Findclouds Manual 26
Normally the software would recognise the white overexposed area near the sun as a cloud. Using
the information from "Sun Pixel" the software can determine, whether the bright pixel area in
"Bright Pixel" is blue sky or comes from clouds or atmospheric opacity. The checkbox
''Use Sunmask''
in "Evaluation BRBG" specifies to use only the sunmask area or the whole bright
area for adjustment.
''Show Sun"
can display the position of the sun as circle
('Show Sun Position') or as pixel area ('Show Sun Pixel') in
the resulting pictures of the calculation of cloudiness.
Evaluation
"Algorithm BRBG":
Next section of evaluation is "Algorithm BRBG"
with images "Colourratio NE", "Colourratio UE",
"Cloudy Sky", "Blue Sky UE" and the result
"Evaluation BRBG".
For this analysis the checkbox “Algorithm BRBG”
has to be activated.
The BRBG Algorithm calculates the ratio blue/red
+ blue/green out of the projected RGB image. It
shows the result in “Colourratio NE” and “Colourratio UE". In reality the result of the three RGB
values is a single "grayscale" value. The Colourratio images are colourised to make them more
demonstrative. The colour bar between these images shows the range of values and scales the
colours. It is valid for both images (NE and UE), so the same colour will show the same value and
the images are directly comparable.
The
"Cloudy Sky"
shows pixel of "Colourratio NE" with values less than a defined value as cloud
pixel. The slider on right hand side of the image allows to adjust the appropriate level and make
the result visually match better to original sky image.
The
"Blue Sky UE"
shows additional blue sky pixel of the underexposed image. These pixel can
be used to adjust the area around the sun (“Merge Underexposed”: Area Of Sunmask), or to adjust
the whole image (“Merge Underexposed”: Whole Blue Sky).
