# US 10,368,795 B2 · Acne imaging methods and apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,368,795 B2 - Document ID: US10368795B2 - Status: Granted - Kind: B2 - Application number: 14/686,824 - Filed: 2015-04-15 - Published: 2015-12-31 - Granted: 2019-08-06 - Earliest claimed: 2014-06-30 - Assignees: Canfield Scientific, Incorporated - Applicants: Canfield Scientific, Incorporated - Inventors: Sachin V. Patwardhan - Web page: https://patentgrep.com/patent/US10368795B2 ## CPC - A61B 5/445: {Evaluating skin irritation or skin trauma, e.g. rash, eczema, wound, bed sore} - A61B 5/0013: {Medical image data (A61B1/00011, A61B6/56, A61B8/56 take precedence)} - A61B 5/0022: {Monitoring a patient using a global network, e.g. telephone networks, internet} - A61B 5/0071: {by measuring fluorescence emission} - A61B 5/0077: {Devices for viewing the surface of the body, e.g. camera, magnifying lens} - A61B 5/443: {Evaluating skin constituents, e.g. elastin, melanin, water} - A61B 5/444: {Evaluating skin marks, e.g. mole, nevi, tumour, scar} - A61B 5/7203: {for noise prevention, reduction or removal} - A61B 5/7246: {using correlation, e.g. template matching or determination of similarity} - A61B 5/742: {using visual displays (displays for heart-related electrical signals, e.g. ECG, A61B5/339)} - A61B 2576/02: specially adapted for a particular organ or body part - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract In an arrangement for detecting acne, particularly in its earliest stages before any humanly visible or palpable manifestations thereof have emerged, a green fluorescence image of skin illuminated with blue light is captured and processed to detect the presence of microcomedones. After correcting the green fluorescence image for the non-uniform distribution of excitation light on the skin, fluorescent spots are detected therein. The subset of fluorescent spots having an intensity lower than an intensity threshold and an area smaller than an area threshold are selected as representing candidate microcomedones. The subset can be further refined by eliminating fluorescent spots having irregular shapes, are associated with inflammation, or exhibit comedone features. Additional filtering can be applied by selecting those spots whose locations correspond to pore locations. A dermatoscope with a blue illumination source and a green-filtered viewer allows live imaging of skin spots indicative of acne, including microcomedones not otherwise visible. ## Claims ### Claim 1 A method of detecting microcomedones in skin comprising: illuminating the skin with a blue light; capturing an image of the illuminated skin through a filter that passes light in a green-yellow band of wavelengths; processing the captured image to detect one or more skin areas containing a porphyrin whose fluorescence emission is primarily in an orange-red band of wavelengths, the one or more areas representing one or more possible microcomedones, wherein processing the captured image includes: detecting fluorescent spots in the captured image, the fluorescent spots representing the one or more skin areas containing the porphyrin; and selecting a subset of the detected fluorescent spots, including selecting spots having an intensity less than an intensity threshold, regular shapes, and an area smaller than a first area threshold and larger than a second area threshold that is lower than the first area threshold and at least 150 microns in diameter or 12 pixels in area, wherein the selected subset of the detected fluorescent spots includes microcomedones; and generating a further image of the skin indicating the subset of spots as possible microcomedones. ### Claim 2 (depends on 1) The method of claim 1, wherein processing the captured image includes: correcting the captured image to generate a corrected image, wherein the fluorescent spots are detected in the corrected image. ### Claim 3 (depends on 1) The method of claim 1, wherein selecting the subset of spots includes selecting spots that are not associated with inflammation or that do not have comedone features. ### Claim 4 (depends on 1) The method of claim 1 comprising detecting pores in the skin, wherein selecting the subset of spots includes selecting spots corresponding to the detected pores. ### Claim 5 (depends on 1) The method of claim 1, wherein the blue light has a center wavelength in the range of 400 nm to 410 nm. ### Claim 6 (depends on 1) The method of claim 1, wherein the filter has a center wavelength in the range of 525 nm to 575 nm. ### Claim 7 (depends on 1) The method of claim 1, wherein the intensity of a spot is determined in accordance with a mean or median pixel intensity of image pixels associated with the spot, and the intensity threshold is 60% to 80% of full scale intensity. ### Claim 8 (depends on 1) The method of claim 1, wherein the first area threshold is at least one of 70% to 90% of the median or 120% to 140% of the mean size of the subset of spots. ### Claim 9 (depends on 2) The method of claim 2, wherein correcting the captured image includes normalizing the captured image against at least one of a chromophore distribution image or an excitation image. ### Claim 10 (depends on 9) The method of claim 9, wherein the chromophore distribution image indicates the distribution in the skin of at least one of hemoglobin or melanin. ### Claim 11 (depends on 9) The method of claim 9, wherein the excitation image is an image of the skin captured while illuminating the skin with the blue light. ### Claim 12 (depends on 1) The method of claim 1 comprising comparing the captured image with a stored image. ### Claim 13 (depends on 1) The method of claim 1 comprising comparing the further image with a stored image. ### Claim 14 An apparatus for detecting microcomedones comprising: an image capture device including a viewing opening; a light source arranged about the viewing opening; a filter for filtering light passing through the viewing opening, wherein light of a blue wavelength is emitted from the apparatus when the light source is activated, and wherein the filter passes light in a green-yellow band of wavelengths; and processing circuitry configured to process an image captured by the image capture device to detect one or more skin areas containing a porphyrin whose fluorescence emission is primarily in an orange-red band of wavelengths, the one or more areas representing one or more possible microcomedones, wherein processing the captured image includes: detecting fluorescent spots in the captured image, the fluorescent spots representing the one or more skin areas containing the porphyrin; and selecting a subset of the detected fluorescent spots, including selecting spots having an intensity less than an intensity threshold, regular shapes, and an area smaller than a first area threshold and larger than a second area threshold that is lower than the first area threshold and at least 150 microns in diameter or 12 pixels in area, wherein the selected subset of the detected fluorescent spots includes microcomedones, wherein the processing circuitry is configured to generate a further image of the skin indicating the subset of spots as possible microcomedones. ### Claim 15 (depends on 14) The apparatus of claim 14, wherein the light source comprises at least one of a blue light emitting light source or a blue filter. ### Claim 16 (depends on 14) The apparatus of claim 14, wherein the blue light has a center wavelength in the range of 400 nm to 410 nm. ### Claim 17 (depends on 14) The apparatus of claim 14, wherein the filter has a center wavelength in the range of 525 nm to 575 nm. ### Claim 18 (depends on 1) The method of claim 1, wherein the porphyrin includes coproporphyrin III. ### Claim 19 (depends on 14) The apparatus of claim 14, wherein the processing circuitry is configured to: correct the captured image to generate a corrected image, wherein the fluorescent spots are detected in the corrected image. ### Claim 20 (depends on 1) The method of claim 1 comprising: detecting pores in the skin; and determining a mean or median pore size of the detected pores, wherein selecting the subset of spots includes selecting spots corresponding to the detected pores and having an area smaller than an area threshold that is based on the mean or median pore size. ### Claim 21 (depends on 14) The apparatus of claim 14, wherein the first area threshold is at least one of 70% to 90% of the median or 120% to 140% of the mean size of the subset of spots. ### Claim 22 (depends on 14) The apparatus of claim 14, wherein selecting the subset of spots includes selecting spots that are not associated with inflammation or that do not have comedone features. ### Claim 23 (depends on 14) The apparatus of claim 14, wherein the intensity of a spot is determined in accordance with a mean or median pixel intensity of image pixels associated with the spot, and the intensity threshold is 60% to 80% of full scale intensity.