Opto-Electronic Engineering, Volume. 36, Issue 4, 7(2009)

Sub-pixel Extraction Method for the Center of Light-spot Image

WEI Zhen-zhong*, GAO Ming, ZHANG Guang-jun, and LIU Zhen
Author Affiliations
  • [in Chinese]
  • show less

    An extraction method in sub-pixel level was proposed to solve the high accuracy center point extraction problem of the light-spot image of the spacial light-emitting-spot. The gray level distribution mathematical model of the light-spot image of the spacial light-emitting-spot with Gauss energy distribution was established, as well as the proof was given for the perspective projection invariability of the spacial light-emitting-spot. Based on the analysis of the second-order directional derivatives and the self-correlation function of the light-spot image, the Hessian matrix was obtained which was used to derive the determinant terms for the pixel level center point. Furthermore, the Taylor expansion was performed on the image gray level within the sub-pixel neighborhood of the pixel level center point, and the maximum of the gray level curved surface of the light-spot image was taken as the wanted sub-pixel center point. Compared with the existing classical methods, the experiment results show that the proposed method has higher accuracy and better robustness which can be widely used in camera calibration and 3D shape measurement, etc.

    Tools

    Get Citation

    Copy Citation Text

    WEI Zhen-zhong, GAO Ming, ZHANG Guang-jun, LIU Zhen. Sub-pixel Extraction Method for the Center of Light-spot Image[J]. Opto-Electronic Engineering, 2009, 36(4): 7

    Download Citation

    EndNote(RIS)BibTexPlain Text
    Save article for my favorites
    Paper Information

    Category:

    Received: Jan. 8, 2009

    Accepted: --

    Published Online: Oct. 9, 2009

    The Author Email: Zhen-zhong WEI (zhenzhongwei@buaa.edu.cn)

    DOI:

    CSTR:32186.14.

    Topics