An optical or symbol reader including CMOS circuitry preferably integrated on a single chip. A CMOS optical reader chip comprises a CMOS imaging array having a plurality of pixels each with a dedicated pixel-site circuit. Charge is accumulated at each pixel location transferred upon demand to a common bus. In a preferred embodiment, exposure time of the imaging array is controlled using a feedback loop. One or more exposure control pixels are positioned adjacent to or within the imaging array and receive light along with the imaging array. The charge of the exposure control pixel or pixels is measured against a threshold level, and the amount of time taken to reach the threshold level determines the time exposure of the pixels of the imaging array. CMOS signal processing circuitry is employed which, in combination with the exposure control circuitry, minimizes time-to-read over a large range of light levels, while performing spatially optimal filtering. Clocking cycles and control signals are time-adjusted in accordance with the varying output frequency of the imaging array so as to provide invariant frequency response by the signal processing circuitry. A multi-dimensional CMOS imaging array is also provided having simultaneous pixel exposure with non-destructive readout of the pixel contents.
RELATED APPLICATION DATA
This application is a continuation of application Ser. No. 08/697,408, filed on Aug. 23, 1996, now U.S. Pat. No. 6,155,488, which is a continuing application of U.S. Provisional application Ser. No. 60/003,256 filed on Aug. 25, 1995, hereby incorporated by reference as if set forth fully herein.
A high Dynamic Range Active Pixel CMOS image sensor architecture has incorporated therein an adaptive pixel reset. The individual sensor pixels are reset only when accumulated charge, or the integration time exceeds certain predetermined limits. The reset is skipped when the integrated charge signal in a given pixel is low. The accumulated number of reset skips in a given time frame, together with the standard analog output, is used to calculate the sensor high DR output signal. A signal processing system is used to simultaneously process both sensor analog and digital outputs.
To provide a drive method for finding out an optimum storage period quickly.In the method for driving the MOS sensor having a plurality of pixels, after all the plurality of pixels are simultaneously reset, signals are then sequentially outputted from said plurality of pixels. The period from the reset time to the time just before said plurality of pixels output saturated signals is termed as the storage period.
Methods of and systems for illuminating objects using planar laser illumination beams having substantially-planar spatial distribution characteristics that extend through the field of view (FOV) of image formation and detection modules employed in such systems. Each planar laser illumination beam is produced from a planar laser illumination beam array (PLIA) comprising an plurality of planar laser illumination modules (PLIMs). Each PLIM comprises a visible laser diode (VLD, a focusing lens, and a cylindrical optical element arranged therewith. The individual planar laser illumination beam components produced from each PLIM are optically combined to produce a composite substantially planar laser illumination beam having substantially uniform power density characteristics over the entire spatial extend thereof and thus the working range of the system. Preferably, each planar laser illumination beam component is focused so that the minimum beam width thereof occurs at a point or plane which is the farthest or maximum object distance at which the system is designed to acquire images, thereby compensating for decreases in the power density of the incident planar laser illumination beam due to the fact that the width of the planar laser illumination beam increases in length for increasing object distances away from the imaging optics. By virtue of the present invention, it is now possible to use both VLDs and high-speed CCD-type image detectors in conveyor, hand-held and hold-under type scanning applications alike, enjoying the advantages and benefits that each such technology has to offer, while avoiding the shortcomings and drawbacks hitherto associated therewith.
Methods of and systems for illuminating objects using planar laser illumination beams having substantially-planar spatial distribution characteristics that extend through the field of view (FOV) of image formation and detection modules employed in such systems. Each planar laser illumination beam is produced from a planar laser illumination beam array (PLIA) comprising an plurality of planar laser illumination modules (PLIMs). Each PLIM comprises a visible laser diode (VLD, a focusing lens, and a cylindrical optical element arranged therewith. The individual planar laser illumination beam components produced from each PLIM are optically combined to produce a composite substantially planar laser illumination beam having substantially uniform power density characteristics over the entire spatial extend thereof and thus the working range of the system. Preferably, each planar laser illumination beam component is focused so that the minimum beam width thereof occurs at a point or plane which is the farthest or maximum object distance at which the system is designed to acquire images, thereby compensating for decreases in the power density of the incident planar laser illumination beam due to the fact that the width of the planar laser illumination beam increases in length for increasing object distances away from the imaging optics. By virtue of the present invention, it is now possible to use both VLDs and high-speed CCD-type image detectors in conveyor, hand-held and hold-under type scanning applications alike, enjoying the advantages and benefits that each such technology has to offer, while avoiding the shortcomings and drawbacks hitherto associated therewith.
A method of equalizing the illumination produced by a planar laser illumination array within a planar laser illumination and (electronic) imaging system, comprising the steps of: providing an image formation and detection module having imaging optics with a field of view (FOV) focused upon an image detecting array; providing a planar laser illumination array having a plurality of planar laser illumination modules, each planar laser illumination module producing a planar laser beam component during image formation and detection operations, which are combined to produce a composite planar laser illumination beam extending through a working range of said FOV, wherein said working range includes both near and far fields, if the near field illumination is brighter then the far field illumination: displacing a first portion of the planar illumination modules in a first direction perpendicular to said FOV and a second portion of the planar illumination modules in a second direction opposite to said first direction, angling each planar laser illumination beam component to overlap at said far field, whereby the power density incident on the near field is reduced; and if the far field illumination is brighter then the near field illumination: displacing a first portion of the planar illumination modules in a first direction perpendicular to the FOV and a second portion of the planar illumination modules in a second direction opposite to said first direction, angling each planar laser illumination beam component to overlap at the near field, whereby the power density incident on the far field is reduced.
