On the basis of the illumination on the camera detector, how can I calculate the angle of emitted beams? We are given the value of numerical aperture of the lens as well as working distance.
Dear Suraj Jat ,
that seems to me as a home work task.
Nevertheless, please have a look at the figures at the section 'Imaging through a convex lens ' of
https://www.tf.uni-kiel.de/matwis/amat/admat_en/kap_5/backbone/r5_1_2.html
Here you can see the image formation via a thin lense and the definition of the numerical aperture.
Unfortunately there is a typing error.
The imaging equation should read: 1/O +1/I = 1/f with O being the distance of the object to the center plane of the lense and I being the distance of the image with respect to the center plane of the lense.
Play around with this figure and the angles and distances to figure out your angle of your 'emitted beam'. All the informations you need are there...
Some hints:
a) From the numerical aperture you can get the focal length, and
b) the beam just crossing the mid of the lense will give you the angle,
c) your pixel position/distance from the optical axis is the 'I' , and 'I' its distance to the center plane of the lense,
d) the 'O' is your working distance
Good luck...
I believe this can be done if the beam angle is small. In such a case, it could be calculated with a simple geometric proportion, the ratio between the radial position of the beam edge to the focal length of the lens. The radial position may be calculated with a proportionality factor for pixels. The proportionallity factor can be calculated with the size of pixels, or the ratio of the number of pixels in the detector to the size of the detector.
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