Point-wise and whole-field laser speckle intensity fluctuation measurements applied to botanical specimens

• Published in: Optics and lasers in engineering Vol. 28; no. 6; pp. 443 - 456
• Main Authors: Zhao, Yang, Wang, Junlan, Wu, Xiaoping, Williams, Fred W., Schmidt, Richard J.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-12-1997; Elsevier
• Subjects: Biospeckle; botanical; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Imaging and optical processing; laser speckle; non-destructive testing; Optics; Physics; Speckle and moire patterns; laser speckle; botanical; Biospeckle; non-destructive testing; Speckles; Leaves; Non destructive method; Statistical analysis; Age estimation; Botany; Theoretical study; Multiple scattering; Vitality
• ISSN: 0143-8166; 1873-0302
• DOI: 10.1016/S0143-8166(97)00056-0

Based on multi-scattering speckle theory, the speckle fields generated by plant specimens irradiated by laser light have been studied using a pointwise method. In addition, a whole-field method has been developed with which entire botanical specimens may be studied. Results are reported from measurements made on tomato and apple fruits, orange peel, leaves of tobacco seedlings, leaves of shihu seedlings (a Chinese medicinal herb), soy-bean sprouts, and leaves from an unidentified trailing houseplant. Although differences where observed in the temporal fluctuations of speckles that could be ascribed to differences in age and vitality, the growing tip of the bean sprout and the shihu seedling both generated virtually stationary speckles such as were observed from boiled orange peel and from localised heat-damaged regions on apple fruit. Our results suggest that both the identity of the botanical specimen and the site at which measurements are taken are likely to critically affect the observation or otherwise of temporal fluctuations of laser speckles.