Using a skip block mask to reduce bitrate from a monitoring camera

Patent metadata

Field	Value
Publication number	US-11055976-B2
Application number	US-202016947659-A
Country	US
Kind code	B2
Filing date	Aug 11, 2020
Priority date	Sep 19, 2019
Publication date	Jul 6, 2021
Grant date	Jul 6, 2021

Abstract

Methods and apparatus, including computer program products, implementing and using techniques for reducing bitrate from a monitoring camera. A first input is received that identifies first regions of an image representing a camera field of view. The first regions contribute significantly to the bitrate. A second input is received that identifies second regions of the image. The second regions contain information that is deemed to be of little visual interest to a user of the monitoring camera. Third regions of the image are determined. The third regions are regions where the first and second regions overlap at least in part. Video encoder settings are applied to force skip blocks in at least some of the third regions, thereby reducing contributions to the bitrate from the third regions.

First claim

The invention claimed is:

1. A method for reducing bitrate from a monitoring camera, comprising:
receiving a first input identifying first regions of an image captured by a camera and representing a camera field of view, the first regions having a bitrate contribution over a predetermined threshold;
receiving a second input identifying second regions of the image, the second regions containing information deemed to be of little visual interest to a user of the monitoring camera;
determining third regions of the image, the third regions being regions where the first and second regions overlap; and
applying video encoder settings to encode at least some of the third regions as inter-mode coded blocks of pixels referring to a corresponding block of pixels in a reference frame, from which corresponding image content is completely copied, thereby reducing contributions to the bitrate from the third regions.

2. The method of claim 1 , wherein the first, second and third regions are represented as blocks of pixels in an image captured by the camera.

3. The method of claim 1 , wherein the second input is a user input.

4. The method of claim 3 , wherein the second input is generated by the user through a graphical user interface or an application programming interface.

5. The method of claim 1 , wherein the second input is automatically generated, based on an image segmentation.

6. The method of claim 1 , wherein the first input is generated by the video encoder, based on a threshold value representing a cost for encoding the first regions.

7. The method of claim 1 , wherein the first input is generated by an image analysis algorithm, based on a complexity of the image.

8. The method of claim 1 , further comprising:
prior to applying the video encoder settings, providing a suggestion of the third regions to a user of the monitoring camera, to allow the user to confirm or reject individual regions among the third regions.

9. The method of claim 8 , wherein the suggestion of the third regions is provided on a user interface as an overlay on the image.

10. The method of claim 1 , further comprising:
calculating an estimated bitrate from the monitoring camera;
modifying at least some of the first and second regions to determine modified third regions; and
calculating a modified estimated bitrate from the monitoring camera using the modified third regions.

11. The method of claim 10 , further comprising:
using the results of the calculations to modify one or more of the first and second inputs; and
applying video encoder settings in accordance with the modified first and second inputs.

12. A system for reducing bitrate from a monitoring camera, the system comprising:
a skip region calculation unit, configured to:
receive a first input identifying first regions of an image representing a camera field of view, the first regions having a bitrate contribution over a predetermined threshold,
receive a second input identifying second regions of the image, the second regions containing information deemed to be of little visual interest to a user of the monitoring camera,
determine third regions of the image, the third regions being regions where the first and second regions overlap,
and
an encoder configured to encode at least some of the third regions as inter-mode coded blocks of pixels referring to a corresponding block of pixels in a reference frame, from which corresponding image content is completely copied, thereby reducing contributions to the bitrate from the third regions.

13. A computer program product for reducing bitrate from a monitoring camera, comprising a non-transitory computer readable storage medium having program instructions embodied therewith, the program instructions being executable by a processor to perform a method comprising:
receiving a first input identifying first regions of an image representing a camera field of view, the first regions having a bitrate contribution over a predetermined threshold;
receiving a second input identifying second regions of the image, the second regions containing information deemed to be of little visual interest to a user of the monitoring camera;
determining third regions of the image, the third regions being regions where the first and second regions overlap; and
applying video encoder settings to encode at least some of the third regions as inter-mode coded blocks of pixels referring to a corresponding block of pixels in a reference frame, from which corresponding image content is completely copied, thereby reducing contributions to the bitrate from the third regions.

Assignees

• Axis Ab

Inventors

• Nystrom Johan
• Danielsson Fan Xing

Classifications

• H04N19/132 Primary

  Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking · CPC title

• H04N7/183 Primary

  for receiving images from a single remote source · CPC title

• H04N19/174

  the region being a slice, e.g. a line of blocks or a group of blocks · CPC title

• H04N19/167

  Position within a video image, e.g. region of interest [ROI] · CPC title

• H04N7/18

  Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast · CPC title