Anyone with a few dollars or good credit can go and buy a laser scanner. And the truth is, they are not very difficult to operate. Similar to your iPad, they have one button, a touch screen and a battery or two, plus a place to plug in a USB. One can be out in the field doing 3D laser scanning the next day. But without experience, they may make some common mistakes. Here are five things that you should never do when attempting 3D laser scanning.
1. Touch the scanner or tripod
It may seem like common sense, but touching the scanner or tripod while performing 3D laser scanning is a big no-no. When using such a high precision instrument, the slightest movement can shift the position of the scanner and cause errors in the resulting point cloud. Even if your touch is light, this is not recommended. Perhaps you have good reason to, such as if you are doing 3D laser scanning in high wind and are worried about it tipping over. If that is the case, perhaps you should re-think whether it is wise to scan in high wind. Sometimes we have to scan in environments where there is a lot of foot traffic, and someone may kick the tripod by mistake. It is fine as long as you realize that the 3D laser scan is ruined, and you must redo that one.
2. Walk near the scanner when on non-rigid floor
There are plenty of great surfaces to do 3D laser scanning on. Grass, dirt, concrete, asphalt, all good stable surfaces. But when doing 3D laser scanning on built structures such as homes, offices, catwalks and gratings, things may be moving underfoot, and it may not be too obvious. For example, a floorboard may bend as you walk over it. If the scanner is nearby, you may cause it to shift slightly. Even in industrial environments where the 3D laser scanning instrument is on what appears to be very solid grating, you are not safe. Especially tricky is if you are on some sort of scaffolding or lift. This can move very slightly at the slightest disturbance. If you are scanning on a surface that is suspect, your best bet is to stay far away while the 3D laser scanner is doing its thing. Remote control 3D laser scanning is handy here.
3. Scan without a plan
When in a hurry, it can be tempting to bust out the scanner and hit the ground running. But a person experienced in 3D laser scanning will always take time to create a plan. This means walking the grounds and identifying the 3D laser scanning scope, and taking note of how many scans will be needed as well as planning potential scan positions. The plan is always geared toward making things easier later. You can always tell how well a 3D laser scanning plan went when doing the scan registration. A poor plan can lead to disastrous results.
4. Scan too far apart
When the scanner manufacturer tells you the range is 500 ft, it can be tempting to thing that it is possible to take large jumps in scan positions. But the truth is that regardless of the scanner’s range, there is usually a limit to how far apart you can take the scans and still be able to obtain an accurate registration. It has more to do with objects in the environment than the scanner’s range. If you are scanning the grand canyon using Leica’s P50 which has incredible range, perhaps you could take huge jumps and still find a registration. But the typical scan is not like the Grand Canyon, and has many corners and obstacles to get around. The tripod height is also a factor if you want continuous coverage on the ground.
5. Take scans that are too big
This is probably the most common rookie mistake when doing 3D laser scanning. It comes from a desire to do a good job and be thorough. If you don’t have a good feel for what minimum resolution is needed for any situation, there is a tendency to take scans that are too large. This may seem prudent while in the field, but you pay for it later when processing. It can needlessly add a lot of time to the processing. The file sizes will be bigger than needed, making every step in the process more cumbersome than necessary, and with no real benefit.
3D laser scanning – getting it right
3D laser scanning is not hard, but if done wrong can be a complete waste of time and money. If you’d like to enjoy all the benefits of scanning without the hassle, let us do the work for youGive us a call and we’d love to discuss potential opportunities to benefit your business.
