# US 2021/0080321 A1 · Augmented reality system and method for spectroscopic analysis > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0080321 A1 - Document ID: US20210080321A1 - Status: Published application - Kind: A1 - Application number: 16/982,426 - Filed: 2019-03-21 - Published: 2021-03-18 - Earliest claimed: 2018-03-21 - Assignees: Magic Leap, Inc. - Applicants: Magic Leap, Inc. - Inventors: Adrian Kaehler; Christopher M. Harrises; Eric Baerenrodt; Mark Baerenrodt; Nastasja U. Robaina; Nicole Elizabeth Samec; Tammy Sherri Powers; Ivan Li Chuen Yeoh; Adam Carl Wright - Web page: https://patentgrep.com/patent/US20210080321A1 ## CPC - G01J 3/0262: {Constructional arrangements for removing stray light} - G01J 3/28: Investigating the spectrum (using colour filters G01J3/51) - G01J 3/42: Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry (beam switching arrangements G01J3/08) - G01N 21/255: {Details, e.g. use of specially adapted sources, lighting or optical systems} - G01N 21/27: using photo-electric detection (G01N21/31 takes precedence){; circuits for computing concentration (logarithmic circuits G06G7/24; photometric circuits in general G01J)} - G02B 6/0076: {Stacked arrangements of multiple light guides of the same or different cross-sectional area} - G02B 27/0172: {characterised by optical features} - G06F 3/013: {Eye tracking input arrangements (G06F3/015 takes precedence)} - G09G 5/37: Details of the operation on graphic patterns (G09G5/38 takes precedence) - G01N 2201/0221: Portable; cableless; compact; hand-held - G02B 2027/0134: {of stereoscopic type} - G02B 2027/0194: {with combiner of laminated type, for optical or mechanical aspects} - G09G 2354/00: Aspects of interface with display user - G09G 2360/144: the light being ambient light - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) ## Abstract Wearable spectroscopy systems and methods for identifying one or more characteristics of a target object are described. Spectroscopy systems may include a light source configured to emit light in an irradiated field of view and an electromagnetic radiation detector configured to receive reflected light from a target object irradiated by the light source. One or more processors of the systems may identify a characteristic of the target object based on a determined level of light absorption by the target object. Some systems and methods may include one or more corrections for scattered and/or ambient light such as applying an ambient light correction, passing the reflected light through an anti-scatter grid, or using a time-dependent variation in the emitted light. ## Claims ### Claim 1 A wearable spectroscopy system comprising: a head-mounted display system removably mountable on a user's head; one or more light sources coupled to the head-mounted display system and configured to emit light in an irradiated field of view; one or more electromagnetic radiation detectors coupled to the head-mounted display system and configured to receive reflected light from a target object irradiated by the one or more light sources within the irradiated field of view; one or more processors; and one or more computer storage media storing instructions that, when executed by the one or more processors, cause the system to perform operations comprising: causing the one or more light sources to emit light; causing the one or more electromagnetic radiation detectors to detect light from the irradiated field of view including the target object; determining an ambient light correction by detecting ambient light levels; applying the ambient light correction to the detected light to determine levels of light absorption related to the emitted light and reflected light from the target object; identifying, based on the levels of light absorption, a characteristic of the target object; and displaying an output associated with the characteristic of the target object to the user on the head-mounted display system. ### Claim 2 (depends on 1) The system of claim 1, further comprising an absorption database of light absorption properties of a plurality of materials. ### Claim 3 (depends on 1) The system of claim 1, wherein the ambient light correction comprises one or more of an ambient light intensity value, an average of a plurality of ambient light intensity values, a median of a plurality of ambient light intensity values, and a time-domain ambient light intensity function. ### Claim 4 (depends on 1) The system of claim 1, further comprising at least one eye tracking camera configured to detect a gaze of the user, wherein the irradiated field of view is substantially in the same direction as the detected gaze. ### Claim 5 (depends on 1) The system of claim 1, wherein the one or more electromagnetic radiation detectors are further configured to detect the ambient light levels. ### Claim 6 (depends on 1) The system of claim 1, further comprising an ambient light detector coupled to the head-mounted display system and configured to capture ambient light not emitted by the one or more light sources, the ambient light including one or more wavelengths emitted by the one or more light sources. ### Claim 7 (depends on 6) The system of claim 6, wherein the ambient light detector comprises at least one of a photodiode, a photodetector, and a digital camera sensor. ### Claim 8 (depends on 6) The system of claim 6, wherein the instructions, when executed by the one or more processors, further cause system to perform operations comprising: causing the ambient light detector to detect light while the one or more light sources are not emitting light; and determining the ambient light correction based at least in part on the light detected by the ambient light detector. ### Claim 9 (depends on 1) The system of claim 1, further comprising an anti-scatter grid coupled to the head-mounted display system between the target object and the one or more electromagnetic radiation detectors, the anti-scatter grid aligned to attenuate at least a portion of scattered light and ambient light incident upon the anti-scatter grid. ### Claim 10 (depends on 9) The system of claim 9, wherein the anti-scatter grid is further disposed between the target object and a detector for detecting ambient light levels. ### Claim 11 (depends on 1) The system of claim 1, wherein the one or more light sources are configured to emit the light in a series of time-separated pulses, and wherein the instructions, when executed by the one or more processors, further cause the system to perform operations comprising: identifying time-separated pulses of reflected light corresponding to the time-separated pulses emitted by the one or more light sources; and determine the ambient light correction based at least in part on an intensity of light detected at the one or more electromagnetic radiation detectors between the time-separated pulses of reflected light. ### Claim 12 (depends on 11) The system of claim 11, wherein the time-separated pulses of reflected light are detected at the one or more electromagnetic radiation detectors. ### Claim 13 (depends on 1) The system of claim 1, wherein the one or more electromagnetic radiation detectors comprises at least one of a photodiode and a photodetector. ### Claim 14 (depends on 1) The system of claim 1, wherein the one or more electromagnetic radiation detectors comprises a digital image sensor. ### Claim 15 (depends on 1) The system of claim 1, wherein the head-mounted member further comprises an inertial measurement unit positional system. ### Claim 16 (depends on 15) The system of claim 15, wherein the inertial measurement systems determines a pose orientation of the user's head. ### Claim 17 (depends on 16) The system of claim 16, wherein the irradiated field of view is at least as wide as the pose orientation. ### Claim 18 (depends on 1) The system of claim 1, wherein the head-mounted display system comprises a waveguide stack configured to output light with selectively variable levels of wavefront divergence. ### Claim 19 (depends on 18) The system of claim 18, wherein the waveguide stack comprises waveguides having optical power. ### Claim 20 A wearable spectroscopy system comprising: a head-mounted display removably mountable on a user's head; one or more light sources coupled to the head-mounted display system and configured to emit light in an irradiated field of view; one or more electromagnetic radiation detectors coupled to the head-mounted display system and configured to receive reflected light from a target object irradiated by the one or more light sources within the irradiated field of view; an anti-scatter grid disposed between the electromagnetic radiation detector and the target object, the anti-scatter grid configured to attenuate at least one of scattered light and ambient light incident thereon; one or more processors; and one or more computer storage media storing instructions that, when executed by the one or more processors, cause the system to perform operations comprising: emitting, from the one or more light sources, light of a first wavelength in an irradiated field of view; detecting, at the one or more electromagnetic radiation detectors, light of the first wavelength reflected from a target object within the irradiated field of view; identifying, based on an absorption database of light absorption properties of at least one material, a material characteristic of the target object; and causing a graphics processor unit to display, to the user, an output associated with the material characteristic. ### Claim 21 A wearable spectroscopy system comprising: a head-mounted display removably mountable on a user's head; one or more light sources coupled to the head-mounted display system and configured to emit light in an irradiated field of view; one or more electromagnetic radiation detectors coupled to the head-mounted display system and configured to receive reflected light from a target object irradiated by the one or more light sources within the irradiated field of view; one or more processors; and one or more computer storage media storing instructions that, when executed by the one or more processors, cause the system to perform operations comprising: detecting ambient light of a first wavelength within the irradiated field of view; emitting light of the first wavelength toward the target object; detecting light of the first wavelength reflected by the target object; subtracting an intensity of the detected ambient light of the first wavelength from an intensity of the detected light reflected by the target object to calculate a level of light absorption related to the emitted light and the reflected light from the target object; identifying, based on an absorption database of light absorption properties of a plurality of materials, a material characteristic of the target object; and displaying, to the user, an output associated with the material characteristic. ### Claim 22 A wearable spectroscopy system comprising: a head-mounted display removably mountable on a user's head; one or more light sources coupled to the head-mounted display system and configured to emit light in an irradiated field of view; one or more electromagnetic radiation detectors coupled to the head-mounted display system and configured to receive reflected light from a target object irradiated by the one or more light sources within the irradiated field of view; one or more processors; and one or more computer storage media storing instructions that, when executed by the one or more processors, cause the system to perform operations comprising: emitting light of a first wavelength in an irradiated field of view, the light comprising a time-encoded variation; detecting light of the first wavelength reflected from a target object within the irradiated field of view; identifying, based at least in part on the detected light and the time-encoded variation, an ambient light component of the detected light and a reflected component of the detected light; identifying, based at least in part on the reflected component and an absorption database of light absorption properties of at least one material, a material characteristic of the target object; and displaying, to the user, an output associated with the material characteristic.