People are paying attention to crash, crime, fire, post-blast, and forensics in general and calling for work based in science and math with quantifiable results. That is right in our wheelhouse as each of our instruments, from total stations to GPS to laser scanners – they all produce survey-grade measurements with a validated known error.
A U.S. reform in forensic science and public safety is shaping the future. Proposed legislation in the United States has had a major impact on how we consider our movement forward in administering technology in public safety and to put the science back in forensic science. No matter what your role in any public safety agency, if you are using any kind of a laser scanner, these discussions apply to you.
Leica Geosystems is a leader in the field of measurement instrumentation meeting the growing requirements for accountability. Institutes in the U.S. like the National Institute of Standards and Technology (NIST), the National Institute of Justice (NIJ), and the American Society of Crime Lab Directors (ASCLD) are establishing high thresholds and processes for acceptable use or determining error of instrumentation.
Leica Geosytems has been and will continue to be ready to face any challenges and requirements with a winning combination:
- We collect data using a sound methodology,
- Our instrumentation is tested using a rigorous methodology
- The output or product is within the threshold of the known error rate of the instrument.
As we swim into the crowded waters of the competitive laser scanning market, here are some tips to remember as you think to yourself: “Which one of these products is right for me?”
1. Public Safety folks – police, sheriff, federal, forensics, crime lab, and crime scene – you will need to scan in the rain or snow. Period. Evidence waits for no one and not every scanner will do.
The PS-series scanners will scan in the rain or snow all day every day. The world of public safety can be a matter of life or death. Sometimes the data will aid in solving the crime, sometimes it will aid in convicting the guilty or exonerating the innocent. If it’s raining and your scanner won’t scan….well, do you want to explain to your Sheriff or Chief why your fancy new tool doesn’t work when you really need it?
Use the tool that will work all the time. Be wary of what you read only on the tech data sheet – IP54 means the scanner will be fine if it gets wet. Our scanner has an enclosed mirror and will give very sound data even in the nastiest weather.
2. Scanning when it’s very cold or just plain hot. Unfortunately, we all can’t scan every project in San Diego-like conditions. When the temp nears 0° F (-18° C) or breaks past 100° F (38° C), Leica is there for you. In fact our operating temperature ranges from -5°F (-20° C) up through 122°F (50° C).
On a particular New Year’s Eve in Overland Park, KS, I had the unfortunate opportunity to work a homicide that occurred around 6am and we worked the site, completely outdoors, from about 7am to around 2pm with a morning temperature of 10° F (-12° C). The Leica ScanStation was outdoors, powered on, and intermittently collecting data through the morning. The ScanStation, never wavered or slowed and delivered on every expectation.
3. When you use the Leica ScanStation, you have validated accuracy (3mm positional accuracy at 50m/6mm positional accuracy at 100m) across the entire temperature operating spectrum.
Beware when considering the temperature operating range. Other scanners may require accessories to extend their temperature range and if so, read the fine print when making your decision. If a scanner can operate at 0° (-18° C) or 120° (-49° C) make sure their statement of accuracy applies across the entire “extended operating temperature”.
If you are going to see a demo, request that all necessary accessories for cold weather operation or hot weather operation be brought so you can see the entire equipment footprint with which you will be working.
The Leica ScanStation scanner works in the heat or the cold with no special steps or added accessories.
Laser return is a critical component of how your resulting data will actually look. When choosing a scanner, the effective range is more important than the stated range. In a scanner demo, get out of the conference room and into the real world. Inspect the resulting scans in close-up 3-D detail, look at objects and areas of your scene far down range. The ability to capture down range spatial detail is also relevant when you consider a scanner’s ability to measure down range targets.
With the Leica ScanStation, you can scan targets out to 75 to 80 meters away from the scanner.
In the snapshot above, a 1.000m Leica Twin Target Pole was placed 80 yards downfield. The target was scanned and the target was verified to be 1.000m (100% of expected value) from target center to target center.
4. A scanner out of calibration may produce a seam or vertical shift at the end of a scan along the line matching up with where it began. No matter the brand or model, ask your product rep about the possibility of a seam. If they say yes, ask them if there’s a way to compensate for it. If they say yes, have them demonstrate the process from beginning to end.
With Leica ScanStation dual-axis compensation every measured data point is corrected against gravity and the horizon using a dual-axis check at a rate of up to 1,000,000 points per second. Field conditions such as vibrations, traffic, and wind, are corrected in 1-to-1 real-time by our dual-axis liquid-filled compensator. If the scanner moves outside the compensation range the equipment lets you know!
You wouldn’t want to collect bad data and if anyone tells you that leveling the instrument isn’t important, they really aren’t shooting for survey grade results.
Ask your scanner rep: Are the collected data points corrected in real time? Or is a tilt sensor measurement applied during data import into the computer? Our motto is, “-when it has to be right” for a reason.
Check out this video to see how Jurgen Mayer elaborates below on the Leica ScanStation Dual-Axis Compensator.
Our scanner sits solid as a rock on the heavy-duty surveyor tripod and/or tripod dolly. It will scan through anything shy of a tornado.
The other scanners on the market? Well, some of them use 25 lb. gym weights hanging from huge connectors to weigh down their tripod so it won’t blow around or tip over. And remember, their scanners don’t scan in the rain. You can build a tent over the scanner however, if the weather is bad, it is likely to be also windy and a tent would quickly become a kite that can be easily blown away.
The solution to all of the above
The Leica ScanStation professional grade PS-Series Laser Scanner is the hardware built to champion the success of you, the user! The PS-series scanner is the right tool for all situations. The high-definition scanning tool that can take on any project you put in its path, rain or shine, day or night.
And there’s more! I didn’t even get to mention:
- Mixed Pixel Filtration for cleaner date/noise reduction
- The Wave Form Digitizer which ensures crisper data return from the laser
- The ability to record a high resolution scan within a parent scan
- High Dynamic Range Photography
- External camera workflows to expedite scene processing
- Software solutions that allow for seamless sharing of TruView data, full point clouds, and analysis of the point cloud data using survey programming, forensic solutions, or specialty software components that allow you to analyze the reality that you have captured.
The Leica ScanStation laser scanner is a scientific instrument with parameters that collect impeccable, survey-grade data. Leica Geosystems doesn’t cut corners and the result is durable equipment that will hold its calibration over time and perform as expected job after job.
Leica ScanStation instrumentation combined with software engineered specifically for your needs will be the most robust solution for you, your agency, and the right tool to serve your community with a huge range of public safety, infrastructure protection, and emergency management uses.
The Leica ScanStation answers the call – now. For public safety – when it has to be right…right now. Be prepared with Leica Geosystems scanning instrumentation and the expertise of the Leica Geosystems Public Safety Group.
This post was featured initially on Ryan Rezzelle’s Linkedin. To keep up to date with Ryan Rezzelle’s latest tips on Laser Scanning for Public Safety visit Ryan’s Linkedin page.
Ryan M. Rezzelle is a 16+ year crime scene and forensic investigator and now works as a 3-D laser scanning specialist, focusing on public safety and forensic science. He is a part of the Leica Geosystems Public Safety Group