Coded apertures for three-dimensional position measurement

Francis M. Ngai; Waldean A. Schulz

doi:10.1117/12.309470

5 June 1998 Coded apertures for three-dimensional position measurement

Francis M. Ngai, Waldean A. Schulz

Proceedings Volume 3262, Surgical-Assist Systems; (1998) https://doi.org/10.1117/12.309470
Event: BiOS '98 International Biomedical Optics Symposium, 1998, San Jose, CA, United States

Abstract

A new optical improvement for image-guided surgical navigation employs coded apertures to measure with submillimeter accuracy the 3D locations of surgical instruments equipped with point light sources relative to a patient. The system consists of multiple angular sensors to measure the position of each light source in several angular dimensions. Each sensor includes a coded aperture to image the light from the point source onto a linear charge-coupled device (CCD) detector array. A coded aperture consists of spatially redundant slits of various widths. This replaces the cylindrical optics or single precision slit which has been used heretofore to focus light from the point source into a linear image crossing the CCD. Although cylindrical lenses have adequate light-gathering capability and tolerate dust, off-axis focus is a major problem. A slit has excellent depth of field and focus but forms a dim image, and dust affects accuracy. A coded aperture combines the advantages of slits and lenses, but does require computing the correlation function using the wide image and a corresponding kernel. The peak in the correlation determines the angular position of the point light source. Sub-pixel accuracy is achieved by interpolation near the correlation peak. Image magnification problems are solved by sing scaled kernels.

Citation Download Citation

Francis M. Ngai and Waldean A. Schulz "Coded apertures for three-dimensional position measurement", Proc. SPIE 3262, Surgical-Assist Systems, (5 June 1998); https://doi.org/10.1117/12.309470

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
10 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Charge-coupled devices

Light sources

Sensors

Coded apertures

Light

CCD image sensors

Monte Carlo methods

Show All Keywords

Keywords/Phrases

Search In:

Publication Years