Devices and methods of reading monochromatic patterns

• US 9,213,882 B2
• Filed: 01/20/2014
• Issued: 12/15/2015
• Est. Priority Date: 03/11/2010
• Status: Active Grant

• Current Assignee: Ramot at Tel Aviv University Limited (Tel Aviv University)
• Original Assignee: Ramot at Tel Aviv University Limited (Tel Aviv University)
• Inventors: Milgrom, Benjamin, Marom, Emanuel, Konforti, Naim, Golub, Michael
• Primary Examiner(s): Li, Ruiping
• Application Number:
  US14/158,885
• Publication Number:
  US 20140131447A1
• Time in Patent Office: 694 Days
• Field of Search: 382/165, 382/190, 235/462.04, 235/469
• US Class Current: 1/1
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/12 using a selected wavelength, e.g. to sense red marks and ignore blue marks
• CPC Class Codes: G06K 7/1491 the method including a reconstruction step, e.g. stitching two pieces of bar code together to derive the full bar code

Abstract

A method of extracting data from an identifiable monochromatic pattern. The method comprises separating a polychromatic optical signal, received from an object having identifiable monochromatic pattern, into a plurality of wavelength components, separately capturing each of the wavelength components, reconstructing a plurality of images each from a different wavelength component, detecting the identifiable monochromatic pattern in one or more of the images, and extracting data associated with or encoded by the detected identifiable monochromatic pattern. The images have different depths of field.

Claims

1. A device of extracting data from an identifiable monochromatic pattern, said device comprising:

an optical assembly having a mask with at least one concentric ring for separating a polychromatic optical signal received from an object with an identifiable monochromatic pattern into a plurality of wavelength components;

an image sensor which separately captures each of said plurality of wavelength components in one of a plurality of color channels; and

a processing unit which reconstructs a plurality of images each from a different color channel of said plurality of color channels that includes a different wavelength component of said plurality of wavelength components, detects said identifiable monochromatic pattern in at least one of said plurality of images, and extracts data associated with or encoded by said identifiable monochromatic pattern;

wherein each of said plurality of images has a different depth of field, wherein said at least one concentric ring for optically delivering an exhibited phase shift of Π

(modulus 2π

) for a first wavelength component a phase shift of 0 (mod 2π

) for the second wavelength component, and an exhibited phase shift of Π

/2 (mod 2π

) for the third wavelength component.

2. The device of claim 1, wherein said optical assembly includes a mask with a plurality of concentric rings each exhibits a phase shift different that of the remaining mask regions.

4. The device of claim 1, wherein said mask exhibits different phases for different wavelength components.

6. The device of claim 1, wherein said image sensor is an active pixel image sensor converting said plurality of wavelength components to three separated color channels, said processing unit reconstructs each of said plurality of images.

7. The device of claim 1, wherein said optical assembly captures images exhibiting a modulation transfer function (MTF) with a contrast of at least 25%.

8. The device of claim 1, further comprising an illumination source which illuminates said object with a plurality of wavelength component signals;

wherein said optical element optically delivers a different exhibited phase shift for each of said plurality of wavelength component signals.

3. A device of extracting data from an identifiable monochromatic pattern, said device comprising:

an optical assembly having a mask with at least one concentric ring for separating a polychromatic optical signal received from an object with an identifiable monochromatic pattern into a plurality of wavelength components;

an image sensor which separately captures each of said plurality of wavelength components in one of a plurality of color channels; and

a processing unit which reconstructs a plurality of images each from a different color channel of said plurality of color channels that includes a different wavelength component of said plurality of wavelength components, detects said identifiable monochromatic pattern in at least one of said plurality of images, and extracts data associated with or encoded by said identifiable monochromatic pattern;

wherein each of said plurality of images has a different depth of field, wherein said at least one concentric ring for optically delivering an exhibited phase of 3Π

for a first wavelength component, an exhibited phase of 2.45Π

for a second wavelength component, and an exhibited phase of 2.077 for a third wavelength component.

10. The device of claim 3, wherein said optical assembly includes a mask with a plurality of concentric rings each exhibits a phase shift different that of the remaining mask regions.

11. The device of claim 3, wherein said mask exhibits different phases for different wavelength components.

12. The device of claim 3, wherein said image sensor is an active pixel image sensor converting said plurality of wavelength components to three separated color channels, said processing unit reconstructs each of said plurality of images.

13. The device of claim 3, wherein said optical assembly at least 25%.

14. The device of claim 3, further comprising an illumination source which illuminates said object with a plurality of wavelength component signals;

wherein said optical element optically delivers a different exhibited phase shift for each of said plurality of wavelength component signals.

5. A device of extracting data from an identifiable monochromatic pattern, said device comprising:

an optical assembly having a mask with at least one concentric ring for separating a polychromatic optical signal received from an object with an identifiable monochromatic pattern into a plurality of wavelength components;

an image sensor which separately captures each of said plurality of wavelength components in one of a plurality of color channels; and

a processing unit which reconstructs a plurality of images each from a different color channel of said plurality of color channels that includes a different wavelength component of said plurality of wavelength components, detects said identifiable monochromatic pattern in at least one of said plurality of images, and extracts data associated with or encoded by said identifiable monochromatic pattern;

wherein each of said plurality of images has a different depth of field, wherein said mask having a single ring that extends between 0.1 and 0.7 of a radius of said mask.

15. The device of claim 5, wherein said optical assembly includes a mask with a plurality of concentric rings each exhibits a phase shift different that of the remaining mask regions.

16. The device of claim 5, wherein said mask exhibits different phases for different wavelength components.

17. The device of claim 5, wherein said image sensor is an active pixel image sensor converting said plurality of wavelength components to three separated color channels, said processing unit reconstructs each of said plurality of images.

18. The device of claim 5, wherein said optical assembly at least 25%.

19. The device of claim 5, further comprising an illumination source which illuminates said object with a plurality of wavelength component signals;

wherein said optical element optically delivers a different exhibited phase shift for each of said plurality of wavelength component signals.

9. An optical assembly for magnifying an effective reading range of a reading device for identifying identifiable monochromatic patterns, said optical assembly comprising:

an optical element having a mask with at least concentric ring for separating a polychromatic optical signal received from an object having an identifiable monochromatic pattern into a plurality of wavelength components; and

an adaptor which allows connecting said optical element to an optical train of an image sensor of a reading device; and

a changing color filter that allows a first of said plurality of wavelength components to pass separately along the optical train in a first time interval while filtering a second of said plurality of wavelength components and allows said second wavelength component to pass separately along the optical train in a second time interval while filtering said first wavelength component;

wherein said plurality of wavelength components are set so as to allow reconstructing a plurality of images of said identifiable monochromatic pattern, said plurality of images having different depth of fields.