Asked by S
on 1 Apr 2013

how can I write code for finding band depth of a parabola which is going from three points (7.8 0.96), (8.25 0.99) and (8.55 0.94)?

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Answer by Image Analyst
on 1 Apr 2013

You can get the coefficients of the formula using **polyfit**(). It's so **really really easy** that I shouldn't have to even give you the code. Just look at the help for polyfit(). After that just use whatever formula you have for "band depth". By the way, why did you tag this "image processing"?

S
on 2 Apr 2013

Band depth is defined as the absorption band depth, D, was defined relative to its continuum:

D = 1 - Rb/Rc

where Rc is the reflectance of the continuum at the band center, and Rb is the reflectance at the band center.

How can I compute band depth of this polyfit curve or parabola using this formula?

I thought it comes under image processing so I tagged?

In this problem x co-ordinate represents wavelengths and y co-ordinate represents emissivity(= 1-reflectance).

Image Analyst
on 2 Apr 2013

I'm not sure what all those terms mean. If you have a parabola, the equation is y = coeffs(1)*x.^2 + coeffs(2)*x + coeffs(3). You can get coeffs from

coeffs = polyfit(xArray, yArray, 2);

So what is D, Rb, and Rc in terms of the coefficients?

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