3D terrestrial laser scanning elevates forensics investigations to a whole new level

By QUAH BengChieh, Head of Marketing, FARO Asia Pacific

‘Every contact leaves a trace’. Locard’s Exchange Principle – as formulated in the early 20^th century by Dr. Edmund Locard, a French scientist and criminologist who had studied law and medicine –continues to influence crime scene investigations today. Forensic scientists and investigators play a pivotal role in ensuring justice is served in courts of law. Whether in a criminal case or the civil court, they are often called upon to present their professional, independent analysis of a crime or crash scene.

For most crime scene or accident investigators, the current work protocol – which includes the documentation of the crime scene, preservation and collection of evidence and manual recording of measurements – is not just laborious and time-consuming, but also prone to human error. More importantly, the intrusive nature of these traditional tools (e.g. tape measure, measuring wheel, still photo/video cameras) increases the likelihood of evidence contamination.

In recent years, technological advances in the areas of three-dimensional (3D) terrestrial laser scanning (TLS) and 3D documentation are allowing forensic professionals to do much more in a shorter time than ever before.3D documentation involves capturing accurate 3D geometry and images of real objects that are reproducible at a certain point in time, and then saving it as an informational model. These models are digital representations of the object or environment of interest in its current, true state.3D TLS minimizes the chance of evidence subjected to compromise, and it is one of the most popular methods that practitioners rely on to collect data today.

Benefits of 3D Terrestrial Laser Scanning in Forensic Investigations

Here are some ways in which forensic scientists have benefited from using 3D TLS in their crime scene investigations:

1. Speed Up the Data Acquisition Process

Today’s 3D laser scanners are capable of acquiring large volumes of data at extremely high speeds, creating high-fidelity, virtual copies of reality with millimeter accuracy. What this means for forensic scientists is that the scene of a crime or accident can be captured in a shorter time and in much greater detail. A task that used to take multiple personnel several hours to measure, can now be completed in minutes, with just the touch of a button. With a laser scanner, road closure scan be cleared more quickly, crime scenes are documented sooner, and fire investigators can reduce their exposure to health hazards that are typically present in a fire scene.

2. Avoid a Situation of Compromised Evidence/Scenes

When it comes to the investigation of a crime, crash, or fire scene, there is great value in preserving every single detail that can potentially shed light on the cause of the incident. Ideally, forensic scientists should get to work with images and spatial data that reflect evidence in the exact condition and location it was in when discovered by the first responder.

The reality is, the scene of an incident changes rapidly as vehicles or victims are removed and debris is cleared.Exposure to natural elements also affects the ability to view tiny details.The use of a 3D laser scanner ensures that the entire scene is accurately preserved, exactly as it appeared at the time of the scan.

3D TLS also offers non-contact scanning capabilities that eliminate these concerns. The technology’s ability to reproduce highly accurate 3D models and capture photo realistic 3D color scans takes some pressure off the forensic scientist on duty, since they do not have to decide at the scene exactly what details might be important to the case. The laser scanner ensures that a crime scene is fully preserved, documenting even seemingly irrelevant detail that might not fit an investigator’s initial judgment or hypothesis. In this regard, the laser scanner becomes an ‘impartial observer’ that documents an entire scene as it is,with the result providing a reliable account that stands up to courtroom scrutiny.

3. Revisit Evidence or Reconstruct a Scene

Once captured, a crime or crash scene is digitally preserved forever. Whether an incident occurred 3 hours, 3 days, or 3 years ago, a forensic scientist can review critical evidence at any time or retrieve data to present an animated and interactive reconstruction of the scene. Details such as blood spatter, bullet trajectory, and lines of sight can be examined and extracted from the point cloud data that was captured by the laser scanner. The objective evidence collected by the 3D laser scanner easily becomes the basis of a variety of compelling courtroom materials, including diagrams, animations, and walk-throughs.If a case goes to court, the investigator can even take everyone in the courtroom on a 300˚ × 360˚ walkthrough of the scene.

4. Store & Share Information with Collaborating Experts

Scanning a crime scene also allows investigators from various departments or different locations to view and analyze the same case simultaneously. Point cloud data can be shared in a variety of formats that are compatible with many software applications. Discussions and information sharing can take place in real-time, and analyses of different aspects of a case can be done concurrently, improving efficiency levels by leaps and bounds.

Success Stories of FARO Customers

• Significant Savings for Inter-Agency Investigation Team with 3D Laser Technology

The Clackamas County Sheriff’s Officein Oregon, USA, leads an inter-agency group known as the Criminal Reconstruction and Forensic Team (CRAFT), which includes reconstructionists from eight different police agencies. In the past, the team used a total station to map crash scenes and a handheld distance meter for interior scenes. Today, their measurement device of choice is a FARO^® Laser Scanner Focus^3D X 330.

Criminalist Bryon O’Neil commented on the effectiveness of the FARO scanner incapturing crash and crime scenes. “By using the scanner, we spend less time on the scene, we obtain better data, and we can use a smaller crew. I prefer to have two people to set targets and move the scanner, but, if necessary, I can do it all myself.” O’Neil calculated that using the FARO Focus^3D X 330 scanner has saved the Clackamas County Sheriff’s Office (CCSO) more than $50,000 in overtime hours in just 24months of operation.

CCSO investigators utilize the data that they capture with the Focus^3D X 330 scanner to create crash animations in FARO^® Crash Zone software.The data points indicating the start and end of skid marks or gouges, marked by evidence placards, are used in the creation of the animation in Crash Zone. The virtual vehicles are made to pass through the data points, allowing the team to step through the animation and verify its accuracy.

As an inter-agency team of one full-timer and 18 on-call reconstructionists, CRAFT is traditionally called on to investigate fatal and serious-injury crashes in Clackamas County and to assist with crime-scene investigations. Since investing in the Focus^3D X 330, CRAFT can now handle more investigations than ever before.

CRAFT is now called out to scan scenes whenever there is an officer-involved shooting, an officer-involved crash, or where a county or city liability may exist. The scanner provides the investigators with a unique ability to accurately verify line of sight issues in a crash or shooting incident. According to Criminalist O’Neil, “In an officer-involved shooting, you can position the view of the point cloud to be at the officer’s eye level. As you move through the cloud, you can see the scene exactly as they saw it.”

O’Neil and CRAFT were called out to investigate an incident where a Portland TriMet bus hit a skateboarder, who sustained serious injuries. While it might have been easy to believe that the bus driver was at fault, the point cloud captured at the scene and O’Neil’s analysis proved otherwise. “I was able to show that it was the fault of the skateboarder – not the bus driver,” explained O’Neil. With the evidence exposed, the case did not go to court, potentially saving the city from an expensive liability case.

The Focus^3D X 330 scanner has become so important to CRAFT’s investigations that the agency has taken special precautions to make sure that they are never without access to a scanner while on the job.

• Accident Reconstruction Studies Help Car Manufacturers Improve Vehicle Safety

Shanghai-based Tongji University (Tongji) is one of China’s leading universities that offers diverse courses ranging from hard sciences to liberal arts. The College of Automotive Engineering (CAE), one of the schools within Tongji, shaped its programs to be industry-relevant through partnerships with various local companies. In return, the college then offers its academic expertise, actively involving itself in research for the Chinese automotive industry. At Tongji CAE, the analysis of traffic accidents is a key focus area of research.

Professor Wang Hongyan at the College of Automotive Engineering, Tongji University, shared, “The primary motivation behind studying traffic accidents is to improve safety. With in-depth analysis, the causes of accident and injury can then be better established. We hope that a better understanding of the ‘mechanisms of injury’ behind car accidents can inspire automotive manufacturers to develop better safety features for their vehicles.”

Accident reconstructionists generally agree that four key factors are at play when analyzing any given collision: human, vehicle, road, and environment. To accurately reconstruct and study a crash, evidence collection needs to be completed quickly and thoroughly. The availability of precise, comprehensive data is therefore fundamental to the accurate analysis of the crash.

“Previously, our analysis always depended on manually drawn diagrams,” expressed Mr. Sang Xinhao, Assistant Researcher at Tongji CAE. “We relied on the traditional tape measure and largely estimated distances by eye.” With these methods, there was an inherent lack of accuracy and a wide margin for error.

The data collected limited the types of analyses that could be done, and typically required a long duration of field work time. It was clear that the team needed a better, more efficient method to deepen its data collection and research efforts.

When Prof. Wang learned about the FARO Focus^3DLaser Scanner, he was immediately attracted toits technical abilities. The new device enabled the team to capture much more data in less time than they could using previous measurement methods. “The Focus3D can perform high-fidelity scans in a matter of minutes, documenting every aspect of the actual scene so that nothing is missed,” said Mr. Sang.

The Focus^3D’s prowess translated to several benefits for the research team. First, the amount of data available for the researchers to work with increased exponentially, allowing more in-depth study of any given traffic accident. The speed at which scans were made also significantly reduced the number of hours required outdoors on field work. Time saved on collecting data onsite was then utilized more efficiently for analyzing databack in the lab.

In addition, it was now possible to capture time-sensitive evidence from crash sites. The Focus^3D can produce a completely accurate,3D model of a crashed vehicle and its surroundings within minutes. This point cloud can be used to take measurements, analyze crush, analyze skid marks, and create diagrams and animations of the crash. Using the Focus^3D also facilitates faster clean-up of accident scenes so roads can be opened quickly, preventing undesired traffic congestion.

Aside from academic pursuits, the objective scientific results can aid in police investigations and a car manufacturer’s product development process. “We are proud to be able to contribute back to the society in more ways than one,” expressed Prof. Wang. “We hope our research efforts will continue to benefit and impact others in time to come.”

Further information: www.faro.com/sg