What Is SLS?
SLS stands for Structured Light Sensor — a technology that projects an invisible infrared grid of dots onto a space and uses a camera to map the three-dimensional structure of the environment. In paranormal investigation, SLS cameras have gained widespread popularity for their reported ability to detect and display humanoid figures that are not visible to the naked eye, rendering them as stick-figure representations on a connected screen.
How SLS Works
SLS technology was originally developed for motion-sensing gaming systems, most notably the Microsoft Kinect sensor. The device projects thousands of infrared dots into a room, and a depth sensor measures how those dots are reflected back. Software analyzes the depth data to identify shapes that match human body proportions — head, torso, limbs, and joints — and renders them as a stick figure overlay on the camera’s display. Paranormal investigators repurpose this technology by using the device in allegedly haunted locations to detect human-shaped forms that have no corresponding visible source.
Use in Investigation
During paranormal investigations, SLS cameras are typically swept across rooms, hallways, and areas of reported activity. When the software detects a humanoid shape, a colored stick figure appears on the display, often in locations where no person is standing. Investigators document these detections alongside other environmental data including EMF (Electromagnetic Field) readings, temperature measurements, and EVP (Electronic Voice Phenomenon) recording. Some investigators report that SLS figures appear to interact with the environment — sitting on furniture, waving, or moving in response to verbal prompts.
Criticism
SLS cameras face significant skeptical criticism. The software is specifically designed to find human shapes, and it can produce false positives by interpreting furniture, architectural features, clothing, and other objects as humanoid forms. The pattern-matching algorithm operates on probability rather than certainty, meaning it will occasionally “see” figures where none exist. Critics argue that without strict controls — such as thoroughly documenting all objects in a room before scanning — SLS detections cannot be considered meaningful evidence.
Related Terms
SLS cameras are part of the modern paranormal investigation toolkit alongside EMF (Electromagnetic Field) detectors, FLIR (Forward Looking Infrared) thermal imaging, REM Pods, and EVP (Electronic Voice Phenomenon) recording equipment.