학술논문
고광택 물체 3D 형상 측정시 발생되는 잡음개선에 관한 연구
Document Type
Academic Journal
Source
한국산학기술학회 논문지. 2023-09 24(9):750-755
Subject
Language
Korean
ISSN
1975-4701
2288-4688
2288-4688
Abstract
PMP 삼차원 형상 측정법은 측정할 물체에 격자 패턴을 일정한 주기로 위상 이송을 하면서 영사하고, 동시에 카메라로 이미지를 획득하여 3D 형상을 측정하는 방법이다. 이때 획득된 이미지들의 픽셀 광량 변화로부터 위상값을 구할 수 있다. 하지만 반사율이 높은 고광택 물체에 격자 패턴을 영사하면 반사광이 한쪽 방향으로 크게 포화된 준정반사의 경향이 자주 나타나고, 이에 해당되는 부분은 카메라의 이미지 센서에서 매우 밝거나 어두운 값으로 얻어지게 된다. 이때의 픽셀 광량 변화는 매우 적어 비정현파의 형태가 되고, 위상값에 많은 잡음이 포함되게 된다. 본 논문에서는 PMP 형상 측정법으로 고광택 물체 측정 시, 준정반사에 의해 발생되는 잡음을 두 종류로 분류하였고, 카메라 노출시간을 변경하여 두 종류의 잡음을 줄이는 연구를 진행하였다. 제안된 방법을 적용한 결과, 이미지 전체 픽셀에서의 두 종류의 잡음이 1.827 %에서 0.201 %로 감소하는 것을 확인하였다.
The PMP 3D shape measurement technique projects a grating pattern onto an object to be measured. The pattern undergoes phase shifting at regular intervals, and a camera captures images to determine the 3D shape. The phase values can be determined from the acquired image"s pixel intensity variations. However, when projecting the grating pattern onto highly reflective glossy objects, specular reflection often appears saturated in one direction. The regions affected by this have extremely bright or dark values on the camera"s image sensor. The pixel intensity variation becomes minimal and take the form of a non-sinusoidal wave, leading to significant noise in the phase values. This study classified the noise generated by specular reflection during PMP shape measurement of glossy objects into two types. The two types of noise were reduced by adjusting the camera"s exposure time. Upon implementing the proposed method, it was observed that the noise across all pixels of the image was reduced from 1.827% to 0.201%.
The PMP 3D shape measurement technique projects a grating pattern onto an object to be measured. The pattern undergoes phase shifting at regular intervals, and a camera captures images to determine the 3D shape. The phase values can be determined from the acquired image"s pixel intensity variations. However, when projecting the grating pattern onto highly reflective glossy objects, specular reflection often appears saturated in one direction. The regions affected by this have extremely bright or dark values on the camera"s image sensor. The pixel intensity variation becomes minimal and take the form of a non-sinusoidal wave, leading to significant noise in the phase values. This study classified the noise generated by specular reflection during PMP shape measurement of glossy objects into two types. The two types of noise were reduced by adjusting the camera"s exposure time. Upon implementing the proposed method, it was observed that the noise across all pixels of the image was reduced from 1.827% to 0.201%.