False color images

[lluis.brotons]

Hi,

I am trying to create false color images from Sequoia outputs. However, when i try to create a false color composite using raster calculator and selecting the three bands in the corresponding menu I always get a just plain white image without any info. Gray scale by band works well, but i guess I am not doing something right during the process.

Thanks
Lluís

[Alexey Pasumansky]

Hello Lluís,

The color values - as a result of raster transformation by the formulas in the Raster Calculator dialog, should fit 8-bit interval (i.e. - 0 255), so you may need to divide the values by the constant, for example, please try: B1 / 128, B2 / 128, B3 / 128.

The original range is 16 bit (0 - 65535), whereas after the reflectance calibration the 100% reflectance would correspond to the middle of that range - 32768.

[lluis.brotons]

Hi,

No change. I still obtain a white image when I select the False color option from palette... In fact when I select B1,B2,B3 in a RGB image i do not get the RGB image as I was suppoused to get... or am I getting something wrong here on what false color composite from palette is able to deliver?
thanks
Lluís

[Alexey Pasumansky]

Hello Lluís,

I've tried on some random Sequoia project and got False Colors  results by using 65536 ratio: