Hi! We are trying to process images taken with Mavic 3M into reflectance according to the processing guide. However we cannot seem to find this px parameter needed to calculate the Xref values in Eq 4 and 6. Where could we find this or how to calculate it?

Wow, that is a very very specific question.
I doubt anybody on the forum will have an answer.

Montfrooij Posted at 1-3 11:32
Wow, that is a very very specific question.
I doubt anybody on the forum will have an answer.

Well I hope someone from DJI could answer..

djiuser_bIVF61cKaG4E Posted at 1-6 22:59
Well I hope someone from DJI could answer..

I'm not sure if they are around, but you might want to try asking a specific forum admin in a personal message.

yo use estos parametros :

#Quick Reply Here# I used these parameters : bits_per_sample=int(metadata_exif.get('Image BitsPerSample').values[0])
black_level = int(metadata_xmp['BlackCurrent'])
sensor_gain = float(metadata_xmp['IrradianceGain'])
exposure_time = float(metadata_xmp['SunSensorExposureTime'])
irradiance = float(metadata_xmp['Irradiance'])
sun_sensor = float(metadata_xmp['SunSensor'])
and this formula:  
def radiometric_correction(image, black_level, gain, exposure_time, irradiance, bits_per_sample, sun_sensor):     
# Normalizar el nivel de negro     
normalized_black = black_level / (2 ** bits_per_sample)     
# Normalizar los valores crudos de los píxeles     
normalized_image = image / (2 ** bits_per_sample)     
# Corrección de radiancia     
radiance = (normalized_image - normalized_black) / (gain * exposure_time *1000000)     
# Ajuste usando irradiancia y el sensor solar     
reflectance = (radiance / (irradiance/(2 ** bits_per_sample))) * (sun_sensor)     
return reflectance  
I think it's moderately correct; the manual is not very clear. Now I want to align the four multispectral images, but I can't find the HMatrix anywhere. If you know how to create it, please let me know. Greetings from Chile!