Detecting zero curvature points for the direction-dependent tangent on discrete curves

Wai-Him Wong; Horace H. S. Ip

doi:10.1117/12.216412

11 August 1995 Detecting zero curvature points for the direction-dependent tangent on discrete curves

Wai-Him Wong, Horace H. S. Ip

Proceedings Volume 2573, Vision Geometry IV; (1995) https://doi.org/10.1117/12.216412
Event: SPIE's 1995 International Symposium on Optical Science, Engineering, and Instrumentation, 1995, San Diego, CA, United States

Abstract

Many techniques in machine vision require tangent estimation. The direction-dependent tangent (DDT) is introduced. The representation makes explicit the direction of curve following and the concavity, hence facilitating shape matching. The scheme is a simple but powerful enhancement to the standard tangent notation. However, discrete tangent and curvature estimations are very sensitive to noise and quantization errors, and the original DDT formulation is difficult to apply directly to digital curves. Based on the geometric property of DDT, we propose to detect zero curvature points to determine the DDT values. Traditional approaches to zero curvature detection rely heavily on discrete tangent and curvature estimations, which are difficult to approximate accurately. Hence, most researchers adopted the multi-scale solutions, which are costly to compute. In this paper, we put forth a new measure, which we called `turning angle', for zero curvature detection. Based on this measure, we develop an efficient conditioning algorithm to tackle the zero curvature detection problem. Although the conditioning algorithm is quite straightforward, the zero curvature points detected are quite stable across scales.

Citation Download Citation

Wai-Him Wong and Horace H. S. Ip "Detecting zero curvature points for the direction-dependent tangent on discrete curves", Proc. SPIE 2573, Vision Geometry IV, (11 August 1995); https://doi.org/10.1117/12.216412

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