Method and apparatus for processing video pictures

• US 6,940,474 B2
• Filed: 01/10/2003
• Issued: 09/06/2005
• Est. Priority Date: 01/16/2002
• Status: Expired due to Fees

• Current Assignee: Thomson Licensing (Vantiva SA)
• Original Assignee: Thomson Licensing (Vantiva SA)
• Inventors: Goetzke, Axel, Thebault, Cédric, Weitbruch, Sébastien
• Primary Examiner(s): Wu, Xiao
• Assistant Examiner(s): Abdulselam, Abbas I
• Application Number:
  US10/340,146
• Publication Number:
  US 20030137473A1
• Time in Patent Office: 970 Days
• Field of Search: 345/60, 345/55, 345/62, 345/66, 345/67, 345/691, 345/692, 345/693, 345/215, 345/33, 315/169.1, 315/169.2
• US Class Current: 345/60
• CPC Class Codes: G09G 2320/0238 Improving the black level
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/2029 the sub-frames having non-binary weights
• CPC Class Codes: G09G 3/2927 Details of initialising

Abstract

The present invention relates to a method for processing video signals for display on a display panel comprising a matrix array of cells which could only be “ON” or “OFF”, wherein the time duration of a video field is divided into N sub-fields during which the cells can be activated, each sub-field comprising at least an addressing period and a sustaining period, the duration of which corresponding to the weight associated with said sub-field, said method comprising at least a priming period, characterized in that the position of the priming period is determined as follows:

• • determination of a sustain threshold value D for a given addressing speed and panel technology,
  • calculation of the number of sustain pulses in each sub-field n, n being such that 1≦n≦N,
  • if the number of sustain pulses is above or equal to D, addition of a priming pulse before at least the sub-field n+1.

This method is mainly applicable to plasma display panel.

Claims

1. A method for processing video signals for display on a display panel comprising a matrix array of cells which could only be “

ON”

or “

OFF”

, wherein the time duration of a video frame is divided into N sub-fields during which the cells can be activated, each sub-field comprising at least an addressing period and a sustaining period, the duration of which corresponding to the weight associated with said sub-field, said method comprising at east a priming period for putting the cells in homogeneous states, with a position determined using the following steps;

determination of a sustain threshold value D for a given addressing speed and panel technology,

calculation of the number of sustain pulses in each sub-field n, n being such that 1≦

n≦

N, and

for at least one sub-field n with n ≦

N−

1 and for which the number of sustain pulses is above or equal to D, addition of a priming period the beginning of the sub-field n+1.

2. A method according to claim 1, wherein for each sub-field n with n≦

N−

1 and for which the number of sustain pulses is above or equal to D, a priming period is added at the beginning of the subfields n+1.

3. A method according to claim 1, wherein priming period is added at the beginning of each frame.

4. A method according to claim 3, wherein the video value are coded with the sub-fields so that there is never more than one sub-field switched OFF between two sub-fields switched ON.

5. A method according to claim 1, wherein the determination of a sustain threshold value is done using a specific test pattern, modifying the sustain pulses number and determining for which sustain pulses number a response fidelity problem is visible, said number giving the sustain threshold value D.

6. An apparatus for carrying out the method according to claim 1, characterized in that it comprises a peal luminance enhancement (PLE measuring unit, a sub-field coding unit and a plasma control unit, said plasma control unit comprising at least an encoding look up table for storing various sub-field codes per PLE value giving the sustain threshold value, a selection of appropriate sustain table and priming table for POP controlling.