Visual Target Detection in Damselflies
Final rept. 2 Oct 2006-1 Jul 2009
HAWAII UNIV HONOLULU DEPT OF ZOOLOGY
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Insect predators accomplish difficult visual tasks with tiny visual systems, and may provide important information for machine vision and remote sensing applications in variable light environments. We studied the visual system of the damselfly Megalagrion xanthomelas, which possesses 1.5mm diameter eyes with 360 degree field of view, lives in dark habitats, and detects small objects against complex backgrounds. We accomplished four objectives 1 Mapped regional variation in light sensitivity and spatial resolving power across the thousands of individual sensory units. Compound eyes multiple, non-focusing lenses may inspire microsensor array design. 2 Developed methods to quantify light heterogeneity viewed by the sensor array in nature along four principle viewing directions. These spectroradiometric measurements provide critical data on limits to target detection imposed by ambient brightness and color contrast. 3 Established color as an essential sensory channel for target discrimination in insect vision, especially when light levels are too dim to detect achromatic contrast. 4 Discovered that damselflies extend the performance range of their eyes through behavioral means, pointing their high-resolution frontal regions toward backgrounds against which visual targets will appear most conspicuous. This behavior may provide insight for the design and deployment of artificial sensory systems for target detection in low light.
- Anatomy and Physiology
- Optical Detection and Detectors