CMOS digital optical navigation chip
First Claim
1. A CMOS integrated circuit chip for capturing and processing images, comprising:
- imaging circuitry including a photo cell array for capturing an image projected thereon and for generating an analog signal representative thereof, regions of the array being selectable to be active in operation of the imaging circuitry, the array including a preselected number of photo transistors and a preselected number of photo diodes, each photo cell in the array having a programmable shutter speed, the imaging circuitry further including transfer amplifier circuitry for converting output from the photo cell array into the analog signal;
conversion circuitry including an n-bit SAR analog-to-digital converter for converting the analog signal to a corresponding digital signal;
filter circuitry including a spatial filter for enhancing edges and contrast of the image represented by the digital signal;
compression circuitry for reducing storage needs of the digital signal;
correlation circuitry for processing the digital signal to generate a result surface on which a minima resides, the minima representing a best fit image displacement between the captured image and previous ones thereof;
interpolation circuitry for mapping the image as represented by the result surface into spatially-defining coordinates, wherein selected ones of the filter circuitry, the correlation circuitry and the interpolation circuitry have programmable parameters, values of said parameters corresponding to predesired adaptions of the digital signal; and
interface circuitry for formatting the digital signal so as to be compatible for signal communication with a preselected device.
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Abstract
A CMOS digital integrated circuit (IC) chip on which an image is captured, digitized, and then processed on-chip in substantially the digital domain. A preferred embodiment comprises imaging circuitry including a photo cell array for capturing an image and generating a representative analog signal, conversion circuitry including an n-bit successive approximation register (SAR) analog-to-digital converter for converting the analog signal to a corresponding digital signal, filter circuitry including a spatial filter for edge and contrast enhancement of the corresponding image, compression circuitry for reducing the digital signal storage needs, correlation circuitry for processing the digital signal to generate result surface on which a minima resides representing a best fit image displacement between the captured image and previous images, interpolation circuitry for mapping the result surface into x- and y-coordinates, and an interface with a device using the chip, such as a hand-held scanner. The filter circuitry, the compression circuitry, the correlation circuitry and the interpolation circuitry are all advantageously embodied in an on-chip digital signal processor (DSP). The DSP embodiment allows precise algorithmic processing of the digitized signal with almost infinite hold time, depending on storage capability. The corresponding mathematical computations are thus no longer subject to the vagaries of CMOS chip structure processing analog signals. As a result, precise and accurate navigation enables a predictable, reliable and manufacturable design. Parameters may also be programmed into the DSP'"'"'s “software,” making the chip tunable, as well as flexible and adaptable for different applications.
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Citations
9 Claims
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1. A CMOS integrated circuit chip for capturing and processing images, comprising:
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imaging circuitry including a photo cell array for capturing an image projected thereon and for generating an analog signal representative thereof, regions of the array being selectable to be active in operation of the imaging circuitry, the array including a preselected number of photo transistors and a preselected number of photo diodes, each photo cell in the array having a programmable shutter speed, the imaging circuitry further including transfer amplifier circuitry for converting output from the photo cell array into the analog signal;
conversion circuitry including an n-bit SAR analog-to-digital converter for converting the analog signal to a corresponding digital signal;
filter circuitry including a spatial filter for enhancing edges and contrast of the image represented by the digital signal;
compression circuitry for reducing storage needs of the digital signal;
correlation circuitry for processing the digital signal to generate a result surface on which a minima resides, the minima representing a best fit image displacement between the captured image and previous ones thereof;
interpolation circuitry for mapping the image as represented by the result surface into spatially-defining coordinates, wherein selected ones of the filter circuitry, the correlation circuitry and the interpolation circuitry have programmable parameters, values of said parameters corresponding to predesired adaptions of the digital signal; and
interface circuitry for formatting the digital signal so as to be compatible for signal communication with a preselected device. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9)
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2. The chip of 1, in which the photo cell array is a 47×
- 47 array of photo cells.
Specification