Sensing data from physical objects

• US 8,842,876 B2
• Filed: 07/17/2012
• Issued: 09/23/2014
• Est. Priority Date: 01/23/2006
• Status: Active Grant

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Rodriguez, Tony F., Bradley, Brett A., Rhoads, Geoffrey B.
• Primary Examiner(s): Akhavannik, Hadi
• Application Number:
  US13/551,278
• Publication Number:
  US 20120281880A1
• Time in Patent Office: 798 Days
• Field of Search: 382/100
• US Class Current: 382/100
• CPC Class Codes: G06Q 20/347 Passive cards
• CPC Class Codes: G06Q 20/388 using mutual authentication without cards, e.g. challenge-response
• CPC Class Codes: G06T 1/005 Robust watermarking, e.g. average attack or collusion attack resistant
• CPC Class Codes: G06T 2201/0062 Embedding of the watermark in text images, e.g. watermarking text documents using letter skew, letter distance or row distance
• CPC Class Codes: G06T 2201/0065 Extraction of an embedded watermark; Reliable detection
• CPC Class Codes: G06V 10/60 relating to illumination properties, e.g. using a reflectance or lighting model
• CPC Class Codes: G06V 20/80 Recognising image objects characterised by unique random patterns
• CPC Class Codes: G06V 30/413 Classification of content, e.g. text, photographs or tables
• CPC Class Codes: G07D 7/12 Visible light, infrared or ultraviolet radiation
• CPC Class Codes: G07D 7/2033 Matching unique patterns, i.e. patterns that are unique to each individual paper
• CPC Class Codes: G07F 7/08 by coded identity card or credit card or other personal identification means without personal verification means G07F7/02
• CPC Class Codes: G07F 7/0813 Specific details related to card security
• CPC Class Codes: G07F 7/1008 Active credit-cards provided with means to personalise their use, e.g. with PIN-introduction/comparison system
• CPC Class Codes: G07F 7/1016 Devices or methods for securing the PIN and other transaction-data, e.g. by encryption arrangements for secret communication, see H04L9/00
• CPC Class Codes: G07F 7/125 Offline card verification
• CPC Class Codes: H04L 2209/608 Watermarking
• CPC Class Codes: H04L 2209/805 Lightweight hardware, e.g. radio-frequency identification [RFID] or sensor
• CPC Class Codes: H04L 9/3278 using physically unclonable functions [PUF]

Abstract

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.

Claims

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.