Optical reader having reduced parameter determination delay

• US 20020125317A1
• Filed: 03/12/2001
• Published: 09/12/2002
• Est. Priority Date: 01/22/2001
• Status: Active Grant

• Current Assignee: Welch Allyn Incorporated
• Original Assignee: Welch Allyn Incorporated
• Inventors: Hussey, Robert M., Pankow, Matthew, Gardiner, Robert
• Granted Patent: US 7,268,924 B2
• Time in Patent Office: Days
• US Class Current: 235/454
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10732 Light sources
• CPC Class Codes: G06K 7/10821 further details of bar or optical code scanning devices
• CPC Class Codes: G06K 7/1413 1D bar codes
• CPC Class Codes: G06K 7/1417 2D bar codes
• CPC Class Codes: H04N 25/42 by switching between different modes of operation using different resolutions or aspect ratios, e.g. switching between interlaced and non-interlaced mode
• CPC Class Codes: H04N 25/76 Addressed sensors, e.g. MOS or CMOS sensors

Abstract

In the present invention, an optical reader image sensor is adapted to clock out image data from an image sensor according to “low resolution” mode of operation in order to reduce a parameter determination delay of the reader. In a low resolution mode, some pixels of the readers image sensor array are clock out at normal clock out speed sufficient to develop electrical signals accurately reflecting the intensity of light at the respective pixel positions, while other pixels of the array are either not clocked out or are clocked out at a higher clock out rate which may be insufficient to allow development of electrical signals that accurately represent light incident on the image sensor'"'"'s sensor array but which nevertheless, results in a reduction of the overall frame clock out rate of the frame of image data. An optical reader according to the invention operates in a low resolution frame clock out mode to capture a low resolution parameter determining frame of image data at high speed, reads pixel data from the parameter determination frame to determine an operation parameter based on actual illumination conditions, then utilizes the operation parameter in operating an optical reader.

Claims

1. A method for operating an optical reader having an image sensor, said method comprising the steps of:

clocking out at least one frame of image data in a low resolution frame clock out mode of operation;

reading pixel values from said at least one frame clocked-out in said low resolution clock out mode to determine an operating parameter of said reader; and

utilizing said operating parameter in operating said reader.

2. The method of claim 1, wherein said low resolution mode clock out step includes the step of clock out electrical signals corresponding to some pixel values of said image sensor at a higher than normal clock out rate so that an overall frame clock out rate is increased.

3. The method of claim 1, wherein said low resolution mode clock out step includes the steps of clocking out some rows of said image sensor array at a normal clock out rate and other rows of said image sensor at a higher than normal clock out rate.

4. The method of claim 1, wherein said low resolution clock out step includes the step of selectively clocking out electrical signals corresponding to some pixels of said image sensor and not clocking out electrical signals corresponding to other pixels of said sensor.

5. The method of claim 1, wherein said image sensor includes a discharge function actuated by activation of a discharge control signals, wherein said low resolution mode clock out step include the step of intermittently activating said discharge control signal while clocking out a frame of image data.

6. The method of claim 1, wherein said operating parameter is an exposure parameter value.

7. The method of claim 1, wherein said operating parameter is an illumination intensity value.

8. The method of claim 1, wherein said operating parameter is an illumination on-time value.

9. The method of claim 1, wherein said operating parameter is an amplifier gain parameter value.

10. The method of claim 1, wherein said operating parameter is a dark level adjustment value.

11. The method of claim 1, wherein said operating parameter is a light level adjustment value.

12. The method of claim 1, further comprising the step of decoding a decodable symbol representation represented in a frame of image data developed utilizing said operating parameter.

13. The method of claim 1, wherein said frame clocked out in said low resolution frame clock out mode is clocked out to produce a low resolution parameter determination frame of image data in which valid and invalid data zones are defined by rows of said image sensor.

14. The method of claim 1, wherein said image sensor includes a one frame buffer and wherein said low resolution clock out step includes the step of clocking out three frames of image data in a low resolution frame clock out mode.

16. The method of claim 15, wherein said clock out step includes the steps of clock out some rows of said image sensor array at a normal clock out rate and other rows of said image sensor at a higher than normal clock out rate.

17. The method of claim 15, wherein said image sensor includes a discharge function actuated by activation of a discharge control signals, wherein said clock out step include the step of intermittently activating said discharge control signal while clock out a frame of image data.

20. The reader of claim 19, wherein said controller develops said low resolution frame of image data by clocking out electrical signals of said frame at a higher than normal rate.

21. The reader of claim 19, wherein said controller develops said low resolution frame of image data by not clocking out electrical signals corresponding to some pixels of said frame.

22. The reader of claim 19, wherein said operating parameter is an exposure parameter value.

23. The method of claim 19, wherein said operating parameter is an illumination intensity value.

24. The method of claim 19, wherein said operating parameter is an illumination on-time value.

25. The method of claim 19, wherein said operating parameter is an amplifier gain parameter value.

26. The method of claim 19, wherein said operating parameter is a dark level adjustment value.

27. The method of claim 19, wherein said operating parameter is a light level adjustment value.

28. The reader of claim 19, wherein said controller is further adapted to decode a decodable symbol representation represented in a frame of image data developed utilizing said operating parameter.

29. The reader of claim 19, wherein said imaging assembly includes an illumination assembly.

30. The reader of claim 19, wherein said illumination assembly includes white LEDs.

15. A method for operating an optical reader having an image sensor, said method comprising the steps of:

switching operation of said reader to a low resolution mode of operation; and

in said low resolution mode, clocking out electrical signals corresponding to some pixel values of said image sensor at a higher than normal clock out rate so that an overall frame clock out rate is increased.

18. A method for operating an optical reader having an image sensor, said method comprising the steps of:

switching operation of said reader to a low resolution mode of operation; and

selecting in said low resolution mode, clocking out electrical signals corresponding to some pixels of said image sensor and not clocking out electrical signals corresponding to other pixels of said image sensor.

19. An optical reader comprising:

an imaging assembly having an image sensor;

a controller, wherein said controller is adapted to clock out at least one low resolution frame of image data, wherein said controller is adapted to read pixel values from said at least one low resolution frame of image data to determine an operating parameter of said reader, and wherein said controller is adapted to utilize said operating parameter in operating said reader.