Motion vector detector employing image subregions and median values

• US 5,157,732 A
• Filed: 10/02/1991
• Issued: 10/20/1992
• Est. Priority Date: 03/20/1989
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Ishii, Hirofumi, Morimura, Atsushi
• Primary Examiner(s): Moore, David K.
• Assistant Examiner(s): Cammarata, Michael
• Application Number:
  US07/769,521
• Time in Patent Office: 384 Days
• Field of Search: 382/1, 382/21, 382/42, 382/19, 358/105, 358/136, 358/133
• US Class Current: 382/107
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 7/223 using block-matching
• CPC Class Codes: H04N 19/523 with sub-pixel accuracy
• CPC Class Codes: H04N 5/145 Movement estimation for video coding H04N19/51

Abstract

An image motion vector detection apparatus effectively reduces influences of false vectors arising at a certain probability and suppresses time lags. An image fluctuation stabilizer highly stabilizes images or frames without causing unnatural visual feelings. An image motion vector detection apparatus comprises means for detecting motion vectors in each of motion vector detection regions defined in the whole or part of picture frame, means for judging the reliability of the motion vector in each region, and signal processing means which, in obtaining a motion vector of the whole or part of the frame from the motion vectors of the regions and in case the number of motion vectors judged to be reliable is more than or equal to a predetermined number, outputs a representative value of a set of the reliable motion vectors as a motion vector of the frame.

Claims

1. An image motion vector detection apparatus, comprising:

representative image memory means for storing portions of each field of an image signal inputted precedently in time sequence in correspondence with image subregions of a whole frame image region corresponding to said image signal such that said stored portions of said precedent image signal are employed for detection of plural image motion vectors of said whole frame image region of said image signal continuously inputted;

image motion vector detection means for detecting on each of said image subregions correlation values between precedent image signals stored in said memory means and image signals inputted subsequent to said precedent image signals by accumulation of differential absolute values of said precedent image signals and the subsequently inputted image signals in order to detect a value of an image motion vector of each of said image subregions from the detected correlation values;

reliability judging means for judging a reliability of a respective image motion vector of each of said image subregions as to whether the detected value of the respective image motion vector is reliably proper in order to correct the inputted image signal against fluctuations possibly caused therein, said judging means outputting a signal representative of the detected value of the respective image motion vector when it is judged reliably proper; and

signal processing means including median value selection means for receiving from said judging means a set of input signals representative of image motion vector values judged reliably proper by said judging means among those values detected respectively on said image subregions and outputting a median signal having a median value of the image motion vector values of the received set of signals as a signal representing an image motion vector of the whole frame image region, said signal processing means checking the total number of image motion vectors judge reliably proper by said judging means with respect to said image subregions of a current field of the image signal and adding said set of input signals received by said median value selection means with at least one of said signals representative of image motion vector values judged reliably proper by said judging means of representative of resultant values of arithmetic processing thereof before the current field of the image signal, when said total number of image motion vectors judged reliably proper is lower than a predetermined number.

2. An image motion detection apparatus according to claim 1, wherein said signal processing means adds, for said total number of image motion vectors lower than said predetermined number, said set of input signals received by said median value selection means with at least one outputted signal having a median value of the image motion vector values of the received set of signals which was outputted to represent an image motion vector of an entire field image region of the image signal of at least one field or frame preceding to the current field.

3. An image motion detection apparatus according to claim 1, wherein said signal processing means adds, for said total number of image motion vectors lower than said predetermined number, said set of input signals received by said median value selection means with at least one signal of an image motion vector which was judged reliably proper with respect to a corresponding one of said image subregions of the image signal of at least one field or frame preceding to the current field.

4. An image motion detection apparatus according to claim 1, wherein said predetermined number is an integer not smaller than 3.

5. An image motion detection apparatus according to claim 2, wherein said predetermined number is an integer not smaller than 3.

6. An image motion detection apparatus according to claim 3, wherein said predetermined number is an integer not smaller than 3.

7. An image fluctuation correction system comprising:

(a) memory means for temporarily storing portions of an input image signal;

(b) interpolation means for interpolating partially the stored image signal portions to enlarge a partial image of said input image signal;

(c) an image motion detection apparatus for detecting an image motion vector of the input image signal, said apparatus comprising;

representative image memory means for storing portions of each field of an image signal inputted precedently in time sequence in correspondence with image subregions of a whole frame image region corresponding to said image signal such that said stored portions of said precedent image signal are employed for detection of plural image motion vectors of said whole frame image region of said image signal continuously inputted;

image motion vector detection means for detecting on each of said image subregions correlation values between precedent image signals stored in said memory means and image signals inputted subsequent to said precedent image signals by accumulation of differential absolute values of said precedent image signals and the subsequently inputted image signals in order to detect a value of an image motion vector of each of said image subregions from the detected correlation values;

reliability judging means for judging a reliability of a respective image motion vector of each of said image subregions as to whether the detected value of the respective image motion vector is reliably proper in order to correct the inputted image signal against fluctuations possibly caused therein, said judging means outputting a signal representative of the detected value of the respective image motion vector when it is judged reliably proper; and

signal processing means including median value selection means for receiving from said judging means a set of input signals representative of image motion vector values judged reliably proper by said judging means among those values detected respectively on said image subregions and outputting a median signal having a median value of the image motion vector values of the received set of signals as a signal representing an image motion vector of the whole frame image region, said signal processing means checking the total number of image motion vectors judged reliably proper by said judging means with respect to said image subregions of a current field of the image signal and adding said set of input signals received by said median value selection means with at least one of said signals representative of image motion vector values judged reliably proper by said judging means or representative of resultant values of arithmetic processing thereof before the current field of the image signal, when said total number of image motion vectors judged reliably proper is lower than a predetermined number; and

(d) control means for controlling memory reading operations to control said interpolation enlargement means and stabilize possible image fluctuations of the image signal in accordance with said detected image motion vector.

8. An image fluctuation correction system according to claim 7, wherein said signal processing means adds, for said total number of image motion vectors lower than said predetermined number, said set of input signals received by said median value selection means with at least one outputted signal having a median value of the image motion vector values of the received set of signals which was outputted to represent an image motion vector of an entire field image region of the image signal of at least one field or frame preceding to the current field.

9. An image fluctuation correction system according to claim 7, wherein said signal processing means adds, for said total number of image motion vectors lower than said predetermined number, said set of input signals received by said median value selection means with at least one signal of an image motion vector which was judged reliably proper with respect to a corresponding one of said image subregions of the image signal of at least one field or frame preceding to the current field.

10. An image fluctuation correction system according to claim 7, wherein said predetermined number is an integer not smaller than 3.

11. An image fluctuation correction system according to claim 8, wherein said predetermined number is an integer not smaller than 3.

12. An image fluctuation correction system according to claim 9, wherein said predetermined number is an integer not smaller than 3.