Our works. Publication of the most interesting works performed by our experts.

28.09.2020

Our works. Publication of the most interesting works performed by our experts.

Determination of grain volumes in silos and flat warehouses by means of laser scanning.

Our company has received an offer from one of the largest grain processing companies in Ukraine to carry out measurement work at the grain processing terminal. The offers were also sent to other companies. The main criteria for choosing an inspection company for performing measurement work were:

  1. Experience in performing similar work.
  2. Carrying out measurement works in the shortest possible time, since to complete these works it was necessary to stop the work of the grain processing terminal.
  3. High accuracy of measurement work.

Our company was selected and received a request for the execution of these works for the following reasons:

  1. Extensive experience in performing similar work.
  2. The ability to carry out measurement work in the shortest possible time due to the use of the Leica RTC360 laser scanner, since it is currently the fastest scanner in the world and performs 3D reality capture at a speed that was unattainable before. Measuring up to 2M points per second and advanced HDR image capture, the scanner generates 3D color point clouds in less than two minutes. Automated, stamp-free field data logging based on VIS technology further accelerates fieldwork and increases productivity. Combined with Cyclone FIELD 360 software for automatic data logging in the field, the Leica RTC360 scanner delivers incredible accuracy that can be verified on site. In comparison with other inspection companies, we got an advantage, since they usually use the simplest means of determining the level of filling of silos and floor warehouses with grain – laser rangefinders, which allow determining only the average filling level of a silo or warehouse, but they do not provide either the shape of the mound or the exact consideration of the size and shape of the silo or warehouse and, as a result, there is a large measurement error.
  3. The presence of a measuring department created specifically at the company’s laboratory.
  4. Highly qualified staff.
  5. Methodology for performing this type of work.

The only measuring tool that gives a high-precision ability to measure the inside of silos and warehouses is a 3D laser scanner. The achievable accuracy of determining the volume of grain in silos by laser scanning is 0.1%, provided there is a possibility of preliminary shooting of empty silos from the inside and building their accurate 3D models, and for flat warehouses – up to 1%.

Measurement work to determine the volume of grain in silos

To determine the filling level of the silos and the shape of the “reverse cone” of the grain embankment in the silos, there was only single possibility – to carry out a 3D laser scan of the interior of each silo through a special inspection hatch located on the border of the upper cone / roof and the vertical wall of the silo.

It took about 2 minutes to prepare for the scan and another 3 minutes to scan each silo, excluding the time required to get to the inspection hatch. During the scanning of each silo with a Leica RTC360 laser scanner, about 240 million measurements of the grain surface were made.

Data processing, 3D modeling and calculation of grain volumes in silos

After field work at the facility, we completed the office stage of this work. Laser scanning results were processed using Leica Cyclone software. Further, a set of works was performed for each of the scanned silos, which included cleaning the obtained data from extraneous noise, thinning point clouds for modeling, building accurate 3D models of grain heap surfaces, calculating grain volumes by calculating the volumes of the resulting geometric shapes from the top surface of the heaps to the bottom each silo. At the final stage, our specialists compiled a detailed report on the results of measurement work and the calculation of grain volumes in silos, which included a description of the types of work, 3D models of all grain piles in each silo and the results of calculating the grain volumes in each silo.

Measurement work to determine the volume of grain in the warehouse

When inspecting the warehouse prior to carrying out the measurement work, we faced the fact that the warehouse was almost full to its full capacity and it was not possible to perform a floor scan of the warehouse – the only way to perform the measurement work was scanning from the viewing gallery. Thus, it was necessary to tinker on-site a mount for the scanner, since the use of the scanner provides for the possibility of shooting in an inverted form, the scanner was fixed between the structures of the conveyor belt and the gallery, after which scanning was performed.

Time spent for preparation and scanning:
Eight scanning stations were performed, the scanning time for one station was 3 minutes. The preparation time for scanning was about 3 minutes, since it was necessary to place the scanner between the conveyor belt structure and the gallery. The total time was about 1 hour. During the scanning of the grain warehouse with the Leica RTC360 laser scanner, 1,920 million measurements of the grain surface in the warehouse were made with a step of 3 mm. For comparison, using traditional measurement methods by rangefinders or tacheometers, it would take more than a dozen years to take such a number of measurements of the grain surface in a warehouse with a step of 3 mm and determine the volume with the same accuracy. Experts of our company, using a Leica RTC360 laser scanner, performed these measurements in 24 minutes, excluding the preparation time for scanning.
Unlike measuring the volume of grain crops in a warehouse using tacheometers or laser rangefinders, 3D laser scanning technology allows you to measure and reflect the shape of the surface of the material in the warehouse in detail, with a step of up to millimeters. Such detail of measurements with a 3D laser scanner allows obtaining measurement accuracy that is unattainable when using any other existing measurement technology. Summarizing the above, we can safely say that the higher the density of measurement points, the more accurate the measurement will be and the volume of grain in the warehouse will be determined.

Data processing, 3D modeling and calculation of grain volumes in silos

After field work at the facility, we completed the office stage of this work. Laser scanning results were processed using Leica Cyclone software. Further, a set of works was performed for each of the scanned silos, which included cleaning the obtained data from extraneous noise, thinning point clouds for modeling, building accurate 3D models of grain heap surfaces, calculating grain volumes by calculating the volumes of the resulting geometric shapes from the top surface of the heaps to the bottom each silo.

At the final stage, our specialists compiled a detailed report on the results of measurement work and the calculation of grain volumes in silos, which included a description of the types of work, 3D models of all grain piles in each silo and the results of calculating the grain volumes in each silo.