Detecting encoded signals under adverse lighting conditions using adaptive signal detection
The disclosure relates to image signal processing, encoded signals and fingerprinting. Lighting information, associated with image capture, is used to adapt a signal encoder to fingerprint generator. The encoder or generator can be adapted by applying different weightings to different color channels, the different weightings being associated with the lighting information.
1. A method for controlling a portable apparatus, the portable apparatus comprising: a camera for capturing data representing imagery or video; a touchscreen display; a graphical user interface for providing an interface for display on the touchscreen display; an encoded signal detector; and one or more processors, said method comprising:
obtaining data representing imagery or video captured by the camera;
obtaining lighting information via the graphical user interface, the lighting information associated with the data representing imagery or video captured by the camera; and
adapting the encoded signal detector based on the lighting information, in which the adapted encoded signal detector is configured to detect whether auxiliary data is encoded within the data representing imagery or video captured by the camera.
2. The method of claim 1 in which the adapting applies different weightings to different color channels of the imagery or video for detection, the different weightings being associated with the lighting information.
3. The method of claim 2 in which the lighting information is associated with incandescent lighting, and the weightings deemphasize a blue color channel.
4. The method of claim 3 in which the blue color channel is deemphasized to the point of not being used for detection.
5. The method of claim 2 in which the lighting information is associated with daylight or cool white fluorescent lighting, and the weightings are applied across red, green and blue channels.
6. The method of claim 1 in which the adapted encoded signal detector operates on a grayscale representation of the data representing imagery or video captured by the camera.
7. A method of operating a portable apparatus comprising: a camera for capturing data representing imagery or video; a touchscreen display; and one or more processors, said method comprising:
obtaining data representing imagery or video, the imagery or video having been captured with the camera;
obtaining lighting information associated with image capture of the imagery or video, in which the lighting information is associated with a light level or color temperature;
adapting an encoded signal detector based on the lighting information; and
controlling the adapted encoded signal detector to process the data representing imagery or video to determine whether auxiliary data is encoded therein.
8. The method of claim 7 in which the lighting information is associated with the light level and the color temperature.
9. The method of claim 7 in which the color temperature is associated with incandescent lighting.
10. The method of claim 8 in which the color temperature is associated with incandescent lighting.
11. The method of claim 7 in which the data representing imagery or video comprises a plurality of color channels including at least a blue channel, and in which the blue channel is deemphasized by the adapted encoded signal detector.
12. The method of 8 in which the data representing imagery or video comprises a plurality of color channels including at least a blue channel, and in which the blue channel is deemphasized by the adapted encoded signal detector.
13. The method of claim 8 in which the color temperature is associated with daylight or cool white fluorescent lighting.
14. The method of claim 7 in which said adapted encoded signal detector processes a grayscale representation of the data.
15. The method of claim 7 in which the data representing imagery or video comprises two color channels, with a watermark signal embedded in a first color channel, and the watermark signal embedded in a second color channel with a signal polarity that is inversely related to a signal polarity of the watermark signal in the first color channel.
16. A method of operating a portable apparatus comprising: a camera for capturing imagery or video; a touchscreen display; and one or more electronic processors, said method comprising:
obtaining lighting information associated with capturing of the imagery or video by the camera;
changing a signal fingerprinting process to deemphasize signal contribution of a blue color channel with the lighting information; and
analyzing the data representing imagery or video to derive fingerprint information therefrom with the changed signal fingerprinting process.
17. The method of claim 16 in which the signal fingerprinting process is changed by applying different weightings to different color channels, the different weightings being associated with the lighting information, and in which the weightings deemphasize the signal contribution of the blue color channel.
18. The method of claim 16 in which the lighting information is associated with incandescent lighting.