# US 9,519,840 B2 · Cardiovascular OCT image making method and method for detecting stents using thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,519,840 B2 - Document ID: US9519840B2 - Status: Granted - Kind: B2 - Application number: 14/667,882 - Filed: 2015-03-25 - Published: 2015-10-01 - Granted: 2016-12-13 - Earliest claimed: 2014-03-25 - Assignees: Industry-Academic Cooperation Foundation, Yonsei University - Applicants: Industry-Academic Cooperation Foundation Yonsei University - Inventors: Chulmin Joo; Chi Young Ahn; Jung Heo - Web page: https://patentgrep.com/patent/US9519840B2 ## CPC - G06T 5/94: based on local image properties, e.g. for local contrast enhancement - G06T 12/30: Image post-processing, e.g. metal artefact correction - G06T 2207/10101: Optical tomography; Optical coherence tomography [OCT] - G06T 2207/30052: Implant; Prosthesis - G06T 2207/30101: Blood vessel; Artery; Vein; Vascular - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract A cardiovascular OCT image making method which reduces artifacts includes the steps of: inputting a cardiovascular OCT image; converting coordinates of the inputted OCT image into two-dimensional polar coordinates (θ and r); generating a brightness control function of the A-line direction based on the blood wall relative to each θ value; forming a brightness image in the A-line direction based on the blood wall depending on the brightness control function; and forming an OCT image of which brightness is controlled by the brightness image by applying the brightness image formed on the inputted OCT image. ## Claims ### Claim 1 A cardiovascular OCT image making method which reduces artifacts comprising steps of: inputting a cardiovascular OCT image; converting coordinates of the inputted OCT image into two-dimensional polar coordinates (θ and r); generating a brightness control function of an A-line direction based on a blood wall relative to each θ value; forming a brightness image in the A-line direction based on the blood wall and depending on the brightness control function; and forming an OCT image of which brightness is controlled by the brightness image by applying the brightness image formed on the inputted OCT image. ### Claim 2 (depends on 1) The cardiovascular OCT image making method according to claim 1, wherein the brightness control function is a Gaussian function. ### Claim 3 (depends on 2) The cardiovascular OCT image making method according to claim 2, wherein the Gaussian function is W ⁡ ( θ , r ) := exp ( - ( r - μ ⁡ ( θ ) ) 2 2 ⁢ σ 2 ) , wherein μ(θ) is a position of a blood wail boundary on the A-line in a θ-direction, and σ is a minimum value of distances between the blood wall and a catheter in each A-line. ### Claim 4 A method for detecting stents using a cardiovascular OCT image which reduces artifacts comprising steps of: inputting a cardiovascular OCT image; converting coordinates of the inputted OCT image into two-dimensional polar coordinates (θ and r); generating a brightness control function of an A-line direction based on a blood wall relative to each θ value; forming a brightness image in the A-line direction based on the blood wall and depending on the brightness control function; forming an OCT image of which brightness is controlled by the brightness image by applying the brightness image formed on the inputted OCT image; and detecting stents from the image of which brightness is controlled. ### Claim 5 (depends on 4) The method for detecting stents using a cardiovascular OCT image according to claim 4, wherein the brightness control function is a Gaussian function. ### Claim 6 (depends on 5) The method for detecting stents using a cardiovascular OCT image according to claim 5, wherein the Gaussian function is W ⁡ ( θ , r ) := exp ( - ( r - μ ⁡ ( θ ) ) 2 2 ⁢ σ 2 ) , wherein μ(θ) is a position of a blood wall boundary on the A-line in a (θ)-direction, and σ is a minimum value of distances between the blood wall and a catheter in each A-line. ### Claim 7 (depends on 4) The method for detecting stents using a cardiovascular OCT image according to claim 4, wherein the step of detecting stents comprises steps of: applying a second derivative in a θ-direction to the image of which brightness is controlled; applying a second derivative in the A-line direction to the image to which the θ-direction second derivative is applied; and detecting the stents by detecting a peak value of the image to which the A-line direction second derivative is applied. ### Claim 8 A method for automatically detecting stents using a cardiovascular OCT image which reduces artifacts comprising steps of: inputting a cardiovascular OCT image; converting coordinates of the inputted OCT image into two-dimensional polar coordinates (θ and r); sensing a blood wall boundary of a first two-dimensional plane OCT image from the two-dimensional polar converted image; generating a brightness control function of an A-line direction based on the blood wall relative to each θ value; forming a brightness image in the A-line direction based on the blood wall and depending on the brightness control function; forming an OCT image of which brightness is controlled by the brightness image by applying the brightness image formed on the inputted OCT image; detecting stents from the image of which brightness is controlled; and repeating the above-mentioned steps, which range from the brightness control function generating step to the stent detecting step, to a final two-dimensional plane OCT image. ### Claim 9 (depends on 8) The method for automatically detecting stents using a cardiovascular OCT image according to claim 8, wherein the brightness control function is a Gaussian function. ### Claim 10 (depends on 9) The cardiovascular OCT image making method according to claim 9, wherein the Gaussian function is W ⁡ ( θ , r ) := exp ( - ( r - μ ⁡ ( θ ) ) 2 2 ⁢ σ 2 ) , wherein μ(θ) is a position of a blood wall boundary on the A-line in a θ-direction, and σ is a minimum value of distances between the blood wall and a catheter in each A-line. ### Claim 11 (depends on 8) The method for automatically detecting stents using a cardiovascular OCT image according to claim 8, wherein the step of detecting stents comprises steps of: applying a second derivative in a θ-direction to the image of which brightness is controlled; applying a second derivative in the A-line direction to the image to which the θ-direction second derivative is applied; and detecting the stents by detecting a peak value of the image to which the A-line direction second derivative is applied. ### Claim 12 A method for automatically detecting and displaying stents using a cardiovascular OCT image which reduces artifacts comprising steps of: inputting a cardiovascular OCT image; converting coordinates of the inputted OCT image into two-dimensional polar coordinates (θ and r); sensing a blood wall boundary of a first two-dimensional plane OCT image from the two-dimensional polar converted image; generating a brightness control function of an A-line direction based on the blood wall relative to each θ value; forming a brightness image in the A-line direction based on the blood wall and depending on the brightness control function; forming an OCT image of which brightness is controlled by the brightness image by applying the brightness image formed on the inputted OCT image; detecting stents from the image of which brightness is controlled; repeating the above-mentioned steps, which range from the brightness control function generating step to the stent detecting step, to a final two-dimensional plane OCT image; and displaying the detected stents. ### Claim 13 (depends on 12) The method for automatically detecting and displaying stents using a cardiovascular OCT image according to claim 12, wherein the brightness control function is a Gaussian function. ### Claim 14 (depends on 13) The method for automatically detecting and displaying stents using a cardiovascular OCT image according to claim 13, wherein the Gaussian function is W ⁡ ( θ , r ) := exp ( - ( r - μ ⁡ ( θ ) ) 2 2 ⁢ σ 2 ) , wherein μ(θ) is a position of a blood wall boundary on the A-line in a θ-direction, and σ is a minimum value of distances between the blood wall and a catheter in each A-line. ### Claim 15 (depends on 12) The method for automatically detecting and displaying stents using a cardiovascular OCT image according to claim 12, wherein the step of detecting stents comprises steps of: applying a second derivative in a θ-direction to the image of which brightness is controlled; applying a second derivative in the A-line direction to the image to which the θ-direction second derivative is applied; and detecting the stents by detecting a peak value of the image to which the A-line direction second derivative is applied. ### Claim 16 (depends on 12) The method for automatically detecting and displaying stents using a cardiovascular OCT image according to claim 12, wherein in the step of displaying, the two-dimensional polar coordinate converted image is returned to its original form and is displayed.