Which focusing principle enabled early Islamic scholars like Ibn al-Haytham derive accurate solar imagery using the camera obscura?

💡 Explanation

When light rays pass through a small pinhole, rectilinear propagation projects an inverted image of the external scene because each point emits light in all directions, but only rays passing straight through contribute to the image. Therefore, pinhole projection leads to image formation, rather than refractive index gradients, interference or polarization, which require optical lens or filters instead.

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