Ring Laser Scanner

Ring Laser

WinCan can be optionally configured with WinCan LaserScan, which is a module that allows the user to capture 3D pipe geometry. There are a number of applications for this module and the data can be used a number of ways. This section will cover how to configure the DT340 with the required equipment, how to configure the software, and how to process the data. For more information on using WinCan, refer to “WinCan Software Integration” prior to reading this section. 

This option will ship with: 

• one laser module (complete with 3 AAA batteries)

• Laser module mount

• 1 Calibration ruler

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Preparing the Crawler 

The crawler will need to be outfitted with the laser attachment prior to deploying the crawler. Note that the scanner will function best with an elevating arm and the standard 340 wheels. It may be easiest to assemble the crawler with the elevating arm in the fully upright position.

Begin by attaching laser module to the chosen camera head (PTZ) as shown below

Laser Module 

The laser module included in the laser scanner kit has been pressure tested and certified to operate at depths of up to 50M (164ft). It comes ready to operate out of the box. The battery pack has been isolated with a film to prevent accidental activation during shipping. To remove this film, unscrew the rear cap and remove it from the spring contact.

To turn the laser on, tighten the laser until the cap is tight. The cap should contact the body of the laser. To turn it off, simply unscrew the cap. 

Maintenance on the laser module is minimal. The battery life should provide at least 15 hours of operation, at which point 3X AAA batteries are required to replace the depleted ones. To replace the batteries, remove the rear cap fully and slide the battery pack out. Ensure to maintain the correct orientation when placing the pack back into the laser. If the cap becomes difficult to tighten over time, it may need to be lubricated around the sealing O-ring on the cap. To do this, simply apply a small amount of Molykote 111 or another silicone-based grease.

There should never be a need to remove any screws or components from the laser module. The module is designed to be resilient, however, if there are any signs of water ingress, contact Deep Trekker support.

Performing a Pipe Scan

By this point, the crawler should be plugged into the controller and reel, powered on, and the laser installed and ready (do not turn on the laser until right before deploying the crawler). It is important to test the WinCan software prior to launching the crawler. Follow the instructions in “WinCan Software Integration” to configure the crawler. Once configured, test the recording. Assuming the test has produced a functional video file, deploy the crawler into the pipe. 

Beginning at any section, set the camera to its home position (straight ahead with no tilt or zoom), reset the OSD distance to “0”, and begin recording. Disable all lighting: a darker environment produces better contrast and a better overall scan. Drive ahead at a constant speed. For long sections of pipe, using the “cruise control” function is recommended. 

When finished with a section, do not disable the recording. Reel in the crawler and pull it onto the surface. Place the calibration ruler around the knob on the laser tip as shown and hold it there. This image will be used as a still frame later to calibrate the scan. This step can be done before deploying the crawler if preferred.

Processing a Pipe Scan

Assuming the section has been captured in a recording adequately, the scan can now be processed. To do this, launch the WinCan LaserScan module. It is found under extended modules.

Notice: For an in depth understanding of each function and how to get the most out of the LaserScan module, an on-board manual is included with the software. To access it, simply navigate to “Help” as shown. This manual provides detailed step-by-step instructions on each individual function. The purpose of this section of the manual is to provide the user with a baseline on how to create their first scan.

Assuming an MP4 file has been recorded, the module should open. Begin by calibrating the video. To do this, scrub through the video to find the frames where the calibration ruler was displayed. Select “Calibration” from the top menu, then “calibrate by mouse clicks”.

The software will instruct the user to click on the calibration ruler at the intervals. Select points on the ruler as shown.

Next, the centre of the laser and those points will need to be defined. The centre should be automatically detected, however, ensure that each circle corresponds with the correct diametrical measurement on the ruler. Notice how in the provided image below, the 200mm diameter corresponds with the 100mm radius, the 400mm diameter with the 200mm radius, etc.

The calibration can be verified by scrubbing to a point in the video and ensuring the detected pipe radius corresponds with the expected pipe size. 

Next, the scan settings should be adjusted. Begin by setting the start and end time to the beginning and end of the scan. This will temporarily crop the video file for rendering the scan. Set the start time to the 0000.0M mark, and the end time to the point at which the crawler was stopped. Next, customize the scan settings. 

As shown below, there are two major settings that will need to be adjusted for each scan: scan properties, and image filtration. The properties will allow the user to filter out noise such as reflections and residual water, while the image filtration will help create better contrast for the software. While customization of each scan will require individual settings, a breakdown of each setting is given below to help in this process:

• Scan Step Distance: Modifies distance between two cross sectional measurements. A lower number will increase accuracy and scan time. This number can be adjusted to compensate for a particularly dirty pipe.

• Points on a circle: Modifies the number of points on a circle. A larger number of points will increase accuracy and scan time.

• Min Radius: the minimum radius expected in the pipe (in %). Defining this will prevent reflections from further down the pipe from interfering. This will need to be adjusted depending on the size of the ring in the pipe. 

• Max Radius: the maximum radius expected in the pipe (in %). Defining this will prevent reflections closer to the camera head from interfering.

• Ignore Clock Angle: will ignore data from a given range. Clock defines position, while angle defines the angle of exclusion on either side. This is important to define around the rods and residual water in the bottom of the pipe. 

An example of a scan with correctly adjusted settings is shown below. Note that the radii found is above 80%, which is reasonable considering over 10% is excluded. Note the ovality is 3.6%. If the software returns an ovality number that is unreasonably high, it is likely it is not detecting the radius of the pipe correctly and the settings must be adjusted further. 

To adjust image filtration, use the settings as described:

• The value for Contrast is increased (value > 1) or decreases (value < 1) the contrast. Standard value is 1.0 (= no contrast change).

• The value for Brightness increases or decreases the luminosity of the image. Standard value is 0 (= no brightness change).

The color image will be converted to a grayscale image with gray values between 0

(black) and 255 (white). There are now two types of thresholds to choose from.

• Red Threshold: With this option Red color component is used as threshold. This option makes only sense if the laser ring is clearly red and the pipe walls are not red. This option makes e.g. sense in black PVC pipes with white chalk spots that reflect brighter than the red laser ring.

• Gray Threshold: With this option brightness is used for the grayscale conversion. Automatic by %: With this option on the Gray threshold will be set automatically by the percentage of remaining Gray pixels. With a percentage of e.g. 1.0% the threshold is set so that 1.0% of the pixels remain in grayscale and the rest (99%) are converted to black. With this option set the settings of the contrast and brightness do have a lot less influence. By default this option is turned on.

Once these settings have been fully defined, the scan can be started by selecting “start scan”. Make sure to scrub to the beginning of the video file prior to starting. The scan will output several files, including a PDF deliverable. The report will contain data on all deformities and ovality, and using the software, the user will be able to navigate to any detected deformities and view the un-processed image to make a visual inspection. The data generated by the software can be exported and used in a number of ways, including 3D reconstruction.

For more details on the full capabilities of the LaserScan module, consult the on-board manual.