Content sharing methods and systems

Abstract

A first device (such as a cell phone) is equipped with a micro-projector, and used to present imagery on a display surface. A second device (such as a second cell phone) is equipped with a digital camera, and used to capture some of the projected imagery. The captured imagery allows a user of the second device to access digital content of interest from a user of the first device, or from elsewhere. The content may be visual, or of other form (content examples include audio, games, maps, text documents, video, spreadsheets, etc.). In one particular arrangement, the projected imagery is encoded with digital watermark data. Through such arrangements, one user can readily share content, and also engage in collaborative activities—such as cooperative game play, with one or more other users. A great variety of other features and arrangements are also detailed.

I claim: 
     
         1 . A content sharing system comprising:
 first and second portable user devices, each including a processor and a memory, at least the first device including a projector, at least the second device including a camera;   instructions in the memory of the first device enabling the first device to steganographically encode image content projected by said projector with a plural-bit digital watermark payload, said payload including data identifying said image content;   instructions in the memory of the second device enabling the second device to decode a plural-bit digital watermark payload from imagery captured by the camera, and to use said payload in obtaining a copy of said image content from a network resource;   wherein a user of the first device can project image content, and a user of the second device can identify said content, and obtain a copy from the network resource.   
     
     
         2 . The system of  claim 1  in which said instructions in the memory of the first device enable the first device to write an entry to a data structure associating said data with information about how the image content can be obtained, and said instructions in the memory of the second device enable the second device to retrieve said information from said data structure. 
     
     
         3 . The system of  claim 1  in which said data comprises part or all of a uniform resource locator. 
     
     
         4 . The system of  claim 1  in which said data comprises a spreadsheet file name. 
     
     
         5 . The system of  claim 1  in which said instructions in the memory of the first device enable the first device to restrict sharing of the image content, so that only one user at a time can have it. 
     
     
         6 . The system of  claim 1  in which said instructions in the memory of the first device enable the first device to restrict distribution of the image content by the second device. 
     
     
         7 . The system of  claim 1  in which said instructions in the memory of the first device enable the first device to encode the image content with a watermark payload comprising plural fields, including at least two selected from the list: a user identifier, access key data, an identifier of the image content, and data indicating the date and time of projection. 
     
     
         8 . The system of  claim 1  in which said instructions in the memory of the first device enable the first device to encode the image content with a watermark payload that enables a user of the second device to benefit from game features that a user of the first device has earned. 
     
     
         9 . The system of  claim 1  in which said instructions in the memory of the first device enable the first device to encode the image content with a watermark payload comprising plural data fields, including at least two fields selected from the list: a user identifier field, an access key data field, an identifier of the image content data field, and a date/time of projection data field. 
     
     
         10 . The system of  claim 9  including at least three fields selected from said list. 
     
     
         11 . The system of  claim 9  including all four fields from said list. 
     
     
         12 . A content sharing method employing first and second portable user devices, at least the first device including a projector, at least the second device including a camera, the method comprising the acts:
 steganographically encoding image content with a plural-bit digital watermark payload, said payload including data identifying said image content;   the first device projecting the encoded image content on a surface, using a projector having a projection axis;   the second device capturing image data from the surface, using a camera having a camera axis;   decoding a plural-bit digital watermark payload from the captured image data; and   using the payload in obtaining a copy of the image content for the second device from a network resource;   wherein the projection axis is different than the camera axis.   
     
     
         13 . The method of  claim 12  that further includes the first device writing an entry to a data structure associating said data with information about how the image content can be obtained, and the second device retrieving retrieve said information from said data structure. 
     
     
         14 . The method of  claim 12  in which said data comprises part or all of a uniform resource locator. 
     
     
         15 . The method of  claim 12  in which said data comprises a spreadsheet file name. 
     
     
         16 . The method of  claim 12  that includes the first device restricting sharing of the image content, so that only one user at a time can have it. 
     
     
         17 . The method of  claim 12  that includes the first device restricting distribution of the image content by the second device. 
     
     
         18 . The method of  claim 12  that includes encoding the image content with a watermark payload that enables a user of the second device to benefit from game features that a user of the first device has earned. 
     
     
         19 . The method of  claim 12  that includes steganographically encoding the image content with a watermark payload comprising plural data fields, including at least two fields selected from the list: a user identifier field, an access key data field, an identifier of the image content data field, and a date/time of projection data field. 
     
     
         20 . The method of  claim 19  including at least three fields selected from said list. 
     
     
         21 . The method of  claim 19  including all four fields from said list. 
     
     
         22 . A device including a processor, memory and projector, the memory containing software instructions enabling the device to maintain a history of image content projected by the projector.