A Psychophysical Study Exploring Judder Using Fundamental Signals and Complex Imagery

There are well-known observations of movie content being displayed at different frame rates. While the terms are not consistent across the industry, there are four main degradations of the signal as compared to non-sampled motion (i.e., real-world motion). These are: 1. Non-smooth motion 2. False multiple edges, 3. Flickering, and 4. Motion blur. In natural imagery, all four of these effects are generally visible at typical movie frame rates. The spatiotemporal window of visibility [1] has proved successful in describing when motion looks distorted from the real-world smooth motion. However, that model only predicts detection performance, and doesn't address the appearance or magnitude of motion distortions. In addition, there are also well-known image capture and display parameters involved with frame rate questions, such as exposure duty cycle (angle), object speed, and object contrast. There are also known interactions with brightness and contrast, which are also generally linked in the end-to-end system. For example, the Ferry-Porter law of psychophysics indicates the temporal frequency bandwidth of vision increases with increasing adapting luminance. We aimed to isolate the non-smooth motion component of judder in a psychophysical study by using fundamental test signals, such as the Gabor signal. Two interval forced choice methodology was used to generate interval scales of the magnitude of judder, or judderness. Results are presented for the viewer assessment of the magnitude of judder, or judderness, as a function of these key parameters tested in isolation.

Published

2014-10

Content type

Original Research

Keywords

Judder, Motion Artifacts, Frame-Rate, Subjective Study

DOI

10.5594/M001593

ISBN

978-1-61482-954-6