Development of traceability methodology for optical coherence tomography (OCT) using step height standard as calibration reference

Abstract

This paper presents a methodology for providing traceability to OCT measurements linked to Length SI unit. The link to primary length standard is provided by an interference microscope (IM). The chosen transfer standard was a step height gauge block. The results for IM and OCT showed good agreement for step height standards, such that the OCT will be able to perform reliable measurements of complex surface topographies and to ensure traceability to the length scale. The main uncertainty components were evaluated for the OCT system. In addition, OCT also was used for measuring a surface roughness standard -a depth standard -in order to test this methodology for round groove profiles. Results were found to be in good agreement with the calibration certificate.

Optical coherence tomography applied to tests of skin care products in humans – a case study

“…Figure 1 presents typical topographic profiles of skin as obtained by OCT in periorbital areas. We obtained typical values of 30 lm for R a and 95 lm for R Z , with uncertainty of 5% for both determinations (13). We verified changes in R a and R Z for treated and non-treated regions, with stronger changes in treated areas, reaching the maximum of approximately 10% day 14, from the values obtained on day zero, as shown in Fig.…”

Certification of Standard Reference Material® 2196 Axial Resolution Standard for Optical Medical Imaging

“…The rectangular region is defined in pixels by its w (width) x h (height). The values for w and h used in the experiment are w = 31 and h = [3,5,7,9,11,13,15]. We chose w =31 because this is the safe axial length across which the curvature in the image is negligible with no distortion in the axial scale.…”

“…A calibration of the NIST SD-OCT was performed by imaging a NIST-traceable step height reference material (step height standard, part #SHS -50.0 Q, serial #13153-01-11, VLSI Standards Incorporated). Step height standards have been used to establish SI traceability of the axial length scales in confocal and interference microscopy [10] in addition to OCT [11]. The step height standard used here consists of a 25 mm x 25 mm x 3 mm quartz block with a precisely etched trench (negative step).…”