Research on the algorithm of marker center positioning under the occlusion of thermoplastic film

Yanlu Wang; Feng He; Zaihong Hou; Xu Jing; Yilun Cheng

doi:10.1117/12.2624221

27 March 2022 Research on the algorithm of marker center positioning under the occlusion of thermoplastic film

Yanlu Wang, Feng He, Zaihong Hou, Xu Jing, Yilun Cheng

Proceedings Volume 12169, Eighth Symposium on Novel Photoelectronic Detection Technology and Applications; 121694W (2022) https://doi.org/10.1117/12.2624221
Event: Eighth Symposium on Novel Photoelectronic Detection Technology and Applications, 2021, Kunming, China

Abstract

Because of its high positioning accuracy, easy identification and high stability, circular markers are widely used in patient positioning in the medical field. However, during radiotherapy, the marker points on the patient's body surface are blocked by the thermoplastic film that fixes the patient, which makes it difficult to extract and locate the center of the marker points. Commonly used circular marker positioning algorithms cannot accurately locate the markers when there are a large number of random deletions. Therefore, a marker center positioning algorithm for this situation is needed. First, the image is converted to the HSV color space to extract the landmark points through threshold processing; then the Canny edge detection algorithm is used to extract the edges of the landmarks under the occlusion; then the Graham scanning method is used to obtain the convex hull points of the edge points. Finally, the improved least squares circle fitting algorithm is used to fit the convex hull points to locate the center of the marker. Verified by experiment, the accuracy of this method for extracting the center of the circular marker is within 0.05 pixel, and the positioning accuracy is much higher than that of the gray-scale centroid method under the same circumstances.

Citation Download Citation

Yanlu Wang, Feng He, Zaihong Hou, Xu Jing, and Yilun Cheng "Research on the algorithm of marker center positioning under the occlusion of thermoplastic film", Proc. SPIE 12169, Eighth Symposium on Novel Photoelectronic Detection Technology and Applications, 121694W (27 March 2022); https://doi.org/10.1117/12.2624221

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
6 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

RGB color model

Detection and tracking algorithms

Radiotherapy

Image processing

Edge detection

Hough transforms

Machine vision

Show All Keywords

Keywords/Phrases

Search In:

Publication Years