I would like to understand more in detail the effect of the type of radiometric correction over reflectance’s calculation by Pix4D. Specifically between the options “Camera and Sun Irradiance” or “Camera, Sun Irradiance and Sun angle”.
I processed my data, obtained by the camera Parrot Sequoia, using “Camera, Sun Irradiance and Sun angle” option. When I analyzed the data, I detected unexpected values for developed vegetation. The values for red edge band were higher than the values of the band near infrared, opposite to the expected. Then I changed the type of radiometric correction to “Camera and Sun Irradiance”. The reflectance values were more logical showing the typical reflectance curve of vegetation.
Why was able the software to overcame this problem only changing the type of radiometric correction from “Camera, Sun Irradiance and Sun angle” to “Camera and Sun Irradiance” ? Is it related with diffuse irradiation? When is taking in count the solar angle, is the sun irradiance recieved for the camera on the Drone during the fly modified? In case it is right, in which way?
Thank in advance for your help.
Thanks Kapil_Khanal for your reply. Now, the process done by Px4D is clearer for me. Best regards.