Image Engineering
Seite
7
von
12
exposure control of the camera is used. This only applies to the camSPECS hardware with the
sequential capturing mode (“Multi
-
shot”).
4.
Apply dark frame subtraction. Supported image types are: TIFF, PGM, BMP, PNG, PPM and raw
files. Take an image with the same camera exposure settings as used for the camSPECS images.
It will be subtracted from each image in the processing list. This option is used to subtract the
offset value, inherent in all images, that has its origin in the dark current of the sensor. This offset
value has a negative impact on the spectral measurement.
5.
Set the maximum allowed digital value in accordance with the
Exposure
guidelines given above. If
this value is exceeded in an image, an error message is displayed.
6.
Add image(s) to processing list. Supported image types are: TIFF, PGM, BMP, PNG, PPM and raw
files (The term "raw file" means files that are created by a digital camera in "RAW
-
Mode" and are
readable by the software
dcraw
. This does not include raw files that do not follow any image file
format. You should convert these files to 16
-
bit Tiff images first.). Depending on the selected
calibration file (see item 1) you can choose one or more images that must contain the filter
arrangement of camSPECS device. With the '+', '
-
' and 'C' buttons you can add images, remove
one selected image or clear the whole list. After the measurement the spectral curve of the first
image in the list is displayed. By clicking on the other images in the list the corresponding results
are displayed.
7.
Check the advanced settings.
8.
Start the processing procedure. The filters in the images are detected automatically. After the
detection process a confirm dialog is shown where the ROIs for each filter can be manually
repositioned if necessary. By double
-
clicking on the background, the processing starts. The
resulting spectral curves are displayed and saved to a plain text (.txt) and an XML file in the same
directory as the original image directory. For the camSPECS version a tile image is saved to the
same directory as the origin of the images directory assembled from the single images. Check this
image for correct positions of the ROIs or all filters.
In some cases, the filters of camSPECS images may not be detected automatically. In this case
you are guided by semi
-
automatic filter detection with some controllers which restrict a couple of
constraints for correct detection of the filters.
9.
When the measurement is done you can switch between raw and normalized RGB spectral curves
data.
10.
Export the spectral curves to an image (JPEG, PNG, TIFF, BMP, GIF) for documentation
purposes.
