Abstract: A method of operating a solid state image sensor (1) for the acquisition of an image generated by an asynchronous stimulus (S) is described in which the sensor is operated in conjunction with at least one detector (4) which detects the said asynchronous stimulus. The sensor is regularly reset so as to commence integration from a reset state of the sensor each time a period Tr has elapsed. The output of the detector(s) prior to each reset (R) is used to determine whether that reset is inhibited or not, whereby the likelihood of the stimulus being corrupted is prevented, or at least substantially reduced. A method is also proposed in which a portion of the sensor array is itself used as the detector (4) for detecting the asynchronous stimulus. A solid state image sensor incorporating a reset inhibition control function for carrying out the described method is also claimed.

Abstract: A signal processing method for estimating luminance is provided, for use with matrix patterned image sensors where elected sensor pixels (G), preferably green pixels, from which luminance-representative signals are taken, only occupy alternate horizontal and vertical positions in the matrix pattern. The method is designed for detecting luminance contour edges and/or stripes in an image so as to enable images obtained form the sensor to be enhanced. Each pixel site (Hc) which is at the centre of both a row and a column of five pixels, and which is not the site of an elected (green) pixel, is identified and, for each such identified site (Hc), the signals output from the immediately adjacent four pixels (Gn,Ge,Gs,Gw) in said row and column are processed to establish both signal amplitude and pixel position.

Abstract: An integrated circuit suitable for use as a multi-spectral image array sensor (1) comprises an array of pixels (2) for sensing radiation of different wavelengths e.g. different colours. The array has at least one row of cells containing a plurality of series (R,G) of pixels which series are interspersed with each other. Each series consists essentially of pixels (2) for sensing radiation of substantially the same wavelength e.g. the same colour. At least two horizontal shift registers (16,18) are provided, each register being coupled to pixels (2) of a respective one of the plurality of series (R,G) of pixels so as to enable the outputs from the pixels of each series to be read out consecutively at an array output (11). In a preferred embodiment the pixels (2) are preferably arranged in a Bayer matrix of Red, Green and Blue pixels and two interleaved shift registers (16,18) are provided for reading out the pixel outputs for each colour consecutively, in each row.

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: 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.