Portable data collection device with color imaging assembly

• US 5,714,745 A
• Filed: 03/01/1996
• Issued: 02/03/1998
• Est. Priority Date: 12/20/1995
• Status: Expired due to Fees

• Current Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Original Assignee: Metanetics Corporation
• Inventors: Ju, Paul B., Wang, Ynjiun P.
• Primary Examiner(s): Hajec, Donald T.
• Assistant Examiner(s): Le, Thien Minh
• Application Number:
  US08/609,344
• Time in Patent Office: 704 Days
• Field of Search: 235/462, 235/465, 235/469, 235/472, 382/14, 382/16, 358/76, 358/78
• US Class Current: 235/469
• CPC Class Codes: G01J 3/2803 using photoelectric array detector
• CPC Class Codes: G01J 3/51 using colour filters
• CPC Class Codes: G01J 3/513 having fixed filter-detector pairs
• CPC Class Codes: G01J 5/08 Optical arrangements
• CPC Class Codes: G06K 2207/1011 Aiming
• CPC Class Codes: G06K 7/10752 Exposure time control
• CPC Class Codes: G06K 7/14 using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence

Abstract

A portable data collection device includes an imaging assembly including a two dimensional (2D) photosensor array overlied by a RGB color filter. The imaging assembly is selectively actuatable with a first trigger for reading a dataform in the imaging assembly'"'"'s target area and actuatable with a second trigger for capturing a color image of the target area. The imaging assembly includes compensation circuitry to compensate for illumination transmittivity differences between the red, green and blue colors of the color filter. The compensation circuitry is invoked when the imaging assembly is actuated to read a bar code dataform. The imaging assembly further includes compression circuitry for compressing digital data representative of the target area when the imaging assembly is actuated to capture a color image of the target area.

Claims

1. A portable data collection device for reading a dataform in a two dimensional target area, the device comprising:

a) a camera assembly, including a color photosensor array assembly comprising a two dimensional photosensor array overlaid by a filter having red, green and blue areas, the photosensor array including a matrix of photosensor elements which are read out after an exposure period generating a signal representative of an image of the two dimensional target area, the signal including luminance component values and corresponding chrominance component values, a given luminance component value representing an intensity of reflected illumination during the exposure period received by a set of one or more photosensor elements of the color photosensor array, a given chrominance component value corresponding to the given luminance component value representing a color of a potion of the filter overlying the set of one or more photosensor elements; and

b) image processing and decoder circuitry receiving said signal and generating decoded data representative of the dataform, the image processing and decoder circuitry including;

i) an analog to digital converter for converting the luminance component values and the chrominance component values into digital luminance component values and digital chrominance component values;

ii) buffer circuitry for storing the digital luminance component values and digital chrominance component values; and

iii) compensation circuitry for combining the digital luminance component values and the corresponding digital chrominance component values to generate gray scale digital data values representative of the image of the two dimensional target area, the gray scale digital data values being decoded by the image processing and decoder circuitry to generate the decoded data representative of the dataform.

3. The device of claim 1 wherein the compensation circuitry further adjusts at least a portion of the gray scale digital data values corresponding to selected sets of one or more photosensor elements of the color photosensor array assembly prior to the gray scale digital data values being decoded by the image processing and decoder circuitry to generate the decoded data representative of the dataform.

4. The device of claim 3 wherein the selected sets of one or more photosensor elements consist of sets having photosensor elements overlaid by a selected one of the red color filter, the blue color filter and the green color filter.

5. The device of claim 4 wherein the compensation circuitry generates an intensity value representative of an intensity of illumination reflected from the target area onto the selected sets of one or more photosensor elements during the exposure period, generates a compensation value representative of the intensity value and adjusts the portion of the gray scale digital data values corresponding to the selected sets of one or more photosensor elements in accordance with the compensation value.

6. The device of claim 5 wherein the intensity value is an average of reflected illumination intensity over the exposure period on the selected sets of one or more photosensor elements and the compensation value represents the difference between the intensity value and a similarly calculated average intensity value based on reflected illumination intensity over the exposure period for a set of photosensor elements other than photosensors elements in the selected sets of one or more photosensor elements.

7. The device of claim 6 wherein the set of photosensor elements other than photosensors elements in the selected sets of one or more photosensor elements comprise photosensor elements overlaid by the green color filter.

8. The device of claim 5 wherein the selected sets of one or more photosensor elements are farther limited to sets having photosensor elements receiving reflected illumination from the dataform.

2. A portable data collection device for reading a dataform in a target area, the device comprising:

a) a camera assembly, including a color photosensor array assembly generating a signal representative of illumination reflected from the target area and incident on the color photosensor array assembly over an exposure period;

b) image processing and decoder circuitry receiving said signal and generating decoded data representative of the dataform;

c) the color photosensor array assembly including a matrix of photosensor elements, each photosensor element overlaid by one of a red color filter, a blue color filter and a green color filter;

d) the signal being a lower resolution Y-C video signal including a plurality of luminance component values and corresponding plurality of chrominance component values;

e) the image processing and decoder circuitry including buffer circuitry for storing digital image data, the digital image data including data values corresponding to the plurality of luminance component values and the corresponding plurality of chrominance component values; and

f) wherein only the data values corresponding to the plurality of luminance component values are used by the image processing and decoder circuitry for decoding the dataform.

9. A portable data collection device for imaging a target area, the device comprising:

a) a camera assembly, including a color photosensor array assembly generating a signal representative of illumination reflected from the target area over an exposure period;

b) image processing and decoder circuitry, receiving said signal and being actuatable to generate a selected one of decoded data representative of a dataform in the target area and digital color image data representative of the target area

c) the color photosensor array including a matrix of photosensor elements, each overlaid by one of a red, blue or green color filter;

d) the signal being a lower resolution Y-C video signal including a luminance component and a chrominance component; and

e) wherein the image processing and decoder circuitry includes compensation circuitry and decoding circuitry;

f) the compensation circuitry being selectively acutuable for;

i) receiving digital data representative of said signal, said digital data including luminance component values and chrominance component values,

ii) converting the digital data to higher resolution digital image data, each data value of the higher resolution digital image data corresponding to an intensity of illumination incident on a different set of one or more photosensor elements over the exposure period, and

iii) adjusting at least a portion of the data values of the higher resolution digital image data corresponding to selected sets of one or more photosensor elements;

g) the decoding circuitry selectively actuatable to decode the higher resolution digital image data and generate decoded data representative of a dataform in the target area.

10. The device of claim 9 wherein the selected sets of one or more photosensor elements consist of photosensor elements overlaid by a selected color filter.

11. The device of claim 9 wherein the image processing and decoding circuitry includes buffer circuitry for storing digital data including luminance component values and chrominance component values corresponding to the exposure period.

12. The device of claim 9 wherein the compensation circuitry generates an intensity value representative of an intensity of illumination reflected from the target area onto the selected sets of one or more photosensors, generates a compensation value representative of the intensity value and adjusts the values of the higher resolution digital data corresponding to the selected sets of one or more photosensors in accordance with the compensation value.

13. The device of claim 12 wherein the intensity value is an average of reflected illumination intensity over the exposure period on selected sets of one or more photosensors elements and the compensation value represents the difference between the intensity value and a similarly calculated average intensity value based on reflected illumination intensity over the exposure period for a set of photosensor elements other than photosensor elements in the selected sets of one or more photosensor elements.

14. The device of claim 13 wherein the non-selected photosensor elements comprise photosensor elements overlaid by the green filter.

15. The device of claim 12 wherein the selected sets of one or more photosensor elements are further limited to photosensor elements receiving reflected illumination from the dataform.