Short of them actually publishing the image signature the camera takes as the random input, no. Imagine just how much sensor noise is sitting across the image, and figure on other elements others have mentioned: the angle, the aperture, etc. I imagine two near-identical frames without any movement between them taken on a single camera might still have a significant amount of entropy between them, especially if you're using the camera raw data, for those reasons.

They (CF) discuss this on their deep dive:

>>>The flow of the “lava” in a lava lamp is very unpredictable,6 and so the entropy in those lamps is incredibly high. Even if we conservatively assume that the camera has a resolution of 100x100 pixels (of course it’s actually much higher) and that an attacker can guess the value of any pixel of that image to within one bit of precision (e.g., they know that a particular pixel has a red value of either 123 or 124, but they aren’t sure which it is), then the total amount of entropy produced by the image is 100x100x3 = 30,000 bits (the x3 is because each pixel comprises three values - a red, a green, and a blue channel). This is orders of magnitude more entropy than we need. [1]

1: https://blog.cloudflare.com/lavarand-in-production-the-nitty...