Methods and arrangements employing mixed-domain displays

• US 8,331,724 B2
• Filed: 08/11/2011
• Issued: 12/11/2012
• Est. Priority Date: 05/05/2010
• Status: Active Grant

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Rhoads, Geoffrey B.
• Primary Examiner(s): CHANG, JON CARLTON
• Application Number:
  US13/208,180
• Publication Number:
  US 20120077542A1
• Time in Patent Office: 488 Days
• Field of Search: 382/191, 382/248, 382/280, 382/295
• US Class Current: 382/280
• CPC Class Codes: G06T 1/0064 Geometric transfor invariant watermarking, e.g. affine transform invariant
• CPC Class Codes: G06T 2201/0052 Embedding of the watermark in the frequency domain
• CPC Class Codes: G06T 2201/0601 whereby calibration information is embedded in the watermark, e.g. a grid, a scale, a list of transformations
• CPC Class Codes: G06V 10/225 based on a marking or identifier characterising the area
• CPC Class Codes: H04N 1/32 Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device H04N1/38, H04N1/387 take precedence
• CPC Class Codes: H04N 1/32133 on the same paper sheet, e.g. a facsimile page header
• CPC Class Codes: H04N 1/32187 with selective or adaptive application of the additional information, e.g. in selected frequency coefficients
• CPC Class Codes: H04N 1/32309 in colour image data
• CPC Class Codes: H04N 2201/3269 of machine readable codes or marks, e.g. bar codes or glyphs
• CPC Class Codes: H04N 2201/327 which are undetectable to the naked eye, e.g. embedded codes
• CPC Class Codes: H04N 2201/3273 Display

Abstract

An image is encoded to define one or more spatial regions that can be sensed by a suitably-equipped mobile device (e.g., a smartphone), but are imperceptible to humans. When such a mobile device senses one of these regions, it takes an action in response (e.g., rendering an associated tone, playing linked video, etc.). The regions may overlap in layered fashion. One form of encoding employs modification of the color content of the image at higher spatial frequencies, where human vision is not acute. In a particular embodiment, the encoding comprises altering a transform domain representation of the image by adding signal energy in a first chrominance channel, where the added signal energy falls primarily within a segmented arc region in a transform domain space. In another arrangement, a smartphone display presents both image data captured from a scene, and a transform representation of the image data (e.g., in the Fourier domain). This latter information can aid a user in positioning the phone, e.g., to enhance decoding of a steganographic digital watermark. In still another arrangement, foveal filtering is applied to of smartphone-captured image data in connection with other image processing.

Claims

1. A method comprising:

receiving image data;

presenting an image on a screen of a portable device in accordance with the received image data;

transforming at least a portion of the received image data to obtain Fourier domain data corresponding thereto; and

presenting a visual representation of the Fourier domain data on said screen, together with said presented image.

2. The method of claim 1 that includes capturing the image data from an object using a camera portion of said device.

3. The method of claim 2 that further includes presenting on the screen a portable device positioning aid, said positioning aid comprising a target region into which a user can cause said visual representation to be placed, by moving said camera portion relative to said object.

4. The method of claim 1 that includes presenting said visual representation only for components of the Fourier domain data above a threshold spatial frequency.

5. The method of claim 1 in which said visual representation comprises a pentagonal constellation of Fourier domain impulses.

6. The method of claim 1 in which said visible representation of the Fourier domain data represents imperceptible image details that are too high in frequency for human perception.

7. The method of claim 6 in which the visual representation of the Fourier domain data is presented with a visibility that varies with strength of said imperceptible image details.

8. The method of claim 7 in which the visibility varies non-linearly with strength of said imperceptible image details, wherein no visual representation of the Fourier domain data is presented if the imperceptible image details are lesser in strength than a threshold value.

9. The method of claim 6 in which the visual representation of the Fourier domain data is presented with a color that varies with strength of said imperceptible image details.

10. The method of claim 1 that includes transforming only a sub-portion of the received image data.

11. The method of claim 1 in which the Fourier representation presented on the portable device screen comprises a depiction of a portion of a u,v plane.

12. A portable device including a camera, a screen, and processing circuitry, the processing circuitry being configured to cause the device to perform operations comprising:

capture image data from an object;

present an image on the screen in accordance with the captured image data;

transform the captured image data to obtain Fourier domain data corresponding thereto; and

present a visual representation of the Fourier domain data on said screen, together with said presented image.

13. The device of claim 12 in which the processing circuitry comprises a processor configured by instructions in a memory.

14. A method comprising:

capturing image data from an object using a sensor in a portable device camera;

computing a transform domain representation based on at least part of the captured image data;

presenting on a portable device screen a display that includes said transform domain representation; and

guiding a user in moving the portable device relative to the object, by reference to said presented transform domain representation.

15. The method of claim 14 in which the transform domain comprises a spatial frequency domain.

16. The method of claim 14 in which said guiding comprises presenting on the portable device screen a display that includes both (a) said transform domain representation, and (b) a visual guide with which the transform domain representation is aligned when the camera has a particular view of the object.

17. The method of claim 16 wherein said particular view comprises a plan view of the object.

18. A method comprising:

capturing image data from a scene using a portable device that includes a 2D image sensor having a uniform density of sensing elements thereacross;

applying a foveal filtering function to said image data, yielding a set of lower resolution image data outside a foveal zone, and a set of higher resolution image data within the foveal zone; and

further processing the foveal-filtered image data, said further processing including computing a transform domain representation of the foveal-filtered image data, and presenting on a screen of said device a display that includes said transform domain representation.

19. A non-transitory computer-readable medium having instructions stored therein that, if executed by a computing device, cause the computing device to perform operations comprising:

receive image data in a spatial, rather than a spatial frequency, domain;

transform the received image data to obtain Fourier domain data corresponding thereto; and

generate data for presentation on a display screen, the generated data corresponding to a visual representation of the Fourier domain data, together with a visual representation of said image data.