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We report on the design and exploitation of a real-field laboratory demonstrator combining active polarimetric and multispectral functions. Its building blocks, including a multiwavelength pulsed optical parametric oscillator at the emission side and a hyperspectral imager with polarimetric capability at the reception side, are described. The results obtained with this demonstrator are illustrated on some examples and discussed. In particular it is found that good detection performances rely on joint use of intensity and polarimetric images, with these images exhibiting complementary signatures in most cases.

A compact laboratory demonstrator providing both active polarimetric and multispectral images is designed. Its buildings blocks include, at emission part, a multi-wavelength optical parametric oscillator and, at the reception part, a polarimetric hyperspectral imager. Some of the results obtained with this system are illustrated and discussed. In particular, we show that a multispectral polarimetric image brings additional information on the scene, especially when interpreted in conjunction with its counterpart intensity image, since these two images are complementary in most cases. Moreover, although hyperspectral imaging might be mandatory for recognition of small targets, we evidence that the number of channels can be limited to a set of few wavelengths as far as target detection is considered.

Traditional forensic methods that highlight the spatial distribution of properties such as blood and fingerprints have two main disadvantages: they often apply chemicals that may influence further analyses, and they cannot easily be modified to search for new compounds/properties. A new instrument (called PryJector) avoids these problems by dynamically projecting back onto the surface under study spatially distributed information of compounds/properties (chemical images) obtained from multivariate analysis of hyperspectral images. Selectivity to target compounds/properties is ensured by multivariate modeling which makes the instrument much more flexible compared to traditional methods. The functionality of the PryJector is demonstrated in an application related to the detection of counterfeit pharmaceuticals where compounds otherwise indistinguishable to the human eye are made clearly visible by projection of false-colored chemical images. The PryJector is shown to be a noninvasive and very flexible instrument for highlighting spatial distributions of various compounds/properties.

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