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Tue, October 23, 2018

NCHC’s Remote Crack-measuring System A world first technology that is easy to operate, fast, and low cost2016/07/22

Earthquakes frequently occur in Taiwan, have any small cracks appeared in your home after a major earthquake? Will these cracks affect the seismic resistance of your house? How do we verify that our house is safe?

Over a thousand felt earthquakes occur in Taiwan every year because Taiwan is located on a seismic belt, and cracks will inevitably appear in houses, buildings, dormitories, and bridges. Inspection of cracks generally involves observation and the use of measuring tools to document the width, length, position, and distribution. This information is used for an initial determination of the deterioration or damage caused to a building or bridge. Therefore, effectively measuring cracks and the timely repair of cracks are of great concern to the safety of people’s lives and assets.

The National Center for High-performance Computing (NCHC), National Center for Research on Earthquake Engineering (NCREE), and Instrument Technology Research Center (ITRC) invented the “Remote Crack-measuring System” to help the general public and professionals rapidly and effectively measure the size of cracks at a distance, so that dangerous cracks will not go unnoticed, allowing people to feel safe where they live.

A world first technology that is easy to operate, fast, and low cost

At present, most methods for measuring cracks in buildings require contact, i.e. a crack measuring device or handset measuring instrument sold in the market must be placed against the crack for measurement. Even though there are also imported instruments that can measure at a distance, they are extremely complex to operate, slow, and very expensive.

The “Remote Crack-measuring System” is the first independently developed technology in Taiwan that can measure cracks at a distance. The system utilizes the focused beam and accuracy of lasers Note 1 to project four laser beams arranged in the shape of a rectangle next to a crack, and then takes a picture of the crack and four points. Next, the image is analyzed and the length and width of the crack is calculated. This method for measuring cracks from a distance is a world first.

智慧型手機版 智慧型相機版
The remote crack-measuring system invented by NCHC.(Left: the smart phone version; Right: the smart camera version)

The “Remote Crack-measuring System” can measure cracks up to 50 meters away (roughly 15 floors high). It is easy to operate, fast, and low cost. There are currently three versions of the system, a smart phone version, smart camera version, and DSLR camera version. Users only need to download the Crackphone App developed by the NCHC and will be able to measure cracks by themselves. The App will record the length and width of the crack and provide the information to specialists who will further examine or repair the crack to ensure building safety. For professionals, the App enables them to effectively measure cracks of bridges and tall buildings that are far and hard to reach, allowing them to gain information on cracks that were originally impossible or hard to reach, thereby improving safety at home and on the road.

遠距拍攝 CrackPhone APP
When the crack is being photographed (Left), the crack and all four points of the lasers
must be in the picture. Then, the crack image is analyzed in Crackphone APP developed by NCHC (Right), enabling it to calculate the real length and width of the crack.

Crack data in the cloud allow automated notices to be sent

Many small cracks are inconspicuous at first, but once they accumulate over a period of time, they might become the cause of endangering building safety. In the light of this, the NCHC is prepared to further develop a crack system in the cloud, helping users keep track of each crack over a long period of time, and automatically compare and analyze data of the crack, sending automated notices to users when the system detects abnormal changes in one or more cracks.

The NCHC hopes to integrate this crack system with Taiwan’s geographic information system in the future, and document changes of each crack along with cracks in nearby locations. This will allow diagnosis and analysis of large or small regions, and help related departments gain information on the numerous cracks and complex changes, which will allow precautionary measures to be taken.

Both practical and academic value to ensuring living safety have been recognized

The “Remote Crack-measuring System” has gained recognition and support from the NCREE in academia and T.Y. LIN International Taiwan, CECI, and Resources Engineering Services Inc. in the industry. The NCREE has already made plans to make the crack-measuring system the crack-inspection module in its bridge disaster prevention and management system, making it a necessary tool for bridge inspections. The system has already received innovation patents in Taiwan and the U.S., and both practical and academic value of the system have been recognized as it received the highest honor in the 2015 Taipei International Invention Show – Platinum Award, 2015 Thesis Award of the Chinese Institute of Civil and Hydraulic Engineering, and 2015 Excellent Paper Award of the Chinese Society of Surveying Engineering.

The Meinong Earthquake in February this year devastated Taiwan and the earthquakes in Kumamoto, Japan and Ecuador in April caused many buildings to collapse. The government launched the home safety program and began actively carrying out inspections of old buildings. President Tsai Ing-Wen also indicated that all old buildings in Taiwan must be inspected to ensure their safety. However, there are over 750 thousand buildings and over 27 thousand old bridges in Taiwan. This is where the “Remote Crack-measuring System” developed by the NCHC comes in. The system is fast, easy to operate, low cost, and can measure cracks at a distance, and is able to save a considerable amount of human and material resources for the government, achieving more with less. With this system, people can measure cracks in their home by themselves and achieve “protect your own house,” jointly making a safer society in Taiwan.

Note: How to measure cracks at a distance

Two conditions must be satisfied to measure the length and width of cracks: The camera must be vertical to the wall and a reference scale.

The “Remote Crack-measuring System” installs lasers on the four corners of the rectangle case of a mobile phone or camera, using the lasers for positioning.

Laser can maintain a concentrated beam over a long distance, and the blue rectangle can be maintained (see figure on the right). However, in reality, the wall is not perpendicular to the photographer, and the actual laser beams on the wall are the red parallelogram (when observing the crack from a position perpendicular to the wall). Before photographing the crack, the mobile phone or camera must first be perpendicular to the wall to reset, and the mobile phone or camera will record the starting angle for taking the picture. Then turn the mobile phone or camera to photograph the crack, the mobile phone or camera will record the change in angle, and the blue rectangle will be calibrated into the red parallelogram when observing perpendicular to the wall. The image of the crack will also be adjusted to the image when observed perpendicular to the wall, which is the real image of the crack.
When photographing the crack, the crack and all four points of the lasers must be in the picture; the red parallelogram formed by the four laser beams serves as the reference scale, and the mobile phone or camera will compare the image of the crack with the red parallelogram, allowing it to calculate the real length and width of the crack.

NARLabs Media Contacts

Chang Wen-Yi, NCHC, NARLabs
Tel: 03-5776085#271 / 0958-042551
E-mail: c00wyc00@nchc.narl.org.tw

Wang Ying-Chun, NCHC, NARLabs
Tel: 03-5776085#304 / 0988-208833
E-mail: alphawang@narlabs.org.tw

Li Ming-Yang, NARLabs
Tel: 02-6630-0622 / 0931-162081
E-mail: tomlee@narlabs.org.tw

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