Integrated circuit architecture of contact image sensor for generating binary images
AssigneesSyscan, Inc., Shenzhen Syscan Technology Co. Ltd.
InventorDongtai Liu
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Abstract
An integrated circuit architecture of contact image sensor for generating bi-level images and associated method are disclosed. The architecture comprises an image sensor, an amplifier, an analyzing circuit and a comparator, in one particular embodiment, it further comprises an electrically erasable programmable read-only memory (EEPROM). The amplifier is coupled to the image sensor and receives electronic signals therefrom and further receives pairs of gain and offset from the EEPROM. The electronic signals are adjusted in the amplifier respectively and sequentially in accordance to the pairs of gain and offset. The analyzing circuit determines a dynamic threshold to the comparator that subsequently produces the bi-level images.
Claims19
A circuit architecture for producing a binary image, said architecture comprising:
- an image sensor to produce an analog video signal, said image sensor comprising a plurality of photodetectors, each producing an electronic signal when said image sensor is activated, said analog video signal comprising electronic signals respectively from said photodetectors;
- an amplifier coupled to said image sensor and receiving said analog video signal, said amplifier further receiving an array of pairs of gain and offset, each of said pairs of gain and offset corresponding to one of said photodetectors, said amplifier adjusting said analog video signal sequentially according to each of said array of pairs of gain and offset;
- an analyzing circuit coupled to said amplifier and receiving said analog video signal, said analyzing circuit producing a dynamic threshold from said analog video signal according to a threshold determination procedure, wherein the threshold determination procedure includes determining a sequence of middle values, each of the middle values determined from a high value and a low value in a locale of said analog video signal;
- and
- a comparator receiving said adjusted analog video signal from said amplifier and said dynamic threshold from said analyzing circuit, said comparator generating said binary image from said analog video signal with respect to said dynamic threshold.
A method for producing a binary image, said method comprising:
- producing an analog video signal from an image sensor comprising a plurality of photodetectors, each of said photodetectors respectively producing an electronic signal when said image sensor is activated, wherein said analog video signal comprises electronic signals from all of said photodetectors;
- adjusting each of said electronic signals sequentially in an amplifier with respect to each of groups of parameters to overcome adverse impacts caused by inherent noises from said image sensor, wherein each of said groups of parameters corresponds to one of said photodetectors and derived through a self-calibration process with at least a test sheet so that undesirable signals can be detected from said image sensor to tune the parameters, wherein the test sheet does not have a known reflectivity but provides one of two extreme cases;
- deriving, in an analyzing circuit, a dynamic threshold from said analog video signal, and
- generating by a comparator a bi-level signal from said analog video signal in accordance with said dynamic threshold.
A circuit architecture for producing a bi-level signal, said architecture comprising:
- an image sensor producing an analog video signal, said image sensor comprising a number of sensor chips concatenated in series, each of said sensor chips comprising a plurality of photodetectors, each of said photodetectors producing an electronic signal when said image sensor is activated, said analog video signal comprising electronic signals respectively from said photodetectors in all of said sensor chips;
- an electrically erasable programmable read-only memory (EEPROM) storing pairs of predetermined gain and offset, each of said pairs of gain and offset corresponding respectively to one of said photodetectors and derived through a self-calibration process with at least a test sheet so that undesirable signals can be detected from said image sensor to tune the parameters;
- an amplifier coupled to said image sensor and receiving said electronic signals, said amplifier further receiving said pairs of gain and offset from said EEPROM, said amplifier adjusting said electronic signals respectively and sequentially in accordance to each of said pairs of gain and offset;
- an analyzing circuit coupled to said amplifier and receiving said electronic signals, said analyzing circuit producing threshold values from said electronic signals according to a threshold determination procedure, wherein the threshold determination procedure includes determining a sequence of middle values, each of the middle values determined from a high value and a low value in a locale of said analog video signal;
- and
- a comparator receiving said adjusted electronic signals from said amplifier and said threshold values from said analyzing circuit, said comparator generating said bi-level signal from said electronic signals with respect to said threshold values.
Dependencies are inferred from the claim text.