Raman checkpoint system

Abstract

Raman spectroscopy is a contact-free technique for identifying different chemicals. In Raman spectroscopy, a Raman pump beam illuminates a sample, which scatters Raman light at different wavelengths. The spectrum of this Raman light can be used to identify the sample's chemical composition. An inventive Raman checkpoint system can be used to identify containers and their contents at security checkpoints without expert operator intervention. The operator places the container in an eye-safe, interlocked sample compartment, and the Raman checkpoint system uses exterior and through-imaging modes to automatically identify regions in and / or on the container to measure. The Raman checkpoint system measures the Raman spectra of the container and its contents, identifies the contents, and presents the results to the operator via a touchscreen or other suitable user interface.

Description

Attorney Docket No. PEND-015W001Raman Checkpoint SystemCROSS REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims the priority benefit, under 35 U.S.C. 119(e), of U.S. Application No. 63 / 745,547, filed January 15, 2025, which is incorporated herein by reference in its entirety for all purposes.GOVERNMENT SUPPORT

[0002] This invention was made with government support under 70RSAT23CB0000009 awarded by the Department of Homeland Security. The government has certain rights in the invention.BACKGROUND

[0003] Ensuring the safety of air travel and other security checkpoints requires effective identification of hazardous materials contained in liquids, gels, solids, and powders, which may be transported in a variety of containers, including bottles, vials, envelopes, and packages. Current secondary screening technologies, including Explosive Trace Detectors (ETDs), suffer from limitations such as:1. Limited selectivity and chemical libraries, leading to false alarms; and2. Requirements for consumables and manual sampling, increasing operational costs and contamination risks.

[0004] To address these limitations, Raman spectroscopy has emerged as a powerful, noncontact technique for chemical identification. However, traditional Raman systems are hindered by several challenges, including:• Fluorescence interference from highly colored or dyed materials, which overwhelms the Raman signal;• Poor signal throughput through opaque or complex container walls;• Insufficient safety controls, including risks of igniting sensitive materials due to tightly focused, high-power laser beams; andAttorney Docket No. PEND-015W001• Training requirements and cognitive burdens on security officers may be too onerous for effective use of the technology.SUMMARY

[0005] Existing screening systems, such as those using Spatially Offset Raman Spectroscopy (SORS), suffer from reduced signal strength, dependence on static container libraries, and susceptibility to fluorescence. In contrast, the inventive Raman checkpoint systems disclosed here combine Shifted Excitation Difference Raman Spectroscopy (SERDS), machine vision automation, and dynamic container subtraction to deliver superior performance. By eliminating fluorescence interference, increasing signal quality, and offering advanced targeting capabilities, inventive system sets a new benchmark for checkpoint screening applications.

[0006] An inventive Raman checkpoint system uses SERDS to identify chemical compositions of liquids, solids, powders, and gels contained within various containers, such as bottles, vials, envelopes, and packages. The system addresses limitations of current screening technologies by offering:1. Enhanced Fluorescence Suppression:o Dual-laser SERDS technology provides isolated, baseline-free Raman signals by subtracting measurements taken at slightly shifted laser wavelengths. o Effectively suppresses fluorescence even from highly colored or dyed materials, ensuring accurate chemical identification.2. Dynamic Container Signature Subtraction:o The system can acquire reference spectra of container-only regions (e.g., above a fill line) and subtract them dynamically from measurements taken under the fill line for each container inserted into the system.o The system can also use multi-component regression to identify up to 5-6 chemicals, and a library of standard container reference spectra, allowing the system to extract the signature of the container’s content even in the absence of a new reference measurement.3. Automated and Flexible Targeting:o Integrates a machine vision system with two imaging modes (exterior and transmission-mode imaging) to identify object features including fill lines, boundaries, and internal anomalies and to suggest reference and target points.Attorney Docket No. PEND-015W001A motorized Raman probe with multi-degree motion control (X-Y-Z and tilt) enables automated aiming, focusing, and precise positioning on user-selected or system-suggested targets.The system supports multiple measurement points per object, addressing compositional heterogeneities, multi-layered contents, and / or irregular distributions of materials.The system supports multiple levels of users with corresponding automation capabilities: minimally trained users can rely extensively on automation for target selection and measurement routines, while expert users can take full control of the instrument to manually select targets and adjust measurement settings.The system may include a fast autofocus sensor that selects the probe position quickly, allowing increased signal collection and faster measurements.nal Raman Collection:A large-area laser spot (e.g., ~2 mm diameter) reduces the risk of igniting the object while integrating Raman signals across spatial inhomogeneities.The system can use either a fiber bundle or a large-core diameter fiber to collect Raman signals from a large area, ensuring high signal throughput while preserving spectral resolution. The choice between these options allows flexibility depending on system design and application specifications.A fiber bundle-based collection system can ensure high signal throughput while preserving high spectral resolution by converting a circular input on the probe side to a linear output at the spectrometer input slit.d Imaging SystemsThe system features dual imaging modes to assist in target selection and object analysis:o Exterior Illumination: White-light LEDs illuminate the outer surface of the object, enabling clear identification of labels, boundaries, and external features.o Through-Object Transmission Imaging: Infrared or near-infrared light (e.g., in a wavelength range of 700-2500 nm or 900-1100 nm) illuminates the object from behind to detect internal features such as fill lines, hidden compartments, or irregular contents. This imaging mode assists inAttorney Docket No. PEND-015W001identifying transmissivity and anomalies that cannot be detected with surface-level imaging alone.o The imaging system provides real-time feedback to the user and machine vision subsystem, ensuring accurate target selection and enabling rapid triage of non- measurable containers (e.g., metal cans with no near-infrared transmissivity). 6. Safety Features:o Class 1 laser safety compliance with an interlocked sample compartment that disables the laser when the sample compartment door is open.o Fail-safe beam rastering technology distributes the laser energy over a wide area, reducing energy density and ensuring sample safety.o Real-time motion monitoring ensures automatic laser shutdown if probe movement does not meet predefined safety parameters.7. Dual Measurement Modalities:o Through-container mode for analyzing the contents of transparent or semitransparent containers through the container side walls.o Top-down mode using relay optics to measure a container’s contents from the top down, through open lids or container openings, providing flexible accessibility.8. Operational Efficiency:o Designed for non-expert personnel (e.g., Transportation Security Officers):o Intuitive touchscreen interface for target selection and operation.o Automated measurement routines.o Simple go / no-go feedback for chemical identification.o Eliminates the need for:o Consumables and manual sampling, reducing contamination risks and operational costs;o Frequent maintenance; ando Clear-down times allowing the instrument to clear the signal from a prior sample and reset to a zero baseline measurement.

[0007] The system integrates these features into a robust, enclosed platform that can accurately identify hazardous chemicals while addressing fluorescence interference, safety concerns, and operational inefficiencies.Attorney Docket No. PEND-015W001

[0008] An inventive Raman checkpoint system can be used to inspect contents of a container as follow. The Raman checkpoint system acquires visible and infrared images of the container and selects a target point on or in the container based on the visible and / or infrared images, where the target point is a point where the contents of the container are expected to contribute to a Raman signal. Then the Raman checkpoint system measures a Raman spectrum of the target point and determines a Raman spectrum of the contents of the container based on the Raman spectrum of the target point.

[0009] The Raman checkpoint system can acquire the visible image of the container by illuminating an exterior surface of the container with white light and imaging the exterior surface of the container. Similarly, the Raman checkpoint system can acquire the infrared image of the container by illuminating the container with infrared light at a wavelength of 700 nm to 2500 nm and detecting the infrared light transmitted through the container.

[0010] The Raman checkpoint system can measure the Raman spectrum of the target point by making a Shifted Excitation Difference Raman Spectroscopy (SERDS) measurement. It can also scan a laser beam across an area of the container to prevent ignition of the contents of the container. The laser beam may illuminate the contents of the container through a wall of the container or through an opening in the container. In any case, the container can be sealed in an eye-safe housing before the Raman checkpoint system measures the Raman spectrum of the target point.

[0011] In some cases, the Raman checkpoint system automatically selects or suggests a reference point on or in the container based on the visible and / or infrared images, where the reference point is a point where the contents of the container are not expected to contribute to a Raman signal. The Raman checkpoint system measures a Raman spectrum of the reference point and uses the Raman spectrum of the reference point in determining the Raman spectrum of the contents of the container. To select the reference and target points, a processor of the Raman checkpoint system can detect a fill line of the contents of the container and the pick the reference point to be on the container above the fill line and the target point to be on or in the container below the fill line.

[0012] An example Raman checkpoint system can include an eye-safe housing with a door for inserting an object, such as a container and its contents, into the eye-safe housing; a laser source, contained within the eye-safe housing, to illuminate the object within the eye-safe housing when the door is closed; and an interlock, operably coupled to the door and the laserAttorney Docket No. PEND-015W001source, to prevent the laser source from illuminating the object when the door is open. It can also include relay optics, in optical communication with the laser source, to direct a laser beam from the laser source through an opening in the container to contents of the container.

[0013] One or more actuators, contained within the eye-safe housing, can adjust a focus position of a laser beam emitted by the laser source. These actuators can also scan a spot formed by the laser beam across a surface of the object. In some cases, the Raman checkpoint system may also include a monitoring system, operably coupled to the actuator(s) and / or to the laser source, that detects a malfunction of the actuator(s) and / or of the laser source that could cause the laser beam to ignite and / or damage the object and to at least one of attenuate, redirect, block, or turn off the laser beam in response to detection of the malfunction.

[0014] The Raman checkpoint system can also include a detector, contained within the eyesafe housing, that detects a Raman signal scattered from the object in response to illumination of the object by the laser source. In some cases, the laser source and the detector are configured to make a Shifted Excitation Difference Raman Spectroscopy (SERDS) measurement of the object.

[0015] As mentioned above, the Raman checkpoint system can include a visible light source and visible camera for acquiring a visible image of the object and an infrared light source and infrared camera for acquiring an infrared image of the object. A user interface, operably coupled to the visible and infrared cameras, displays the visible and / or infrared images to an operator of the system. The user interface can also display an indication of a transmissivity of the object and an indication of a likelihood of successfully inspecting the object. And the user interface can display the reference and / or target points to the operator and enable the operator to select and / or change the reference and / or target points.

[0016] In some cases, the Raman checkpoint system includes an actuator to move the container while the visible camera acquires the visible image of the container and / or the infrared camera acquires the infrared image of the container. Moving the container during image acquisition can make it easier to identify the fill line or meniscus formed by the container’s contents.

[0017] The Raman checkpoint system’s processor can generate a Raman spectrum of the contents of the container based on the Raman spectra of the reference and target points.

[0018] The Raman checkpoint system can include a spectrometer, in optical communication with the object, to measure a spectrum of light scattered from the object as well as an autofocus sensor, operably coupled to the spectrometer, to adjust a focus of the laser source based on anAttorney Docket No. PEND-015W001amplitude of the light collected by the spectrometer. For example, the autofocus sensor can detect a specular reflection from a grating of the spectrometer.

[0019] Embodiments of the Raman checkpoint system may include an internal calibration module for calibrating the Raman probe, spectrometer, and / or processor. This internal calibration module can include both a dark reference material having negligible Raman scattering characteristics and one or more Raman calibration standards having known Raman spectra.

[0020] If desired, the Raman checkpoint system can include a metal detector to detect whether the object includes or contains any metal.

[0021] All combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the inventive subject matter disclosed herein. The terminology explicitly employed herein that also may appear in any disclosure incorporated by reference should be accorded a meaning most consistent with the particular concepts disclosed herein.BRIEF DESCRIPTIONS OF THE DRAWINGS

[0022] The skilled artisan will understand that the drawings primarily are for illustrative purposes and are not intended to limit the scope of the inventive subject matter described herein. The drawings are not necessarily to scale; in some instances, various aspects of the inventive subject matter disclosed herein may be shown exaggerated or enlarged in the drawings to facilitate an understanding of different features. In the drawings, like reference characters generally refer to like features (e.g., functionally similar and / or structurally similar components).

[0023] FIG. 1 A shows a perspective view of an inventive Raman checkpoint system.

[0024] FIG. IB is a schematic diagram of an inventive Raman checkpoint system.

[0025] FIG. 2 illustrates how an inventive Raman checkpoint system scans a Raman pump across a large area of the sample / object to reduce the risk of igniting the object and reduce the effects of spatial inhomogeneities.Attorney Docket No. PEND-015W001

[0026] FIG. 3 illustrates a camera and white-light LED(s), along with a Raman probe, of an inventive Raman checkpoint system for imaging the exterior of an object, such as a container (e.g a bottle, envelope, vial, bag, etc.) and its contents (e.g., powder, gel, solid, liquid, etc.).

[0027] FIG. 4A illustrates a camera and near-infrared (NIR) LED(s), along with a Raman probe, of an inventive Raman checkpoint system for imaging through an object.

[0028] FIG. 4B shows “through-images” of different substances made with an inventive Raman checkpoint system.

[0029] FIG. 5 A illustrates a user interface for an inventive Raman checkpoint system, showing both exterior (left) and through (right) images and reference (R) and sample (S) measurement points superimposed on the through image.

[0030] FIG. 5B illustrates a user interface for an inventive Raman checkpoint system, showing a blended or composite exterior / through images and with reference (R) and sample (S) measurement points.

[0031] FIG. 6 shows a user interface of an inventive Raman checkpoint system displaying through (left) and exterior (right) images of a container containing a sample to be measured with automatically identified sample and reference points.

[0032] FIG. 7 shows a container with target measurement points on three different material layers below the fill line and a reference measurement point above the fill line.

[0033] FIG. 8 illustrates one implementation of an autofocus subsystem for an inventive Raman checkpoint system.

[0034] FIG. 9A shows a cross-sectional view of an inventive Raman checkpoint system making a through-container measurement of a liquid in a transparent container.

[0035] FIG. 9B shows a cross-sectional view of an inventive Raman checkpoint system making a top-down, into-container measurement of a liquid in an open container.

[0036] FIGS. 10A and 10B show through-container and top-down, into-container Raman measurements, respectively.

[0037] FIG. 11 illustrates relay optics used in an inventive Raman checkpoint system for top-down, into-container Raman measurements.

[0038] FIG. 12 illustrates a Raman checkpoint system with internal calibration standards.Attorney Docket No. PEND-015W001

[0039] FIG. 13 illustrates a Raman checkpoint system with a metal detection element integrated into the base of the sample compartment and configured to detect the presence of a metallic container or metallic components associated with the object under analysis.

[0040] FIG. 14 illustrates a Raman checkpoint system with a mechanical actuator configured to induce motion of the object under analysis.

[0041] FIG. 15 illustrates an architecture for distributed data collection and centralized system management within a network of Raman checkpoint systems.DETAILED DESCRIPTION

[0042] An inventive Raman Checkpoint System can be used to identify hazardous materials in liquids, gels, powders, and solids transported in various containers such as bottles, vials, pouches, and envelopes. The system combines Shifted Excitation Difference Raman Spectroscopy (SERDS), machine vision, advanced motion control, and safety mechanisms within an enclosed platform to deliver reliable chemical analysis for checkpoint environments.

[0043] FIGS. 1 A and IB show an inventive Raman checkpoint system 100 with a housing 102 that fully encloses Class 1 laser-safe compartment 101 that contains an object 10 (e.g., a bottle, pouch, or envelope and its contents 11) under analysis. An optional rotating state 106 supports and spins the object 10 within the laser-safe compartment 101 in the housing. The housing 102 can be modestly sized, with example exterior dimensions of a 22-inch width, 22-inch height, and 17-inch depth and comparable interior dimensions defining the laser-safe compartment 101. Larger and smaller housing dimensions are also possible, with correspondingly larger and smaller laser-safe compartments 101.

[0044] The housing 102 also contains a laser source 110, which may include one or more lasers as described below, a Raman probe 112, and a spectrometer 116 for making Raman measurements of the object 10 and / or its contents 11. The laser-safe compartment 101 ensures user safety by incorporating an interlocked door 104 with an interlock sensor 108 that immediately disables the laser source 110 used for the Raman measurement if the door 104 is opened during operation. The Raman probe 112 that focuses pump light, also called a Raman pump laser beam, Raman pump beam, or pump beam, from the laser source 110 onto the sample (object 10 and / or contents 11 or the object 10) and collects the Raman signal scattered from the sample. The Raman probe 112 contains filters that attenuate or suppress Raleigh scattering that would otherwise swamp the returned Raman signal. Optical fibers 114 (e.g., aAttorney Docket No. PEND-015W001fiber bundle and / or large-mode-area (LMA) fiber(s)) couple the laser source 110 to the Raman probe 112 and the Raman probe 112 to the spectrometer 116. This allows the Raman probe 112 to be mounted on a moving stage 117 or moved with one or more other actuators while the laser source 110 and spectrometer 116 remain static.

[0045] Electronics 120 coupled to the laser source 110, spectrometer 116, and stage 118 power and control the Raman measurements. The electronics 120 are also coupled to one or more cameras 130 that image the object 10 and / or the object contents 11 as described in detail below. The electronics 120 uses the image(s) acquired by the camera 130 to select one or more aiming points for the Raman pump laser beam, then cause the stage 117 and / or relay optics 118 to move so that the Raman probe 112 can focus the Raman pump laser beam to the aiming point. The electronics 120 also processes the signal that the spectrometer 116 generates in response to receiving the Raman scattered light from the object 10 and / or object contents 11. The electronics 120 can provide the processed results and accept user input, e.g., for choosing the aiming point(s), via a user interface 122, such as a touchscreen coupled to the housing or a tablet, computer, smartphone, or other device wirelessly or physically connected to the Raman checkpoint system 100. The electronics 120, laser source 110, spectrometer 116, and other components can be powered with a simple wall plug connection.

[0046] To further mitigate safety risks, the Raman probe 112 incorporates fail-safe beam rastering, where the state and / or actuator(s) rapidly moves the Raman pump laser beam across the object 10, distributing its energy over a spot with a diameter of at least 2 mm. By spreading the Raman pump laser beam energy in this way, the system 100 reduces the risk of igniting sensitive or energetic materials while ensuring robust signal collection. A sensor or monitoring system measures the laser beam’s movement, dwell time on a particular spot on the object 10, and / or power level; if any of these quantities exceed acceptable limits, then the monitoring system interrupts the laser beam to prevent igniting or damaging the object 10 or its contents 11, e.g., by turning off the laser source 110, attenuating the Raman pump laser beam, or redirecting the Raman pump laser beam away from the object 10. For more on fail-safe beam rastering, please see U.S. Patent No. 10,527,495, entitled “Methods and Devices for Standoff Differential Raman Spectroscopy with Increased Eye Safety and Decreased Risk of Explosion,” which is incorporated herein by reference in its entirety for all purposes.

[0047] At the core of the Raman checkpoint system is the SERDS-based Raman spectroscopy subsystem, which uses a laser source 110 with two lasers emitting at slightly shifted wavelengths (e.g., 825 nm and 827 nm, or 785 nm and 786 nm) or a single tunable laser thatAttorney Docket No. PEND-015W001emits sequentially at slightly shifted wavelengths. Taking the difference of these dual-laser measurements isolates the Raman signal, effectively suppressing fluorescence and providing baseline-free Raman spectra even for highly fluorescent materials like dyed or colored samples. The Raman probe 112 focuses the Raman pump laser beam onto the object surface or within the object 10, while a large-mode-area (LMA) optical fiber or an optical fiber bundle 114 efficiently gathers the Raman-scattered light from the sample (object 10 and / or object contents 11). The collected signal is transformed from a circular area into a linear format to match the spectrometer slit, maximizing signal throughput while maintaining high spectral resolution. For example, the fibers at the end of the optical fiber bundle 114 closest to the spectrometer slit may be arranged in a straight line or a line that is slightly curved to compensate for the field curvature of the spectrometer optics. An LMA optical fiber can be butt-coupled to a narrower spectrometer slit or its output can be magnified to the dimensions of the spectrometer slit to maintain the spectrometer resolution.

[0048] To achieve automated and precise targeting, the Raman checkpoint system 100 includes a motion control subsystem that can move the Raman probe beam with multiple degrees of freedom as shown in FIG. 2. For example, the stage 117 (FIG. 2, left) can translate and / or tilt the Raman probe 112 and the Raman pump beam laterally and vertically axes to target specific regions on or in the object 10. The Raman probe 112 may also include an adjustable zoom lens that can focus the Raman pump beam to varying depths along the Raman probe’s optical axis. Tilting the Raman probe beam at an angle with respect to the object 10 and / or its contents 11 is particularly useful for probing meniscus surfaces or pushing the Raman probe beam focus deeper into the object 10. In addition, or instead, the Raman checkpoint system 100 may include an adjustable wedge 202 between the Raman probe 112 and the object 10. Translating and / or rotating the adjustable wedge scans and / or tilts the Raman pump beam with respect to the obj ect 10. Additionally, the rotating sample plate 106 in the compartment can spin or rotate the object 10 such that the object’s most transmissive side is presented to the camera 130 and light source(s) (described below) for through-container measurements. Encoders monitor the position, scan speed, and / or dwell time of the Raman pump beam. If these encoders detect that the Raman pump beam is not scanning far or fast enough, the Raman pump beam is automatically turned off, attenuated, or blocked to prevent damage to or ignition of the object 10 or its contents 11.Vision System and Imaging-Based Target SelectionAttorney Docket No. PEND-015W001

[0049] The Raman checkpoint system 100 incorporates an integrated vision system comprising one or more cameras 130 and illumination sources to capture images of the object placed within the sampling compartment. The imaging system provides both exterior illumination, which reveals surface features such as labels or obstructions, and transillumination (through-object illumination), which enhances internal features such as liquid fill levels or structural discontinuities. These images are used both for visualization and for informing Raman measurement workflows.

[0050] The Raman checkpoint system 100 can present a real-time image of the object to the user via the user interface 122, allowing the user to select one or more target locations for Raman measurements. In addition, the Raman checkpoint system 100 supports automated analysis of the captured image, using computer vision processing techniques to segment the object 10 from the background, identify the object’s contours, and detect regions that may obstruct optical access (e.g., printed labels or opaque regions). The Raman checkpoint system 100 can automatically suggest or select measurement points based on factors such as surface accessibility, optical clarity, and physical features of the object.

[0051] The Raman checkpoint system’s vision subsystem also enables detection of liquid fill lines, particularly when combined with transillumination. The Raman checkpoint system 100 analyzes contrast discontinuities and geometric cues to infer the position of the fill line. In some embodiments, this detection is enhanced by mechanical actuation that gently nudges or vibrates the sample platform, inducing motion in the liquid meniscus (e.g., as described below with respect to FIG. 14). The camera 130 captures sequential images, and the Raman checkpoint system 100 identifies the moving boundary to locate the fill line with greater precision. This capability may be used for transparent or semi-transparent containers and ensures that Raman measurements are taken within the filled portion of the container 10, avoiding false signals from air gaps or container walls.

[0052] The Raman checkpoint system’s machine vision subsystem can operate in two imaging modes: (1) an exterior imaging mode as shown in FIG. 3 and (2) a through-object (transmission) imaging mode as shown in FIGS. 4A and 4B. As shown in FIG. 3, in exterior imaging mode, the camera 130 captures clear images of the object’s exterior under exterior illumination from white-light LEDs or another suitable visible light source 302. The electronics 120 can use these clear images of the object’s exterior for identifying boundaries, labels, and features. In transmission imaging mode, shown in FIG. 4A, an infrared (IR) or near-infrared (NIR) light source 402 illuminates one side of the object 10 with light within the RamanAttorney Docket No. PEND-015W001spectral range (e.g., infrared or near-infrared light within a wavelength range of 700-2500 nm, 900-1100 nm, or another suitable range) and the camera 130, which is on the other side of the object 10, detects the light transmitted through the object 10. Transmission or through imaging mode allows detection of fill lines inside bottles, different layers / heterogenous contents, and anomalies, such as hidden compartments or irregular internal structures like those shown in FIG. 4B. Additionally, transmission imaging helps determine an object’s transmissivity, enabling rapid triage of items like metal cans that cannot be analyzed through their walls.

[0053] The Raman checkpoint system’s user interface 122, shown in FIGS. 5 A, 5B, and 6, can display exterior and through images captured by the camera(s) 130. FIG. 5A shows an exterior image (left) of the object 10, including the object label 12, which may be both legible on the user interface 122 and useful for identifying the object 10 and its contents 11. FIG. 5A also shows a through image (right) of the object 10 and its contents 11 along with aiming points for a container Raman measurement 501 (above the upper surface of the contents) and a contents Raman measurement 503 (below the lower surface of the contents). FIG. 5B shows a blended or composite image formed from both the exterior and through images of the object 10. A slider 502 or other adjuster allows the user to adjust the apparent opacity of the object’s walls and reveal the contents 11.

[0054] The user interface 122, which can be implemented as a touch screen or a display and mouse, touchpad, keyboardjoystick, etc., enables operators to select or adjust the sample and reference (container) aiming points, e.g., as shown in FIG. 6. The Raman checkpoint system’s machine vision system can also automatically identify object features — such as boundaries, fill lines, or anomalies — and suggest measurement points, e.g., indicated by the X’s on different layers in FIG. 7. Users can confirm these suggestions or manually select one or more points for analysis. This capability is particularly valuable for complex objects with compositional heterogeneities, as the system enables flexible targeting across multiple locations.

[0055] To enhance measurement accuracy, the Raman checkpoint system performs dynamic container signature subtraction. Before analyzing the container’s contents, the system acquires a reference spectrum from a container-only region, such as above the fill line (e.g., indicated by the container measurement point 501 in FIG. 5A). By subtracting this container reference spectrum, the system isolates the Raman signal of the container contents 11, even when the measurement contains contributions from the container 10 too. Built-in mixture analysis further identifies up to five or six chemicals, even in cases where no reference spectrum is available.Attorney Docket No. PEND-015W001

[0056] In addition to acquiring a container-only reference measurement 501 directly from the object (e.g., above the fill line), the Raman checkpoint system may also perform library-based container subtraction. In this mode, the system selects a suitable reference spectrum from a library of pre-recorded container materials, based on image analysis, object recognition, or prior learning. This library contains Raman spectra of common container types (e.g., PET bottles, HDPE containers, glass vials) and is used when a direct reference measurement is not feasible, for example, when no clear container-only region is accessible with the Raman probe. The Raman checkpoint system 100 may perform a matching process that compares features of the object image or measured spectrum with the container library to select the most appropriate container reference. The library -based subtraction can be used independently or in combination with measured references to improve content identification accuracy.

[0057] The Raman checkpoint system 100 can also perform multi-point sampling, in which multiple distinct target locations on the object are selected and measured independently. For example, FIG. 7 illustrates multi-point sampling of the container and of distinct layers within the container. These targets may be suggested by the machine vision subsystem or manually defined by the user through the user interface 122. Each target point is individually interrogated using the Raman probe 112, with separate SERDS or standard Raman measurements acquired at each location. This process enables spatial mapping of chemical composition across the object and is particularly useful for analyzing heterogeneous samples, layered structures (e.g., as in FIG. 7), or non-uniform distributions of materials. The Raman checkpoint system 100 may also compute a combined result or identify threat materials from any single measurement that triggers a match to the threat library.

[0058] The Raman checkpoint system may also include an autofocus subsystem (implemented with the electronics 120) that aligns the Raman probe 112 accurately with respect to the sample. The Raman signal, combined with laser-induced fluorescence, is monitored in real time to identify the optimal focus position along the Z-axis (optical axis of the Raman pump beam). This focus is achieved by increasing or maximizing the integrated signal entering the spectrometer 116. If desired, an offset can be applied to probe slightly deeper regions within the container.

[0059] FIG. 8 illustrates an autofocus sensor 808 integrated with the spectrometer 116. The spectrometer 116 receives both scattered Raman light and reflected light from the object 10 through a slit 802. A grating 804 diffracts the scattered Raman light to a detector array, such as a CCD or CMOS array, which detects the spectrum of the scattered Raman light. At theAttorney Docket No. PEND-015W001same time, the autofocus sensor 808 detects specular reflections from the grating 804. The electronics 120 actuates the stage 117 or zoom lens on the Raman probe 112 to maximize the power detected by the autofocus sensor 808, allowing real-time feedback for rapid, video-rate autofocus, which senses and maximizes the detected power.

[0060] Alternatively, the autofocus system can be designed to maximize the portion of the signal that remains once the signal contribution from the container 10 is removed, subtracted, or regressed out. The container signature can be acquired from each object as a reference measurement (e.g. measurement above the container’s fill line, where only the container is expected to contribute signal) or can be based on pre-recorded spectra of common container materials.

[0061] The autofocus, dynamic container signature subtraction, machine vision, user interface, and Raman spectroscopy subsystem can include and / or be controlled by one or more processors or controllers (e.g., in the onboard electronics 120 and / or in separate devices coupled to the Raman checkpoint system 100). For example, the electronics 120 in the Raman checkpoint system 100 may include a microcontroller and field-programmable gate array (FPGA) for local instrument control (for example motion control, CCD readout, control of thermo-electric coolers, laser driver, etc.). The electronics 120 can also include an embedded processor that hosts the system software and performs data processing and / or it can transmit the collected data via a wired or wireless connection to an external computer for processing and analysis.

[0062] The Raman system checkpoint may perform additional automated routines, including automated exposure adjustment of the CCD in the spectrometer 116. The auto-exposure control varies CCD acquisition settings, including integration time or electronic gain, to increase or maximize the signal-to-noise ratio without causing saturation of the CCD. Additionally, the system may automatically regulate the power of the Raman pump laser beam to balance the desire for higher Raman signal strength against the risk of sample degradation, especially for heat- or light-sensitive materials. These automation features operate in a closed-loop manner, using either pre-scans, live signal monitoring, or real-time image analysis as input. They ensure consistent spectral quality, reduce user burden, and reduce the risk of operator error. The Raman checkpoint system may further include safety thresholds or diagnostics to halt acquisition or reduce laser power if rapid saturation or unexpected signal behavior is detected. Together, these automation routines enable robust, repeatable measurements even when used by non-expert operators or in field conditions with diverse container types and sample chemistries.Attorney Docket No. PEND-015W001

[0063] The combination of SERDS, high-signal fiber collection, automated targeting, and dynamic container subtraction means that the Raman checkpoint system is a highly accurate chemical identification system. Designed specifically for non-expert users, such as Transportation Security Officers, the Raman checkpoint system 100 provides an intuitive touchscreen interface (user interface 122) that simplifies operation while maintaining robust analytical performance. By automating the measurement workflow and delivering simple pass / fail (go / no-go) feedback, the Raman checkpoint system dramatically reduces operator cognitive burden and alarm escalation.

[0064] This Raman checkpoint system 100 operates in two primary measurement modes:1. Through-container mode, shown in FIGS. 9A and 10A, where the Raman probe 112 interrogates the content through the container sidewall. Through-container mode works well for transparent or semi-transparent objects.2. Top-down mode, shown in FIGS. 9B and 10B, which enables analysis of the contents through an open lid or container opening. This mode is facilitated by a set of relay optics 118, shown in FIGS. 9 A, 9B, 10 A, and 11, that extend the Raman probe’s focus vertically into the container.The Raman checkpoint system’s robust design eliminates the need for consumables, manual sampling, and frequent maintenance, making it highly efficient and cost-effective for checkpoint screening applications. With its ability to address fluorescence interference, safety concerns, and operational inefficiencies, the Raman checkpoint system represents a significant advancement in secondary screening technology.Triage Capabilities

[0065] The Raman checkpoint system 100 can act as a chemical identification tool and an effective triage instrument. In through-object transmission imaging mode, the Raman checkpoint system 100 determines the opacity of an object 10 by measuring the light transmission within the Raman spectral range, which may include both the pump wavelength and the expected range of Raman scattered wavelengths. If the transmission is below a predefined threshold, indicating that the object 10 is too opaque for effective Raman analysis, the Raman checkpoint system 100 immediately advises the user via the user interface 122 to employ an alternative alarm resolution technology. Similarly, in exterior imaging mode, in conjunction with machine vision technology, the Raman checkpoint system 100 can assess the nature of the object 10 and estimate its likely transmissivity based on prior learning. If theAttorney Docket No. PEND-015W001Raman checkpoint system 100 predicts insufficient transmissivity (e.g., by recognizing the object 10 as having a metal outer surface), it can preemptively direct the user via the user interface to bypass Raman analysis, avoiding delays caused by fruitless measurement attempts. This dual imaging-based triage capability enhances operational efficiency by ensuring that Raman analysis is only applied to objects with a high likelihood of successful identification.

[0066] The Raman checkpoint system 100 includes a decision logic subsystem (implemented, e.g., in the onboard electronics 120) that uses through-object imaging to assess whether Raman analysis is likely to succeed. The system 100 illuminates the object 10 with infrared or nearinfrared light and measures transmitted intensity through the object 10. If the detected transmission falls below a configurable threshold — indicating that the object 10 is too opaque for effective Raman interrogation — the system 100 can either: (a) automatically bypass Raman analysis and prompt the user to employ an alternate detection method (e.g., X-ray, explosive trace detection), or (b) display a warning or advisory through the user interface 122, indicating a low likelihood of successful inspection. This decision logic may be further informed by exterior-surface imaging and machine vision analysis, which can recognize opaque container types (e.g., metal cans) or detect known high-opacity surface patterns. By implementing this pre-screening step, the system 100 reduces unnecessary measurements, accelerates throughput, and prevents false negatives due to insufficient optical access.Laser System

[0067] The Raman checkpoint system 100 includes a laser source 110 that serves as the primary excitation source for inducing Raman scattering in the sample under analysis. The laser source 110 is configured to emit a monochromatic, coherent beam of light, typically in the visible or NIR spectral range, depending on the specific application and the nature of the sample.

[0068] The laser source 110 can operate at a fixed wavelength, selected to increase or maximize the Raman scattering cross-section while reducing or minimizing fluorescence from the sample. Common wavelengths for Raman spectroscopy include 532 nm (green), 785 nm (NIR), and 1064 nm (NIR), each offering different advantages based on the sample's characteristics. Other wavelengths (e.g. 830 nm) can also be chosen depending on the application. Alternative laser sources 110 may be tunable over a range of closely spaced wavelengths and configured to emit Raman pump beams at different wavelengths for Shift Excitation Difference Raman Spectroscopy (SERDS) measurements as described above. AndAttorney Docket No. PEND-015W001as discussed above and immediately below, the laser source 110 may include two separate lasers that emit at slightly different wavelengths for implementing SERDS.

[0069] The output power of the laser source 110 is adjustable, allowing for fine-tuning of the excitation intensity to prevent sample damage while optimizing signal-to-noise ratio.

[0070] The laser source 110 is coupled to the optical system via a series of mirrors or fiber optics, ensuring stable and efficient delivery of the excitation light to the sample.

[0071] In some configurations, the laser source 110 may be pulsed or modulated, depending on the specific requirements of the measurement.Shifted Excitation Raman Difference Spectroscopy (SERDS)

[0072] The Raman spectroscopic system can be equipped with SERDS capability, an advanced technique designed to enhance the quality of Raman measurements, particularly in challenging scenarios where laser-induced fluorescence is present.

[0073] In SERDS, the Raman checkpoint system makes two Raman measurements in quick succession using Raman pump laser beams at slightly different wavelength, typically shifted by a few nanometers. This wavelength shift can be achieved by using a single tunable laser or two different lasers. The tunable laser’s wavelength can be finely tuned, for example, by adjusting the tunable laser’s temperature. This allows for precise control of the wavelength shift without the need for additional laser sources.

[0074] Alternatively, the laser source 110 can include two lasers, each emitting at a slightly different wavelength. These lasers may utilize grating feedback, a distributed feedback structure directly on the semiconductor laser, a distributed Bragg grating mirror, or other wavelength-selective mechanisms to define their emission wavelengths accurately. The lasers are typically designed or selected to ensure that the wavelength shift between them is optimal for SERDS. The lasers may be packaged into a single laser package and beam-combined using various existing means of laser beam combining.

[0075] One benefit of using SERDS is its ability to effectively mitigate the interference caused by laser-induced fluorescence, which can often overshadow the weak Raman signals. Fluorescence typically remains constant over small wavelength shifts, while the Raman signals shift in direct proportion to the excitation wavelength. By taking two measurements with slightly different excitation wavelengths, the fluorescence background, which is nearly identical in both measurements, can be subtracted, leaving the Raman signal, which varies withAttorney Docket No. PEND-015W001excitation wavelength. This subtraction process highlights the Raman signal while significantly reducing or eliminating the fluorescence contribution. The result is a much clearer Raman spectrum, free from the distorting effects of fluorescence, allowing for more accurate and reliable identification of the sample’s molecular components.

[0076] The integration of SERDS into the Raman checkpoint system is particularly advantageous for samples prone to fluorescence, such as biological materials, complex mixtures, or substances with intrinsic chromophores. SERDS enhances the system’s capability to deliver high-quality spectral data even in the presence of strong fluorescence, expanding the range of samples that can be effectively analyzed.Internal Calibration Standards

[0077] FIG. 12 shows the Raman checkpoint system 100 with an optional internal calibration module 1200 that enables automated self-calibration routines without user intervention. Placing the calibration module 1200 inside the instrument enclosure / housing but outside of the sample compartment 101 as shown in FIG. 12 protects the calibration module 1200 and its contents from the user and from contamination, e.g., by samples being measured. A transparent window 1206 separates the sample compartment 101 from the internal compartment that holds the Raman probe 112, calibration module 1200, and other components.

[0078] This calibration module 1200 comprises at least two reference elements: a dark reference material 1202 and a chemical Raman calibration standard 1204. These calibration standards 1202 and 1204 can be accessed via an automated calibration routine positioning the Raman probe 112 to focus on or in front of one or the other standard and acquire data. The data is then processed by the spectrometer 116 and electronics 120 to update the calibration values of the Raman checkpoint system 100.

[0079] The dark reference material 1202 is selected for its extremely low reflectivity and negligible Raman scattering characteristics. Suitable dark reference materials include black plastics that are very absorptive and produce essentially no detectable Raman signal. The dark reference material 1202 serves to capture the Raman checkpoint system’s dark current, electronic noise, and background signal, enabling accurate subtraction of baseline artifacts during both calibration and sample analysis.

[0080] The Raman calibration standard 1204 includes a chemically stable calibration sample, such a common white pharmaceutical powder, chosen for its long-term stability and reproducible Raman signature. The material is preferably non-hygroscopic and inert, exhibitingAttorney Docket No. PEND-015W001distinct Raman peaks distributed across the system’s spectral range. To prevent contamination and degradation over time due to environmental factors such as humidity or oxidation, the Raman calibration standard 1204 is housed within a sealed enclosure, transparent to the excitation and scattered Raman light. The Raman checkpoint system 100 can even include more than one Raman calibration standard 1204, each with a different Raman spectrum, for more comprehensive calibration.

[0081] During a self-calibration procedure, the system automatically positions the Raman probe 112 in front of the calibration standards 1202 and 1204 and, at the proper focus, acquires spectra from both calibration standards 1202 and 1204. These spectra are used to adjust baseline offsets, calibrate the wavelength axis, and normalize system response, ensuring consistent spectral accuracy and signal fidelity across varying environmental and operational conditions. The automated use of internal calibration standards 1202 and 1204 eliminates the need for manual calibration and supports field-deployable or unattended operation scenarios.Metal Detector

[0082] FIG. 13 shows the Raman checkpoint system 100 with an optional metal detector 1302 integrated into the base of the sample compartment 101 and operably coupled to the electronics 120 and user interface 122. For instance, the metal detector 1302 can include an inductive coil that generates an electromagnetic field. When a conductive object (metal) enters the electromagnetic field, eddy currents are induced, changing the inductive coil’s impedance. This change is measured and used to infer the presence of metal.

[0083] The metal detector 1302 can be on, part of, or separate from the rotation stage 106 that supports the object 10. It can be positioned to touch object 10 or to be apart from the object 10, so long as it is close enough to the object 10 to sense whether the object 10 includes any metal. In operation, the metal detector 1302 senses whether the object 10 is composed of or includes any metal (e.g., aluminum cans). Upon detection of significant metal content, the Raman checkpoint system may determine that the object is likely opaque to Raman interrogation and may prompt the user with appropriate guidance (e.g., “Open container and use top measurement mode” or “Use alternate detection method”) via the user interface 122.Mechanical Actuator

[0084] FIG. 14 shows the Raman checkpoint system 100 with an optional mechanical actuator 1402 configured to induce motion of the object 10 under analysis. For example, the mechanical actuator 1402 can agitate, shake, spin, translate, and / or rock the object 10 back-and-forth, eitherAttorney Docket No. PEND-015W001gently or more violently. Moving the object 10 like this during the targeting / aiming phase induces motion in the object’s contents 11, including displacement of the liquid fill line or meniscus within the object 10, thereby facilitating more accurate identification of the fill line by the user or by an automated image analysis workflow. The mechanical actuator 1402, metal detector 1302, and calibration module 1200 can all be used individually, together, or in different sub-combinations (mechanical actuator 1402 and metal detector 1302, mechanical actuator 1402 and calibration module 1200, or metal detector 1302 and calibration module 1200).Raman Measurement Modes

[0085] As explained above, the Raman checkpoint system 100 supports two measurement modes — (1) through-container / side mode and (2) into-container / top-down mode — to provide flexible and comprehensive chemical analysis of a wide range of objects, including containers such as bottles, vials, packages, pouches, and envelopes and their contents such as liquids or powders. Each mode is optimized for specific object types and operational scenarios.1. Through-Container / Side Mode

[0086] In through-container mode, shown in FIGS. 9A and 10A, the Raman probe 112 is positioned to measure the contents 11 of a container 10 by directing the Raman probe laser beam through the container’s wall. This mode is particularly effective for transparent or semitransparent containers, such as plastic bottles, pouches, or coated packages, where the system can penetrate the container material to access the chemical composition inside.

[0087] To perform a measurement in through-container mode, the Raman checkpoint system 100 uses the integrated motion control subsystem (including stage 117) to align the Raman pump laser beam laterally (X-Y translation) and focus it to a specific depth within the container (Z-axis adjustment). This depth can be determined by using the autofocus to find the depth that produces the maximum total signal (Raman + laser-induced fluorescence), then either focusing the Raman pump laser beam to this depth or to depth that about 1 mm ahead or behind this depth on the optical axis under the assumption that most containers are less than about 1 mm thick. The machine vision system assists this process by imaging the object and identifying features such as labels, boundaries, and fill lines. The user interface 122 displays the captured images and allows the operator to confirm or select target points on the container surface.

[0088] One feature of through-container mode is the Raman checkpoint system’s ability to acquire a reference spectrum of the container-only region, typically above the fill line. UsingAttorney Docket No. PEND-015W001machine vision analysis, the Raman checkpoint system 100 determines the most suitable position for the reference measurement and then acquires the container signal. Once the reference spectrum is captured, the Raman probe laser beam is focused deeper into the object, targeting regions that include both the container wall and the contents. The Raman checkpoint system 100 then dynamically subtracts the container spectrum to remove the container’s spectral contribution and isolate the Raman signal of the contents.

[0089] Through-container mode also benefits from the rotating sample plate (rotation stage 106), which allows the object 10 to be repositioned for optimal transmissivity or signal collection. By aligning the container’s most favorable face or side with the Raman probe laser beam, the Raman checkpoint system 100 increases signal penetration and reduces measurement interference caused by irregular or highly absorptive surfaces.2. Into-Container / Top-Down Mode

[0090] In top-down mode, shown in FIGS. 9B and 10B, the Raman probe 112 analyzes the contents 11 of a container 10 by directing the laser vertically through an opening in the container, such as an open lid or cap, or a bottle or pouch opening. This mode is well-suited for containers with metallic walls or particularly thick walls and is particularly effective for direct access to contents like powders, gels, and liquids.

[0091] To facilitate this measurement mode, the Raman checkpoint system 100 includes a set of relay optics 118 mounted on the motion control subsystem, which may include one or more translation stages and / or other actuators. The relay optics 118 extend the probe’s focal point downward into the container 10, enabling accurate targeting of the contents 11. During operation, the Raman probe 112 and relay optics 118 are precisely positioned over the container 10 opening as shown in FIG. 9B using the system’s X-Y-Z motorized stages. For instance, the relay optics 118 can be placed above the container’s opening at the desired distance from the surface of the container’s contents (e.g., the relay optics focus should be on or below the top surface of the contents). Then the Raman probe 112 is positioned with respect to the relay optics 118 to match the probe focus with the nominal relay input. In other words, the relay optics 118 may be designed assuming a source at a specific point such that proper positioning of the Raman probe 112 places the probe focus at that point. Machine vision assists this alignment by imaging the obj ect’ s top surface and identifying the opening for optimal targeting.

[0092] The relay optics 118 can be translated laterally and vertically as desired, ensuring the Raman probe laser beam focuses accurately on the desired region inside the container 10. OnceAttorney Docket No. PEND-015W001the Raman probe laser beam is aligned properly, the Raman checkpoint system 100 performs a top-down Raman measurement, capturing the signal directly from the contents 11. This mode eliminates the need for signal penetration through container walls, providing high-quality Raman spectra without interference.

[0093] In top-down mode, the relay optics 118 are automatically aligned with respect to the container 10 opening using real-time feedback from the machine vision subsystem. The Raman checkpoint system 100 dynamically adjusts focus depth based on signal optimization, ensuring the Raman pump beam laser targets the desired internal region accurately.Workflow for Chemical Identification

[0094] The Raman checkpoint system 100 operates through a streamlined, automated workflow designed for non-expert personnel such as Transportation Security Officers (TSOs). The system’s machine vision, motion control, and advanced control processes work together to minimize user input while ensuring accurate and reliable chemical identification.Step 1: Object Placement and Imaging

[0095] The operator places the object 10 (e.g., a bottle, vial, pouch, or envelope containing a liquid, gel, or powder) onto the rotating sample plate (rotation stage 106) inside the sample compartment 101 and closes the interlocked door 104. The interlock system ensures that the laser source 110 cannot activate until the door 104 is fully closed, ensuring Class 1 laser safety compliance.

[0096] Once the door 104 is secured, the Raman checkpoint system 100 initiates the imaging process using its dual-imaging subsystem:1. Exterior Illumination: White-light LEDs 302 provide clear images of the object’s exterior, including any labels, boundaries, or visible markings.2. Through-Object Transmission Imaging: One or more (near-)infrared light sources 402 illuminate the object 10 from behind, revealing internal features such as fill lines, hidden compartments, or irregularities. The Raman checkpoint system 100 also assesses the object’s transmissivity to determine its suitability for through-container measurements.

[0097] The captured images are displayed on the user interface 122 for operator review, and the machine vision system processes the images to identify reference and target measurement regions.Attorney Docket No. PEND-015W001Step 2: Target Selection and Probe Alignment

[0098] Based on the processed images, the Raman checkpoint system 100 suggests one or more measurement points, including:• Reference points (e.g., container Raman measurement aiming point 501 in FIG. 5A):Locations where only the container 10 is expected to contribute to the signal (e.g., above the fill line).• Target points (e.g., contents Raman measurement aiming point 503): Regions likely to contain the contents 11 for chemical identification.

[0099] The operator can confirm these suggested points or manually select additional targets using the (touchscreen) user interface 122. Once the points are defined, the motion control subsystem aligns the Raman probe 112 to each location. The Raman probe’s position is adjusted using X-Y lateral translation, Z-axis focus adjustment, and, if appropriate, a tilt angle to optimize the measurement depth and targeting. For top-down mode, the relay optics 118 are precisely positioned with respect to the container opening.Step 3: Raman Measurements

[0100] The Raman probe 112 and spectrometer 116 perform measurements at the selected target points. For through-container mode, the Raman checkpoint system 100 may first acquire a reference spectrum from a container-only region, such as a portion of the container 10 above the fill line. This reference spectrum may be used to dynamically subtract the container’s contribution from the subsequent measurements taken deeper into the object 10. The system’s SERDS technology can capture two spectra at slightly shifted laser wavelengths, effectively suppressing fluorescence and isolating the Raman signal.

[0101] For each measurement point, the Raman checkpoint system 100 collects the Raman signal using a fiber bundle 114, which increases signal throughput while preserving high spectral resolution. The autofocus subsystem ensures precise focusing by monitoring the integrated Raman signal in real time and adjusting the probe position for optimal alignment. Step 4: Data Processing and Chemical Identification

[0102] Once the Raman measurements are completed, the Raman checkpoint system 100 processes the collected spectra using:1. Container Subtraction: The reference spectrum is subtracted from the target spectrum to isolate the Raman signal of the contents.Attorney Docket No. PEND-015W0012. Mixture Analysis: The system identifies the chemical composition of the sample (e.g., the contents of a container), resolving up to 5-6 individual chemicals even in complex mixtures.3. Threat Detection: The identified chemicals are compared against a built-in chemical library that includes known hazardous materials such as explosives, toxic industrial chemicals, and precursors. If one or more identified constituents matches a threat entry, the Raman checkpoint system generates a threat indication, which may include visual alerts (e.g., red screen or icon) displayed via the user interface 122, audible alarms, and / or automated reporting or flagging in the system log. The alert is designed to support checkpoint triage workflows and ensure immediate operator attention.

[0103] The results are displayed on the user interface 122 with clear, actionable feedback. Threat chemicals can be flagged using a color-coded system (e.g., red for hazardous, green for safe), allowing operators to make rapid decisions about potential risks.

[0104] The Raman checkpoint system’s threat material library may be stored locally within the Raman checkpoint system 100 (e.g., by a memory in or coupled to the onboard electronics 120) and is optionally updatable via secure administrative access. This capability enables the operator or system administrator to incorporate newly identified threat substances, remove outdated entries, or tailor the library to specific operational contexts (e.g., regionspecific precursors or industry-specific hazards). Support for secure updates ensures that the system remains responsive to evolving chemical threats and maintains long-term operational relevance in dynamic security environments.Step 5: Review and Reporting

[0105] The Raman checkpoint system 100 generates a summary of the analysis, including:• Images of the object and target measurement points;• Raman spectra and identified chemicals; and• Threat assessment results. These results can be saved, reviewed, or exported for further analysis, providing a complete and transparent record of the screening process. The user interface 122 can show this summary to the user.Attorney Docket No. PEND-015W001

[0106] The Raman checkpoint system 100 combines advanced spectroscopy, automation, and safety features to deliver a comprehensive solution for chemical identification. By supporting both through-container and top-down measurement modes, the Raman checkpoint system 100 offers unmatched flexibility for a wide range of checkpoint applications, ensuring fast, reliable, and operator-friendly performance.Field Data Capture and Machine Learning Integration

[0107] To support ongoing system optimization and performance improvements, the Raman checkpoint system 100 includes a data capture and learning architecture configured to collect, store, and utilize paired data sets of object images and associated Raman spectral measurements. This architecture is designed to operate across distributed checkpoint installations, each of which can contribute to a centralized data repository.

[0108] Each time a Raman measurement is performed, the Raman checkpoint system 100 may capture and associate the following elements:• A visible-light image of the object acquired under exterior illumination;• A through-object infrared or near-infrared transmission image;• The set of reference and target points selected by the system or user;• The corresponding Raman spectra acquired at each target point, including SERDS differential spectra;• Metadata such as scan time, operator actions, laser power, exposure settings, and system outcome (e.g., pass / fail, threat identified, bypass triggered).

[0109] These data elements are stored locally (e.g., in memory in or coupled to the onboard electronics 120) and optionally transmitted to a centralized server for aggregation. The central repository builds a continuously growing multi-modal dataset combining imaging data and spectroscopic measurements, with links to any chemical identification results, user annotations, or post-measurement labels (e.g., forensic lab confirmation in law enforcement applications).

[0110] This enables a variety of downstream capabilities, including:• Automated detection of unknown or out-of-library spectra, for example by clustering spectra with low confidence matches;• Training of machine learning models that integrate visual features and Raman spectral features to improve signal interpretation, fill line detection, or optimal point selection;Attorney Docket No. PEND-015W001• Predictive modeling to optimize measurement strategy, such as prioritizing top-down versus through-container mode based on container appearance and history;• Adaptive expansion of the chemical or container reference library, using aggregated high-confidence matches and curated examples;• Operator training gap analysis and system performance tuning, using usage statistics derived from interaction logs, error rates, and throughput metrics.

[0111] In some implementations, a central administrative interface may allow review and approval of spectra proposed for inclusion in the reference library, and deployment of updated libraries to field-deployed systems. These updates may be distributed as signed packages, either manually installed or automatically delivered based on user permissions and network connectivity.

[0112] FIG. 15 illustrates an architecture for distributed data collection and centralized system management within a network of Raman checkpoint systems. Multiple Raman checkpoint systems 100-1 through 100-7V are each configured to communicate with a central server 1500. The Raman checkpoint systems 100 transmit data including Raman spectra, images, system status information, usage statistics, and alarm events to the central server 1500. In return, the central server 1500 can distribute software and library updates, as well as alarm resolution information, back to the individual Raman checkpoint systems 100. The central server 1500 also interfaces with supervisory personnel and developers. Supervisors may access real-time or historical data for oversight and incident response. Developers 1502 can receive aggregated data from the central server 1500 to support the development and improvement of models, software, reference libraries, and detection techniques. Updated versions of these components may be sent back through the central server 1500 to deployed Raman checkpoint systems 100. This architecture enables field-driven learning, centralized oversight, and continuous improvement of Raman checkpoint performance across a distributed deployment.Conclusion

[0113] While various inventive embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and / or structures for performing the function and / or obtaining the results and / or one or more of the advantages described herein, and each of such variations and / or modifications is deemed to be within the scope of the inventive embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurationsAttorney Docket No. PEND-015W001described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and / or configurations will depend upon the specific application or applications for which the inventive teachings is / are used. Those skilled in the art will recognize or be able to ascertain, using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, inventive embodiments may be practiced otherwise than as specifically described and claimed. Inventive embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and / or methods, if such features, systems, articles, materials, kits, and / or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure.

[0114] Also, various inventive concepts may be embodied as one or more methods, of which an example has been provided. The acts performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.

[0115] All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms.

[0116] The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”

[0117] The phrase “and / or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the components so conjoined, i.e., components that are conjunctively present in some cases and disjunctively present in other cases. Multiple components listed with “and / or” should be construed in the same fashion, i.e., “one or more” of the components so conjoined. Other components may optionally be present other than the components specifically identified by the “and / or” clause, whether related or unrelated to those components specifically identified. Thus, as a non-limiting example, a reference to “A and / or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including components other than B); in anotherAttorney Docket No. PEND-015W001embodiment, to B only (optionally including components other than A); in yet another embodiment, to both A and B (optionally including other components); etc.

[0118] As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of components, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of’ or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one component of a number or list of components. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e., “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law.

[0119] As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more components, should be understood to mean at least one component selected from any one or more of the components in the list of components, but not necessarily including at least one of each and every component specifically listed within the list of components and not excluding any combinations of components in the list of components. This definition also allows that components may optionally be present other than the components specifically identified within the list of components to which the phrase “at least one” refers, whether related or unrelated to those components specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including components other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including components other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other components); etc.

[0120] In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’ shallAttorney Docket No. PEND-015W001be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

Claims

Attorney Docket No. PEND-015W001CLAIMS1. A method of inspecting contents of a container, the method comprising:acquiring a visible image of the container;acquiring an infrared image of the container;selecting a target point on or in the container based on the visible image of the container and / or the infrared image of the container, the target point being a point where the contents of the container are expected to contribute to a Raman signal;measuring a Raman spectrum of the target point; anddetermining a Raman spectrum of the contents of the container based on the Raman spectrum of the target point.

2. The method of claim 1, wherein acquiring the visible image of the container comprises:illuminating an exterior surface of the container with white light; andimaging the exterior surface of the container.

3. The method of claim 1, wherein acquiring the infrared image of the container comprises:illuminating the container with infrared light at a wavelength of 700 nm to 2500 nm; anddetecting the infrared light transmitted through the container.

4. The method of claim 1, wherein measuring the Raman spectrum of the target point comprises making a Shifted Excitation Difference Raman Spectroscopy (SERDS) measurement.

5. The method of claim 1, wherein measuring the Raman spectrum of the target point comprises scanning a laser beam across an area of the container to prevent ignition of the contents of the container.

6. The method of claim 1, wherein measuring the Raman spectrum of the target point comprises illuminating the contents of the container with a laser beam through an opening in the container.Attorney Docket No. PEND-015W0017. The method of claim 1, further comprising, before measuring the Raman spectrum of the target point:sealing the container in an eye-safe housing.

8. The method of claim 1, further comprising:selecting a reference point on or in the container based on the visible image of the container and / or the infrared image of the container, the reference point being a point where the contents of the container are not expected to contribute to a Raman signal; and measuring a Raman spectrum of the reference point,wherein determining the Raman spectrum of the contents of the container is further based on the Raman spectrum of the reference point.

9. The method of claim 8, wherein selecting the reference point and selecting the target point comprises:detecting a fill line of the contents of the container;selecting the reference point to be on the container above the fill line; and selecting the target point to be on or in the container below the fill line.

10. The method of claim 9, wherein detecting the fill line of the contents of the container comprises:moving the container while acquiring the visible image of the container and / or acquiring the infrared image of the container.

11. The method of claim 1, further comprising:calibrating a spectrometer used to measuring the Raman spectrum of the target point against a dark reference material having negligible Raman scattering characteristics and a Raman calibration standard having a known Raman spectrum.

12. The method of claim 1, further comprising:detecting whether the container includes or contains any metal.

13. A system for inspecting an object, the system comprising:an eye-safe housing with a door for inserting the object into the eye-safe housing; a laser source, contained within the eye-safe housing, to illuminate the object within the eye-safe housing when the door is closed; andAttorney Docket No. PEND-015W001an interlock, operably coupled to the door and the laser source, to prevent the laser source from illuminating the object when the door is open.

14. The system of claim 13, wherein the object comprises a container, and further comprising:relay optics, in optical communication with the laser source, to direct a laser beam from the laser source through an opening in the container to contents of the container.

15. The system of claim 13, further comprising:at least one actuator, contained within the eye-safe housing, to adjust a focus position of a laser beam emitted by the laser source.

16. The system of claim 15, wherein the at least one actuator is further configured to scan a spot formed by the laser beam across a surface of the object, and further comprising:a monitoring system, operably coupled to the at least one actuator and / or to the laser source, to detect a malfunction of the at least one actuator and / or of the laser source that could cause the laser beam to ignite and / or damage the object and to at least one of attenuate, redirect, block, or turn off the laser beam in response to detection of the malfunction.

17. The system of claim 13, further comprising:a detector, contained within the eye-safe housing, to detect a Raman signal scattered from the object in response to illumination of the object by the laser source.

18. The system of claim 17, wherein the laser source and the detector are configured to make a Shifted Excitation Difference Raman Spectroscopy (SERDS) measurement of the object.

19. The system of claim 13, further comprising:a visible light source, contained within the eye-safe housing, to illuminate the object with visible light;an infrared light source, contained within the eye-safe housing, to illuminate the object with infrared light;a visible camera, contained within the eye-safe housing, to acquire a visible image of the object; andan infrared camera, contained within the eye-safe housing, to acquire an infrared image of the object.Attorney Docket No. PEND-015W00120. The system of claim 19, further comprising:a user interface, operably coupled to the visible camera and the infrared camera, to display the visible image and / or the infrared image to an operator of the system.

21. The system of claim 20, wherein the user interface is further configured to display an indication of a transmissivity of the object and an indication of a likelihood of successfully inspecting the object.

22. The system of claim 20, wherein the object is a container, and further comprising: a processor, operably coupled to the laser source, the visible camera, the infrared camera, and the user interface, to automatically select a reference point and a target point based on the visible image and / or the infrared image, the reference point being a point on or in the container where contents of the container are not expected to contribute to a Raman signal and the target point being a point in the container where the contents of the container are expected to contribute to a Raman signal,wherein the user interface is configured to display the reference point and / or the target point to the operator of the system and to enable the operator of the system to select and / or change the reference point and / or the target point.

23. The system of claim 22, wherein the processor is configured to generate a Raman spectrum of the contents of the container based on a Raman spectrum of the reference point and a Raman spectrum of the target point.

24. The system of claim 19, wherein the object is a container, and further comprising: an actuator to move the container while the visible camera acquires the visible image of the container and / or the infrared camera acquires the infrared image of the container.

25. The system of claim 13, further comprising:a spectrometer, in optical communication with the object, to measure a spectrum of light scattered from the object; andan autofocus sensor, operably coupled to the spectrometer, to adjust a focus of the laser source based on an amplitude of the light collected by the spectrometer.

26. The system of claim 25, wherein the autofocus sensor is configured to detect a specular reflection from a grating of the spectrometer.Attorney Docket No. PEND-015W00127. The system of claim 25, further comprising:an internal calibration module for calibrating the spectrometer, the internal calibration module comprising a dark reference material having negligible Raman scattering characteristics and a Raman calibration standard having a known Raman spectrum.

28. The system of claim 13, further comprising:a metal detector to detect whether the object includes or contains any metal.

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