Video movement detection

• US 4,240,109 A
• Filed: 02/27/1979
• Issued: 12/16/1980
• Est. Priority Date: 10/14/1976
• Status: Expired due to Term

• Current Assignee: Quantel Limited 37 Victoria Avenue Southend On Sea Essex
• Original Assignee: Micro Consultants Ltd. (Belden Inc.)
• Inventors: Taylor, Richard J., Michael, Peter C., Trump, Martin R.
• Primary Examiner(s): Murray, Richard
• Application Number:
  US06/015,700
• Time in Patent Office: 658 Days
• Field of Search: 358/105
• US Class Current: 348/701
• CPC Class Codes: G06T 7/254 involving subtraction of images
• CPC Class Codes: H04N 5/21 Circuitry for suppressing or minimising disturbance, e.g. moiré or halo
• CPC Class Codes: H04N 7/01 Conversion of standards , e.g. involving analogue television standards or digital television standards processed at pixel level

Abstract

A movement detection method and system capable of detecting picture point movement in portions of a picture in the presence of noise. Each picture point within the frame in turn is examined with a corresponding picture point from the previous frame to detect when movement has occurred for that particular picture point. To distinguish between noise and movement, a number of selected picture points adjacent the picture point are also examined to see if movement is occurring. By examining a number of picture joints noise tends to be attenuated while movement is not, so that true movement can be detected.

Claims

1. A movement detector for detecting picture point movement in video data in the presence of noise comprising:

input means for measuring the difference between incoming data from a selected number of picture points on one field with data from a selected number of corresponding picture points from a previous field adjacent the picture point for which movement is to be determined, and output means for providing a control signal in dependence on the measured difference between the selected picture points from said input means.

2. A movement detector according to claim 1, wherein the input means comprises a subtractor and said output means comprises a comparator which compares the difference from said input means with a threshold level to provide a control signal which varies in dependence on whether the threshold level has been exceeded by the selected picture points.

3. A movement detector according to claim 1, wherein the input means comprises a subtractor and said output means comprises a memory which is addressed in dependence on the difference between the selected picture points measured by the input means to provide a control signal which varies in dependence on this measured difference.

4. A movement detector according to claim 3, wherein the memory comprises a read only memory having a plurality of values for the control signal stored in locations therein and a particular location being assessed in dependence on the difference indicative of movement detected.

5. A movement detector according to claim 4, wherein the values stored in the memory correspond to coefficient values for a noise reduction system multiplier and said control signal is the value of the coefficient selected for use by said multiplier.

6. A movement detector according to claim 3, wherein a integrator is provided to average the difference measured over a period exceeding one picture point interval.

7. A movement detector according to claim 6 wherein a comparator is provided to compare the integrated output with a threshold level to determine picture movement.

8. A movement detector according to claim 3, wherein the control signal produced by the memory is linearily proportional to the measured difference.

9. A movement detector according to claim 3, wherein the output means generates a code signal indicative of movement in addition to the control signal.

10. A movement detector according to claim 9 wherein the memory includes two sets of control signal levels which are selectable in dependence on the code signal previously generated.

11. A movement detector according to claim 1, wherein averaging means are provided for averaging a portion of picture comprising the selected number of picture points.

12. A movement detector according to claim 11, wherein the averaging means are adapted to detect movement in a predetermined number of the selected picture points to determine that movement has occured.

13. A movement detector according to claim 11, wherein the averaging means averages a portion of picture comprising small area of the picture.

14. A movement detector according to claim 11, wherein the averaging means averages a portion of the picture comprising a vertical line of picture points for detecting camera panning.

15. A movement detector according to claim 11, wherein the averaging means averages a portion of picture from two fields in the same frame with a corresponding portion from two fields in a previous frame.

16. A movement detector according to claim 11, wherein point by point detection is provided in combination with detection within the selected picture portion.

17. A method of detecting picture point movement in video data in the presence of noise comprising measuring the difference between data from a selected number of picture points on one field and data from a selected number of corresponding picture points from a previous field adjacent the picture point for which movement is to be determined to provide an indication that movement has occured.

18. A method according to claim 17, wherein a portion of picture comprising several picture points from two fields of the same frame is compared with a corresponding portion from two fields from an earlier frame.

19. A method according to claim 17 wherein the selected number of picture points comprise a number of picture points along one line.

20. A method according to claim 17 wherein the selected number of picture points comprise a small area of picture.

21. A method according to claim 20, wherein a small area is taken from two picture fields of the same frame to provide the selected number of picture points.

22. A method according to claim 17 wherein movement is deemed to have taken place if a predetermined number of the picture points have a difference therebetween.

23. A method according to claim 17, wherein a combination of single picture point detection and movement detection using a selected number of picture points is used to determine that movement has occured.