Evaluation environment
Coaxial tube: Kohler illumination type / Critical illumination type
Objective lens: PEIR Plan 10X
Camera:BU406M(2048 x 2048, 5um)
Light source: SIS-150-AIR + band pass 1100nm
Inspecting object: Mirror
<How to calculate the contrast>
(The average brightness in red square – The average brightness in blue square) / ( The average brightness in red square + The average brightness in blue square)
<Original image / Kohler illumination type>
Mean of brightness in red square : 169.169375
Mean of brightness in blue square : 26.015625
Contrast : 0.7334259804800574
<Original image / Critical illumination type>
Mean of brightness in red square :155.194375
Mean of brightness in blue square : 33.10875
Contrast : 0.6483462502281893
Result :
Comparing each contrast values, Kohler illumination type allows to show higher contrast image.