Variable Frame Rate Lightboard
CALCULATE VEHICLE SPEED ACCURATELY FROM ANY SURVEILLANCE CAMERA
TIME = The new Variable Frame Rate (VFR) Lightboard provides an easy workflow to provide frame duration timing from any surveillance camera device for the speed calculation formula within a reported margin of error.
Distance = In order to establish the distance, you would use iNPUT-ACE’s Overlay Tool to produce a distance calculation from the same surveillance video.
- Simple Methodology
- Same Methodology for Every Case
- Accurate Margin of Error to the Millisecond
- Rolling Shutter Analysis
- Verified Speed & Distance Calculations
- Device Calibration Report
Video evidence from surveillance systems is not always what it appears to be. Timing is often inaccurate; frame rates are often misidentified and misleading and the method of counting frame and assuming a consistent frame rate has led many investigators to produce inaccurate measurements.
These technical limitations have forced many agencies to prohibit speed calculations from video evidence as they learned that the data can have a significant variation and compromise even the best report. It is not uncommon to see comprehensive scientific presentations being entirely dismissed over a single critical element, like misrepresenting speed through a frame rate calculation.
The new Variable Frame Rate (VFR) Lightboard provides an easy workflow to provide frame duration timing for the speed calculation formula from any surveillance camera device within a reported margin of error.
The VFR Lightboard answers the question of how much time can pass on a minimum and maximum level and provides the exact measurements that the Accident Reconstructionist would need to use in their timing calculations. In order to establish the distance, you would use iNPUT-ACE’s Overlay Tool to produce a distance calculation from the same surveillance video.
By utilizing the VFR lightboard calculation to obtain the minimum and maximum timing that can elapse and the Overlay Tool’s reverse projection calculation, which provides the minimum and maximum distance that elapsed, you can now calculate the speed within a calculated margin of error. By using more frames and more measurement points, your margin of error decreases.
Video: What Is the VFR Lightboard?
This 17-minute video is an excerpt from the original 90-minute session where we introduced the VFR Lightboard during the 2020 Online Video Evidence Training Symposium. In this video, Andrew Fredericks explains why counting frames to obtain speed/distance calculations can lead to errors and how the new VFR Lightboard can be used to get precise calculations within a specified margin of error.
How Does the VFR Lightboard Work?
The VFR Lightboard calculates the tolerance of the recording device to provide a measurement of how much time can pass on that system for the number of frames specified. The VFR Lightboard provides a minimum and maximum time that can elapse during the recorded intervals, so unlike using a frame rate calculation which is inaccurate in many cases, the Lightboard provides an accurate measurement of minimum and maximum time that could have passed during the recorded intervals. As you leverage more frames, most systems will have a dramatically reduced margin of error.
As an example, If you were reviewing a video whereby the traffic light was presented at the top of the video, and the vehicle in question was at the bottom of the video and the light turns red and a frame after the light turns red the vehicle’s tire crosses the intersection line, did that car run the red light? The typical answer is yes, but in reality, we cannot answer that definitively, until we understand the timing intervals of the surveillance device and know whether there is a rolling shutter in play. This is the power of the VFR Lightboard.
This new workflow within iNPUT-ACE starts with the lightboard, it gets used at the scene in front of the surveillance camera(s), a test recording is obtained from the surveillance device and that test recording is brought into iNPUT-ACE, with a few quick selections, in the iNPUT-ACE VFR Calculator Tool a report is generated which will include the minimum and maximum time that could have elapsed for the frames in question and the effect the rolling shudder plays*.
*Raw data for the rolling shutter will be available, but will not be included in the report until release 1.2
VFR Lightboard Physical Specs
- 334 mm (13.125”) wide
- 238mm (9.375”) high
- 34mm (1.3125”) deep
- standard 1/4-20 UNC