Insect Wing Displacement Measurement Using Digital Holography

• Main Authors: Aguayo, Daniel D, Santoyo, Fernando Mendoza, Mendez, Cristian I Caloca
• Format: Conference Proceeding
• Language: English
• Subjects: AERODYNAMICS; AMPLITUDES; CAMERAS; CHARGE-COUPLED DEVICES; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; HOLOGRAPHY; INSECTS; INTERFEROMETRY; LASER RADIATION; RESOLUTION; SENSORS; SURFACES
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/1.2926974

Insects in flight have been studied with optical non destructive techniques with the purpose of using meaningful results in aerodynamics. With the availability of high resolution and large dynamic range CCD sensors the so called interferometric digital holographic technique was used to measure the surface displacement of in flight insect wings, such as butterflies. The wings were illuminated with a continuous wave Verdi laser at 532 nm, and observed with a CCD Pixelfly camera that acquire images at a rate of 11.5 frames per second at a resolution of 1392X1024 pixels and 12 Bit dynamic range. At this frame rate digital holograms of the wings were captured and processed in the usual manner, namely, each individual hologram is Fourier processed in order to find the amplitude and phase corresponding to the digital hologram. The wings displacement is obtained when subtraction between two digital holograms is performed for two different wings position, a feature applied to all consecutive frames recorded. The result of subtracting is seen as a wrapped phase fringe pattern directly related to the wing displacement. The experimental data for different butterfly flying conditions and exposure times are shown as wire mesh plots in a movie of the wings displacement.