Effects of speckle on resolution*
Abstract
The effect of speckle in the imaging of diffusely illuminated gratings and continuous-tone objects was studied. It was found that when imaging diffuse gratings, the aperture of a coherently illuminated system must be 2.6 times as large as that of an incoherent system to obtain comparable resolution. This factor must be increased to five when imaging continuous-tone objects and to a factor of seven if the coherent image is subsequently low-pass filtered. A coherent system can achieve resolution which is comparable to an incoherent system of equal aperture if the coherent image is smoothed so that the mean to standard deviation ratio is ten or more.
- Publication:
-
Journal of the Optical Society of America (1917-1983)
- Pub Date:
- November 1976
- DOI:
- 10.1364/JOSA.66.001257
- Bibcode:
- 1976JOSA...66.1257K
- Keywords:
-
- Coherent Light;
- Gratings (Spectra);
- Image Enhancement;
- Resolution;
- Speckle Patterns;
- Apertures;
- Light Scattering;
- Low Pass Filters;
- Signal To Noise Ratios;
- Standard Deviation;
- Instrumentation and Photography