Agisoft Metashape

Agisoft Metashape => Camera Calibration => Topic started by: Christina K on April 15, 2021, 09:29:09 PM

Title: How does Agisoft calculate the reflectance values for the calibration panel
Post by: Christina K on April 15, 2021, 09:29:09 PM
Hi all,

Didn't find this mentioned earlier so made a new topic.
I am curious on how the reflectance values are calculated in agisoft based on the .csv file for the calibration detection module.
So for the following bands with these specific wavelengths, how does Agisoft reach the reflectance value per band?
Blue (B): 475 nm ± 32 nm;
Green (G): 560 nm ± 27 nm;
Red (R): 668 nm ± 14 nm;
Red edge (RE): 717 nm ± 12 nm;
Near-infrared (NIR): 842 nm ± 57 nm

when I am manually trying to calculate this with a script like below, I get these values
dtype: float64, reflectance 0.691253
dtype: float64, reflectance 0.702969
dtype: float64, reflectance 0.69715
dtype: float64, reflectance 0.688833
dtype: float64, reflectance 0.43085

import pandas as pd
reflectance_factors_excel_path = r"RP02-1603082-SC.xlsx"
df = pd.read_excel(reflectance_factors_excel_path)
df.info()
df2 = refl_df.set_index('wavelength')
middle_nm = 842
nm = 57
nm = int(nm/2)
first = int(middle_nm - (nm))
last = int(middle_nm + (nm))
row_list = list(range(first,last))
df2.loc[row_list].mean()

But agisoft gives different values, so I would like to know the details on how we get from csv to the panel calibration reflectance value if possible!

Kind regards,
Christina
Title: Re: How does Agisoft calculate the reflectance values for the calibration panel
Post by: Alexey Pasumansky on April 17, 2021, 06:52:05 PM
Hello Christina,

Where from you are taking the averaging range for each band? Metashape is using WavelengthFWHM value from the image meta data to get the averaging range for each band.