Oldal 74 [74]
d. Capturing Reflected Images
i. Visible-reflected Images
The workflow shown in Figure 2-21 summarises the corrections proposed as a result of the
discussions in Chapter 1 and also highlights the general transformations to be carried out by
the post-processing software.
;
Camera output Corrected for Corrected Corrected for Corrected
spatial for camera response Visible reflected
inhomogeneities Spectral (colour calibration) image
of light source density
(Flat fielding)
Figure 2-21. Schematic of the workflow proposed for visible-reflected images.
The requirements in order to carry out the image correction procedure are as follows:
1) The camera output file, i.e. the visible-reflected image;
2) The ICC profile (which records all the metadata including the gamma correction applied to
the image. This describes and is created on the conversion from RAW into a standard 16¬
bit TIFF file, see Chapter 3). This profile is contained within the TIFF file and is
automatically retrieved by the post-processing software;
3) An image of a uniform reflective board under the same experimental conditions for flat
fielding, if available;
4) An image of a Macbeth chart for colour calibration, included as part of the image to be
calibrated or in another image taken with the same camera and lighting conditions;
5) An image of a Spectralon diffuse reflectance grey scale or any number of Spectralon
diffuse reflectance standards as available (included as part of the image to be calibrated
or in another image taken with the same camera and lighting conditions). Required for
comparison to IRR/UVR images and post-processing of luminescence images.
A workflow has been developed to ensure that these requirements are collected according to
the optimised and standardised acquisition protocols. The instructions below describe the
workflow for the capture of visible-reflected images. A checklist of the requirements for the
image correction procedure is included at the end of the workflow.
Version No. 1.0 66 Date : 14/10/2013