Why Did the Earwitnesses to the John F. Kennedy Assassination Not Agree About the Location of the Gunman?

Earwitnesses to the 1963 assassination of President John F. Kennedy (JFK) did not agree about the location of the gunman even though their judgments about the number and timing of the gunshots were reasonably consistent. Even earwitnesses at the same general location disagreed. An examination of the acoustics of supersonic bullets and the characteristics of human sound localization help explain the general disagreement about the origin of the gunshots. The key fact is that a shock wave produced by the supersonic bullet arrived prior to the muzzle blast for many earwitnesses, and the shock wave provides erroneous information about the origin of the gunshot. During the government's official re-enactment of the JFK assassination in 1978, expert observers were highly accurate in localizing the origin of gunshots taken from either of two locations, but their supplementary observations help explain the absence of a consensus among the earwitnesses to the assassination itself.

SUBSTANTIATION OF PERSPECTIVES OF USING THE LIBRARY OF COMPUTER VISION OpenCV IN THE DEVELOPMENT OF SOFTWARE FOR PROCESSING VIDEO INFORMATION TESTS

The article highlights the practicability of developing our own software for processing video information obtained during testing of weapons and military equipment (WME) specimens. To obtain measurement information of processes which are distributed in space and time, namely: motion trajectories, velocity, acceleration of the object, propagation of gun muzzle blast ejection, dynamics of explosion of ammunition of various purposes. The basic operations of video information processing were outlined: 1) perspective correction; 2) compensation (correction) of distortion (optical effect "fish eye”); 3) scale determination of the video material’s frame; 4) conducting of static measurements; 5) position determination of the image object in a sequence of video stream’s frames. A brief overview of major open-access computer libraries (Accord.NET, VXL (Vision-something-Libraries), OpenCV (Open Source Computer Vision Library)) were conducted. To demonstrate how the above operations were performed by the OpenCV library, examples of the results of using it in Kinovea program were presented. An analysis of the popularity of computer vision libraries was conducted, which made it possible to assess the prospects for their further development and information support. The rationale for using OpenCV in software was fulfilled, that can be developed to process the video information obtained during testing of weapons and military equipment specimens.

Gunshot Airborne Surveillance with Rotary Wing UAV-Embedded Microphone Array

Unmanned aerial vehicles (UAV) are growing in popularity, and recent technological advances are fostering the development of new applications for these devices. This paper discusses the use of aerial drones as a platform for deploying a gunshot surveillance system based on an array of microphones. Notwithstanding the difficulties associated with the inherent additive noise from the rotating propellers, this application brings an important advantage: the possibility of estimating the shooter position solely based on the muzzle blast sound, with the support of a digital map of the terrain. This work focuses on direction-of-arrival (DoA) estimation methods applied to audio signals obtained from a microphone array aboard a flying drone. We investigate preprocessing and different DoA estimation techniques in order to obtain the setup that performs better for the application at hand. We use a combination of simulated and actual gunshot signals recorded using a microphone array mounted on a UAV. One of the key insights resulting from the field recordings is the importance of drone positioning, whereby all gunshots recorded in a region outside a cone open from the gun muzzle presented a hit rate close to 96%. Based on experimental results, we claim that reliable bearing estimates can be achieved using a microphone array mounted on a drone.