Code Delay
This archived page provides the MATLAB source code and example recordings described in Massimiliano Di Luca’s article, “New Method to Measure End-to-End Delay of Virtual Reality”, published in Presence: Teleoperators & Virtual Environments. The related publication page is available here.
The software implements a method based on two photodiodes and two gradients: one physical gradient shown on a flat-panel display and one virtual gradient rendered by the system under test. The photodiode signals are recorded through a stereo audio input, making it possible to compare physical and virtual trajectories without specialised recording hardware.
The method can be used for repeated recordings and for testing whether end-to-end delay varies with movement frequency, movement direction, movement amplitude, or stimulus location.
Example setups
- For head-mounted displays, a photodiode is attached to the HMD and moved in front of the flat-panel display. A second photodiode records the virtual gradient displayed in the HMD.
- For fixed-screen VR systems, a photodiode is attached to the tracked object and moved in front of the flat-panel display. A second photodiode records the luminance generated by the virtual gradient in the VR scene.
The analysis script estimates the movement frequency and delay for each recording.
Archive contents
test_{1/2}_{1/2/3/4}.mat: example recordings.test_recording.m: checks whether the photodiodes are connected correctly and whether the audio card has a stereo line input.signal_recording.m: records signals generated by one movement.calculate_delay_gui.m: loads a series of recordings and estimates relative delay and the largest frequency component.myfilteronefreq.m,finddelay.m,fsplot.m, andfindfreq.m: files required bycalculate_delay_gui.m.
Terms
Copyright (c) 2010, Massimiliano Di Luca.
Permission is hereby granted, free of charge, to any person obtaining a copy of this software, the data files, and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.