Image Engineering camSPECS User Manual page 24

purpose.
6. Add Image Folder selects the folder containing the image capture files of each spectrum specified in
item 5 above. When performing image captures of an iQ-LED device, it is recommended to fill the frame
and set the exposure to ensure that the range of the maximum values of the captures uses
approximately three-quarters of the allowable encoding range for the camera. Add Images selects
individual image files rather than an entire folder. - removes an individual selection while C clears all
selections. Each entry in the Image list must have a corresponding Spectrum entry. The images should
be captured in the same order as the Spectrum list. The image naming convention is illustrated in the
iQ-LED Images window and should be of the form alpha description followed by the image number.
7. Start initiates the computation of the test camera spectral sensitivities and produces several outputs,
including:
•
iQ-LED...spectral.txt are the computed spectral sensitivities of the test camera
•
iQ-LED...quantum.txt are the computed quantum efficiencies of the test camera
•
cameraRGBs.txt are measured camera values for each Image and are helpful when checking to
ensure that the camera values use the desired encoding range and are not clipped
•
LEDspectra.txt are the spectral power distributions for each Spectrum
8. The Results panel shows several outputs, including:
•
Reference Spectral Sensitivities allows entry of the known spectral sensitivities file for the test
camera measured with camSPECS. If entered, the Difference shows the mean squared error
between the computed and the Reference Spectral Sensitivities. The parameters described above
can be quantitatively optimized by monitoring the difference for the set of test cameras.
•
Spectral Sensitivity displays the computed spectral sensitivities for the test camera
•
Illumination spectra are the spectral power distributions of the various Spectrum samples selected
as described above in point 4
•
Quantum Efficiency shows the computed quantum efficiencies for the test camera
•
Images preview the Image selected as described above in point 5 and allow the specification of the
ROI size in a percent: wherein the region of interest may be selected by either entering a
percentage value or by dragging the square itself
Image Engineering
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