Non-contact handheld continuous point reflectance spectrometry scanner and methods therefor

Abstract

Provided are a system, method, and handheld scanner for non-contact continuous point reflectance spectrometry. The scanner includes light sources for illuminating a sample, an aperture for collecting reflected light from the sample and a fiber optic cable for transmitting the reflected light to a spectrometer. An LED strip comprising a plurality of LEDs for indicating a speed and a direction for scanning is positioned adjacent the sample. The system further includes a backpack unit housing one or more spectrometers. A method for non-contact continuous reflectance measurements includes holding the scanner 6-20 cm above the sample; illuminating the sample by the light sources on the scanner; moving the scanner, by hand, over the center line of the sample in a speed and direction indicated by illuminated LEDs on the LED strip; and collecting reflectance measurements off the sample while moving the scanner, by hand, along the centerline of the sample.

Description

NON-CONTACT HANDHELD CONTINUOUS POINT REFLECTANCE SPECTROMETRY SCANNER AND METHODS THEREFORTechnical Field

[0001] The embodiments disclosed herein relate to reflectance spectrometry, and, in particular to a non-contact, handheld continuous point scanner.Introduction

[0002] Reflectance spectrometry is a form of spectrometry that analyzes reflected electromagnetic energy. Reflectance spectrometry typically involves illuminating a sample and collecting reflectance data from the surface of the sample to determine the composition of the sample material. For example, reflectance spectrometry is routinely used to identify the mineralogical composition of both intact rock and crushed rock.

[0003] Existing reflectance spectrometry sensor systems typically operate in the following ways. Point spectrometers, typically mounted over a conveyor belt or a movable sample stage or as part of a movable sensor-head, collect point data in continuous collection mode (e.g., hundreds of spectra can be collected per minute). Point spectrometers also collect point-by-point data in non-continuous collection mode with the spectrometer or the samples being moved between individual measurements (e.g., <10 spectra collected per minute). Spectral imaging cameras acquire reflectance imagery data in continuous collection mode using either push-broom scanning or frame-grabbing (e.g., millions of spectra collected per minute).

[0004] Point spectrometers used for continuous data collection are operated at variable distances from the sample (i.e. , without contacting the sample), and samples are moved beneath the sensor by an electronic control system or the spectrometer is mounted on a movable sensor-head above a stationary sample. In non-continuous collection mode, point spectrometers can be fitted with a probe that is pressed flush against a sample surface and is moved stepwise by hand from one contact point to the next to collect point measurements. Non-continuous data collection can also be carried out without sample contact. Spectral imaging cameras are typically operated at a distanceof >20 centimeters from the surface of the sample and either the sample or the cameras are moved by an electronic control system.

[0005] A limitation of non-continuous point data collection systems is that low data volumes are produced and continuous sample coverage is not possible. Point collection systems operating in continuous mode can produce higher data volumes and provide continuous sample coverage, but their electronic control systems for sample or spectrometer movement can make them larger in size and more prone to electronic or mechanical failures compared to non-continuous point spectrometer systems. This can make them difficult to operate in remote locations. Spectral imaging cameras collect extremely large volumes of data which can make it difficult to rapidly transfer and process the data. In addition, continuous imaging cameras and conveyor belt systems are also often large and heavy (e.g., exceeding 1000 kg in some cases) and contain complex electronic control systems, making them also difficult to transport and reliably operate in remote locations.

[0006] Accordingly, there is a need for a non-contact handheld continuous point spectrometer scanner to overcome the limitations of existing systems.Summary

[0007] A portable, handheld scanner (HHS) for analyzing intact rock and crushed rock is provided. The HHS is a discrete point data reflectance spectrometry system that operates in continuous collection mode for capturing reflectance data (e.g., visible and / or infrared) measurements from a target material. The HHS operates at a distance of about 6 to 20 centimeters above the surface of the material and is moved by the operator’s hand.

[0008] The HHS includes a handheld unit that is used to scan across the surface of the material. The handheld unit has light sources and reflectors to illuminate the sample. The light sources are configured to enable continuous, non-contact collection of spectral measurements at a specified distance to the target material. The light sources are aligned at oblique angles with respect to one another to provide maximum intensity and to reduce shadows. A fiber optic cable transmits the reflected electromagnetic radiation to one ormore spectrometers, which can detect different electromagnetic wavelengths. The handheld unit is accompanied by a separate or integrated display screen. The handheld unit may optionally include a light shield for outdoor use, a height above sample indicator, and spacers to keep the HHS at consistent distance above the surface of the target material. An LED strip can also be used to provide information about where the measurements should be collected at a given time.

[0009] The one or more spectrometers may be commercially available small-form factor spectrometers that are carried in a backpack by the user. If two spectrometers are present, each one will detect a different electromagnetic range (e.g., visible and / or infrared). The backpack may further house a battery and power supply components for powering the HHS and spectrometer(s). A control device (e.g., computer and / or tablet) running software for configuring the spectrometer(s) is carried by the user or is housed in the backpack and is connected to the spectrometer (wired or wirelessly).

[0010] The HHS is lightweight, easy to ship, easy to use in remote locations, and provides sufficient coverage of the sample surface, with a measurement spot size of 1 to 2 centimeters and >100 spectral measurements collected per meter of scanning. The HHS can take 30 to 60 seconds to scan one meter of material, and the data volumes produced by this scanning are relatively low (e.g., 2-3 MB per meter) allowing for efficient data processing. The spectral data can be stored locally on the an acquisition device and processed, and / or the spectral data can also be uploaded to a dedicated computing cloud-based platform where the data is stored and processed. The data are processed to identify different rock compositional groups that can subsequently be linked to lithology, alteration, and mineralization. The HHS is moved by hand avoiding the need for complex electronics or robotics.

[0011] According to some embodiments, there is a handheld scanning system comprising a handheld scanner, an LED strip and a backpack unit. The handheld scanner includes two or more light sources for illuminating a sample, an aperture disposed between the light sources for collecting reflected light from the sample and a fiber optic cable in communication with the aperture for transmitting the reflected light to the spectrometer(s). The LED strip is positioned adjacent to the sample and includes aplurality of LEDS for indicating a speed and a direction for scanning the sample. The backpack unit houses one or more spectrometers and a battery pack for powering the scanner and spectrometer(s).

[0012] The scanning system further comprises an acquisition and control device configured to receive and process reflectance data from the spectrometer(s). The acquisition device is further configured to transmit reflectance data to a cloud server for further spectral data processing / analysis.

[0013] According to an embodiment, there is a method for non-contact continuous reflectance measurements. The method comprises positioning an LED strip parallel to the center line of the sample; holding a handheld scanner 6-20 cm above the sample; illuminating the sample by light sources on the scanner; moving the scanner, by hand, over the center line of the sample in a speed and direction indicated by illuminated LEDs on the LED strip; and collecting reflectance measurements off the sample while moving the scanner, by hand, along the centerline of the sample. The method may further comprise adjusting the speed and direction of scanning according to the illuminated LEDs on the LED strip.

[0014] Other aspects and features will become apparent, to those ordinarily skilled in the art, upon review of the following description of some exemplary embodiments.Brief Description of the Drawings

[0015] The drawings included herewith are for illustrating various examples of articles, methods, and apparatuses of the present specification. In the drawings:

[0016] FIG. 1 is a block diagram of a handheld scanning system, according to an embodiment;

[0017] FIGS. 2A and 2B are top and bottom plan views, respectively of a handheld scanner, according to an embodiment;

[0018] FIG. 2C is a front view of the handheld scanner shown in FIGS. 2A and 2B;

[0019] FIG. 2D is a side cross-sectional view of the handheld scanner through section A-A in FIG. 20;

[0020] FIG. 2E is a diagram showing illumination of a sample by the handheld scanner in FIGS. 2A-2D; and

[0021] FIG. 3 is a flow chart of a method for non-contact continuous reflectance measurements, according to an embodiment.Detailed Description

[0022] Various apparatuses or processes will be described below to provide an example of each claimed embodiment. No embodiment described below limits any claimed embodiment and any claimed embodiment may cover processes or apparatuses that differ from those described below. The claimed embodiments are not limited to apparatuses or processes having all of the features of any one apparatus or process described below or to features common to multiple or all of the apparatuses described below.

[0023] As used herein, the terms “scan” or “scanning,” refer to the act of holding and moving a handheld scanner over a sample.

[0024] Referring to FIG. 1 , illustrated therein is a block diagram of a handheld scanning system 100, according to an embodiment. The system 100 provides for collecting infrared and / or visible light reflectance data from the surface of a sample such as intact and crushed rock to identify rock type, alteration, and mineralization.

[0025] The system 100 includes a handheld scanner 110 that is held by a user, a backpack unit 120 worn by the user, an acquisition device 140 carried by the user and a cloud server 150.

[0026] The handheld scanner 100 includes two or more light sources 111 a, 111 b for illuminating a sample with infrared and / or visible light. The light sources 111 a, 111 b are preferably halogen lamps with heat sinks having an output of at least 10 W. According to other embodiments, the light sources 111 a, 111 b are LEDs. The light sources 111 a, 111 b are arranged in a light source module (FIGS. 2A-2D).

[0027] The handheld scanner 100 includes a fiber optic cable 132, for collecting the light reflected off the surface of the sample.

[0028] The handheld scanner 110 includes a printed circuit board (PCB) 114 comprising one or more circuits for controlling operation of the scanner 110. The PCB optionally includes an accelerometer 116, for collecting data to monitor movement of the scanner 110 during scanning.

[0029] A challenge in scanning the sample by hand is determining the right scan speed for obtaining the correct data coverage and resolution. The system 100 includes an LED strip 118 that is placed adjacent to the sample / material being scanned with a long axis of the LED strip 118 substantially parallel to a center line of the sample. The LED strip 118 comprises a flexible plastic band with an adjustable length of up to 1 .5 m and a width of 1-2 cm, which contains a plurality of individual LEDs mounted at intervals for indicating where the measurements should occur at a given time. The LED strip 118, contains a control unit for controlling the sequence and timing of LED illumination. Both, LED strip 118 and control unit are powered by a battery.

[0030] When switched on, individual LEDs on the strip 118 are illuminated in successive order and at a time sequence set by the control unit to match a required scanning speed. The sequence of illuminated LEDs provides a visual indication of the appropriate scan speed and direction to the operator. Multiple illuminated LEDs, separated by non-illuminated LEDs, can go through the sequence repeatedly, resulting in a continuous scan speed indication.

[0031] The handheld scanner 110 may optionally include a camera 115 configured for scanning QR codes, barcodes, or the like. The QR code may encode information about the sample that is scanned such as a name, a location, a date / time of scan, etc. The QR code information may be transmitted to an acquisition device and stored with the scan data.

[0032] The backpack unit 120 houses one or more spectrometer(s) 122 for receiving and processing reflectance data. The spectrometer(s) 122 is / are preferably small formfactor spectrometer(s). The spectrometer(s) 122 is connected to a fiber optic cable 132 passing from the backpack unit 120 to the handheld scanner 110. The fiber optic cable 132 transmits the collected light to the spectrometer(s) 122. The fiber optic cable 132preferably includes SMA-905 couplers, or the like, for connecting to the spectrometer(s) 122 and the scanner 110, respectively.

[0033] The backpack unit 120 further houses a replaceable battery pack 126 and a power supply 128 for powering the spectrometer(s) 122 and the components 111 a, 111 b, 114, 115, 116, 118 in the handheld scanner 110. According to some embodiments, the battery pack is external to the backpack unit 120. The power supply 128 may include a voltage converter for outputting a suitable voltage for the spectrometer(s) 112 and / or the light sources 111 a, 111 b and / or the acquisition and control device 140.

[0034] A conduit 130 carries the fiber optic cable 124 and a power cable 134 between the backpack unit 120 and the handheld scanner 110. According to some embodiments, the conduit 130 is at least partially contained in a handle of the handheld scanner 110. The handheld scanner 110 and the backpack unit 120 include loom connectors 136a, 138a, 136b, 138b for connecting the power cable 134 and the fiber optic cable 132 to the backpack unit 120 and the handheld scanner 110, respectively. The cables 132, 134 may be disconnected, from one or both of the handheld scanner 110 and the backpack unit 120, for storage and transport.

[0035] The acquisition and control device 140 is a tablet, a laptop computer, a smartphone, or the like, having a separate or an integrated display and input interface (e.g., a touchscreen). The acquisition device 140 is installed with software configured to receive and process reflectance data from the spectrometer(s) 122. The software is also used to adjust the spectrometer(s) 122 settings. A connection 142 between the spectrometer(s) 122 and the acquisition device 140 may be a wired (e.g., USB) or a wireless (e.g., WiFi or Bluetooth) connection. According to some embodiments, the spectrometer(s) 122 and the acquisition device 140 may be a single device housed within the backpack unit 120.

[0036] The acquisition device 140 is further configured to wirelessly transmit the reflectance data over a communication network (e.g., the internet) to the cloud server 150 for analysis. The acquisition device 140 stores the reflectance data and transmits the data to the cloud server 150 when an internet connection is available. The cloud server 150 may be a single server or multiple connected servers configured to receive reflectancedata output by the spectrometer(s) 122 and analyze the data to identify different compositional groups. The results can be downloaded from the cloud server 150 for further analysis such as modeling ore deposits.

[0037] Compared to existing scanning systems, the system 100 is compact, lightweight and easily portable making it convenient to transport and use in remote locations. The weight of the handheld scanner 110 is on the order of 0.5-1 .5 kg and the weight of the backpack unit 120 is on the order of 3-8 kg.

[0038] Fast data collection speed is key to the usefulness of the system 100 in an operational setting. The system 100 provides for the acquisition of discrete point data in continuous collection mode such that >100 reflectance spectra (e.g., visible to infrared) can be collected per linear meter by moving the handheld scanner 110 along the surface of a scanned material in 30 to 60 seconds using the user’s hand. This provides sufficient coverage of the material surface for data collection. The system 100 also offers the flexibility to perform discrete point-by-point data measurements if desired. The handheld scanner 110 may include a button or selector to switch between continuous and point-by- point data measurement modes.

[0039] To further provide for fast data collection and analysis, the system 100 collects continuous spectral data but no spectral images. This results in modest data volumes (e.g., 2-3 megabytes per 30 second scan) that can be rapidly uploaded to the server 150 and processed without significant lag.

[0040] Referring to FIGS. 2A-2C, shown therein are various views of a handheld scanner 210, according to an embodiment. The handheld scanner 210 may be the handheld scanner 110 of FIG. 1 .

[0041] The scanner 210 includes a light module 202 housing at least two light sources 211a, 211 b and a fiber optic cable aperture 212 disposed between the light sources 211 a, 211 b. During operation, the light module 202 is pointed toward the sample and held at a distance of about 6 to 10 centimeters above the sample to illuminate the sample and to collect the reflected light off the surface of the sample, without directly contacting the sample. The scanner 210 may optionally include a spacer (not shown) adjacent to the light module 202 to aid in maintaining the appropriate distance above the sample andprevent the scanner from contacting the sample. Light reflected from the sample, passes through the aperture 212 and is collected by a fiber optic cable. If used outdoors or in conditions where ambient light could interfere with the collection of spectra, a light shield can be attached to the scanner 210 (not shown) to block ambient light from passing through the aperture 212.

[0042] According to some embodiments, the scanner 210 includes a camera (not shown) on a front end of the scanner 1 10 adjacent the light source module 202.

[0043] The scanner 210 includes loom connectors 236 at the base of the handle 204 for attaching the fiber optic and power cables to connect the scanner 210 to the backpack unit. The scanner 210 includes two switches / buttons 206, 207 for turning the light sources on / off and for starting scanning / data collection, respectively.

[0044] The scanner 210 includes a handle 204 for gripping and orienting the scanner 210. The handle 204 is preferably a “pistol-grip” to make it easier to hold the scanner 210 with one hand and point the light sources 202 in the desired direction. According to some embodiments, the handle 204 is adjustable / pivotable. As the scanner 210 is handheld and scanned by hand across the sample, it avoids the need for complex and heavy robotic or electronic scanning means.

[0045] Referring to FIGS. 2D-2E, each light source 211 a, 211 b is provided with a reflector 213a, 213b to concentrate and direct the light from the light sources 211 a, 211 b into a cone of illumination 240, which forms an illumination spot 244 size diameter of about 3 cm when the scanner is held 6-20 cm above the surface of the sample 246. The light sources 211 a, 211 b and reflectors are arranged such that light from each light source is directed at an oblique angle with respect to the other light source to provide an illumination spot 244 of sufficient intensity while reducing shadow in the cone of illumination 240.

[0046] The aperture 212 is disposed between the light sources and sized such that the area of reflected light that individual spectral measurements are collected from, (i.e. , the measurement spot size) is about 2 cm in diameter centered within the illumination spot.

[0047] Referring to FIG. 3, shown therein is a flow chart of a method 300 for noncontact continuous reflectance measurements, according to an embodiment. The method 300 may be implemented by the system 100 and the handheld scanner 210 shown in FIGS. 1 and 2, respectively.

[0048] At 301 , an LED strip is positioned adjacent to a sample or material to be measured and switched on. The indicator strip is positioned such that a long axis of the indicator strip is substantially parallel the center line of the sample or material.

[0049] At 302, a handheld scanner is held above a sample such that the front end of the scanner and the light sources illuminating the sample are about 6 to 20 centimeters above the sample.

[0050] At 304, the sample or material is illuminated by light sources on the scanner.

[0051] At 305, the scanner is moved, by the operator’s hand, over sample in a speed and direction indicated by illuminated LEDs on the LED strip. The operator views the LEDs on the strip and moves the scanner over the center line of the sample tracking the LEDs as they illuminate in sequence along the LED strip.

[0052] At 306, reflectance measurements off the sample are collected while moving the scanner, by hand, over the sample or material. Preferably, >100 reflectance spectra (e.g., visible to infrared) are collected per linear meter. Generally, steps 305 and 306 are performed concurrently.

[0053] At 307, according to some embodiments, the speed and direction of scanning is adjusted by the user according to the illuminated LEDs on the LED strip.

[0054] At 308, according to some embodiments, the collected reflectance data is processed / analyzed to identify different compositional groups in the sample. According to various embodiments, the reflectance data may be transmitted to a cloud server via an acquisition device for processing / analysis or the reflectance data may be processed / analyzed locally on the acquisition device. Step 308 may be performed concurrent to steps 305 and 306 and processing / analysis of the reflectance data may be performed substantially in real time.

[0055] While the above description provides examples of one or more apparatus, methods, or systems, it will be appreciated that other apparatus, methods, or systems may be within the scope of the claims as interpreted by one skilled in the art.

Claims

Claims:1 . A handheld scanner, comprising: two or more light sources for illuminating a sample, each light source being configured to direct light at an oblique angle with respect to the other light source to form a cone of illumination; an aperture, disposed between the light sources, for collecting reflected light from the sample; a fiber optic cable in communication with the aperture, for transmitting the reflected light to a spectrometer; and a handle for grasping and moving the scanner over the sample.

2. The handheld scanner of claim 1 , wherein the handle is a pistol grip.

3. The handheld scanner of claim 1 , further comprising a light shield configured to block ambient light from passing through the aperture.

4. The handheld scanner of claim 1 , further comprising a spacer for maintaining the scanner at a distance above the sample.

5. The handheld scanner of claim 1 , wherein the cone of illumination forms an illumination spot about 3 cm in diameter when the scanner is held about 6-20 cm above the sample.

6. The handheld scanner of claim 1 , wherein the aperture is sized to collect light from a measurement spot about 2 cm in diameter.

7. The handheld scanner of claim 1 , wherein each light source includes a reflector for directing light from the light source at an oblique angle with respect to the other light source.

8. The handheld scanner of claim 1 , further comprising a camera configured for scanning QR codes.

9. A handheld scanning system, comprising: a handheld scanner, comprising: two or more light sources for illuminating a sample; an aperture, disposed between the light sources, for collecting reflected light from the sample; a fiber optic cable in communication with the aperture, for transmitting the reflected light to a spectrometer; an LED strip comprising a plurality of LEDs for indicating a speed and a direction for scanning the sample; and a backpack unit for housing the spectrometer and a replaceable battery pack for powering the scanner and the spectrometer.

10. The handheld scanning system of claim 9, further comprising a conduit carrying the fiber optic cable between the handheld scanner and the backpack unit.11 . The handheld scanning system of claim 9, wherein the handheld scanner and the backpack unit comprise loom connectors for removably connecting the fiber optic cable to the handheld scanner and the backpack unit, respectively.

12. The handheld scanning system of claim 9, further comprising: an acquisition device configured to receive and process reflectance data from the spectrometer.

13. The handheld scanning system of claim 12, wherein the acquisition device is the spectrometer.

14. The handheld scanning system of claim 12, further comprising: a cloud server connected to the acquisition device over a communication network, the could server configured to: receive reflectance data from the acquisition device; and analyze the reflectance data to determine a composition of the sample.

15. A handheld scanning system of claim 9, wherein the LED strip comprises a control unit configured to illuminate the plurality of LEDs in a time sequence matching a required scanning speed.

16. A method for non-contact continuous reflectance measurements, comprising: positioning an LED strip parallel to a center line of a sample; holding a handheld scanner about 6-20 cm above the sample; illuminating the sample by light sources on the scanner; moving the scanner, by hand, over the center line of the sample at a speed and direction indicated by illuminated LEDs on the LED strip; and continuously collecting reflectance measurements off the sample while moving the scanner, by hand, along the centerline of the sample.

17. A method of claim 16, further comprising: adjusting the speed and direction of scanning according to the illuminated LEDs on the LED strip.

18. The method of claim 16, further comprising: processing / analyzing collected reflectance data to identify a composition of the sample.

19. The method of claim 16, wherein continuously collecting reflectance measurements comprises collecting >100 reflectance spectra per linear meter of the sample.

Images