METHOD FOR BLURRED IMAGE JUDGMENT

• US 20070252907A1
• Filed: 07/06/2006
• Published: 11/01/2007
• Est. Priority Date: 04/28/2006
• Status: Active Grant

• Current Assignee: Primax Electronics Limited
• Original Assignee: Primax Electronics Limited
• Inventors: Hsu, Wei
• Granted Patent: US 7,528,883 B2
• Time in Patent Office: Days
• US Class Current: 348/248
• CPC Class Codes: H04N 23/64 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

Abstract

A method for blurred image judgment is provided. Firstly, a focus value FV1 of an original image is calculated. By using a blur function, the original image is obfuscated to generate a blurred image, and then the focus value FV2 of the blurred image is calculated. A blur ratio FV1/FV2 is compared with a blur threshold value Tp, thereby discriminating whether the original image is blurred according to the comparing result. The method for blurred image judgment is applicable to a digital image capture device. If the original image is deemed blurred, a blur image signal is issued to notify the user whether the retaking operation is done.

Claims

1. A method for blurred image judgment, comprising steps of:

providing a blur threshold value Tp;

calculating a focus value FV1 of an original image;

obfuscating said original image by using a blur function, thereby generating a blurred image, and calculating a focus value FV2 of said blurred image;

comparing a blur ratio FV1/FV2 with said blur threshold value Tp; and

discriminating whether said original image is blurred according to the comparing result.

2. The method for blurred image judgment according to claim 1 wherein said blur threshold value Tp is ranged between 1.1 and 1.3.

3. The method for blurred image judgment according to claim 1 wherein said blur function is a Gaussian filter'"'"'s function.

4. The method for blurred image judgment according to claim 1 wherein said blur function is a low-pass filter'"'"'s function.

5. The method for blurred image judgment according to claim 1 wherein said original image is deemed sharp when said blur ratio FV1/FV2 is greater than or equal to said blur threshold value Tp, and said original image is deemed blurred when said blur ratio FV1/FV2 is less than said blur threshold value Tp.

6. A digital image capture device for generating an image signal of an object, said digital image capture device comprising:

an image signal generator for generating said image signal of said object; and

an image judging module for discriminating whether said image signal is blurred.

7. The digital image capture device according to claim 6 wherein said image judging module discriminates whether said image signal is blurred according to the steps of:

calculating a focus value FV1 of said image signal;

obfuscating said image signal by using a blur function, thereby generating a blurred image, and calculating a focus value FV2 of said blurred image;

comparing a blur ratio FV1/FV2 with a blur threshold value Tp; and

discriminating whether said image signal is blurred according to the comparing result.

8. The digital image capture device according to claim 7 wherein said image signal is deemed sharp when said blur ratio FV1/FV2 is greater than or equal to said blur threshold value Tp, and said image signal is deemed blurred when said blur ratio FV1/FV2 is less than said blur threshold value Tp.

9. The digital image capture device according to claim 6 wherein said digital image capture device further comprises a display screen, and a blur image signal is shown on said display screen when said image signal is deemed blurred.