Coordinated illumination and image signal capture for enhanced signal detection

Patent metadata

Field	Value
Publication number	US-11386281-B2
Application number	US-202016927730-A
Country	US
Kind code	B2
Filing date	Jul 13, 2020
Priority date	Jul 16, 2009
Publication date	Jul 12, 2022
Grant date	Jul 12, 2022

Abstract

Signal detection and recognition employees coordinated illumination and capture of images under to facilitate extraction of a signal of interest. Pulsed illumination of different colors facilitates extraction of signals from color channels, as well as improved signal to noise ratio by combining signals of different color channels. The successive pulsing of different color illumination appears white to the user, yet facilitates signal detection, even for lower cost monochrome sensors, as in barcode scanning and other automatic identification equipment.

First claim

We claim:

1. A method for machine readable code detection in images comprising:
illuminating an object with pulsed LED illumination, the pulsed LED illumination comprising illumination with plural different LED light sources;
obtaining parts of image frames captured under illumination of the plural different LED light sources; and
with plural processors, performing digital watermark detection on the parts of image frames, each part corresponding to an image signal captured under different illumination, wherein the digital watermark signal detection comprises detection of a synchronization pattern followed by extraction of data from a part of an image frame based on detection of the synchronization pattern.

2. The method of claim 1 wherein the parts of image frames are captured under pulsed illumination in which two or more different color light sources are selectively illuminated.

3. The method of claim 1 wherein the pulsed LED illumination comprises pulsing of different color light sources in succession at a rate sufficient for the light source illumination to appear white to a user.

4. The method of claim 2 wherein images captured under different color light sources are combined to boost out-of-phase signals in distinct chrominance channels.

5. The method of claim 3 wherein pulsing comprises selectively turning off light sources while a first light source remains on to capture an image frame under illumination of the first light source.

6. The method of claim 3 wherein the plural different LED light sources include a white light LED and another LED of a first color, and pulsing comprises selectively turning off the white light LED to capture an image frame under illumination of the first color.

7. A method for machine readable code detection from an image comprising:
obtaining parts of image frames captured under different wavelength illumination, wherein the different wavelength illumination comprises pulsing of different light sources, including pulsing an infrared light source and visible color light source;
from the image signals, separating the parts of image frames for detection operations on plural processors, the parts of image frames corresponding to a channel of illumination corresponding to one of the different light sources, and
with the plural processors, performing digital watermark detection on the parts of image frames, wherein the digital watermark signal detection comprises detection of a synchronization pattern followed by extraction of data from a part of an image frame based on detection of the synchronization pattern.

8. The method of claim 7 wherein a layer of an object illuminated by the infrared (IR) light source is captured and the signal detection is performed on a signal conveyed in an IR channel.

9. The method of claim 8 wherein the IR channel is captured with a visible color sensor.

10. The method of claim 8 wherein the layer is hidden under a layer of material that is transparent to IR illumination.

11. The method of claim 10 wherein the layer comprises a flat layer hidden under a non-flat layer of a 3D object, and provides a reference signal for determining orientation of the 3D object.

12. The method of claim 11 wherein the flat layer provides an image based code signal conveying variable encoded information.

13. An imaging device comprising:
an illumination source for providing pulsed LED illumination of different wavelength illumination, the pulsed LED illumination comprising illumination with plural different LED light sources;
an image sensor for capturing image signals in coordination with the pulsed LED illumination;
a controller for coordinating the pulsed LED illumination and corresponding image capture of parts of image frames under illumination of the plural different LED light sources; and
plural processors in communication with the image sensor for obtaining image signals captured under different wavelength illumination, the plural processors are configured to obtain the parts of image frames and are configured to perform digital watermark detection on the parts of image frames, each part corresponding to an image signal captured under different wavelength illumination, wherein the digital watermark signal detection comprises detection of a synchronization pattern followed by extraction of data from a part of an image frame based on detection of the synchronization pattern.

14. The imaging device of claim 13 wherein the controller and the plural processors are integrated in a signal detector device.

15. The imaging device of claim 14 wherein the signal detector device comprises a memory on which is stored instructions executed on the plural processors.

16. The method of claim 1 wherein the parts of image frames are captured under illumination of the plural different LED light sources, including a visible color LED and an infrared LED, and obtaining information about the object from detection based on a part of an image frame under visible color LED illumination and a part of an image frame under infrared LED illumination.

17. The method of claim 1 wherein the parts of image frames comprise rows of pixels from an image frame captured by a camera under illumination from one color of illumination.

18. The method of claim 7 wherein the parts of image frames comprise rows of pixels from an image frame captured by a camera under illumination from one color of illumination.

19. The imaging device of claim 13 wherein the parts of image frames are captured under illumination of the plural different LED light sources, including a visible color LED and infrared LED, and the plural processors are configured to obtain information about an object from detection based on a part of an image frame under visible color LED illumination and a part of an image frame under infrared LED illumination.

20. The imaging device of claim 13 wherein the parts of image frames comprise rows of pixels from an image frame captured by a camera under illumination from one color of illumination.

21. An imaging device comprising:
means for generating pulsed illumination of different wavelength illumination;
an image sensor for capturing image signals in coordination with generated pulsed illumination;
means for coordinating the generated pulsed illumination and corresponding image capture by said image sensor by capturing parts of image frames under illumination of the different wavelength illumination; and
means for processing image signals captured under different wavelength illumination, said means for processing the image signals operable to obtain the parts of image frames; and
means for detecting digital watermarking from the parts of image frames, each part of the parts of image frames corresponding to an image signal captured under different wavelength illumination, wherein said means for detecting digital watermarking is operable for synchronization of a part of an image frame and extraction of data from the part of an image frame based the synchronization.

22. The imaging device of claim 21 in which said means for coordinating, said means for processing and said means for detecting digital watermarking are integrated in a signal detector device.

23. The imaging device of claim 22 wherein said means for detecting digital watermarking comprises plural processors and memory on which is stored instructions for execution on said plural processors.

24. The imaging device of claim 21 wherein the par

Assignees

• Digimarc Corp

Inventors

• Boles Jacob L
• Reed Alastair M
• Lord John D

Classifications

• H04N1/482 Primary

  using the same detector device sequentially for different colour components · CPC title

• G06K7/10722 Primary

  Photodetector array or CCD scanning · CPC title

• H04N23/56

  provided with illuminating means · CPC title

• G06V10/141

  Control of illumination · CPC title

• G06V10/147

  Details of sensors, e.g. sensor lenses (fingerprint or palmprint sensors G06V40/13; vascular sensors G06V40/145; eye sensors G06V40/19) · CPC title