Cartesian analysis: A computer-video interface for measuring motion without physical contact

Abstract

In this paper, we describe a computer-video interface capable of measuring videotaped motion without physical contact. It constructs imaginary X-, yo, z-coordinates around a moving object by juxtaposing front and side views on one video record. A special effects generator (SEG) superimposes this two-part image onto the microcomputer's graphic output. The user watches the SEG's output and traces the motion of interest in real-time with a computer-generated cursor, a process that assesses the onset time, termination time, duration, linear displacement (i.e., length), and velocity of each traced movement. Reliability coefficients between two independent users were .99 for onset time, .85 for duration, .89 for displacement, and .90 for velocity. In 80 gestures, the correlation between estimated displacement and measured displacement was. 73; the correlation between estimated duration (determined from frame-by-frame inspection of the videotape) and measured duration was .80. Twenty-five measurements of displacement for a motorized target traveling 75.4 in. differed from the true value by 1.061, 1.061, and 1.30I in. for the x, y, and z dimensions, respectively.

Novel Activity Detection Algorithm to Characterize Spontaneous Stepping During Multimodal Spinal Neuromodulation After Mid-Thoracic Spinal Cord Injury in Rats

“…Several strategies have been developed for detecting rat activity within a caged setting using a variety of sensing methods. These include the use of vibration/tilt sensing (Parreno et al, 1985;Megens et al, 1987;Ganea et al, 2007), IR beams (Clarke et al, 1985), IR and non-IR video tracking (Tamborini et al, 1989;Morrel-Samuels and Krauss, 1990;Aragão et al, 2011;Gad et al, 2013a;York et al, 2013), capacitive flooring (Pernold et al, 2019), optical touch sensors (Mendes et al, 2015), RFID (Redfern et al, On the left is a cumulative sum plot of the step-like events occurring over time for each treatment (blue, red, gold, and magenta represents rat #1, #2, #3, and #4, respectively). On the right is the averaged cumulative sum plot.…”

Do conversational hand gestures communicate?

“…This yielded a total of 221 narrative descriptions and a corpus of 2,328 hand movements whose displacement had been determined by a computer-video interface to have exceeded 1.5 in. (3.8 cm) per 0.8 s (see Morrel-Samuels & Krauss, 1990, for details). On average, describers made about five such hand movements during each 70-s narration.…”

EthoVision: A versatile video tracking system for automation of behavioral experiments

“…However, with early systems the actual path of the animal still had to be entered manually by the experimenter, by following the track of the animal with a computer mouse (Pereira & Oliveira, 1994), a joystick (Morrel-Samuels & Krauss, 1990), or a digitizing tablet or similar device (Santucci, 1995). Another early method, still used in some commercially available systems, is to feed the analog video signal to a dedicated video tracking unit, which detects peaks in the voltage of the video signal (indicating a region of high contrast between the tracked animal and the background), and use this to produce the x,y coordinates of the tracked animals.…”