Method and system for calculating blur artifacts in videos using user perception threshold

• US 8,150,191 B2
• Filed: 10/14/2008
• Issued: 04/03/2012
• Est. Priority Date: 10/14/2008
• Status: Active Grant

• Current Assignee: Interra Systems, Inc.
• Original Assignee: Interra Systems, Inc.
• Inventors: Madnani, Shekhar
• Primary Examiner(s): Zarka, David
• Application Number:
  US12/287,830
• Publication Number:
  US 20100092100A1
• Time in Patent Office: 1,267 Days
• Field of Search: 382/255
• US Class Current: 382/255
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/30168 Image quality inspection
• CPC Class Codes: G06T 5/73 Deblurring; Sharpening
• CPC Class Codes: G06T 7/0002 Inspection of images, e.g. flaw detection

Abstract

A method and system for calculating a blur artifact in a video are disclosed. The video includes a series of frames captured at a predefined interval of time. The frames include one or more pixels. Calculating the blur artifact in the video includes identifying a focused area in a set of frames. Further, edges are detected in each of the frames. Furthermore, the blur artifact is calculated as a ratio of number of blurred pixels and total number edge pixels.

Claims

1. A computer implemented method for calculating a blur artifact in a motion picture, the motion picture comprising one or more frames defined at a predefined interval of time, each of the one or more frames comprising one or more pixels, the computer implemented method comprising:

determining a set of pixels in a set of frames, wherein the set of pixels comprises one or more pixels having a Sum of Modified Laplacian value that exceeds a second predefined threshold, and wherein a set of edge pixels is determined in the set of pixels, the set of pixels being a focus area of the motion picture;

calculating an edge spread of the set of edge pixels;

determining a set of blurred edge pixels in the set of edge pixels, wherein the set of blurred edge pixels comprises the one or more edge pixels of the set of edge pixels for which the edge spread exceeds a third predefined threshold; and

calculating the blur artifact as a ratio of a number of the blurred edge pixels in the set of the blurred edge pixels and a number of the edge pixels in the set of edge pixels, wherein calculating the blur artifact comprises;

calculating a perception threshold based on a user input; and

comparing the calculated blur artifact with the perception threshold.

2. The computer implemented method according to claim 1 further comprising:

detecting edges of the one or more pixels, wherein the edges are detected using an edge detection method selected from a group consisting of a Sobel operator method, a Canny edge detector method, and a Laplacian edge detector method;

comparing the detected edges with a first predefined threshold; and

determining one or more valid edge pixels, wherein the one or more valid edge pixels has the edges that exceed the first predefined threshold.

3. The computer implemented method according to claim 2, wherein detecting the edges comprises calculating one or more edge gradients of the detected edges.

4. The computer implemented method according to claim 1, wherein calculating the blur artifact comprises calculating a duration of the blur artifact when the calculated blur artifact exceeds the perception threshold.

5. A system for calculating a blur artifact in a motion picture, the motion picture comprising one or more frames defined at a predefined interval of time, each of the one or more frames comprising one or more pixels, the system comprising:

a focus identifier, the focus identifier being capable of determining a set of pixels in a set of frames, wherein the set of pixels comprises one or more pixels having a Sum of Modified Laplacian value that exceeds a second predefined threshold, and wherein a set of edge pixels is determined in the set of pixels, the set of pixels being a focus area of the motion picture; and

a blur artifact calculator, the blur artifact calculator being capable of;

determining a set of blurred edge pixels in the set of edge pixels, wherein the set of blurred edge pixels comprises the one or more edge pixels of the set of edge pixels for which an edge spread exceeds a third predefined threshold;

calculating the blur artifact as a ratio of a number of the blurred edge pixels in the set of the blurred edge pixels and a number of the edge pixels in the set of edge pixels, wherein calculating the blur artifact comprises calculating a perception threshold based on user input, wherein the calculated blur artifact is compared with the perception threshold by the comparator.

6. The system according to claim 5, wherein the system further comprises an input module, the input module being capable of receiving the motion picture.

7. The system according to claim 5, wherein the system further comprises an output module, the output module being capable of displaying the calculated blur artifact.

8. The system according to claim 5, wherein the blur artifact calculator further is capable of:

calculating duration of the blur artifact when the calculated blur artifact exceeds the perception threshold.

9. The system according to claim 5 further comprising:

an edge calculator, the edge calculator being capable of;

detecting edges of the one or more pixels; and

calculating edge spread of the one or more pixels, wherein the edge calculator is capable of detecting the edges using an edge detection method selected from a group consisting of a Sobel operator, a Canny edge detector, and a Laplacian edge detector,

a comparator, the comparator being capable of;

comparing the edges with a first predefined threshold; and

determining one or more valid edge pixels, wherein the one or more valid edge pixels have the edges that exceed the first predefined threshold.

10. The system according to claim 9, wherein the edge calculator is further capable of calculating one or more edge gradients of the detected edges.

11. A computer program product for calculating a blur artifact in a motion picture, the motion picture comprising one or more frames defined at a predefined interval of time, each of the one or more frames comprising one or more pixels, the computer program product comprising instructions stored in a non-transitory computer readable medium, the instructions comprising:

program instructions for determining a set of pixels in a set of frames, wherein the set of pixels comprises one or more pixels having a Sum of Modified Laplacian value that exceeds a second predefined threshold, and wherein a set of edge pixels is determined in the set of pixels, the set of pixels being a focus area of the motion picture;

program instructions for calculating an edge spread of the set of edge pixels;

program instructions for determining a set of blurred edge pixels in the set of edge pixels, wherein the set of blurred edge pixels comprises the one or more edge pixels of the set of edge pixels for which the edge spread exceeds a third predefined threshold; and

program instructions for calculating the blur artifact as a ratio of a number of the blurred edge pixels in the set of blurred edge pixels and a number of the edge pixels in the set of edge pixels, wherein the program instructions for calculating the blur artifact comprises;

calculating a perception threshold, based on user input; and

comparing the calculated blur artifact with a perception threshold.

12. The computer program product according to claim 11, wherein the instructions further comprising:

program instructions for detecting edges of the one or more pixels, wherein the program instructions for detecting the edges comprise program instructions for calculating one or more edge gradients of the detected edges;

program instructions for comparing the detected edges with a first predefined threshold; and

program instructions for determining one or more valid edge pixels, wherein the one or more valid edge pixels have the detected edges that exceed the first predefined threshold.

13. The computer program product according to claim 11, wherein program instructions for calculating the blur artifact comprise:

and

program instructions for calculating a duration of the blur artifact when the calculated blur artifact exceeds the perception threshold.