Image-based system for measuring objects on an oblique plane and its applications in 2-D localization

Ming Chih Lu*, Chen Chien Hsu, Yin Yu Lu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


This paper presents an image-based framework for measuring target objects on an oblique plane by using a single charge-coupled device camera and two laser projectors mounted in parallel beside the camera. Because of the alignment of the laser beams, which form in parallel with the optical axis of the camera, laser-projected spots in the image can be processed to establish relationships between distance and pixel counts of the projected spots in the image. Based on simple geometrical derivations without complex image processing, the proposed approach can successfully measure the photographic distance, the distance between two arbitrary points on the oblique surface, and the incline angle of the oblique surface. Thanks to its ranging capability, the proposed image-based measuring system is further applied to localize objects on a ground surface in addition to depth measurement. To demonstrate the feasibility of the proposed approach for practical applications, we propose a surveillance framework under which a pan-tilt-zoom camera tracks objects in an environment according to the 2-D localization results obtained via the proposed method. Experimental results have demonstrated the effectiveness of the proposed approach in distance measurement, as well as localization of objects on an oblique plane.

Original languageEnglish
Article number6144686
Pages (from-to)2249-2261
Number of pages13
JournalIEEE Sensors Journal
Issue number6
Publication statusPublished - 2012


  • Charge-coupled device (CCD) images
  • digital cameras
  • distance measurement
  • laser
  • localization
  • measuring systems
  • oblique plane
  • pan-tilt-zoom (PTZ) camera
  • pixels
  • surveillance

ASJC Scopus subject areas

  • Instrumentation
  • Electrical and Electronic Engineering


Dive into the research topics of 'Image-based system for measuring objects on an oblique plane and its applications in 2-D localization'. Together they form a unique fingerprint.

Cite this