Stand-off 3D face imaging and vibrometry for biometric identification using digital holography

Lockheed Martin Coherent Technologies (LMCT) has demonstrated 3D face imaging at ~ 1-2 mm lateral resolution and range precision at stand-off distances up to 100 m using digital holography. LMCT has also demonstrated the digital holography technique in a multi-pixel vibrometry mode in the laboratory. In this paper, we report on 3D face imaging using multiple-source (MS) and multiple-wavelength (MW) digital holography breadboards. We will briefly discuss the theory of 3D imaging using MS and MW digital holography with references to the literature. We will also briefly discuss the theory of vibrometry using a digital holographic setup. We then describe our implementation of these techniques in breadboard setups operating at 1550 nm wavelength (for MS digital holography) and at wavelengths near 1617 nm (for MW digital holography). We also present experimental results for 3D imaging and for vibrometry with these digital holographic setups

Can Honey Bees Assist in Area Reduction and Landmine Detection?

Honey bees have recently received considerable attention from the popular press as an innovative method to detect a variety of explosives, landmines and UXO. Many of these reports are inaccurate and may encourage individuals and demining groups to “sell” a service that they poorly understand or lack the experience to properly apply. As the developers of this technology, we offer the following summary about the current status of this alternative for landmine detection, including its strengths and limitations

Two-wavelength digital holography

With two-wavelength digital holography, 3D images of diffuse objects are generated by computing the phase difference between coherent images recorded at two wavelengths. Results are presented that show robust, fine resolution 3D imaging

Contour mapping of Europa using frequency diverse, spatial heterodyne imaging

Three dimensional imaging of planetary and lunar surfaces has traditionally been the purview of Synthetic Aperture Radar payloads. We propose an active imaging technique that utilizes laser frequency diversity coupled with spatial heterodyne imaging. Spatial heterodyne imaging makes use of a local oscillator which encodes pupil plane object information on a carrier frequency. The object information is extracted via Fourier analysis. Snapshots of the encoded pupil plane information are acquired as the frequency of the illumination laser is varied in small steps (GHz). The resulting three-dimensional data cube is processed to provide angle-angle-range information. The range resolution can be adjusted from microns to meters simply by adjusting the range over which the illuminator laser frequency is varied. The proposed technique can provide fine resolution contour maps of planetary surfaces having widely varying characteristics of importance to science exploration, such as the search for astrobiological habitat niches near the surface of heavily irradiated Europa. This information can be used to better understand the geological processes that form the surface features, and help characterize candidate potential habitat sites on the surface of Europa and other planetary bodies of interest. In this paper we present simulations and experimental data that demonstrate the concept

Atmospheric turbulence correction using digital holographic detection: experimental results

The performance of long distance imaging systems is typically degraded by phase errors imparted by atmospheric turbulence. In this paper we apply coherent imaging methods to determine, and remove, these phase errors by digitally processing coherent recordings of the image data. In this manner we are able to remove the effects of atmospheric turbulence without needing a conventional adaptive optical system. Digital holographic detection is used to record the coherent, complex-valued, optical field for a series of atmospheric and object realizations. Correction of atmospheric phase errors is then based on maximizing an image sharpness metric to determine the aberrations present and correct the underlying image. Experimental results that demonstrate image recovery in the presence of turbulence are presented. Results obtained with severe turbulence that gives rise to anisoplanatism are also presented

Proposed digital holographic 3D mapping of coral beds

Digital Holography is a technique which provides a measurement of the complex field reflecting from a coherently illuminated object. When the measurement is performed with two carefully chosen wavelengths a phase difference map can be created providing a three dimensional map of the object. We present results from a laboratory experiment where the surface contours of coral are measured in seawater. Contour maps with step sizes on the order of 0.1 mm can easily be obtained. We propose that this technique be used to remotely monitor the growth of coral in an effort to quantify the health of coral beds. The technique is effective from space, aircraft, ships, buoys or rigid platforms such as a pier. In the last few years we have been successfully using this technique to measure objects through very turbulent atmosphere at ranges of up to 700 meters and we are now applying the concept to shoreline applications