One of the biggest obstacles when researching laser scanners is that there is no published set of standards for the performance of any given laser scanner from a trusted party like the National Institute for Standards and Technology (NIST).
While NIST has published a Landscape Study on 3D Crime Scene Scanning Devices, which outlines some basic performance and policy standards, it remains difficult for public safety users to judge one model against another. Even though some manufacturers have prudently carried common surveying technology standards over to their laser scanner lines, other manufacturers have not. Accuracy and performance categories used in data sheets and other literature sometimes have no basis in any other industry or application. And if you can’t compare spec sheets, how are you going to make an informed decision?
That’s why vendor demonstrations are key. Even then, not all demos show the capabilities of an instrument in public safety applications. In fact, they often don’t, and agencies discover too late that the implementation of the manufacturer’s workflow is not as advertised and certainly not as easy as they anticipated. Worse yet, this realization can sour an agency’s perception on the value of 3D documentation and limit how often the equipment gets deployed.
But if you follow these important do’s and don’ts, you’ll get the quality demonstration your agency deserves and needs to make a well-informed decision. (Note: While we’re specifically talking about laser scanners here, the same guidelines can also be applied to demos of other digital scene documentation technologies to ensure you get the best solution for your agency.)
DON’T Take the Specification Sheet at Face Value
When reviewing manufacturer spec sheets, a little investigation and interrogation will help you reach an informed decision. Look for vertical and horizontal angular accuracy figures. Look for 3D positional/point accuracy. Read the specs with asterisks very carefully, and question the need for “extended” or complex qualifiers alongside specifications like temperature range.
DO Schedule Back-to-Back Demonstrations with Multiple Vendors
To get a well-rounded perspective of what’s out there and what’s possible with each device, get demonstrations from at least three or four manufacturers. Certainly get more than one. Back-to-back demos are ideal as they give you a really good feel for how different scanners operate in the exact same environment on the exact same day. If that’s not possible, schedule demos over two consecutive days so your memory is fresh. It’s also best to have the same observers from your agency at each demonstration.
DON’T Let the Vendor Control the Demonstration Environment
Often, vendor-led demonstrations consist of two or three scans of a conference room, and they’re done. The problem is that demos done in a single room or in a very small geographic area don’t require any kind of sophisticated scanner operation or registration techniques to truly test the viability of that equipment in real-life applications.
For that reason, the vendor should never control the demonstration environment. Rather, present your vendor with a scene to scan that is relatively complex. Make the vendor work for it. You can be sure that a vendor who’s not worried about the environment they’re going to have to work in is confident that their equipment works in any environment. Even better, the vendor that takes your complex assignment in stride is properly trained to get the best out of their equipment in any environment–and likely to give you sound advice.
DO Create a Real-to-Life Demonstration Environment
To get a true picture of how the scanner is going to operate in difficult environments, develop a scenario-based demonstration around the primary uses of your laser scanner. The 30 minutes you’ll invest in setting up a mock crime or collision scene will pay huge dividends on the back end.
If you intend to use the laser scanner primarily for crime reconstruction, set up a mock crime scene that involves indoor and outdoor elements. Scatter items throughout the scene that you’d commonly document, including bullet path trajectory rods and evidence placards. Make sure to set up an environment that requires the vendor to transition between indoor and outdoor environments as well as between one room and another across thresholds. If possible, include stairwells. Transitions between rooms and elevations provide one of the easiest ways to test the capabilities of the registration software, which I’ll explain shortly.
For crash-based use of laser scanner data, set up a vehicle in an open area of roadway. I suggest a large parking lot with a police vehicle that’s been used to establish 20 or 30 feet of skid marks. Vendors should have to traverse at least 600 feet/200 meters of open area to simulate a significant crash event. It should be an open area because oftentimes, even in urban environments, when you’re doing a crash on an interstate, there aren’t a lot of houses or manmade structures close by that would help you register the data. This type of scenario will help you judge how well the laser scanner captures the physical characteristics of the roadway that need to be documented in order to do a proper crash reconstruction.
If you have concerns about the all-weather capabilities of the laser scanner, consider using a water hose or sprinkler to simulate your own rainstorm during the demonstration. The scanner could also be cold-soaked in a freezer or refrigerator for an hour prior to startup to test the robustness of the system.
DON’T Be a Passive Observer
You have two options when it comes to your role in a demonstration: Give the vendor a job to do and watch them do it or take a hands-on approach. Both are good options. It all depends on what kind of time investment you can make.
If you have more than a couple hours to spare, ask to operate the scanner yourself and have the vendor coach you through the scene documentation process. In my opinion, a hands-on demonstration is preferred for one important reason: If you choose to be the operator, you get to see truly how simple or difficult it is to use their equipment.
And ease-of-use is key. Some laser scanners have only three function settings, which means there are few, if any, decisions that need to be made when you operate that piece of equipment. Many manufacturers’ laser scanners have hundreds, maybe thousands, of different combinations of settings. Keep in mind that more decisions just means more opportunities to make a bad decision and more things to explain in court.
There’s another reason to focus on equipment that is easy to operate. Agencies face significant risks in taking on a complex piece of equipment. If a trained operator of a complex laser scanner were to ever leave your unit or not be available, how would you put somebody else in that position? Even if people learn how to operate it properly, that’s a difficult person to replace. That’s a lot of cost and training. Laser scanners that are easy to operate also make it easy to retrain new users and grow the pool of competent scanner operators.
DO Insist on Seeing a Registered Dataset of Your Mock Scene on the Day of the Demonstration
You shouldn’t have to wait three or four days for a finished product for your scene documentation. The laser scanner is an investment that is supposed to make your investigations better, more complete and efficient. And it’s hard to say that’s happening if you can’t get immediate results.
Registration is not an afterthought. It’s an integral part of the laser scanning workflow. Laser scanners are line-of-sight, meaning that multiple viewpoints must be captured to provide comprehensive documentation. Those individual scans are then aligned in a process called registration to create a unified 3D point cloud for the investigation.
The registration, which is typically performed with desktop post-processing software, has long been a hurdle to an efficient workflow for nontechnical users. Depending on the manufacturer and the model, registration can take anywhere from minutes to several hours. And unless the registration process is performed in front of you, you won’t know how easy or difficult it will be until it’s too late.
Require the vendor to provide a fully registered project of your scene or at least be able to show it on their computer before they leave. Don’t settle for a generic canned project shown as part of the demo. You need to see your own data in a scenario-based environment that represents the crime and collision scenes you plan to document should your agency purchase the device.
DON’T Forget About Ongoing Customer Support
The demonstration is also an opportunity to determine the vendor’s level of competence and commitment to ongoing customer support. You should be buying from people who can properly advise you on good scanning techniques for public safety applications.
Police agencies in particular have a lot of staffing turnover. Officers can retire relatively young and they can move to other units. This can be really disruptive if that one person who knows how to operate the instrument leaves your unit.
Ongoing, reliable, and 24-hour customer support is absolutely critical to the success of your program going forward. Make sure to ask about the level of tech support provided as part of your purchase. Then ask for references.
DO Make Sure Your Investment Pays Off
Certainly cost is an important consideration for any public safety agency, but it should never be the sole deciding factor. Ease of use, guaranteed scientific accuracy, speed, agility, and hardware and software compatibility are also critical factors in the cost equation.
Agencies that choose the least expensive option often pay dearly when their investment becomes underutilized due to complexity or low-quality data. In contrast, the advanced survey-grade technology found in more expensive, but still competitively priced, scanners can pay bigger dividends with ease of use and enhanced productivity.
When it comes to investing in laser scanning technology, you need to make sure your investment pays off. By following these do’s and don’ts, you’ll receive a quality demonstration that will enable you to evaluate the capability of each instrument to perform in real-world crime- and crash-scene environments.
You can learn more about laser scanners and digital scene documentation solutions here.
To discuss your agency’s scene documentation and mapping needs, please contact us.