Image Quality and the Display Modulation Transfer Function: Experimental Findings
Abstract
Image quality metrics represent an attempt to quantify differences in the quality of the transmission and display of visual information. This report focuses on components in the image transfer process which contribute to image quality as well as tasks through which image quality may be empirically defined. Components consist of the content of the original image, display device characteristics, and observer characteristics. Special attention within these three components is given to the display Modulation Transfer Function (MTF) which has traditionally been the major contributor to image quality metrics. Ambiguities exist in the definition and measurement of display MTFs and these problems are discussed as they pertain to image quality. Additional discussion includes the use of threshold versus suprathreshold tasks as empirical measures of image quality and the use of the Contract Sensitivity Function (CSF) versus the MTF of the eye in image quality metrics. An argument is presented which questions the use of either the CSF or MTF for suprathreshold tasks. In order to test the use of display MTFs in metrics, a methodology is described for digitally filtering images with filter representing hypothetical display MTFS. Although this method permits a subset of display MTFs to be compared, further efforts are required to compare MTFs which exhibit a crossover effect in the spatial frequency domain. Finally, empirical observations suggest that other display parameters (e.g., luminance) must be weighted more heavily in image quality metrics. Contrast sensitivity function, Fourier transform, Modulation depth, Convolution filter, Image quality, Modulation transfer function, Display quality, Image quality metric, Spatial frequency.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1993
- Accession Number
- ADA274061
Entities
People
- Ronald J. Evans
Organizations
- Armstrong Laboratory