Imaging circuit and method of spatial compensation
AssigneeMotorola, Inc.
InventorsSteven M. Domer, Jeffery E. Bills
Life of this patent
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Abstract
An imaging system (10) and method compensate for different amplitudes of pixel signals generated by photoactive devices in an optical sensor (32) whose responses to projected light are not uniform. The sensor is divided into regions (52) such that the response of the photoactive devices within a region are substantially equal. A processing circuit (34) compensates for different responses among different regions with a programmable gain amplifier (72) whose gain is dynamically adjusted when pixel signals generated in different regions are received.
Claims16
An imaging device, comprising:
- an optical sensor having an output for providing pixel signals generated in response to light projected onto regions of the optical sensor;
- and
- an amplifier having a first input coupled for receiving the pixel signals, a first output for providing an imaging signal, and a control input coupled for receiving control data representative of signal variations from each respective region to amplify the pixel signals to different gains when the pixel signals are generated in different regions of the optical sensor.
An imaging device comprising:
- an optical sensor including a plurality of photoactive devices disposed in regions of the optical sensor, said optical sensor having a output for providing pixel signals generated in response to light projected onto regions of the optical sensor, the optical sensor having an address input coupled for receiving pixel addresses for selecting the pixel signals in different orders;
- an amplifier having a first input coupled for receiving the pixel signals, a first output for providing an imaging signal, and a control input coupled for receiving control data representing a predetermined region characterization to amplify the pixel signals to different gains when the pixel signals are generated in different regions of the optical sensor;
- and
- a memory circuit for storing the control data, the memory circuit having an address input coupled for receiving the pixel addresses and an output coupled to the control input of the amplifier.
A method of capturing an image, comprising:
- altering a gain of pixel signals through an amplifier having a control input in response to control data to compensate for a difference in response to light projected on different regions of an optical sensor;
- storing the control data in a memory circuit having an address input coupled for receiving the pixel address and an output coupled to the control input of the amplifier;
- and
- retrieving the control data with address data.
An image capturing method, comprising the steps of:
- sensing light projected on fast and second regions of an optical sensor to produce first and second pixel signals;
- setting a gain of an amplifier having a control input with first control data representing a known variation of signal from a first predetermined region for amplifying the first pixel signal;
- and
- altering the gain of the amplifier with second control data representing a known variation of signal from a second predetermined region for amplifying the second pixel signal to equalize the responses of the first and second regions of the optical sensor to the light.
An imaging device, comprising:
- an optical sensor having an output for providing pixel signals generated in response to light projected onto a plurality of regions of the optical sensor, wherein each of the plurality of regions has a corresponding control data representative of signal variations from respective ones of said plurality of regions;
- and
- an amplifier having a first input coupled for receiving the pixel signals, a first output for providing an imaging signal, and a control input coupled for receiving the corresponding control data to amplify the pixel signals to different gains according to each of their corresponding signal variations.
Dependencies are inferred from the claim text.