Systems and methods for image scanning

Patent metadata

Field	Value
Publication number	US-9646389-B2
Application number	US-201514624291-A
Country	US
Kind code	B2
Filing date	Feb 17, 2015
Priority date	Aug 26, 2014
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

A method for image scanning by an electronic device is described. The method includes obtaining an image pyramid including a plurality of scale levels and at least a first pyramid level for a frame. The method also includes providing a scanning window. The method further includes scanning at least two of the plurality of scale levels of the frame at a plurality of scanning window locations. A number of scanning window locations is equal for each scale level of the at least two scale levels of the first pyramid level.

First claim

What is claimed is:

1. A method for object detection by an electronic device, comprising:
obtaining an image pyramid comprising a plurality of pyramid levels for a frame and a plurality of scale levels for each pyramid level;
providing a scanning window;
setting a scanning step size that is proportional to dimensions of the frame at a scale level, wherein the scanning step size is uniform for the plurality of pyramid levels corresponding to a same scale level;
scanning at least two of the plurality of scale levels of the frame at a plurality of scanning window locations, wherein a number of scanning window locations is equal for each scale level of the at least two scale levels of a first pyramid level; and
detecting an object based on the scanning.

2. The method of claim 1 , wherein computation by the electronic device for each of the at least two scale levels of the frame is characterized by the number of scanning window locations multiplied by a number of pyramid levels.

3. The method of claim 1 , further comprising:
determining a scanning step for each of the at least two scale levels; and
scanning the at least two scale levels of a subsequent frame, wherein a quantity of the subsequent frames to scan all of the scanning window locations is greater at a lower scale level in comparison to a higher scale level.

4. The method of claim 1 , further comprising selecting a range of scale levels for scanning the frame among the plurality of scale levels, wherein only scale levels within the range of scale levels are scanned.

5. The method of claim 4 , further comprising selecting a second range of scale levels among a plurality of scale levels of a subsequent frame for scanning the subsequent frame, wherein adjacent or non-adjacent scale levels are scanned.

6. The method of claim 1 , further comprising determining a scanning step for each of the at least two scale levels, wherein a first dimension scanning step is proportional to a first dimension of an image at the first pyramid level for each of the scale levels scanned and a second dimension scanning step is proportional to a second dimension of the image at the first pyramid level for each of the scale levels scanned.

7. The method of claim 1 , wherein the number of scanning window locations corresponding to each of one or more additional pyramid levels of a scale level is less than or equal to the number of scanning window locations corresponding to the first pyramid level of the scale level.

8. The method of claim 1 , wherein the plurality of scale levels are octave levels.

9. An electronic device for object detection, comprising:
a processor;
memory in electronic communication with the processor;
instructions stored in memory, the instructions being executable to:
obtain an image pyramid comprising a plurality of pyramid levels for a frame and a plurality of scale levels for each pyramid level;
provide a scanning window;
set a scanning step size that is proportional to dimensions of the frame at a scale level, wherein the scanning step size is uniform for the plurality of pyramid levels corresponding to a same scale level;
scan at least two of the plurality of scale levels of the frame at a plurality of scanning window locations, wherein a number of scanning window locations is equal at each scale level of the at least two scale levels of the first pyramid level; and
detect an object based on the scanning.

10. The electronic device of claim 9 , wherein computation by the electronic device for each of the at least two scale levels of the frame is characterized by the number of scanning window locations multiplied by a number of pyramid levels.

11. The electronic device of claim 9 , wherein the instructions are further executable to:
determine a scanning step for each of the at least two scale levels; and
scan the at least two scale levels of a subsequent frame, wherein a quantity of the subsequent frames to scan all of the scanning window locations is greater at a lower scale level in comparison to a higher scale level.

12. The electronic device of claim 9 , wherein the instructions are further executable to select a range of scale levels for scanning the frame among the plurality of scale levels, wherein only scale levels within the range of scale levels are scanned.

13. The electronic device of claim 12 , wherein the instructions are further executable to select a second range of scale levels among a plurality of scale levels of a subsequent frame for scanning the subsequent frame, wherein adjacent or non-adjacent scale levels are scanned.

14. The electronic device of claim 9 , wherein the instructions are further executable to determine a scanning step for each of the at least two scale levels, wherein a first dimension scanning step is proportional to a first dimension of an image at the first pyramid level for each of the scale levels scanned and a second dimension scanning step is proportional to a second dimension of the image at the first pyramid level for each of the scale levels scanned.

15. The electronic device of claim 9 , wherein the number of scanning window locations corresponding to each of one or more additional pyramid levels of a scale level is less than or equal to the number of scanning window locations corresponding to the first pyramid level of the scale level.

16. The electronic device of claim 9 , wherein the plurality of scale levels are octave levels.

17. An apparatus for object detection, comprising:
means for obtaining an image pyramid comprising a plurality of pyramid levels for a frame and a plurality of scale levels for each pyramid level;
means for providing a scanning window;
means for setting a scanning step size that is proportional to dimensions of the frame at a scale level, wherein the scanning step size is uniform for the plurality of pyramid levels corresponding to a same scale level;
means for scanning at least two of the plurality of scale levels of the frame at a plurality of scanning window locations, wherein a number of scanning window locations is equal for each scale level of the at least two scale levels of the first pyramid level; and
means for detecting an object based on the scanning.

18. The apparatus of claim 17 , wherein computation by the apparatus for each of the at least two scale levels of the frame is characterized by the number of scanning window locations multiplied by a number of pyramid levels.

19. The apparatus of claim 17 , further comprising means for selecting a range of scale levels for scanning the frame among the plurality of scale levels, wherein only scale levels within the range of scale levels are scanned.

20. The apparatus of claim 17 , further comprising means for determining a scanning step for each of the at least two scale levels, wherein a first dimension scanning step is proportional to a first dimension of an image at the first pyramid level for each of the scale levels scanned and a second dimension scanning step is proportional to a second dimension of the image at the first pyramid level for each of the scale levels scanned.

21. A computer-program product for object detection, comprising a non-transitory computer-readable medium having instructions thereon, the instructions comprising:
code for causing an electronic device to obtain an image pyramid comprising a plurality of pyramid levels for a frame and a plurality of scale levels for each pyramid level;
code for causing the electronic device to provide a scanning window;
code for ca

Assignees

• Qualcomm Inc

Inventors

• Gao Dashan
• Zhong Xin
• Kandhadai Ananthapadmanabhan Arasanipalai

Classifications

• G06V10/50 Primary

  by performing operations within image blocks; by using histograms, e.g. histogram of oriented gradients [HoG]; by summing image-intensity values; Projection analysis · CPC title

• G06T7/20 Primary

  Analysis of motion (motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51) · CPC title

• G06T2207/20016

  Hierarchical, coarse-to-fine, multiscale or multiresolution image processing; Pyramid transform · CPC title

• G06T7/207

  for motion estimation over a hierarchy of resolutions (multi-resolution motion estimation or hierarchical motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/53) · CPC title

• G06T7/248

  involving reference images or patches · CPC title