and offsets may be determined from multiple dark field images taken by the sensor over a range of operating temperatures. In some cases, the scale and bias can be determined using a subset of less than all the image pixels. Scale and bias derived for a particular sensor can be used in the calibration of different sensors.

Abstract: Embodiments of the invention describe a system, apparatus and method for obtaining black reference pixels for dark current correction processing are described herein. Embodiments of the invention capture image signal data via a plurality of pixel cells of a pixel unit of an image device, wherein capturing image signal data involves establishing a first state of exposing incident light on each pixel of the pixel unit and a second state of shielding incident light from one or more pixels of the pixel unit via a shutter unit disposed over the pixel unit. Image signal data from each pixel of the pixel unit captured during the first state and the second state is read, and scene image data is created by combining a subset of image signal data captured during the first state with a dark current component including a subset of image signal data captured during the second state.

Abstract: A solid-state imaging device includes: a pixel unit in which pixels that perform photoelectric conversion are arranged in an optical black region and a valid pixel region; a readout processing unit that applies, to a readout signal of the pixel unit, readout processing corresponding to a reference signal subjected to clamp processing; and a clamp processing unit that clamps, referring to a readout signal level in the optical black region, a reference signal in the valid pixel region with an acquired clamp value, which is a value with which the signal level is reduced to zero. The clamp processing unit acquires, when information concerning readout is changed, a clamp value predicted from the clamp value before the change and a ratio of charge accumulation times before and after the change, and the readout processing unit performs first signal readout processing after the change with a reference signal clamped by the predicted clamp value.

Abstract: An image processing apparatus for a radiation image obtains radiation image data obtained by radiation imaging using a radiation detector, and dark current data based on a signal obtained from the radiation detector without irradiating any radiation from a radiation generator. The image processing apparatus generates correction data by changing a ratio of frequency components based on the dark current data, and corrects the radiation image data based on the generated correction data.

Abstract: Various techniques are disclosed for processing statistics data in an image signal processor (ISP). In one embodiment, a statistics collection engine may be implemented in a front-end processing unit of the ISP, such that statistics are collected prior to processing by an ISP pipeline downstream from the front-end processing unit. In one embodiment, the statistics collection engine may be configured to acquire statistics relating to auto white-balance, auto-exposure, and auto-focus, as well as flicker detection. Collected statistics may be output to a memory and used by the ISP to process acquired image data.

Abstract: A solid-state imaging device and an imaging apparatus are provided. The solid-state imaging device performs an AD conversion in a column parallel for an analog pixel signal outputted from each of pixels disposed in a two-dimensional matrix shape. The solid-state imaging device includes: an AD conversion unit including a plurality of pixel signal accumulating units; a first switching unit for disconnecting parallel connection of a second pixel signal accumulating unit other than a first pixel signal accumulating unit which is one of the plurality of pixel signal accumulating units; and a second switching unit for connecting the second pixel signal accumulating unit to a pixel signal line of a second pixel adjacent to the first pixel in a row direction, when parallel connection of the second pixel signal accumulating unit is disconnected by the first switching unit.

Abstract: An image sensor including a pixel array, a sampling circuit and a black level calibration circuit is provided. The pixel array includes a first optical black area, a second optical black area and an active pixel area. The sampling circuit respectively reads first optical black information, second optical black information and active pixel information from the first optical black area, the second optical black area and the active pixel area. The black level calibration circuit determines a black level offset according to the first optical black information, and determines a black level calibration value for calibrating the active pixel information.

Abstract: A black image captured in a light-shielded state is obtained, and the streak intensity is determined for each pixel of the black image from the absolute value of an AC component in a region containing the pixel. An extraction image which extracts streak-like fixed pattern noise in a captured image is generated using a black image obtained by applying, to the obtained black image, the first filter for reducing random noise in the first direction.

Abstract: An image capturing system includes: a first noise reduction unit which roughly removes the effects of an edge component by performing edge-preserving adaptive noise reduction processing on a target pixel within a local region including the target pixel and the neighboring pixels extracted from an image signal acquired from a CCD; a noise estimation unit which dynamically estimates the noise amount with respect to the target pixel based upon the target pixel value thus subjected to the noise reduction processing by the first noise reduction unit; and a second noise reduction unit which performs noise reduction processing on the target pixel based upon the target pixel value thus subjected to the noise reduction processing by the first noise reduction unit and the noise amount thus estimated by the noise estimation unit.

Abstract: An imaging array and a method for operating the same are disclosed. The imaging array includes a plurality of light pixels and a sense amplifier. Each light pixel includes a photodetector that generates and couples a signal indicative of a light exposure to a light pixel node, a readout circuit, and a mixer that mixes a signal on the light pixel node with a pixel oscillator signal. The sense amplifier includes an input node that receives a signal from each light pixel, one light pixel at a time. The sense amplifier also includes a high pass filter that attenuates signals with frequencies less than a cutoff frequency and a mixer that demodulates the signal from the filter to provide a signal that is related to the potential on the light pixel node of the light pixel connected to the first input node.

Abstract: 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.

Abstract: Various embodiments of this disclosure may describe a two-stage ADC circuit, and a time-interleaved system based on the two-stage ADC circuit. The two-stage ADC circuit may include a SAR converter for the first stage and a charge based TDC for the second stage. The two-stage ADC circuit may be used in high performance serial I/O applications. Other embodiments may be disclosed and claimed.

Abstract: Systems and methods are disclosed for applying spatial filtering to raw image data. For example, a spatial filter may identify an n x n block of pixels from an image frame. The spatial filter has filter taps, each corresponding to one of the pixels of the n x n block. Pixel difference values between the input pixel and each of the neighboring pixels in the n x n block may be determined. Attenuation factors may be determined based on the pixel differences and brightness of the input pixel. Applying the attenuation factors to their respective filtering taps may produce attenuated filtering coefficients that are used to obtain filtered pixel values. By normalizing the sum of the filtered pixel values using the sum of the attenuated filtering coefficients, a spatially filtered output value corresponding to the current input pixel (e.g., located at the center of the n x n block) may be determined.

Abstract: This is generally directed to systems and methods for reading optical black pixel cells. For example, in some embodiments, the columns of a pixel array can be shunted together during an optical black pixel readout phase of the imaging system. This may, for example, help improve correction of column fixed pattern noise or other noise. In some embodiments, the column may be shunted together during the optical black pixel readout phase of the imaging system and not shunted during other phases of the imaging system (e.g., when reading values from active pixel cells, barrier pixel cells, etc). In some embodiments, circuitry for providing the column shunting can be implemented as an independent block of the imaging system. In other embodiments, this circuitry can be implemented within other blocks of the imaging system. As an illustration, the shunting circuitry can be implemented within a VLN block of the imaging system.

Abstract: An imaging apparatus includes: an imaging unit configured to image an image using an imaging device; an image obtaining unit configured to obtain a plurality of images equivalent to the time of dark, imaged by the imaging unit; a registering unit configured to register, with an image obtained by the image obtaining unit, the address and change amount of a pixel where the output value of the pixel changes so as to exceed a predetermined threshold; and a correcting unit configured to correct, when taking a pixel corresponding to an address registered by the registering unit as a processing object pixel, the pixel value of the processing object pixel based on comparison between difference of the output values of the processing object pixel and a peripheral pixel of the processing object pixel, and the change amount of the processing object pixel.

Abstract: A method and system is for limiting the x-droop effect in the digital image captured with solid state image sensors with a correction mechanism which instead of using only correction values from the same column to which the correction is applied, also takes the neighboring pixels into account to provide an averaged value to aid in the reduction of temporal and fixed noise contributions associated with the readout of a single pixel.

Abstract: Disclosed are an image pickup apparatus and a dark current correction method that make it possible to correct the dark current at high precision without using a driving pattern of a peripheral circuit or a layout on an image pickup device chip. The image pickup apparatus includes an image pickup device provided with an effective pixel area, an OB part and a drive circuit of the image pickup device.

Abstract: A photographing apparatus including an imaging device configured to obtain a first image of a subject captured with a long shutter exposure time and a second image of the subject captured by setting a short shutter exposure time, wherein the long exposure time is greater than the short exposure time; and a live-view generation unit configured to generate a smear-corrected third image by subtracting pixel values of the second image from the corresponding pixel values of the first image. A smear correction method of a photographing apparatus, the method including capturing a first image of a subject by setting a long electrical shutter exposure time; capturing a second image of a subject by setting a short electrical shutter exposure time; and generating a smear-corrected third image by subtracting pixel values of the second images from the corresponding pixel values of the first image.

Abstract: According to one embodiment, a third optical black portion is arranged in parallel with a first optical black portion in a row direction and in parallel with a second optical black portion in column direction. At least one of the vertical line correction circuit and the horizontal line correction circuit adds/subtracts arithmetic average of the third black level signal generated by the third optical black portion.

Abstract: A method for generating a deselect mapping for a focal plane array according to one embodiment includes gathering a data set for a focal plane array when exposed to light or radiation from a first known target; analyzing the data set for determining which pixels or subpixels of the focal plane array to add to a deselect mapping; adding the pixels or subpixels to the deselect mapping based on the analysis; and storing the deselect mapping. A method for gathering data using a focal plane array according to another embodiment includes deselecting pixels or subpixels based on a deselect mapping; gathering a data set using pixels or subpixels in a focal plane array that are not deselected upon exposure thereof to light or radiation from a target of interest; and outputting the data set.

Abstract: 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.

Abstract: An image pickup apparatus that make it possible to perform image processing under appropriate conditions and secure appropriate image qualities of taken images. The image pickup device has a photoelectric conversion element portion that generates signal electric charge according to the amount of received light, a first optical black unit having a light-shielded photoelectric conversion element structure and having first output characteristics, and a second optical black unit having a light-shielded photoelectric conversion element structure and having second output characteristics different from the first output characteristics. A dark current value is measured based on an output from the first optical black unit and an output from the second optical black unit. Whether or not to perform image processing is determined according to the measured dark current value.

Abstract: An imaging apparatus is provided for reducing noise which is derived from random noise contained in a correction signal used for correcting an image data and is newly generated on correction of the image data. The imaging apparatus drives vertical transfer registers with no signal charge from photoelectric transducers read out to the vertical transfer registers to obtain and store a correction signal into a field memory. The apparatus subtracts the correction signal from the image data by a subtractor.

Abstract: An image capturing apparatus includes an image sensor including a first reference pixel for black level, a second reference pixel for black level, and an effective pixel, and a processing unit which applies first processing to an output signal from the effective pixel based on an output signal from the first reference pixel for black level, and applies second processing to an output signal from the effective pixel based on an output signal from the second reference pixel for black level. The first reference pixel for black level and the second reference pixel for black level each include a charge-voltage converter which converts electric charge into a voltage and a pixel amplifier which amplifies the voltage of the charge-voltage converter. The pixel amplifiers of the first reference pixel for black level and the second reference pixel for black level differ in arrangement.

Abstract: At least one exemplary embodiment is directed to an imaging apparatus including an image sensor including a light-shielded pixel area, a comparison unit configured to compare a light-shielded pixel output value output from at least a part of the light-shielded pixel area with a plurality of preset determination values, a counting unit configured to count a result of comparison performed by the comparison unit with respect to each of the plurality of determination values, and a calculation unit configured to estimate an amount of dark current generated in the image sensor based on a result of counting performed by the counting unit.

Abstract: When an external trigger is received as a predetermined signal after receiving a signal concerning a start of imaging, controls are carried out to stop driving of a CCD type solid-state image sensor (CCD) from receipt of the signal concerning a start of imaging until receipt of the external trigger, and to start the driving of the CCD synchronously with the receipt of the external trigger. Thus, the driving of the CCD is not started immediately upon receipt of the signal concerning a start of imaging, and the driving time of the CCD can be shortened by the time from receipt of the signal concerning a start of imaging until receipt of the external trigger, thereby suppressing heat generation of the CCD.

Abstract: A solid-state image sensor includes a pixel array unit including a plurality of pixels arranged in the form of an array, column signal lines adapted to transmit pixel signals output from pixels in respective columns, a noise adding unit adapted to add temporally constant and two-dimensional spatially random noise to the pixel signals transmitted via the column signal lines, and an analog-to-digital converter adapted to convert a signal level and a reference level of each pixel signal including the noise added thereto by the noise adding unit.

Abstract: A solid-state imaging apparatus includes a comparison section comparing a pixel signal from a pixel with a ramp signal and outputting a comparison signal. A measurement section starts counting in synchronism with the ramp signal and continues the counting until a signal supplied thereto reverses to measure comparison time. A comparator output controlling section interposed between the output of the comparison section and the input of the measurement section stops, if a pixel signal value exceeds a predetermined value determined based on a tanning phenomenon when the counting is started, the counting when the comparison signal is supplied to the measurement section to reverse the comparison signal, but supplies, if the pixel signal value does not exceed the predetermined value, a signal which is not reversed within a measurement period to the measurement section to continue the counting during the measurement period.

Abstract: A black level correction circuit includes: a counter counting a black signal level of an image; a black level determination section determining a feedback gain by comparing data outputted from the counter with a previously set threshold; an average value calculation section calculating an average value from data supplied from the counter; a feedback calculation processing section selecting the feedback gain by a control signal supplied from the black level determination section and calculating the selected feedback gain and the averaged data; and a digital-analog converter correcting data to which feedback calculation processing has been performed and converting the corrected data into analog data to output an analog black signal.

Abstract: An image capturing apparatus includes an image-capturing device having an effective pixel area formed of a plurality of areas, the areas having different dark current characteristics. The image-capturing device also includes a light-shielded pixel area, a storage unit configured to prestore a correlation between dark current differences of the plurality of areas and dark current of the light-shielded pixel area, a detector, a dark current difference obtaining unit, and a correction processor. The dark current differences are obtained from the dark current of the light-shielded pixel area detected during image capture on the basis of the stored correlation, and a video signal captured in the effective pixel area is corrected based on the obtained dark current differences.

Abstract: A solid-state image pickup device includes a pixel array, a gain adjusting unit that adjusts a gain of a pixel signal, an A/D conversion unit that performs A/D conversion on an image pickup signal, a plurality of fixed pattern noise detection units that detect a fixed pattern noise from a digital image pickup signal, a selecting unit that selects one output from outputs of the plurality of fixed pattern noise detection units, a fixed pattern noise correction unit that corrects the fixed pattern noise included in the digital image pickup signal, and a control unit that controls the gain adjusting unit setting a plurality of gain values, the control unit controlling the plurality of fixed pattern noise detection units detecting the plurality of fixed pattern noise based on the plurality of gain values and storing a plurality of correction values.

Abstract: A black level control apparatus and method, particularly for a high-speed video camera (8). The apparatus (10,100) comprises an image signal channel (30,130) for receiving an image signal having a black level from an image sensing device (22,122); a black level sensing device (24,124) for generating a black level signal; a black level signal channel (40,140), independent from the image signal channel, for receiving the black level signal from the black level sensing device; a black level controller (60,160) for receiving an input signal based on the black level signal, measuring a difference between the input signal and a reference signal, generating a control signal based on the difference, outputting the control signal to the image signal channel to adjust the black level of the image signal, and feeding the control signal to the black level signal channel, such that the input signal is based on the black level signal and the control signal.

Abstract: An image pick-up apparatus includes an image pick-up device, a noise reduction processing portion, and a level difference correction portion. The image pick-up device includes at least three kinds of color filters and photoelectric conversion elements formed under the color filters respectively. The noise reduction processing portion applies noise reduction processing to image pick-up signals output from the image pick-up device. The level difference correction portion executes correction to reduce a level difference between first and second ones of the noise reduction-processed image pick-up signals obtained from the photoelectric conversion elements formed under two color filters which are of the same kind but different in arrangement pattern of color filters arranged around the two color filters. The level difference correction portion changes correction strength in accordance with strength of noise reduction processing executed by the noise reduction processing portion.

Abstract: An imaging apparatus in which a matrix of pixels converts light into electric charge. The pixels are disposed in an optically black area that receives no light so as to output optically black signals and in an effective pixel area that receives incident light. An analog amplifier applies predetermined gain to the electric charge read from the pixels in the effective pixel area. A vertical line detector calculates a correction value to remove vertical line-shaped fixed pattern noise. A vertical line corrector adds each of the correction values to the corresponding effective pixel signal to remove the vertical line-shaped fixed pattern noise; and a multiplier multiplies the corrected pixel signals by the digital gain so that the output pixel signal contains no vertical line-shaped fixed pattern noise caused by the digital gain.

Abstract: A fixed pattern noise of an image converter is automatically determined. A first optical image is converted using the image converter into digital image data, the light level of the first optical image is determined, the light level of the first optical image is compared with a threshold value, and the image converter characteristics of the image converter are reset to a dark image setting in such a way that the image data generated over the photosensitive imaging surface of the image converter at constant distribution of the determined light level include no component produced by the light level. Immediately thereafter, using the dark image setting previously set, a first dark image is recorded.

Abstract: An image pickup apparatus includes a frame operation unit configured to perform addition to or subtraction from a frame and a storage unit configured to store a result of an operation performed by the frame operation unit. A data bus including two channels, one for writing to the storage unit and the other for reading from the storage unit, is provided between the frame operation unit and the storage unit.

Abstract: According to one embodiment, a solid-state imaging device includes an effective pixel portion in which effective pixels are provided, a light-shielded pixel portion in which light-shielded pixels are provided, an ADC circuit that performs an AD conversion operation for signal components read from the effective pixel and the light-shielded pixel, on the basis of a result of a comparison with a reference voltage on which a clamping voltage is superimposed, and an AD clamping circuit that calculates a clamping voltage for a target value of a black level read from the light-shielded pixel by extrapolating a relation between the clamping voltage and an AD-converted value of the black level read from the light-shielded pixel at the time when the clamping voltage is applied.

Abstract: An improved method for photon transfer curve (PTC) testing in an image sensor is described. A cost and time savings is achieved by reducing the number of frames necessary for measurements to two that are generated by illuminating a first plurality of pixel rows at a first intensity level m1, a second plurality of pixel rows at a second intensity level t2, and so forth up to an nth plurality of pixel rows illuminated at an nth intensity level mn where mn>m2>m1. The resulting image has “n” regions each with a different brightness. The highest intensity level essentially saturates the pixels in the nth region. In one example, a four row exposure and five intensity levels are employed in the illuminator sequence. An intelligent light source is pre-programmable with illumination intensity settings and is synchronized to the image sensor using HSYNC and VSYNC signals, for example.