Digital light processing display device

• US 9,253,458 B2
• Filed: 03/29/2007
• Issued: 02/02/2016
• Est. Priority Date: 04/03/2006
• Status: Expired due to Fees

• Current Assignee: Thomson Licensing (Vantiva SA)
• Original Assignee: Thomson Licensing (Vantiva SA)
• Inventors: Doyen, Didier, Bourdon, Pascal, Borel, Thierry
• Primary Examiner(s): Xiao, Ke
• Assistant Examiner(s): TRAN, KIM THANH THI
• Application Number:
  US12/225,599
• Publication Number:
  US 20090058875A1
• Time in Patent Office: 3,232 Days
• Field of Search: 345/589, 345/684, 345/3.2
• US Class Current: 1/1
• CPC Class Codes: H04N 2005/91392 using means for preventing making copies of projected video images
• CPC Class Codes: H04N 5/913 for scrambling ; for copy protection
• CPC Class Codes: H04N 9/3123 using pulse width modulation
• CPC Class Codes: H04N 9/3197 using light modulating optical valves

Abstract

The invention relates to a display device using the DLP (Digital Light Processing) technology. This invention is in the field of digital cinema and content protection, where camcorder acquisition followed by immediate illegal distribution creates important revenue losses for content owners. According to the invention, the addressing of the display device is modified in order to introduce an anti-copy processing. The display device comprises modulation means for modulating the color or brightness of video data of video pictures received at a first rate and for outputting at a second rate modulated video data, said second rate being a multiple of the first rate, subfield coding means for coding said modulated video data into subfield data, said subfield data being delivered at the second rate, and addressing means for addressing the array with said subfield data at a third rate. Advantageously, the third rate is not a multiple of the first rate.

Claims

1. A method for displaying video pictures using an array of luminous elements, the method comprising:

generating a plurality of video sub-pictures;

modulating pixel information in a consecutive identical pair of the plurality of sub-pictures such that the consecutive identical pair is modulated to have different pixel patterns associated with brightness or color, while a mean value of the pixel information of the pair equals that of an image to be displayed, the different pixel patterns representing a message, when displayed at a threshold rate;

converting the consecutive identical pair of the plurality of sub-pictures into a binary data stream configured to turn each element in the array of luminous elements on or off; and

addressing the array of luminous elements using the binary data stream at said threshold rate,

wherein the threshold rate changes from at least one video picture to a next video picture, such that an average of said threshold rate over successive video pictures is not an integer value.

2. The method according to claim 1, wherein the threshold rate is equal to one divided by a number of sub-pictures times twenty four hertz.

3. The method according to claim 2, wherein the plurality of sub-pictures is obtained from an input video signal received at an input rate lower than the threshold rate.

4. The method according to claim 2, wherein the threshold rate is selected such that the message represented by the different pixel patterns is imperceptible by a human eye but creates artifacts when the displayed video pictures are captured by a video capturing device.

5. The method according to claim 3, wherein the threshold rate is not a multiple of the input rate.

6. The method according to claim 1, wherein the threshold rate varies dynamically during display of the video pictures.

7. The method according to claim 1, wherein said luminous elements are micro-mirrors values.

8. A display device comprising an array of luminous element for displaying video pictures, the display device comprising:

a memory;

at least one processor configured to;

generate a plurality of sub-pictures;

modulating pixel information in a consecutive identical pair of the plurality of sub-pictures such that the consecutive identical pair is modulated to have different pixel patterns associated with brightness or color, while a mean value of the pixel information of the pair equals that of an image to be displayed, the different pixel patterns representing a message, when displayed at a threshold rate;

convert the consecutive identical pair of the plurality of sub-pictures into a binary data stream configured to turn each element in the array of luminous elements on or off; and

address the array of luminous elements using the binary data stream at said threshold rate,

wherein said threshold rate changes from at least one video picture to a next video picture, such that an average of the threshold rate over successive video pictures is not an integer value.

9. The device according to claim 8, wherein the threshold rate is equal to one divided by a number of sub-pictures times twenty four hertz.

10. The device according to claim 9, wherein the at least one processor is further configured to obtain the plurality of sub-pictures from an input video signal received at an input rate lower than the threshold rate.

11. The device according to claim 9, wherein the at least one processor is further configured to select the threshold rate such that the message represented by the different pixel patterns is imperceptible by a human eye but creates artifacts when the displayed video pictures are captured by a video capturing device.

12. The device according to claim 8, wherein said luminous elements are micro-mirrors values.

13. The device according to claim 10, wherein the threshold rate is not a multiple of the input rate.

14. The device according to claim 8, wherein the threshold rate varies dynamically during the displaying of the video pictures.