Sensing data from physical objects
View Patent ↗Directional albedo of a particular article, such as an identity card, is measured and stored. When the article is later presented, it can be confirmed to be the same particular article by re-measuring the albedo function, and checking for correspondence against the earlier-stored data. The re-measuring can be performed through us of a handheld optical device, such as a camera-equipped cell phone. The albedo function can serve as random key data in a variety of cryptographic applications. The function can be changed during the life of the article. A variety of other features are also detailed.
1. A method of checking authenticity of a printed article, the article conveying hidden data, the method including capturing image data from the article using an imager in a handheld communications device such as a camera-equipped mobile phone, and detecting the hidden data from the captured image data, the method further characterized by generating an audio output comprised of plural audible components, wherein the audible components are dependent on the detected hidden data, so that a user can recognize an authentic article by recognizing a characteristic audio output corresponding thereto, wherein the article conveys first and second hidden data, and the method includes determining orientation of the article by reference to the first hidden data; using the determined orientation in detecting the second hidden data; and processing the second hidden data to generate the audible output.
2. The method of claim 1 wherein the printed article conveys plural different hidden data, and the method includes moving the article relative to the imager, wherein different of said plural hidden data are detected at different times, causing different of said audible components to be generated during the course of said movement.
3. The method of claim 2 wherein the audible components comprise harmonically related tones, wherein an authentic article yields a chime of tones forming a pleasing chord.
4. A method of checking authenticity of a printed article, the article conveying hidden data, the method including capturing image data from the article using an imager in a handheld communications device such as a camera-equipped mobile phone, and detecting the hidden data from the captured image data, the method further characterized by generating an audio output comprised of plural audible components, wherein the audible components are dependent on the detected hidden data, so that a user can recognize an authentic article by recognizing a characteristic audio output corresponding thereto, wherein the article conveys two distinctly-encoded hidden data, the first of said data being represented by colored print that is out-of-gamut for RGB printing, so that same is not accurately reproduced in an RGB-printed copy of the article, and wherein the method includes detecting said two distinctly-encoded hidden data, and processing same to generate the audible output.
5. The method of claim 4 that includes checking the two distinctly-encoded hidden data for correlation, and generating the audio output based thereon.
6. The method of claim 4 wherein the second of said data comprises directional albedo data.
7. The method of claim 4 that includes detecting both of said distinctly-encoded hidden data from the captured image data.