Pinhole camera dimensions

Omniverse Isaac Sim
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1

Hello,

I’m trying to measure illumination via a pinhole camera and I want to understand the effect of each camera property in Omniverse. From tests I’ve conducted, it seems that:

  1. The horizontal_aperture parameter represents the screen width in physical units (and not the pinhole aperture).
  2. The pinhole size appears to be proportional to the focal_length with a factor of approximately 1/25 (meaning f/25 f-number).

However, the typical f-numbers for pinhole cameras are much higher (ranging from f/90 to f/360 or more), so I suspect something might be off with my results.

Test Description:

I used a square plane and illuminated it from above with a white light source (distant light). The scene’s illumination was captured (PtDirectIllumation annotator) using a pinhole camera placed directly above the plane’s center. I then compared the sum of the captured illumination to the light emitted by the plane and from this, I calculated the f-number mentioned above. I used isaacsim.

Could anyone provide insights into whether my interpretation is correct? Is the scaling of the pinhole size and the resulting f-number in line with what should be expected in Omniverse’s pinhole camera model, or might there be some other factors or settings influencing the results?

Thanks

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