# US 2014/0152992 A1 · Method and apparatus for gold detection > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0152992 A1 - Document ID: US20140152992A1 - Status: Published application - Kind: A1 - Application number: 14/131,797 - Filed: 2012-07-11 - Published: 2014-06-05 - Earliest claimed: 2011-07-14 - Assignees: Kendall Technology Inc. - Inventors: James Douglas Kendall; John Henry Cole; Adam Joseph Bucek - Web page: https://patentgrep.com/patent/US20140152992A1 ## CPC - G01N 21/55: Specular reflectivity - G01J 3/0218: {using optical fibers} - G01J 3/0272: {Handheld} - G01J 3/10: Arrangements of light sources specially adapted for spectrometry or colorimetry - G01J 3/42: Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry (beam switching arrangements G01J3/08) - G01N 21/314: {with comparison of measurements at specific and non-specific wavelengths (dual wavelength spectrometry G01J3/427)} - G01N 21/3151: {using two sources of radiation of different wavelengths (G01N21/33 - G01N21/39 take precedence)} - G01N 33/24: Earth materials (G01N33/42 takes precedence) - G01N 2021/3148: {using three or more wavelengths} - G01N 2201/0221: Portable; cableless; compact; hand-held - 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) - 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) ## Abstract A gold detection apparatus capable of detecting gold in field mineral samples such as rock or soil with little or no preparation. Light in red, green and violet wavelengths is directed at a surface of a mineral sample and the reflected light intensity is measured by an array of sensors or photosites. Based on the characteristic reflectance properties of gold, the reflected light intensity in each wavelength is used to determine the presence of gold particles and the gold concentration of the mineral sample. ## Claims ### Claim at position 1 1-11. (canceled) ### Claim 12 A method for detecting gold in a material sample, the method comprising: illuminating the material sample with light in a first preselected wavelength range, a second preselected wavelength range, and a third preselected wavelength range; detecting the light reflected by the material sample in the first, second and third preselected wavelength ranges; and comparing, using a processor, a relative intensity of the reflected light in the second preselected wavelength range to the reflected light in the first preselected wavelength range, and intensity of the reflected light in the third preselected wavelength range to intensity of the reflected light in the first and second preselected wavelength ranges. ### Claim 13 (depends on 12) The method of claim 12, wherein the first preselected wavelength is in the blue-violet spectrum, the second preselected wavelength is in the red-orange-yellow spectrum, and the third preselected wavelength is in the green spectrum. ### Claim 14 (depends on 12) The method of claim 12, further comprising identifying a reflected light intensity in the second preselected wavelength range greater than 55% of the maximum intensity. ### Claim 15 (depends on 12) The method of claim 12, wherein the comparing comprises computing a reflectance slope product, wherein the reflectance slope product is a result of the square of reflected light intensity in the second wavelength multiplied by reflected light intensity in the third wavelength, and divided by the square of reflected light intensity in the first wavelength. ### Claim at position 6 16-34. (canceled) ### Claim 35 An apparatus for detecting gold in a material sample, the apparatus comprising: a) at least one light source for illuminating the material sample with light in a first preselected wavelength range, a second preselected wavelength range, and a third preselected wavelength range; b) an image sensor for detecting the light in the first, second and third preselected wavelength ranges reflected by the material sample; and c) a processor configured to compare a relative intensity of the reflected light in the second preselected wavelength range to the reflected light in the first preselected wavelength range, and compare intensity of the reflected light in the third preselected wavelength range to intensity of the reflected light in the first and second preselected wavelength ranges. ### Claim 36 (depends on 35) The apparatus of claim 35, wherein the first preselected wavelength is in the blue-violet spectrum, the second preselected wavelength is in the red-orange-yellow spectrum, and the third preselected wavelength is in the green spectrum. ### Claim 37 (depends on 35) The apparatus of claim 35, wherein the processor is configured to identify a reflected light intensity in the second preselected wavelength range greater than 55% of the maximum intensity. ### Claim 38 (depends on 35) The apparatus of claim 35, wherein the comparison performed by the processor comprises computing a reflectance slope product, wherein the reflectance slope product is a result of the square of reflected light intensity in the second wavelength multiplied by reflected light intensity in the third wavelength, and divided by the square of reflected light intensity in the first wavelength. ### Claim 39 (canceled) ### Claim 40 A non-transitory computer-readable storage medium with an executable program stored thereon, the executable program configured to instruct a processor to perform a method for detecting gold in a material sample, the method comprising: illuminating the material sample with light in a first preselected wavelength range, a second preselected wavelength range, and a third preselected wavelength range; detecting the light reflected by the material sample in the first, second and third preselected wavelength ranges; and comparing, using a processor, a relative intensity of the reflected light in the second preselected wavelength range to the reflected light in the first preselected wavelength range, and intensity of the reflected light in the third preselected wavelength range to intensity of the reflected light in the first and second preselected wavelength ranges. ### Claim 41 (depends on 40) The computer-readable storage medium of claim 40, wherein the first preselected wavelength is in the blue-violet spectrum, the second preselected wavelength is in the red-orange-yellow spectrum, and the third preselected wavelength is in the green spectrum. ### Claim 42 (depends on 40) The computer-readable storage medium of claim 40, wherein the method further comprises identifying a reflected light intensity in the second preselected wavelength range greater than 55% of the maximum intensity. ### Claim 43 (depends on 40) The computer-readable storage medium of claim 40, wherein the comparing comprises computing a reflectance slope product, wherein the reflectance slope product is a result of the square of reflected light intensity in the second wavelength multiplied by reflected light intensity in the third wavelength, and divided by the square of reflected light intensity in the first wavelength. ### Claim 44 (depends on 40) The computer-readable storage medium of claim 40, wherein the light is detected by an image sensor comprising a two-dimensional matrix of sensor elements ### Claim 45 (depends on 12) The method of claim 12, wherein the light is detected by an image sensor comprising a two-dimensional matrix of sensor elements. ### Claim 46 (depends on 35) The apparatus of claim 35, wherein the image sensor comprises a two-dimensional matrix of sensor elements. ### Claim 47 (depends on 35) The apparatus of claim 35, wherein the at least one light source comprises a first laser or LED source for transmitting light in the first preselected wavelength range, a second laser or LED source for transmitting light in the second preselected wavelength range, and a third laser or LED source for transmitting light in the third preselected wavelength range. ### Claim 48 (depends on 35) The apparatus of claim 35, wherein the at least one light source is a broad spectrum light source, the apparatus further comprising a first filter element to filter the reflected light to isolate the first preselected wavelength range, a second filter element to filter the reflected light to isolate the second preselected wavelength range, and a third filter element to filter the reflected light to isolate the third preselected wavelength range. ### Claim 49 (depends on 5) The apparatus of claim 5, wherein the image sensor is selected from the group consisting of a CCD image sensor and a CMOS image sensor. ### Claim 50 (depends on 5) The apparatus of claim 5, further comprising a portable enclosure, the portable enclosure housing the at least one light source, the image sensor and the processor.