Measurements of the Modulation Transfer Function of image displays

Measurements of the Modulation Transfer Function (MTF) of image displays are often required for objective image quality assessments, but are difficult to carry out due to the need for specialized apparatus. This article presents a simple method for the measurement of the MTF of a sample CRT display system which involves the use of a still digital camera for the acquisition of displayed test targets. Measurements are carried out using, first, the sine wave method, where a number of artificial sine wave images of discrete spatial frequency and constant modulation are captured from a close distance. Fourier techniques are employed to extract the amplitude of the display signal from the resulting macroimages. In a second phase, displayed artificial step edges are captured, and the ISO 12333 SFR (Spatial Frequency Response) Slanted Edge plug-in is used for automatic edge analysis. The display MTF, in both cases, is cascaded from the closed-loop system MTF. The two measuring techniques produced matching results, indicating that under controlled test conditions accurate measurements of the display MTF can be achieved with the use of relatively simple equipment.

[1]  Mark E. Gorzynski,et al.  CRT colorimetry. Part II: Metrology , 1993 .

[2]  Jon Peddie.  High-Resolution Graphic Display Systems , 1993 .

[3]  Mark E. Gorzynski,et al.  CRT colorimetry. part I: Theory and practice , 1993 .

[4]  Don R. Williams,et al.  Benchmarking of the ISO 12233 Slanted-edge Spatial Frequency Response Plug-in , 1998, PICS.

[5]  Peter D. Burns,et al.  Slanted-Edge MTF for Digital Camera and Scanner Analysis , 2000, PICS.

[6]  Sidney Ray,et al.  Applied photographic optics , 1998 .

[7]  Paul M. Hubel,et al.  Color Image Quality in Digital Cameras , 1999, PICS.

[8]  J. C. Dainty,et al.  Image Science: Principles, Analysis and Evaluation of Photographic-Type Imaging Processes , 1974 .

[9]  Ralph E. Jacobson,et al.  Assessment of a CRT display system , 1996 .

[10]  J. C. Dainty,et al.  Methods of measuring the modulation transfer function of photographic emulsions , 1971 .

[11]  Ralph E. Jacobson,et al.  An Evaluation of Image Quality Metrics , 1995 .

[12]  C. I. Coleman,et al.  Image Science: Principles, Analysis and Evaluation of Photographic-type Imaging Processes , 1975 .

[13]  Manuel Rubiño,et al.  Considerations on the calibration of color displays assuming constant channel chromaticity , 1995 .

[14]  Roy S. Berns,et al.  Methods for characterizing CRT displays , 1996 .

[15]  David L. Post,et al.  Further evaluation of methods for producing desired colors on CRT monitors , 2000 .

[16]  Björn Lindström,et al.  MTFA as a measure for computer display screen image quality , 1990 .

[17]  Ralph E. Jacobson,et al.  A Novel Approach to the Derivation of Expressions for Geometrical MTF in Sampled Systems , 1999, PICS.

[18]  David Travis,et al.  Effective Color Displays: Theory and Practice , 1991 .

[19]  J. R. Banbury.  Evaluation of MTF and veiling glare characteristics for CRT displays , 1982 .

[20]  Gerald C. Holst,et al.  CCD arrays, cameras, and displays , 1996 .