William F Pokorny <ano### [at] anonymousorg> wrote:
> On 04/03/2017 10:14 AM, muyu wrote:
> > clipka <ano### [at] anonymousorg> wrote:
> >
> > Great thanks again.
> >
> > Shouyang
> >
>
> Just thinking aloud and perhaps you've covered it with Christoph at some
> point, but there is both the angle of the light original & derived rays
> relative to the surface and the camera ray angle relative to the
> surface. Are you using a perspective camera or an orthogonal one?

I am using the orthogonal camera. I do not know which is better?

> My instinct would be to measure via an orthogonal ground camera up into
> the canopy representation for some area below the canopy unless you are
> trying to match some specification for the camera from your reference
> set up and result.

I need set the camera looking downward to mimic the real set-up.
>
> I wonder some too about the edges, the range, of your canopy discs given
> you are sometimes setting the parallel light source at some offset
> angle. In other words are you sure light is not bleeding in faster at
> the edges of the representation when the light isn't perpendicular to
> your canopy representation and measurement plane?

As I know, there will be some border effect. So I set the camera looking at the
center of the canopy. I do not know exactly how pov-ray manage the parallel
light especially around the border. Thanks in advance.

Shouyang

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