Stranica 74 [74]
OCR
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 16bit 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
