Video compression stream

Patent metadata

Field	Value
Publication number	US-11610461-B2
Application number	US-202117242324-A
Country	US
Kind code	B2
Filing date	Apr 28, 2021
Priority date	May 12, 2020
Publication date	Mar 21, 2023
Grant date	Mar 21, 2023

Abstract

The present disclosure relates to a method performed by a background blurring system (1) for provision of a video compression stream from a video camera (2) adapted for capturing a scene. The background blurring system identifies (1001) in a first image of the scene, at a first point in time, at least a first pixel comprised in a background of the first image. The background blurring system further determines (1002) a blurred pixel value for the at least first pixel. Moreover, the background blurring system provides (1003), subsequent the first point in time, the blurred pixel value in the video compression stream. The background blurring system furthermore identifies (1004) in a second image of the scene, at a subsequent second point in time, that the at least first pixel has altered to be comprised in a foreground of the second image. Moreover, the background blurring system provides (1005) in the video compression stream, subsequent the second point in time—continuously and/or intermittently—identified non-blurred pixel values for the at least first pixel. The background blurring system further identifies (1006) in a third image of the scene, at a subsequent third point in time, that the at least first pixel has altered to be comprised in a background of the third image, wherein a value of the at least first pixel has remained unchanged from an intermediate point in time up to the third point in time. Furthermore, when the third point in time is within a predeterminable background merge time period from the intermediate point in time, the background blurring system provides (1007), subsequent the third point in time, the blurred pixel value in the video compression stream.The disclosure also relates to a background blurring system in accordance with the foregoing, a video camera comprising such a background blurring system, and a respective corresponding computer program product and non-volatile computer readable storage medium.

First claim

The invention claimed is:

1. A method performed by a background blurring system for provision of a video compression stream from a video camera adapted for capturing a scene, said method comprising:
identifying in a first image of said scene, at a first point in time, at least a first pixel comprised in a background of said first image;
determining a blurred pixel value for said at least first pixel;
providing, subsequent said first point in time, said blurred pixel value in said video compression stream;
identifying in a second image of said scene, at a subsequent second point in time, that said at least first pixel has altered to be comprised in a foreground of said second image;
providing in said video compression stream, subsequent said second point in time—continuously and/or intermittently—identified non-blurred pixel values for said at least first pixel;
identifying in a third image of said scene, at a subsequent third point in time when the at least first pixel altered from being a foreground pixel to again become a background pixel, that said at least first pixel has altered to be comprised in a background of said third image; and
when said third point in time is within a predeterminable background merge time period from an intermediate point in time subsequent said second point in time, from which a value of said at least first pixel has remained unchanged:
providing, subsequent said third point in time, said blurred pixel value in said video compression stream.

2. The method according to claim 1 , said method further comprising:
under a condition said third point in time is not within said background merge time period:
determining an updated blurred pixel value for said at least first pixel; and
providing, subsequent said third point in time, said updated blurred pixel value in said video compression stream.

3. The method according to claim 2 , wherein said determining an updated blurred pixel value comprises additionally determining updated blurred pixel values for additional pixels near said at least first pixel, and wherein said providing said updated blurred pixel value comprises additionally providing said updated blurred pixel values for said additional pixels.

4. The method according to claim 1 , said method further comprising:
when said blurred pixel value at a predeterminable supplemental point in time is determined to not have been updated for a predeterminable supplemental time period:
determining from a current image of said scene, an updated blurred pixel value for said at least first pixel; and
providing, subsequent said supplemental point in time, said updated blurred pixel value in said video compression stream.

5. The method according to claim 1 , said method further comprising:
when a predeterminable forthcoming frame of said video compression stream, at a predeterminable I-frame related point in time, is an I-frame:
determining, for said at least first pixel and further pixels of a predeterminable portion out of pixels identified to be comprised in a background of a current image of said scene, updated blurred pixel values; and
providing, subsequent said I-frame related point in time, said updated blurred pixel values in said video compression stream.

6. The method according to claim 1 , wherein a kernel size of an image filter kernel used for determining blurred pixel values of said at least first pixel, aligns with a macro block size of an I-frame of said video compression stream.

7. A non-transitory computer program product comprising a computer program containing computer program code that when executed by a computer or a processor causes the computer or the processor to execute steps of the method according to claim 1 .

8. A background blurring system for provision of a video compression stream from a video camera adapted for capturing a scene, said background blurring system comprising:
a first identifying unit for identifying in a first image of said scene, at a first point in time, at least a first pixel comprised in a background of said first image;
a first blurring unit for determining a blurred pixel value for said at least first pixel;
a first providing unit for providing, subsequent said first point in time, said blurred pixel value in said video compression stream;
a second identifying unit for identifying in a second image of said scene, at a subsequent second point in time, that said at least first pixel has altered to be comprised in a foreground of said second image;
a second providing unit for providing in said video compression stream, subsequent said second point in time—continuously and/or intermittently—identified non-blurred pixel values for said at least first pixel;
a third identifying unit for identifying in a third image of said scene, at a subsequent third point in time when the at least first pixel altered from being a foreground pixel to again become a background pixel, that said at least first pixel has altered to be comprised in a background of said third image; and
a third providing unit for, when said third point in time is within a predeterminable background merge time period from an intermediate point in time subsequent said second point in time, from which a value of said at least first pixel has remained unchanged, providing, subsequent said third point in time, said blurred pixel value in said video compression stream.

9. The background blurring system according to claim 8 , further comprising:
a second blurring unit for, when said third point in time is not within said background merge time period, determining an updated blurred pixel value for said at least first pixel; and
a fourth providing unit for providing, subsequent said third point in time, said updated blurred pixel value in said video compression stream.

10. The background blurring system according to claim 9 , wherein said second blurring unit is adapted for additionally determining updated blurred pixel values for additional pixels near said at least first pixel, and wherein said fourth providing unit is adapted for additionally providing said updated blurred pixel values for said additional pixels.

11. The background blurring system according to claim 8 , further comprising:
a supplemental blurring unit for, when said blurred pixel value at a predeterminable supplemental point in time is determined to not have been updated for a predeterminable supplemental time period, determining from a current image of said scene, an updated blurred pixel value for said at least first pixel; and
a supplemental providing unit for providing, subsequent said supplemental point in time, said updated blurred pixel value in said video compression stream.

12. The background blurring system according to claim 8 , further comprising:
an I-frame blurring unit for, when a predeterminable forthcoming frame of said video compression stream, at a predeterminable I-frame related point in time, is an I-frame, determining for said at least first pixel and further pixels of a predeterminable portion out of pixels identified to be comprised in a background of a current image of said scene, updated blurred pixel values; and
an I-frame providing unit for providing, subsequent said I-frame related point in time, said updated blurred pixel values in said video compression stream.

13. The background blurring system according to claims 8 , wherein a kernel size of an image filter kernel used for determining blurred pixel values of said at least first pixel, aligns with a macro block size of an I-frame of said video compression stream.

14. A video camera comprising a background blurring system according to

Assignees

• Axis Ab

Inventors

• Lundberg Stefan
• Yuan Song
• Borglund Tim

Classifications

• G08B13/19667 Primary

  Details realated to data compression, encryption or encoding, e.g. resolution modes for reducing data volume to lower transmission bandwidth or memory requirements · CPC title

• G08B13/19604

  involving reference image or background adaptation with time to compensate for changing conditions, e.g. reference image update on detection of light level change · CPC title

• H04N21/4318

  by altering the content in the rendering process, e.g. blanking, blurring or masking an image region (image enhancement or restoration in general G06T5/00) · CPC title

• H04N23/64 Primary

  Computer-aided capture of images, e.g. transfer from script file into camera, check of taken image quality, advice or proposal for image composition or decision on when to take image · CPC title

• H04N19/42

  characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software implementation (H04N19/635 takes precedence) · CPC title