Method and device for inspecting surface

• US 9,113,048 B2
• Filed: 01/05/2011
• Issued: 08/18/2015
• Est. Priority Date: 10/04/2010
• Status: Expired due to Fees

• Current Assignee: National Taiwan University (Government of The Republic of China)
• Original Assignee: National Taiwan University (Government of The Republic of China)
• Inventors: Kang, Shih-Chung, Su, Yung-Shuen
• Primary Examiner(s): LI, TRACY Y
• Application Number:
  US12/985,095
• Publication Number:
  US 20120081541A1
• Time in Patent Office: 1,686 Days
• Field of Search: 348/48
• US Class Current: 1/1
• CPC Class Codes: H04N 7/183 for receiving images from a single remote source

Abstract

A surface inspecting device is provided in the present application. The surface inspecting device includes a pair of light modules respectively providing flashes to a surface from two different angles in sequence; an image sensing module acquiring an image of the surface upon a respective one of the flashes; and a computing module electrically connected with the image sensing module and processing the image by an image subtraction algorithm.

Claims

1. A pavement surface inspecting device used in a civil engineering field for inspecting a road surface, comprising:

a pair of light modules being sequentially activated and providing flash lights incident to a pavement surface from two different incident angles, to cause an unevenness distributed with an irregular region on the pavement surface to be exposed on the pavement surface in a form of a light shadow, in which the incident angles are independent of the unevenness;

an image sensing module being activated to acquire images of the pavement surface while one of the light modules are activated, which images contain the light shadow for the unevenness shown on the pavement surface; and

a computing module electrically connected with the image sensing module, receiving the acquired images, transforming the respective acquired images into a digital grayscale image consisting of a plurality of grayscale pixels, each of which grayscale pixels have a grayscale value, subtracting pixel by pixel one of the transformed digital grayscale images from the other to generate a single processed image consisting of a plurality of processed pixels, each of which processed pixels have a discrepant value and among which processed pixels the multiple pixels have the discrepant value greater than a threshold are identified as uneven pixels, and determining the irregular region on the pavement surface to which the uneven pixels are corresponding as an uneven region on the pavement surface.

2. The device according to claim 1 further comprising a control module switching on and off the pair of light modules and the image sensing module.

3. The device according to claim 2 further comprising a mobile vehicle carrying and moving the pair of light modules, the control module, the image sensing module and the computing module.

4. The device according to claim 3, wherein the mobile vehicle is one selected from a group consisting of an engineering mobile platform, a smart inspecting vehicle, a miniature inspecting vehicle, a robot, a wheeled vehicle, a tracked vehicle and a combination thereof.

5. The device according to claim 1, wherein the pair of light modules are one selected from a group consisting of a light bulb, a light tube, a flash light, an LED and a combination thereof.

6. The device according to claim 1, wherein the image sensing module is one selected from a group consisting of a digital camera, a digital video camera, a web cam, an image sensor having a photosensitive element and a combination thereof.

7. The device according to claim 1, wherein the computing module is one selected from a group consisting of a notebook computer, a laptop computer, a personal computer, a web server, a computing host, an embedded computing system, a cloud computing system and a combination thereof.

8. A pavement surface inspecting device used in a civil engineering field for inspecting a road surface, comprising:

a plurality of lights being activated sequentially and providing multiple illuminations from different incident angles incident to a pavement surface to cause an unevenness distributed with an irregular region on the pavement surface to be exposed on the pavement surface in a form of a light shadow, in which the incident angles are unassociated with the unevenness;

an image sensor being activated to form images of the pavement surface while a respective one of the multiple illuminations are activated, which images contain the light shadow for the unevenness shown on the pavement surface; and

a computing unit electrically connected with the image sensor, receiving the acquired images, transforming the formed images into a respective digital grayscale image consisting of a plurality of grayscale pixels, each of which pixels have a grayscale value, and subtracting pixel by pixel one out of the transformed digital grayscale images from the other to generate a single processed image consisting of a plurality of processed pixels, each of which processed pixels have a discrepant value and among which processed pixels the multiple pixels have the discrepant value greater than a threshold are identified as uneven pixels, and determining the irregular region on the pavement surface to which the uneven pixels are corresponding as an uneven region on the pavement surface.

9. A pavement surface inspecting method used in a civil engineering field for inspecting a road surface, comprising:

acquiring at least two images for a pavement surface lightened by flash lights incident from different incident angles in sequence to cause an unevenness distributed with an irregular region on the pavement surface to be exposed on the pavement surface in a form of a light shadow, which at least two images contain the light shadow for the unevenness shown on the pavement surface, in which the incident angles are unassociated with the unevenness;

transforming the acquired at least two images into a respective digital grayscale image consisting of a plurality of grayscale pixels, each of which grayscale pixels have a grayscale value; and

subtracting pixel by pixel one out of the at least two transformed digital grayscale images from the other to generate a single processed image consisting of a plurality of processed pixels, each of which processed pixels have a discrepant value and among which processed pixels the multiple pixels have the discrepant value greater than a threshold are identified as uneven pixels; and

determining the irregular region on the pavement surface to which the uneven pixels are corresponding as an uneven region on the pavement surface.

10. The method according to claim 9, wherein the acquiring step is performed by using a image sensor, and the transforming, subtracting and determining steps are performed by using a digital computing module.