Method for determining the reflectance profile of materials

A method for calculating specular and diffuse reflectance and hence, the emittance of materials at ambient temperatures, the said method comprising the steps of:

• (a) obtaining the input parameters wavelength (λ), refractive index (n), extrinction coefficient (k) and angle of incidence (θ) from the user;
• (b) calculating absorption coefficient (α);
• (c) prompting the user to choose between calculation of specular reflectance and calculation of diffuse reflectance;
• (d) if specular reflectance is selected by the user, calculating u, v, parallel component of specular reflectance (Rs), perpendicular component of specular reflectance (Rp) and calculating the mean of the parallel and the perpendicular components thus obtained above to obtain the specular reflectance;
• (e) if diffuse reflectance is selected, prompting the user to select between K-M Method and statistical method;
• (f) if K-M method is selected by the user, obtaining scattering coefficient (S) from the user and calculating diffuse reflectance;
• (g) if statistical method is selected, obtaining grain size from the user and calculating external reflection coefficient (me) and internal reflection coefficient (mi);
• (h) calculating ‘r’ and ‘t’ using any one of the following four statistical methods, and
• (i) Simplified particle model theory,
• (ii) Modified particle model theory,
• (iii) Plane parallel plate theory, and
• (iv) Melamed theory
• (i) calculating the diffuse reflectance statistically using ‘r’ and ‘t’ thus obtained in step (h).