Methods and systems for signal processing
An object (e.g., a driver's license) is tested for authenticity using imagery captured by a consumer device (e.g., a mobile phone camera). Corresponding data is sent from the consumer device to a remote system, which has secret knowledge about features indicating object authenticity. The phone, or the remote system, discerns the pose of the object relative to the camera from the captured imagery. The remote system tests the received data for the authentication features, and issues an output signal indicating whether the object is authentic. This testing involves modeling the image data that would be captured by the consumer device from an authentic object—based on the object's discerned pose (and optionally based on information about the camera optics), and then comparing this modeled data with the data sent from the consumer device. A great variety of other features and arrangements are also detailed.
1. A method comprising:
obtaining imagery at a user device;
step for processing the captured imagery to yield local image information, said local image information being inadequate to reveal a subject depicted in said imagery;
sending at least some of said local image information to a remote system, wherein the sent local image information is inadequate to reveal a subject depicted in said imagery to said remote system, said sent local image information providing the remote system with information only about a sparse sampling of locations in said imagery; and
receiving, in response, information decoded by the remote system from the sent information using secret information, said secret information being withheld from the user device;
wherein the user device obtains information associated with the subject, without the secret information being available at the user device and without the remote system having information depicting the subject, such reciprocal incompleteness of information serving to aid security.
2. The method of claim 1 in which said step includes:
sending information about said imagery to the remote system; and
receiving from the remote system, in reply, a specification of said sparse locations.
3. The method of claim 1 in which said sparse sampling of locations in one region of the imagery comprises local image information for a plurality of spaced-apart pixels in said region, and not for pixels adjoining said plurality of spaced-apart pixels.
4. The method of claim 1 that further includes receiving, from a remote source, data identifying said sparse sampling of locations for which local image information is to be sent to the remote system.
5. The method of claim 1 in which the imagery depicts an object bearing an authentication marking pattern comprising plural features that are too small to be resolved in said imagery, said features serving to bias luminance or chrominance values of pixels in said imagery.
6. The method of claim 1 in which step includes determining plural parameters describing an affine pose with which an object is depicted in said imagery.
7. The method of claim 6 that includes sending said plural parameters to the remote system with said local image information.
8. The method of claim 1 that further includes determining authenticity of an object depicted in said imagery based on the received information.
9. A non-transitory computer readable medium on which is stored instructions that, when executed, cause one or more processors to perform acts including:
obtain, reference data characterizing an authentication marking pattern;
obtain image data, captured by an optical capture system, depicting an object that possibly bears the authentication marking pattern, said authentication marking pattern comprising plural features that are too small to be resolved by said optical capture system, wherein if the object bears said authentication marking pattern, the features thereof are not resolved in said image, but rather serve simply to bias luminance or chrominance values of pixels in said image;
determine, from the image, affine pose information detailing a pose with which said object is depicted in the image;
determine pixel value gradients between plural pixel locations in the image and respectively neighboring pixel locations;
compare said pixel value gradients determined from the image with corresponding pixel value gradients indicated by said reference data, taking into account said affine pose information; and
indicate that the object is authentic because said comparison indicates more than a threshold level of statistical correspondence between said pixel value gradients determined from the image and said pixel value gradients indicated by the reference data, taking into account the affine pose information.
10. A sub-combination method comprising:
with a mobile phone device, equipped with a processor, camera, and lens, capturing an image depicting an object, the object including an authentication pattern of markings that are too small to be resolved by said camera and lens in said captured image;
obtaining, from a computer system remote from said mobile phone device, data identifying an incomplete subset of pixel locations within the image;
for pixels at said locations, determining value gradients with neighboring pixels using said phone processor, to thereby obtain a set of pixel gradients at the incomplete subset of pixel locations identified by the data obtained from the remote computer system; and
sending, from the mobile phone device to a remote destination, information corresponding to said set of pixel gradients for the incomplete subset of pixel locations.
11. The method of claim 10 that further includes sending said set of pixel gradients for the incomplete subset of pixel locations to a second processor that is configured to determine authenticity of the object based on evaluation of said set of pixel gradients for the incomplete subset of pixel locations.
12. The method of claim 11 that further includes said second processor determining authenticity of the object based on evaluation of said pixel gradients for the incomplete subset of pixel locations.
13. The method of claim 10 in which the sent information corresponding to said set of pixel gradients is inadequate to reveal the object depicted in the image.
14. The method of claim 10 that further includes said processor in the phone device determining an identity of the object using a fingerprinting algorithm;
wherein the incomplete subset of pixel locations obtained from the remote computer system is based on said determined identity of the object.
15. The method of claim 10 that further includes said processor in the phone device determining an identity of the object using a digital watermark decoding algorithm;
wherein the incomplete subset of pixel locations obtained from the remote computer system is based on said determined identity of the object.
16. The method of claim 10 that includes:
discerning orientation information from features in the image; and
using said orientation information in compensating for geometrical distortion of the object depicted in the image.
17. The method of claim 10 that included acts, before said capturing of the image, of:
receiving artwork for a package of a pharmaceutical; and
modifying the received artwork to introduce said authentication pattern of markings;
wherein the depicted object is said package of a pharmaceutical.
18. The method of claim 10 in which a pixel location in said incomplete subset of locations is identified relative to a frame of reference determined by features extracted from the image.
19. The method of claim 10 that includes performing the method first and second times, wherein the first time includes obtaining data identifying a first incomplete subset of pixel locations within the image, and the second time includes obtaining data identifying a second incomplete subset of pixel locations within the image that is different than said first incomplete subset.
20. The method of claim 19 in which the first and second incomplete subsets of pixel locations are randomly selected.