PryJector: A Device for In Situ Visualization of Chemical and Physical Property Distributions on Surfaces Using Projection and Hyperspectral Imaging*,†

Abstract

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.

Rapid Localization of Bone Fragments on Surfaces using Back‐Projection and Hyperspectral Imaging

“…A PryJector is an instrument for making object properties visible in situ on surfaces which are otherwise invisible or difficult for human eyes to detect. This is accomplished using a combination of hyperspectral imaging, chemometric modeling, and back‐projection of spatially distributed chemical information as false colored chemical images using an ordinary computer projector (or with lasers).…”

“…Here, it is decided to use red color to signify the presence of bone at a pixel. The hyperspectral scan speed is 7.5 cm per second with 1 ms integration time and 100 ms frame time .…”

“…These results make it reasonable to expect that an improved technology for localization of bone fragments may be based on rapid spectroscopic analyses of surfaces. Thus, it is here investigated whether a recently invented instrument (called the PryJector) that utilizes a combination of spectroscopy, imaging, chemometric modeling, and false color projection can be used for this purpose.…”

Short-Wavelength Infrared Hyperspectral Imaging for Biomedical Applications

“…In the field of forensics, HSI has been used to investigate crime scenes, to identify stains of biological fluids and blood on soft materials such as clothing, and for characterizing skin bruises. 73,74,[106][107][108] Bruises are caused by ruptured blood vessels and leakage of blood into the tissue. Immediately after the trauma, there will be a wheal and flare reaction, which is characterized by swelling and fluid accumulation.…”

Hyperspectral imaging for non-contact analysis of forensic traces

“…An interesting other approach for presenting the results was demonstrated by Alsberg et al [23], who projected the results of HSI analysis back onto the scene to highlight chemical differences otherwise invisible to the naked eye. This non-destructive technique provides information similarly to traditional forensic methods, e.g.…”