Ncr Canada Ltd. -- Ncr Canada Ltee

Ncr Corporation

Ncr Canada Ltd.

Roger H Therrien

Maninderpal S Chahal

A system is disclosed for automatically controlling the light intensity of a light source as a function of the amount of light received by a photosensor. In a preferred embodiment the light source illuminates a reference background which, in turn, reflects the light incident thereon to a photosensor in a video camera. In response to this reflected light, the photosensor produces a video signal which is proportional to the amount of light reflected thereon. A first processor is responsive to the reception of the video signal over a preselected period of time and provides a first signal which is proportional to the amount of reflected light received by the photosensor over that preselected period of time. A second processor is responsive to the first signal and generater a control signal to automatically cause an adjustable power supply to change the voltage applied to the light source as a function of the amplitude of the control signal. The second processor is also controlled by a sensor signal initiated by the presence of the object to be copied.

Automatic light control system

Disclosed is an automatic self-adjusting CCD activated video camera circuit for adjusting the various CCD channel offset and gain values to the desired levels by utilizing the channels' digitized internal black and white references. Two identical feedback loops are used for offset and gain adjustment, respectively. In the gain/offset adjust loop, the white/black reference is compared to a desired gain/offset set by jumpers or switches on the video camera board. A difference in these values causes a corresponding 10 bit counter to increase or decrease its value. The digital counter value is converted to an analog signal and is used to optimally modify the channel gain/offset.

Self-adjusting video camera

A system and method are disclosed for detecting picture element failures in a multielement array. In a preferred embodiment of the invention the illumination of a reference background by a lamp is controlled by a controlled power supply to be off in a first mode of operation and on in a second mode. During a diagnostic operation, the reference background is scanned by a N element CCD array t provide N reference pixels for each scan during each of the first and second modes of operation. During the first mode, a first error signal is developed for each of the N reference pixels in a first mode scan that is greater than a first reference signal level. During the second mode, a second error signal is developed for each of N reference pixels in a second mode scan that is less than a second reference level. These first and second signals are then respectively utilized by a first counter to store the total number of pixel errors detected in a first preselected scan during the first mode and a second counter to store the total number of pixel errors detected in a second preselected scan during the second mode. The counts of these first and second counters are then utilized in conjunction with address and control signals to selectively store in associated first and second circuits the associated numbers or addresses of the defective elements in the array for each of the first and second modes of operation.

Method and system for automatically detecting camera picture element

An electro-optical imaging system is disclosed which automatically self-diagnoses the operations of its photosensor and its video processing circuitry during each of first and second modes of operation of a processor, when no object is being imaged. In a preferred embodiment, a power supply is controlled by the processor to prevent a light source from illuminating a reference background during the first mode of operation and to enable the light source to illuminate the reference background during the second mode of operation. The photosensor sequentially develops first and second signals respectively proportional to the intensity of reflected light received from the reference background during the first and second modes of operation. The video processing circuitry is responsive to the first and second signals for sequentially developing respective first and second data signals. A first circuit is responsive to the first and second signals for sequentially developing first and second test signals respectively proportional to the average values of respective portions of the first and second signals. A second circuit is responsive to the first and second data signals for sequentially developing third and fourth test signals respectively representative of predetermined portions of the first and second data signals. The processor is selectively responsive to the first, second, third and fourth test signals for automatically testing the operation of each of the photosensor and video processing circuitry during each of the first and second modes of operation.

Growing community of inventors

Waterloo, Canada

Roger H Therrien