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Nina

Please correct me if I'm wrong. Does Le(p,w0) here means the irradiance emitted from point p on surface when not considering light? (eg. When not considering light, we can consider surface point p as a point light source if the surface is shining. If the surface does not shine, then Le(p, w0) can be considered as 0)

Thanks.

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I think slide 36 can answer this question.

kayvonf

@Nina. It is radiance emitted from point p in direction w_o. (But this is very much "considering light"! I think you mean when not considering reflected light.)

lucida

Why don't we also need to weight the emitted light from point p by a cosine? The light emitted from p does not necessary hit the lens at an angle perpendicular to the lens' surface.

kapalani

I think its because we're trying to compute the amount of output radiance from point p in the direction wo. The Le term we are considering is already giving us the radiance along wo, so there's no need to multiply by cosine.