Range-finding system for a portable image reader

• US 20060186205A1
• Filed: 02/24/2005
• Published: 08/24/2006
• Est. Priority Date: 02/24/2005
• Status: Active Grant

• Current Assignee: Psion PLC (Motorola Solutions, Inc.)
• Original Assignee: Symagery Microsystems, Inc. (Motorola Solutions, Inc.)
• Inventors: Page, Harry
• Granted Patent: US 7,416,127 B2
• Time in Patent Office: Days
• US Class Current: 235/462.220
• CPC Class Codes: G06K 7/10851 Circuits for pulse shaping, amplifying, eliminating noise signals, checking the function of the sensing device basic electronic circuitry H03

Abstract

A range-finding system for a portable image reader is described. The range-finding system uses a distance-measuring device, such as an ultrasonic transducer, to determine the distance between the reader and a target, such as a label containing a bar code. An operator receives a visual indication which will assist in positioning the image reader within the optimal reading range of the target. The visual indicator may include three LED'"'"'s of different color or with different blinking rates which will indicate to the operator that the reader is short, long or in the optimal reading range of the reader. In one embodiment, the reader would automatically cycle through an image acquisition or decode sequence when range finder detects that the target is within the optimal reading range of the reader. In another embodiment, the visual indicator will prompt the operator to manually trigger the image acquisition or decode sequence once the reader is positioned within the optimal reading range.

Claims

1. A range-finding system for a portable image reader comprising:

a distance-measuring device to measure the distance of the portable image reader from a target;

a memory for storing values representing at least one optimal range of optimal reading distances from the target;

a processor for comparing the measured distance to the range of optimal reading distance values to determine whether the measured distance is within the optimal range, short of the optimal range or long of the optimal range;

a visual indicator coupled to the processor for providing an operator a visual signal indicating that the reader is at a distance from the target within the optimal range, short of the optimal range or long of the optimal range; and

wherein the processor is adapted to trigger an image acquisition cycle by the image reader to capture an image of the target when the reader is at a distance from the target within the optimal range.

2. The range-finding system for a portable image reader as claimed in claim 1 wherein the processor automatically triggers the image acquisition cycle when the reader is at a distance from the target within the optimal range.

3. The range-finding system for a portable image reader as claimed in claim 1 comprising an interface coupled to the processor and operable by an operator to initiate the triggering of the image acquisition cycle.

4. The range-finding system for a portable image reader as claimed in claim 1 comprising an interface coupled to the processor and operable by an operator to initiate the triggering of the image acquisition cycle only when the reader is at a distance from the target within the optimal range.

5. The range-finding system for a portable image reader as claimed in claim 1 wherein the memory stores values representing a number of ranges of optimal reading distances from the target for a number of different applications for the image reader.

6. The range-finding system for a portable image reader as claimed in claim 5 comprising an interface coupled to the processor and operable by the operator to select a desired range from the ranges of optimal reading distances.

7. The range-finding system for a portable image reader as claimed in claim 1, wherein the distance measuring device comprises an ultrasonic transducer.

8. The range-finding system for a portable image reader as claimed in claim 1, wherein the visual indicator comprises three light sources, a first light source adapted to illuminate when the reader is at a distance from the target long of the optimal range, a second light source adapted to illuminate when the reader is at a distance from the target within the optimal range, and a third light source adapted to illuminate when the reader is at a distance from the target short of the optimal range.

9. The range-finding system for a portable image reader as claimed in claim 8 wherein each light source displays a different color light.

10. The range-finding system for a portable image reader as claimed in claim 8 wherein each light source blinks at a different rate.

11. The range-finding system for a portable image reader as claimed in claim 1, wherein the visual indicator comprises a light source, wherein the light source is adapted to blink at a first rate when the reader is at a distance from the target long of the optimal range, adapted to blink at a second rate when the reader is at a distance from the target within the optimal range, and adapted to blink at a third rate when the reader is at a distance from the target short of the optimal range.

12. The range-finding system for a portable image reader as claimed in claim 1, wherein the portable image reader is adapted to read a bar code symbol.

13. A method of operating a portable image-reader comprising the steps of:

a. positioning the image reader before a target;

b. measuring the distance of the portable image reader from the target;

c. comparing the measured distance with an optimal range of reading distances from the target;

d. providing a first visual indication when the measured distance is within the optimal range;

e. triggering an image acquisition cycle by the image reader when the measured distance is within the optimal range;

f. providing a further visual indication when the measured distance is not within the optimal range;

g. moving the portable image reader towards a position within the optimal range; and

h. repeating steps b. to g. until the image acquisition cycle by the image reader is triggered.

14. The method operating a portable image-reader as claimed in claim 13 wherein step f. comprises:

f.1. providing a second visual indication when the measured distance is long of the optimal range;

or

f.2. providing a third visual indication when the measured distance is short of the optimal range.

15. The method operating a portable image-reader as claimed in claim 14 wherein step g. comprises:

g.1. moving the portable image reader closer to the target when the second visual indication is provided;

or

g.2. moving the portable image reader away from the target when the third visual indication is provided.

16. The method operating a portable image-reader as claimed in claim 13 wherein step c. comprises:

c.1. selecting the optimal range of reading distances from the target from a number of possible optimal ranges for the portable reader.

17. The method operating a portable image-reader as claimed in claim 13 wherein step e. comprises:

e.1. automatically triggering the image acquisition cycle by the image reader when the measured distance is within the optimal range.

18. The method operating a portable image-reader as claimed in claim 13 wherein step e. comprises:

e.1. manually triggering the image acquisition cycle by the image reader when the measured distance is within the optimal range.