System and method for adjusting backlight in measurement of a profile image

• US 8,300,976 B2
• Filed: 12/25/2008
• Issued: 10/30/2012
• Est. Priority Date: 06/20/2008
• Status: Active Grant

• Current Assignee: Hong Fu Jin Precision Industry (Shenzhen) Co., Ltd. (Hon Hai Precision Industry Co., Ltd.), Hon Hai Precision Industry Co., Ltd.
• Original Assignee: Hong Fu Jin Precision Industry (Shenzhen) Co., Ltd. (Hon Hai Precision Industry Co., Ltd.), Hon Hai Precision Industry Co., Ltd.
• Inventors: Chang, Chih-Kuang, Chen, Xian-Yi, Yuan, Zhong-Kui, Jiang, Li
• Primary Examiner(s): Park, Chan S
• Assistant Examiner(s): Nakhjavan, Shervin
• Application Number:
  US12/344,252
• Publication Number:
  US 20090317018A1
• Time in Patent Office: 1,405 Days
• Field of Search: 382/141, 382/270, 382/272, 382/274, 250/205, 372/29.014, 396/164, 369/116, 209/581, 209/582
• US Class Current: 382/274
• CPC Class Codes: G01B 11/24 for measuring contours or curvatures
• CPC Class Codes: G01N 21/8851 Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges G01N21/8806 and G01N21/93 - G01N21/95692 take precedence; optical measurement of dimensions G01B11/00; optical scanning G02B26/10; image transformation G06T3/00; computerised image enhancement G06T5/00; image processing per se for flaw detection G06T7/0002

Abstract

A computer-implemented method for adjusting backlight in measurement of a profile image of an object includes setting a light source of an image measuring machine to an original intensity level, obtaining the profile image of the object laid on the image measuring machine, and performing a mean filter processing and a binary image processing on the profile image. The method further includes setting intensity variables to adjust backlight intensity of the light source, uses the intensity variables to calculate an optimum intensity level of the backlight intensity utilizing an iterative method, and adjusting the backlight intensity of the light source to the optimum intensity level to obtain an optimum profile image of the object.

Claims

1. A computer-implemented method for adjusting backlight in measurement of a profile image of an object, the method comprising:

setting a light source of an image measuring machine to an original intensity level;

obtaining the profile image of the object on the image measuring machine, and performing a mean filter processing and a binary image processing on the profile image;

setting intensity variables to adjust backlight intensity of the light source, the intensity variables comprising an upper approach level and a lower approach level;

calculating an optimum intensity level of the backlight intensity utilizing an iterative method;

adjusting the backlight intensity of the light source to the optimum intensity level to obtain an optimum profile image of the object; and

storing the optimum profile image and the optimum intensity level into a storage system.

2. The method according to claim 1, wherein the optimum profile image has a gray value that is a middle value in the range from 0-255 gray levels.

3. The method according to claim 1, wherein the light source comprises 101 intensity levels ranging from 0-100 intensity levels to reflect the backlight intensity, and wherein the original intensity level is in the range from the 0-100 intensity levels.

4. The method according to claim 3, wherein the calculating block comprises:

(a) initializing the intensity variables to set the upper approach level to the level 100 and set the lower approach level to the level 1;

(b) adjusting the backlight intensity of the light source to an adjusted intensity level, wherein the adjusted intensity level is equal to one half of a sum value of the upper approach level and the lower approach level;

(c) obtaining an adjusted image of the object based on the adjusted intensity level, and calculating a gray value of the adjusted image;

(d) determining whether the gray value of the adjusted image is less than an optimum gray value, wherein the optimum gray value is a gray value of the optimum profile image that is a middle value in the range from 0-255; and

(e) determining that the optimum intensity level is equal to the adjusted intensity level if the gray value of the adjusted image is equal to the optimum gray value.

5. The method according to claim 4, wherein block (d) further comprises:

setting the adjusted intensity level as the lower approach level if the gray value of the adjusted image is less than the optimum gray value, or setting the adjusted intensity level as the upper approach level if the gray value of the adjusted image is greater than the optimum gray value;

determining whether a difference between the upper approach level and the lower approach level is less than a predetermined value; and

returning block (b) if the difference is no less than the predetermined value, or determining that the optimum intensity level is equal to the adjusted intensity level if the difference is less than the predetermined value.

6. The method according to claim 5, wherein the predetermined value equals 2.

7. A computing system for adjusting backlight in measurement of a profile image of an object on an image measuring machine, the computing system comprising:

an image processing module configured for performing a mean filter processing and a binary image processing on the profile image of the object, after a light source of the image measuring machine is set to an original intensity level;

a calculating module configured for setting intensity variables to adjust backlight intensity of the light source, and using the intensity variables to calculate an optimum intensity level of the backlight intensity utilizing an iterative method;

an adjusting module configured for adjusting the backlight intensity of the light source to the optimum intensity level to obtain an optimum profile image of the object;

a reporting module configured for reporting and displaying the optimum profile image, and storing the optimum profile image and the optimum intensity level into a storage system; and

at least one processor that executes the image processing module, the calculating module, the adjusting module, and the reporting module.

8. The system according to claim 7, wherein the light source comprises 101 intensity levels ranging from 0-100 intensity levels to reflect the backlight intensity, and wherein the original intensity level is in the range from the 0-100 intensity levels.

9. The system according to claim 7, wherein a gray value of the optimum profile image is a middle value in the range from 0-255 gray levels.

10. The system according to claim 7, wherein the intensity variables comprise an upper approach level and a lower approach level.

11. The system according to claim 10, wherein the iterative method is performed based on a formula:

Vc=(Vm+Vn)/2, wherein Vc represents a current intensity level of the backlight intensity, Vm represents the upper approach level, and Vn represents the lower approach level.

12. The system according to claim 7, wherein the storage system is at least one of a hard disk drive, a compact disc, a digital video disc, and a tape drive.

13. A non-transitory computer-readable medium having stored thereon instructions for adjusting backlight in measurement of a profile image of an object, the computer-readable medium, when executed by a computer, causing the computer to perform a method, the method comprising:

setting a light source of an image measuring machine to an original intensity level;

obtaining the profile image of the object on the image measuring machine, and performing a mean filter processing and a binary image processing on the profile image;

setting intensity variables to adjust backlight intensity of the light source, the intensity variables comprising an upper approach level and a lower approach level;

calculating an optimum intensity level of the backlight intensity utilizing an iterative method;

adjusting the backlight intensity of the light source to the optimum intensity level to obtain an optimum profile image of the object; and

storing the optimum profile image and the optimum intensity level into a storage system.

14. The non-transitory computer-readable medium according to claim 13, wherein a gray value of the optimum profile image is a middle value in the range from 0-255 gray levels.

15. The non-transitory computer-readable medium according to claim 13, wherein the light source comprises 101 intensity levels ranging from 0-100 intensity levels to reflect the backlight intensity, and wherein the original intensity level is in the range from the 0-100 intensity levels.

16. The non-transitory computer-readable medium according to claim 15, wherein the calculating block comprises:

(a) initializing the intensity variables to set the upper approach level to the level 100 and set the lower approach level to the level 1;

(b) adjusting the backlight intensity of the light source to an adjusted intensity level, wherein the adjusted intensity level is equal to one half of a sum value of the upper approach level and the lower approach level;

(c) obtaining an adjusted image of the object based on the adjusted intensity level, and calculating a gray value of the adjusted image;

(d) determining whether the gray value of the adjusted image is less than an optimum gray value, wherein the optimum gray value is a gray value of the optimum profile image that is a middle value in the range from 0-255; and

(e) determining that the optimum intensity level is equal to the adjusted intensity level if the gray value of the adjusted image is equal to the optimum gray value.

17. The non-transitory computer-readable medium according to claim 16, wherein block (d) further comprises:

setting the adjusted intensity level as the lower approach level if the gray value of the adjusted image is less than the optimum gray value, or setting the adjusted intensity level as the upper approach level if the gray value of the adjusted image is greater than the optimum gray value;

determining whether a difference between the upper approach level and the lower approach level is less than a predetermined value; and

returning block (b) if the difference is no less than the predetermined value, or determining that the optimum intensity level is equal to the adjusted intensity level if the difference is less than the predetermined value.

18. The non-transitory computer-readable medium according to claim 17, wherein the predetermined value equals 2.

19. The non-transitory computer-readable medium according to claim 13, wherein the storage system is at least one of a hard disk drive, a compact disc, a digital video disc, and a tape drive.