Scanning improvements for saturated signals using automatic and fixed gain control methods

• US 9,679,178 B2
• Filed: 12/21/2015
• Issued: 06/13/2017
• Est. Priority Date: 12/26/2014
• Status: Active Grant

• Current Assignee: Hand Held Products Incorporated (Honeywell International Inc.)
• Original Assignee: Hand Held Products Incorporated (Honeywell International Inc.)
• Inventors: Wilz, Sr., David, Hejl, Benjamin, Xian, Tao
• Primary Examiner(s): Marshall, Christle I
• Application Number:
  US14/976,285
• Publication Number:
  US 20160188944A1
• Time in Patent Office: 540 Days
• 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
• CPC Class Codes: G06K 7/1404 Methods for optical code recognition
• CPC Class Codes: G06K 7/1465 using several successive scans of the optical code
• CPC Class Codes: G06K 7/1478 adapting the threshold for pixels in a CMOS or CCD pixel sensor for black and white recognition

Abstract

A method controls the exposure of an image containing a barcode for a barcode reading device. The method obtains a line of scan data from the image and identifies areas of saturation within the scan data. If there are saturated areas within the scan data, the method switches from an automatic gain control to a predetermined gain control. The method then resumes automatic gain control after a predetermined time.

Claims

1. A method of controlling the exposure of an image containing a barcode for a barcode reading device, the method comprising:

obtaining a line of scan data from the image;

identifying areas of saturation within the scan data;

improving the readability of an unsaturated region, comprising switching from an automatic gain control to a predetermined gain control if the identified areas of saturation within the scan data are substantially saturated, the predetermined gain control adjusting at least a gain to increase signal return so that the areas of saturation remain saturated; and

resuming automatic gain control after a predetermined time.

2. The method of claim 1, wherein identifying areas of saturation comprises normalizing the line of scan data.

3. The method of claim 2, wherein normalizing the line of scan data comprises creating a histogram of the line of scan data.

4. The method of claim 1, wherein the predetermined gain control is a fixed gain setting.

5. The method of claim 1, wherein the predetermined gain control is a predetermined sequence of fixed gain settings.

6. A method of controlling the exposure of an image containing a barcode, comprising:

providing a barcode reading device having a processor, memory, barcode reading firmware, and an image sensor package with an exposure control unit connected via a system bus, the exposure control unit having automatic gain control settings and fixed gain control settings;

obtaining a line of scan data from the image captured by the image sensor package;

identifying areas of saturation within the scan data by creating a histogram of the line of scan data;

improving the readability of an unsaturated region, comprising switching from an automatic gain control settings to fixed gain control settings if the identified areas of saturation within the scan data are substantially saturated, the predetermined gain control adjusting at least a gain to increase signal return so that the areas of saturation remain saturated; and

resuming automatic gain control settings after a predetermined time.

7. The method of claim 6, wherein the fixed gain control settings is a single value.

8. The method of claim 6, wherein the fixed gain control settings is a predetermined sequence of values.

9. A barcode reading device, comprising:

a processor, memory, barcode reading firmware, and an image sensor package with an exposure control unit interconnected via a system bus, the exposure control unit having automatic gain control settings and fixed gain control settings;

the barcode reading firmware operative to;

obtain a line of scan data from the image captured by the image sensor package;

identify areas of saturation within the scan data by creating a histogram of the line of scan data;

improve the readability of an unsaturated region by switching from an automatic gain control settings to fixed gain control settings if the identified areas of saturation within the scan data are substantially saturated, the predetermined gain control adjusting at least a gain to increase signal return so that the areas of saturation remain saturated; and

resume automatic gain control settings after a predetermined time.

10. The method of claim 9, wherein the fixed gain control settings is a single value.

11. The method of claim 9, wherein the fixed gain control settings is a predetermined sequence of values.