Abstract: An image capture system for mobile communications systems includes an imaging device for capturing optical image data and a data transfer apparatus coupled to a communications device communications device for transferring the optical image data to the communications device for transmittal over a communications network.

Abstract: In an illustrative embodiment, an instant camera is provided which includes an imager for receiving an image of an object to be photographed. The imager outputs a signal corresponding to the received image, and a memory device stores the signal. A printer prints instant film photographs corresponding to received or stored images, and has the capability to print at least one image on a single piece of instant film. A preview unit has at least one display for displaying an image corresponding to a received or stored image. A controller, in communication with the imager, the memory device, the printer, and the preview unit, controls the transfer of the signal from the imager to the memory device, from the memory device to the printer, and from the memory device to the preview unit.

Abstract: A method for detecting and compensating for thermal asperity in data signals, including the steps of detecting thermal asperity in the data signals and adjusting a parameter prior to amplification of the data signals.

Abstract: Disclosed is an image sensor including one or more dummy pixels that produce a reference signal which is used to compensate for errors within the devices of the main pixel cells. In one embodiment, at least one dummy pixel is used in conjunction with other circuitry to correct for nonlinearities in the transfer characteristic of a source follower transistor within each pixel. In another embodiment, an array of dummy pixels is used to correct for leakage current within the pixels during an electronic shutter mode of operation. The two techniques can be combined whereby both threshold voltage mismatch and leakage current are compensated for.

Abstract: The present invention relates to an automatic gain control circuit in which the automatic gain control function is performed entirely in the digital domain. In an illustrative embodiment, the digital automatic gain control circuit for an image sensor having associated therewith an analog-to digital (A/D) converter for converting analog electrical signals from the image sensor to corresponding digital codes, includes a min/max detector for determining minimum and maximum electrical signal values from the digital codes of the A/D converter for each frame of image. A filter coupled to the min/max detector dampens instantaneous changes of the minimum and maximum values by filtering to provide filtered minimum and maximum values.

Abstract: A CMOS image sensor is provided in which correlated double sampling is performed entirely in the digital domain. In an exemplary embodiment, the image sensor includes a plurality of imager cells arranged in rows and columns, where the imager cells of a particular column are coupled to a column data line of that column. Each active imager cell is capable of selectively providing a first output on an associated column data line indicative of a reset level during a first sampling interval. During a second sampling interval, each active imager cell provides a signal output on the associated column data line indicative of an amount of light incident upon that imager cell. At least one analog to digital (A/D) converter is coupled to the column data lines and converts the first and signal outputs on each column data line to first and second digital codes, respectively, to complete a correlated double sampling operation. The invention eliminates the need for analog capacitors to store the reset and signal levels.

Abstract: Disclosed is an image sensor having A/D conversion circuitry coupled to column data lines of an image sensor array. The A/D conversion circuitry digitizes analog signals on the column data lines, each representing intensity of light incident upon an active imager cell. Higher resolution is provided for darker light levels than for bright light levels, such that a high resolution image is obtained with less storage data than would otherwise be required. In one embodiment, the A/D conversion circuitry includes a plurality of comparators, each having a first input coupled to one or more column data lines and a second input coupled to receive a time-varying reference signal, and a plurality of n-bit counters coupled to the comparator outputs. An n-bit to m-bit converter nonlinearly maps n-bit codes to m-bit codes and provides the m-bit codes to an m-bit D/A converter which produces the time-varying reference signal.

Abstract: Disclosed is an image sensing device having a reduced number of transistors within each imager cell as compared to prior art devices. Each imager cell includes a photosensitive element providing a photocharge responsive to incoming light, and first, second and third transistors. The first transistor is coupled to an activation line, e.g., a row select line, that carries an activation signal to a first plurality of imager cells to selectively activate cells for image data readout. This transistor transfers the photocharge towards a reference circuit node within the image cell in response to the activation signal. The second transistor is operably coupled to the first transistor, and is operative to selectively set a voltage level at the reference node. The third transistor has a control terminal coupled to the reference node, and an output terminal coupled to an output data bus common to a second plurality of image cells, e.g., a column of cells.

Abstract: Disclosed is a circuit for performing correlated double sampling entirely in the digital domain. In an exemplary embodiment, the circuit includes a plurality of comparators, each having a first input coupled to an associated data line for receiving first and second signals in first and second sampling intervals, respectively. A time varying reference signal is applied to the second input of each comparator. A plurality of up/down counters are coupled to respective ones of the comparators, and each is operable to count in a first direction during the first sampling interval and in an opposite direction during the second sampling interval. Each up/down counter is caused to stop counting when the amplitude of the variable reference signal substantially equals the amplitude of the respective first or second signal. As a result, each up/down counter provides an output representing a subtraction of one of said first or second signals from the other.

Abstract: An automatic and adaptive threshold setting circuit for an IR receiver is capable of operating over a broad range of frequencies and power levels. The adaptive threshold circuit allows a very sensitive threshold in environments where little sunlight or other ambient light reaches the receiver, but which will increase the threshold of the receiver when large amounts of ambient light fall on the photo diode. The circuit senses the current flowing through the reverse biased IR photo detector due to ambient light levels. This current measurement is used to adjust the sensitivity of the receiver.