Abstract: An image plane includes a plurality of pixels. Each pixel comprises a photodiode and two transistors, and each pixel is connected by a signal bus to a respective storage node located off the image plane. Each storage node comprises two capacitors and associated switches. One of the transistors applies a reset pulse to the pixel, and the other transistor connects the pixel to a given conductor of the signal bus, which is then connected to the storage node. The pixel transistors can be operated simultaneously, and the sensed values can subsequently be transferred from the storage nodes sequentially.

Abstract: Lighting flicker in the output of a video imaging device is detected. The video imaging device has a main picture area divided into pixels for producing successive images at a frame rate. A series of signals are produced from at least one additional picture area adjacent the main picture area, with the additional picture area having a size substantially larger than a pixel. Each of the signals is a function of light incident on the additional picture area in a time period substantially shorter than that of the frame rate. A predetermined number of the signals are accumulated to form a series of compound samples, and the compound samples are filtered to detect components indicating the lighting flicker. The filtering is performed using a bandpass filter tuned to the nominal flicker frequency. The compound samples are formed at a sample rate which is a multiple of the nominal flicker frequency, and the filtering is performed by taking the fundamental output component of a radix-N butterfly.

Abstract: A method of operating a solid state image sensor having an image sensing array that includes a plurality of active pixels comprises resetting each pixel, and after successive time periods reading outputs from each pixel to obtain multiple sets of image data having different dynamic ranges without resetting the pixels between the successive time periods. The sets of image data are combined to obtain a resultant set of image data having a further dynamic range different from the individual dynamic ranges of the multiple data sets. Images are obtained having low noise, a wide dynamic range, and are resistant to lighting-induced flicker.

Abstract: Solid state image sensors, and methods of operation thereof, includes an array of photosensitive pixels arranged in rows and columns and in which pixel data signals are read out from the pixels via column circuits, which introduces column fixed pattern noise to the signals. The signals are selectively inverted at the inputs to the column circuits and the inversion is reversed following output from the column circuits. Each column circuit may include an analog-to-digital converter and a digital inverter for inverting digital output therefrom. The selective inversion may be applied to alternate rows or groups of rows of the pixel data, and may be applied differently to different frames of the pixel data. These techniques result in column fixed pattern noise being modulated in a manner which makes the noise less apparent to the eye, and which facilitates subsequent cancellation of the noise.

Abstract: An integrated circuit active pixel image sensor comprises an array of active pixels having associated therewith one capacitor in each pixel column for storing a combined pixel output signal comprising an image signal and a fixed offset signal and another capacitor in each column for capturing another signal produced when the pixel is reset. The array may be read row-by-row. Each column includes a comparator and a data latch via which a digitized fixed offset corrected pixel output signal is obtained using a ramp voltage source and a digital count broadcaster provided in the sensor.

Abstract: A low noise operation method for a camera system having an image sensing active pixel array, the method comprising the steps of: (a) providing an optical shutter in front of an image sensing pixel array of a camera system, said image sensing pixel array having an image sensing face defined by a series of active pixels arranged in rows and columns; (b) while said shutter is closed, resetting each said pixel and then reading a first output from each said pixel; (c) opening said optical shutter for a predetermined exposure period so as to allow light to be incident upon said image sensing face of said pixel array; (d) closing said optical shutter and then reading a second output from each said pixel, without resetting said pixels; and (e) subtracting one of said first and second outputs from the other of said first and second outputs for each said pixel, so as to obtain a first difference signal for each said pixel, which first difference signal is substantially free of reset and fixed offset noise components.