Abstract: The present disclosure provides for a system and method for analyzing questioned documents. A sample document is illuminated to thereby generate a first plurality of interacted photons. The first plurality of interacted photons are detected at a first detector to thereby generate a digital image. The digital image is analyzed to thereby identify at least one region of interest of the sample document. This region of interest is illuminated to thereby generate a second plurality of interacted photons. This second plurality of interacted photons are passed through a tunable filter and detected at a second detector to thereby generate a hyperspectral image representative of the region of interest. The hyperpsectral image may then be analyzed to evaluate changes to or differentiate different inks present in the sample document. Chemometric techniques such as k-means clustering, PCA, and/or PLSDA may also be applied.

Abstract: A pulse photobleaching methodology wherein a monochromatic illumination (e.g., laser illumination) having a higher power intensity (photobleaching power) just below the photodamage threshold of a luminescent sample is initially used to significantly attenuate sample luminescence without photothermally destroying the sample material. Thereafter, the laser power density may be reduced to a significantly lower level (analytical power level) to carry out spectroscopic measurements (e.g., collection of Raman scattered photons) on the sample. In one embodiment, the laser illumination wavelength remains the same despite changes in laser power intensity. Some figures-of-merit may be computed from optical measurements made at the analytical power level to guide the photobleaching process. Sample-dependent combinations of laser power density and short exposure times may be obtained to significantly expedite photobleaching to assist in collection of sample spectral data in the field without a long wait.

Abstract: A system and method for obtaining hyperspectral visible absorption images. The system includes a light source which illuminates a sample containing light absorbing material, a platform, an optical lens, a detector. The platform has a section for placement of the sample and a section devoid of sample. The transmitted photons produced by the sample and collected by the optical lens are separated into a plurality of wavelength bands using a filter or a fiber array spectral translator coupled to a spectrometer. The system includes a programmable code for operating in a sample mode or background mode and calculating an absorption image. In the background mode, the platform motion is controlled so the optical lens collects transmitted photons from the, portion of the platform devoid of sample to generate a background transmission image. In the sample mode, the platform motion is controlled so the optical lens collects transmitted photons from the sample to generate a sample transmission image.

Abstract: A pulse photobleaching methodology wherein a monochromatic illumination (e.g., laser illumination) having a higher power intensity (photobleaching power) just below the photodamage threshold of a luminescent sample is initially used to significantly attenuate sample luminescence without photothermally destroying the sample material. Thereafter, the laser power density may be reduced to a significantly lower level (analytical power level) to carry out spectroscopic measurements (e.g., collection of Raman scattered photons) on the sample. In one embodiment, the laser illumination wavelength remains the same despite changes in laser power intensity. Some figures-of-merit may be computed from optical measurements made at the analytical power level to guide the photobleaching process. Sample-dependent combinations of laser power density and short exposure times may be obtained to significantly expedite photobleaching to assist in collection of sample spectral data in the field without a long wait.

Abstract: A system and method for obtaining hyperspectral visible absorption images. The system includes a light source which illuminates a sample containing light absorbing material, a platform, an optical lens, a detector. The platform has a section for placement of the sample and a section devoid of sample. The transmitted photons produced by the sample and collected by the optical lens are separated into a plurality of wavelength bands using a filter or a fiber array spectral translator coupled to a spectrometer. The system includes a programmable code for operating in a sample mode or background mode and calculating an absorption image. In the background mode, the platform motion is controlled so the optical lens collects transmitted photons from the, portion of the platform devoid of sample to generate a background transmission image. In the sample mode, the platform motion is controlled so the optical lens collects transmitted photons from the sample to generate a sample transmission image.

Abstract: The disclosure relates to method and apparatus for interactive hyperspectral image subtraction. In one embodiment, the disclosure relates to a method for obtaining a spectral image of a first specie from a frame of a plurality of pixels defining a composition of the first specie with a second specie. The method may include (i) identifying, for each of the first and second species, an appropriate Raman wavelength; (ii) defining at least one background wavelength for the frame; (iii) identifying pixels defined only by background wavelength; (iv) identifying pixels defined only by the first specie or the second specie; (v) identifying the remaining pixels, the remaining pixels defined by at least a combination of the first and second species; and (vi) forming a spectral image for the first specie.

Abstract: The invention relates to methods of assessing the polymorphic form of a substance by assessing Raman-shifted radiation scattered by a particle of the substance. The method is useful, for example, for assessing particle sizes and size distributions in mixtures containing both particles of the substance and other materials. The invention also relates to methods of selecting and controlling polymorph formation by illuminating a material with non-resonant (i.e., non-absorbed) laser radiation as it is thermally driven through a phase transition temperature.

Abstract: The disclosure relates to method and apparatus for providing a mosaic image based on two or more sub-images. A method according to the disclosure includes irradiating a sample with light to thereby produce photons from the sample and forming two or more sub-images from the photons; the sub-images formed from photons of substantially the same wavelength. The plurality of sub-images of the sample can be combined in a mosaic-type formation to define an image of the sample. Similar images of the sample at different wavelengths can be combined to form a comprehensive mosaic image of the sample at all wavelengths.

Abstract: An apparatus incorporated within a spectroscopic imaging system, typically a microscope, but also applicable to other image gathering platforms, namely fiberscopes, macrolens imaging systems and telescopes employing a polarizing beam splitting element is disclosed. The apparatus allows simultaneous spectroscopic (i.e. chemical) imaging and rapid acquisition spectroscopy to be performed without the need for moving mechanical parts or time sequenced sampling and without introducing significant optical signal loss or degradation to the spectroscopic imaging capability. In addition, the apparatus affords a more compact design, an improved angular field of view and an improved overall ruggedness of optical design at a lower manufacturing and maintenance cost compared to previous devices.

Abstract: An apparatus incorporated within a spectroscopic imaging system, typically a microscope, but also applicable to other image gathering platforms, namely fiberscopes, macrolens imaging systems and telescopes employing a polarizing beam splitting element is disclosed. The apparatus allows simultaneous spectroscopic (i.e. chemical) imaging and rapid acquisition spectroscopy to be performed without the need for moving mechanical parts or time sequenced sampling and without introducing significant optical signal loss or degradation to the spectroscopic imaging capability. In addition, the apparatus affords a more compact design, an improved angular field of view and an improved overall ruggedness of optical design at a lower manufacturing and maintenance cost compared to previous devices.