Methods and systems for signal processing

A method useful for judging authenticity of an object by reference to features encoded therein, the method being performed by a remote system, and also involving a camera-equipped consumer device that captured an image of said object, the method comprising the acts:

• receiving information at the remote system, sent from the consumer device, the received information including intra-image gradient information computed by the consumer device for N pixel locations in said image of the object, where N is less than all the pixel locations in the image, said intra-image gradient information consisting of one value for each of said N locations;
• with a hardware processor in the remote system, processing (a) the received intra-image gradient information, and (b) key information, to yield result data, the key information not being available to the camera-equipped consumer device;
• and
• sending at least some of the result data from the remote system to the consumer device, to confirm the presence of said features encoded in the object;
• wherein the consumer device learns whether the object depicted in the captured image includes the encoded features—while not having key data necessary for such determination, thereby enhancing security;
• and
• wherein the remote system determines whether the object depicted in the captured image includes the encoded features—while not having access to the complete captured image, thereby enhancing privacy.

A non-transitory computer readable medium containing instructions that configure a computer system to confirm the presence of features encoded in an object, to aid in judging authenticity of the object, the object being depicted in an image captured by a camera-equipped consumer device, by performing acts including:

• receiving information at said computer system, sent from the consumer device, the received information including intra-image gradient information computed by the consumer device for N pixel locations in said image of the object, where N is less than all the pixel locations in the image, said intra-image gradient information consisting of one value for each of said N locations;
• processing (a) the received intra-image gradient information, and (b) key information, to yield result data;
• and
• sending at least some of the result data from the computer system to the consumer device, to confirm the presence of said features encoded in the object;
• wherein the consumer device learns whether the object depicted in the captured image includes the encoded features—while not having key data necessary for such determination, thereby enhancing security;
• and
• wherein the remote system determines whether the object depicted in the captured image includes the encoded features—while not having access to the complete captured image, thereby enhancing privacy.