US 6,606,171 B1 · Digitizing scanner

Abstract

A digitizing scanner particularly for scanning transparent films such as X-rays provides an improved illuminator for transmitting light through the film. The illuminator defines a line array of a plurality of individually calibrated and controlled LEDs. The LEDs are calibrated by determining their relative points of projection on a CCD camera array. The camera array scans the LEDs and adjusts them individually to produce a predetermined illumination pattern from the group. The adjustment occurs over a plurality of cycles that address cross-talk between LEDs in the array. The camera includes anti-reflection elements to minimize bounce-back of image light and noise suppression circuitry to reduce low-level signal noise. A central processing unit, interconnected with the camera assembly includes a pixel averager to reduce the inherent resolution of the CCD to a desired level and to attenuate further noise. The scanner can include an illuminator for illuminating a scannable opaque bar-code strip and size-measurement circuitry for determining the relative size and location of the scanned image.

Claims16

Dependent claims

An illuminator for a digitizing scanner a scanning camera interconnected with a central processing unit, the scanning camera defining discrete pixels arranged in a widthwise direction, the pixels being adapted to acquire an image of a transparent film passing through a widthwise field of view of the scanning camera, the illuminator comprising:

a plurality of light sources, each being a light emitting diode and each being individually arranged in a line across the widthwise field of view so as to face a first side of the transparent film opposite to a second side of the transparent film arranged to face the scanning camera;
a plurality of controllers each interconnected with respective of the plurality of individual light sources, each of the controllers providing a variable driving power to a respective of the plurality of individual light sources;
and
wherein the central processing unit is constructed and arranged to instruct the controllers to respectively change the driving power to each of the plurality of the light sources in response to a reading of intensity of predetermined of the pixels that are mapped to each of the plurality of light sources so that the scanning camera receives a predetermined illumination pattern across the widthwise field of view and wherein the controllers are adapted to respectively change the driving power during a calibration procedure that occurs with respect to operation of the digitizing scanner after startup of operation of the scanner.

1 more element

An illuminator for a digitizing scanner having a widthwise field of view, a scanning camera interconnected with a central processing unit comprising:

a plurality of light sources each individually arranged in a line across the widthwise field of view;
a plurality of controllers, each interconnected with respective of the plurality of individual light sources, each of the controllers providing a variable driving power to a respective of the plurality of individual light sources;
wherein the central processing unit is constructed and arranged to instruct the controllers to respectively change the driving power to each of the plurality of the light sources so that the scanning camera receives a predetermined illumination pattern across the widthwise field of view;
wherein the light sources comprise a plurality of light emitting diodes and wherein the controllers provide a plurality of current regulating circuits;
an intensity controller interconnected with each of the plurality of controllers for varying a primary driving power to each of the plurality of light sources, the intensity controller being responsive to the central processing unit based upon a predetermined maximum level of light exposure by each of the plurality of light sources at the scanning camera;
a photodetector for detecting an output of a predetermined light source of the plurality of light sources, the photodetector being constructed and arranged to produce a reference signal, the photodetector being interconnected with the intensity controller whereby the predetermined maximum level of light exposure is set and maintained based upon the reference signal;
and
wherein each of the plurality of controllers comprises a digital/analog converter and a common emitter buffer amplifier interconnected with one of the plurality of light sources, the analog/digital converter being interconnected with and receiving a digital control signal from the central processing unit and interconnected with and receiving the reference signal, the digital/analog converter having an output interconnected with and controlling the common emitter buffer amplifier whereby the driving power of the one of the plurality of light sources is varied.

5 more elements

A method for calibrating an illumination assembly in a digitizing scanner having a camera defining a widthwise line of photosensitive pixels, the camera being adapted to scan widthwise lines of an image in a lengthwise direction and a controller for controlling the illumination assembly and the camera, the method comprising the steps of:

(a) during a calibration procedure that occurs with respect to operation of the digitizing scanner after startup of operation of the scanner, incrementally activating predetermined light sources of a plurality of light sources, each of the plurality of light sources comprising a discrete light emitting diode, being arranged in a widthwise line to each project an illumination light therefrom so as to transmit the light to a side of a film being scanned toward the camera which faces an opposing side of the film, the step of incrementally activating including activating light sources that are each spaced apart by a predetermined number of inactivated light sources until all light sources have been activated;
(b) identifying pixels on the camera activated by each of the plurality of light sources and mapping each of the activated pixels to a predetermined of the plurality of light sources;
(c) activating all of the plurality of light sources at a predetermined power level and deriving an intensity signal based upon projected light from the light sources at the camera;
(d) comparing an intensity value for each of the pixels identified in the step of identifying with a predetermined reference intensity value;
and
(e) changing a power level of each of the plurality of light sources so that a measured exposure value of respective pixels is closer to a desired exposure value based upon readings of intensity at identified pixels mapped to each of the predetermined of the plurality of light sources.

3 more elements

Dependencies are inferred from the claim text.

Digitizing scanner

Life of this patent

Digitizing scanner

Life of this patent

Abstract

Claims16