When the FARO Focus3D laser scanner was introduced in October 2010, our firm was intrigued. The word on the street was that that the scanner was smaller than other systems, scanned at high speeds, and was being introduced in the $40,000 range–a price that could open scanning to a much larger market. We jumped at the chance to review the scanner in person.
A FARO sales representative traveled to our office in Tallahassee, Fla., in mid-November so we could spend some time using the equipment. I was shocked by how small the unit is when I walked into the room. FARO’s marketing photos show the unit standing alone, which makes it difficult to gauge the size. The scanner measures 9.5 x 8 x 4 inches and weighs just 11 pounds. The photo below shows the unit next to a laptop computer for comparison.
We began by examining the unit and reviewing its specifications. The Focus3D is a phase-based system, and the model we tested was the Focus3D 120, an indoor/outdoor unit with a stated range of 120 meters (394 feet). The standard system comes in a pelican case containing the scanner head, battery, external power supply and cable, AC power cable, SD memory card and card reader, laser safety goggles (FARO recommends wearing the goggles while operating the unit), a quick start guide, and a Scene software CD. FARO suggests using a Gitzo carbon fiber camera tripod with a 3/8-inch mounting screw, and that is what we used for the demo. This tripod is very light and also has a 360-degree ring on the base that can be used to help aim the unit.
The exterior case looks solid and seems like it would withstand the abuse of a typical survey crew. The scanner is powered by an on-board rechargeable lithium-ion battery that provides five hours of scan time. The battery can quick-charge in one hour, and a car adapter is also available. The scanner has an integrated 2-megapixel color camera that is coaxial with the laser (it uses the same mirror as the laser). It produces a 70-megapixel color overlay using 84 photos to cover the field of view (360 x 305 degrees). The collected data is stored on an SD card.
Anyone who is familiar with scanners would likely find this system very easy to use. The scanner is driven by a touchscreen graphical user interface (GUI) on the side of the unit that is about the size of an iPhone and can be operated with a finger or stylus. Although the unit we tested was not Wi-Fi enabled, FARO said future units would include Wi-Fi capabilities.
After less than half an hour working with the FARO representative, we had covered most of the system functions and were ready to start testing the unit.
We first did a quick scan inside our office. It was very easy to select all the scanning parameters on the GUI. The parameters can be selected individually or by using a preset profile. These profiles can also be customized and set to the user’s needs by adjusting options such as resolution, quality and scan range; selecting scan with color; and using filters called Clear Contour and Clear Sky. The scan is then started at the push of a button. One feature we liked is that the unit can be set to emit audible tones as it runs so you know when it’s scanning and, better yet, when it’s done.
The scanner collects data very rapidly. Our initial test scan was complete in approximately six minutes, and the color photos were acquired two minutes later. We were immediately able to preview the scanned data on the scanner screen in a flattened panoramic view.
Next, we scanned some areas outside our office building. It was a bright, calm, sunny day with low humidity and temperatures in the mid-60s. With these conditions, we had an operational range of less than 100 feet for the acquisition of targets and data collected on the ground. We also collected data on buildings and other features at ranges averaging about 150 feet. The Focus3D uses spherical targets that can be purchased in two different sizes, and four to six targets are required per scan. We spread the targets out approximately 50 to 90 feet from the scanner. The targets are scanned as part of the overall scene, not individually. Individual scans to targets or detail areas from the same setup are stored as separate scans. FARO’s Scene software automatically detects the sphere targets and registers multiple setups together. We also noted that the Focus3D has a 5-degree inclinometer that can be viewed using the GUI, but it does not have a vertical compensator, so vertical adjustment must be addressed with the targets and post processing.
We again opted to use a preset scanner profile for our scan parameters. Once again, the entire scan was completed with color photos in eight minutes. The unit was very easy to pick up and move to the next position while still on the tripod. We completed three full scans in less than 30 minutes and covered about 150 feet of roadway and one corner of our parking lot. Scanning a larger area under the same ambient conditions would have required more setups and multiple-target requirements compared to most of the time-of-flight scanners we have worked with; however, the scans were captured rapidly with the phase-based system, so there is a trade-off between range and scan speed.
The scans were easily transferred by removing the SD card form the scanner and copying all data files directly to a laptop running FARO Scene. The Focus3D we tested had a 32-gigabyte SD card, but the system can use an SD card up to 64 gigabytes. The file sizes for the data collected depend on the scan speed and scan settings. The Focus3D can scan at 122,000, 244,000, 488,000 or 976,000 points per second. A typical setup (122,000 pps) for the scanner collects about 120 megabytes, but it can go up to 216 megabytes per scan at the high-resolution setting with full-color photos.
For the outdoor scans, we tested the Clear Sky and Clear Contour filters. Clear Sky removes noise created by interference with the sun and seemed to work as intended. Clear Contour filters the points that show up when the laser splits along edges of objects and causes trailing points.
After the scans were completed, the FARO rep used our existing point cloud software to import, register and export the data collected for our review. We did not evaluate FARO’s Scene software. However, the FARO rep did demonstrate some of the software’s capabilities, including a dynamic range feature that provides an automatic adjustment for brightness to improve the color balance of the photos taken by the scanner. The photos from our test scans were very good. The photo data are placed over phase-based data, so the point density is very close. (In fact, at some of the high settings with this scanner, you can have more point data than color pixels from the photo.) Adding the color from the photos appears to be easy to do with the Scene software, but it could be time-consuming on datasets containing multiple setups.
We only ran the system for part of one day, and we didn’t test it in any adverse weather conditions. The user manual states that the Focus3D should not be exposed to rain or moisture and should not be operated when the humidity exceeds 80 percent; however, FARO provided us with data indicating that the scanner has been successfully tested in 100 percent humidity in harsh underground tunnel boring conditions. The unit’s shorter outdoor scan range could limit the use of the system in some applications. But as with all equipment, it’s important to evaluate the system carefully against your goals and requirements.
Overall, the unit’s small size, speed and lower investment cost compared to other systems on the market are sure to make it attractive for some applications, particularly for forensic mapping and interior mapping. The introduction of the Focus3D has opened a new market for scanning by making the technology more affordable. It also makes it imperative to understand the limitations of each type of scanner on the market and carefully weigh which factors are important to you before making a purchase.
For more details about the FARO Focus3D Laser Scanner, visit www.faro.com/focus/us.