KR-102962666-B1 - Calibration device for eye plastic surgery vision inspection system and controlling method for the same

KR102962666B1KR 102962666 B1KR102962666 B1KR 102962666B1KR-102962666-B1

Abstract

The present invention relates to a calibration device and a control method for vision measurement equipment used in eye surgery. By forming multiple calibration boards on the left and right sides, each displaying multiple chess boxes with known width and height information, and estimating and securing sample reference values for each distance through a measurement module while moving back and forth, and then using these sample reference values to calibrate the actual test value of the subject, the MRD1 value for ptosis can be precisely measured through the calibration process regardless of variations in the distance between the subject and the measurement equipment for ptosis measurement. Consequently, the accuracy of ptosis diagnosis can be significantly improved. Furthermore, regardless of the distance between the subject and the equipment or the subject's facial condition used during the ptosis diagnostic test, the subject does not need to undergo repeated ptosis vision examinations; the subject only needs to undergo the measurement once. By correcting the actual measured distance value using the pre-estimated calibration sample reference values for each distance, neither the examiner nor the subject needs to perform repeated measurement tasks for ptosis diagnosis, thereby improving the usability of the ptosis diagnostic system. There is also an effect that can be maximized.

Inventors

조재수
박회종
이성준

Assignees

한국기술교육대학교 산학협력단

Dates

Publication Date: 20260508
Application Date: 20230626

Claims (5)

A calibration module that forms multiple calibration boards on the left and right sides, each displaying multiple chess boxes with known width (w) and height (c) dimensions, and can individually move the multiple calibration boards to estimate sample reference values by distance; A measurement module that measures image pixel values of the calibration boards according to distance when a plurality of calibration boards of the calibration module unit move back and forth along a set sample distance, and The above measurement module includes an analysis module that calculates image pixel values of calibration boards measured from a plurality of calibration boards moving according to sample distances according to a set mathematical formula 1 or 2 to estimate pixel reference values for each distance, applies these to pixel values actually measured by the subject for ptosis diagnosis and estimated distance values, and then calculates the final left and right MRD1 distance measurement values for ptosis diagnosis. Calibration device for vision measurement equipment used in eye surgery.
In paragraph 1, The above calibration module is configured such that a fixed frame member, which mounts a plurality of calibration boards on the perforated inner upper portion of the body, and a body frame member, which is fixed to the upper portion of the fixed frame member and coupled to a base member at a certain height distance via a column member of a certain size, are installed; The above fixed frame member comprises a plurality of movable module members that are inserted into a plurality of fixing holes formed symmetrically at a certain distance from each other on the front of the body and individually move a plurality of calibration boards, to which the lower ends of the body are connected, back and forth; An adjustment knob for finely adjusting the plurality of calibration boards, coupled to the rear end of the above-mentioned fluid module member via a bearing hole member of a fixed frame member; Characterized by the installation of a plurality of distance sensor modules, which are installed on the front surface of the body of the fixed frame member and paired with the plurality of fluid module members to each other, measure the distance of the plurality of calibration boards moving back and forth and display it externally. Calibration device for vision measurement equipment used in eye surgery.
A first step in which the analysis module positions an IR camera performing the role of the left and right eyes of the measurement module, an RGB camera performing the role of the face, and a depth camera measuring distance at a certain distance from the calibration board, and then performs a first calibration process to correct the lens distortion of the said cameras; A second step following the first step, wherein the analysis module unit measures a calibration reference distance value by moving a calibration board, on which multiple chess boxes with known width and height information are displayed, back and forth along a set sample distance through the measurement module unit, and estimates and stores a pixel reference value for each distance using the measured value; A third step following the above second step, in which the analysis module unit measures the left and right eyes through the IR camera of the measurement module unit, the face image through the RGB camera, and the actual distance through the depth camera only once for the diagnosis of ptosis, in which the subject or patient measures the actual distance; A fourth step comprising, after the above third step, in which the analysis module obtains final measurement values for the left and right eyes and the face by correcting using distance-specific reference distance values estimated by referring to distance-specific pixel reference values that have been previously estimated and stored, and calculates these values according to a set program to finally calculate the MRD1 for diagnosing ptosis, wherein the left and right eye information, face image information, and actual distance information, which have been measured at actual distance only once, are corrected, and these values are calculated according to a set program. Control method for a calibration device for vision measurement equipment used in eye surgery.
In paragraph 3, The above-mentioned fourth step is characterized by further including a linear interpolation utilization step in which, when the analysis module corrects left and right eye information, face image information, and actual distance information that have measured the actual distance only once using distance-specific reference distance values (mm/pixel/distance), the calibration reference distance value (Rd) for the distance (d) is calculated by linear interpolation using Equation 1. Control method for a calibration device for vision measurement equipment used in eye surgery. [Mathematical Formula 1] Here, x1 and x2 are the left and right distance values measured during actual calibration, d represents the actual distance measured to the eye, and Rd is the calibration reference distance estimate for the distance value d. And S is x2-x1.
In paragraph 3, The above-mentioned fourth step is characterized by further including a regression analysis step in which, when the analysis module corrects left and right eye information, face image information, and actual distance information that have measured the actual distance only once using a reference distance value for each distance, the calibration reference distance value (Rd) for distance (d) is estimated by regression analysis using sample data with mathematical formula 2. Control method for a calibration device for vision measurement equipment used in eye surgery. [Mathematical Formula 2] Here, in the above mathematical formula 2, the distance d, It performs measurements for each of the left and right eye cameras and the face camera, and estimates them by calculating them through linear regression analysis. That is, it aims to estimate all reference distance values for each distance through linear regression analysis for all three cameras (left, right, and face).

Description

Calibration device for eye plastic surgery vision inspection system and controlling method for the same The present invention is devised as a result of research on the development of medical equipment for diagnosing ptosis using AI technology, and relates to a calibration device and a control method for vision measurement equipment used in eye surgery. In particular, the invention relates to a calibration device and a control method for vision measurement equipment used in eye surgery that can significantly improve the accuracy of ptosis diagnosis by forming multiple calibration boards (also known as chessboards) on the left and right sides, displaying multiple measurement boxes with known width and height information, and estimating and securing sample reference values for each distance through a measurement module while moving a camera back and forth, and then calibrating the actual test value of the subject using these sample reference values, thereby precisely measuring the MRD1 (Marginal Reflex Distance) value for ptosis through the calibration process regardless of variation in the distance between the subject and the measurement equipment for ptosis measurement. Generally, eye surgery is the most frequently performed plastic surgery procedure in Korea; however, in addition to this, surgeries for eyelid conditions have also been steadily increasing in recent years. A representative condition among these is ptosis, which typically refers to a condition where the upper eyelid droops downward, narrowing the eyelid opening. This is known to occur due to a weakening of the muscles connected to the upper eyelid that lift and lower it (levator muscle of the superior arm). Ptosis should be suspected if the eyes appear small and always sleepy, if there is a significant difference in eye size between the two eyes, or if a double eyelid is present on only one side. Normally, the upper eyelid covers the upper part of the iris (cornea) by about 1 to 2 mm; if the iris is covered more than this amount, it can be considered an indication of ptosis. In children, severe ptosis can lead to problems with visual development and negatively affect their emotional well-being due to aesthetic issues. In adults, in addition to cosmetic concerns, severe cases may cause discomfort in daily life as the eyelids obstruct vision, or sometimes headaches may occur as the frontal muscles are used to lift the eyelids. Currently, clinical practice involves doctors roughly measuring the degree of ptosis by holding a ruler in front of the eyes and visually measuring both sides; however, this method is not only inaccurate but also has limitations as it is difficult to obtain a consistent measurement because the head position is not fixed and changes with each measurement. Then, referring to FIG. 1, a conventional ptosis diagnostic device as described above is fixed at a certain distance, and the face of a person (71), particularly both eyes, is captured from the fixed camera (70). Then, the image of the face of the person (71) captured by the camera (70) is analyzed using a ptosis measurement program embedded in a PC (72), and the distance between the eyes of the person is measured and used medically. In other words, to examine the conventional ptosis diagnostic device described above in more detail, a camera (70) fixed at a certain position captures the face of a person (71) and transmits it to a PC (72) connected to it. Then, the PC (72) connected to the camera (70) activates, for example, a set photo measurement program (image J) for ptosis, and then analyzes the image information of the person (71) captured by the camera (70) to determine the MRD1 for diagnosing ptosis. At this time, since the camera (70) is a non-contact measurement sensor, a distance marker of a certain size is used to measure the MRD1 value for diagnosing ptosis. Meanwhile, in the measurement process for diagnosing ptosis as described above, a distance marker is used to measure pixels or the number of pixels in a specific area of both eyes, for example, to measure MRD1. The actual distance (mm) per pixel is calculated from a reference object that serves as a reference value with a known actual length, and the MRD1 for ptosis is measured and utilized for the medical diagnosis of ptosis. However, since the conventional ptosis diagnostic device described above measures pixels of the captured image, there is a significant error due to the facial posture of the subject with ptosis. Therefore, a calculation process comparing with the actual value is required, making it difficult to obtain precise measurement values. Additionally, when taking a photograph with the person's jaw fixed to diagnose ptosis, the subject's face may tilt because the person unconsciously tries to compensate for the parts of their face they are reluctant to expose. In this case, the image must be taken in the most comfortable state, and only the MRD1 value for diagnosing ptosis within the set range l