DN ε [1,2Q]

Where Q is an integer representing the bits. LISS III is 8 bit data.

Lrad = (DN/MaxGray)*(Lmax – Lmin) + Lmin.                   

Lrad: Radiance for a given DN value.

DN: Digital Count.

MaxGray: IRS-1C/1D: 255 for Corrected products.

For IRS-P6: 255 for LISS-3&4, 1023 for AWiFs for corrected products

Lmin/Lmax: Minimum/Maximum radiance value for a given band and unit is mw/cm2/str/um.

  E λ = E0 [ 1.00011 + 0.034221 cos x  + 0.00128

                                   sin x + 0.000719 cos 2x + 0.000077 sin 2x]

 where,          

E λ : Irradiance value in W/m2

 E0 : Average irradiance 1366.9977 w/m2.

 x = 2π (dn - 1) / 365

                                     r λ = Lλ / Eλ                                    

where,

r λ : spectral reflectance is expressed as a percentage.

L λ  : Radiance for a given DN value.

Eλ   : Irradiance value of particular day.

                   Ρ = ∫ r λ E (λ) dλ                                        

where,

Ρ       : Bidirectional Reflectance Distribution Function.

r λ       : Spectral reflectance is expressed as a percentage.

E0 (λ) : Solar irradiance of each wavelengh band in w/m2.

                      α(λ,θ0) = Fu(λ,θ0) / Fd(λ,θ0)                              

 where,

 α(λ,θ0)     : albedo value in no unit.

 Fu(λ,θ0)   : upwelling radiative flux in mw/cm2.

 Fd(λ,θ0)   : downwelling radiative flux in mw/cm2.

 λ             : wavelength in micrometer.

 θ0                    : solar incidence angle in degree.

U try using above formula in Envi band math or Matlab

There is a portal "BHUWAN", ISRO India. You go there and you can download the albedo data free for Indian regions.