Abstract: An image capture method in a digital image sensor implements a continuous sampling technique with a massively parallel thermometer-code analog-to-digital conversion (ADC) technique to generate pixel data having an intrinsic to an ultra-high dynamic range. In one embodiment, the method includes, after an initial exposure period, sampling pixel intensity values at the pixel elements of an image sensor at multiple sampling intervals within a snapshot of a scene; providing an analog reference voltage corresponding to a decrementing digital count value; and comparing the pixel intensity values to the analog reference voltage at each of the multiple sampling intervals. If the pixel intensity value of a first pixel element is less than the analog reference voltage at a first exposure time, an output signal having a first value is generated and the digital count value is recorded as pixel data associated with the first pixel element.

Abstract: A method for removing a stationary noise pattern from digital images uses an adaptive noise estimation algorithm to calculate a prediction of the fixed pattern noise and a confidence estimate for the prediction. In one embodiment, a predicted noise value is obtained from the captured image and a predicted image derived from spatial and temporal pixel value prediction techniques. The predicted noise value is used to update a fixed pattern noise estimate only when the confidence estimate for the predicted image is high. In another embodiment, the confidence estimate is used as a weight factor for blending the noise prediction into the noise estimate. In yet another embodiment, the adaptive noise estimation algorithm is applied to a prediction area in the image for calculating scaling parameters which scaling parameters are used to calculate a noise estimate for the entire image based on a reference noise image.

Abstract: A digital image sensor includes a sensor array of digital pixels which output digital signals as pixel data. Each of the digital pixels includes a photodetector producing an analog signal indicative of the amount of light impinging on the sensor array and a charge transfer amplifier coupled to receive the analog signal and generate an amplified pixel voltage signal. The digital image sensor further includes analog-to-digital conversion (ADC) circuits located within the sensor array. Each of the ADC circuits is connected to one or more charge transfer amplifiers of the digital pixels for converting the amplified pixel voltage signal of each digital pixel to a digitized pixel voltage signal. The charge transfer amplifier operates to increase the sensitivity of the digital image sensor. The charge transfer amplifier can be implemented as a transfer gate with a floating diffusion as a measuring capacitor.

Abstract: A circuit includes an analog-to-digital (A/D) converter for multiplexing between a number of analog input signals and converting the selected analog input signals to a digital code representation. The A/D converter includes a comparator having a first input terminal connected to receive the first signal having a number of levels, a second input terminal connected to receive a multiple number of analog input signals, and a third input terminal for receiving a multiple number of input select signals. The comparator includes a multiplexer coupling the multiple number of analog input signals to a multiple number of corresponding input signal paths. The multiplexer selects one of the multiple number of input signal paths based on the multiple number of input select signals. In one embodiment, the A/D converter is applied in a digital image sensor for performing pixel-level analog-to-digital conversion using a multi-channel bit serial ADC technique.