Image 10

original lighter colour coded

and with an inserted data grid:

(in the middle of tiles, median of raw G-pixels values is given, the bottom value is the tile luminance divided by one candela per square meter).
# Date/Time    : 2006:06:29 02:32:32
# Resolution   : 1280 x 960 in jpeg (1424x1076 in pgm/10.pgm)
# Focal length : 19.2mm  (35mm equivalent: 130mm)
# CCD width    : 5.32mm
# Exposure time: 2.000 s 
# Aperture     : f/3.2
# ISO equiv.   : 200

# Selected image percentils         L=(1.730*0.35*R+1.000*0.65*G+1.570*0.00*B)* 2.17E-4
# %    R     G1    G2    B readings  R        G        B        L / cd/m2
  1   -59   -53   -53   -58        -0.0221  -0.0115  -0.0198  -0.0152
 10   -28   -24   -24   -28        -0.0105  -0.00521  -0.00954  -0.00706
 50     1     0     0     0         3.75E-4   0.00     0.00     1.31E-4
 90    49    44    44    45         0.0184   0.00955   0.0153   0.0126
 99   151   129   130    89         0.0567   0.0281   0.0303   0.0381
100 15869 15866 15866 15867         5.96     3.44     5.40     4.32  
# flux from 0.0580*0.59 sr ( 7.57E-8 sr/4px) is  2.36E-4 lx ( 3.59E-4 lx tilewise);
# tilewise luminance  0.00575 cd/m2 with rel. SD  227 % (summing pixels below 15850 and with non-zero green: there is 59.3 % of them)
# Fuji Devignetting: 2 # dark frame dark/43.pgm subtracted from all values
# Red  average=  24.8  minimum= -336  maximum=15869   over 15850:  77 zero: 33.4 %
# GrUp average=  23.7  minimum= -118  maximum=15866   over 15850:  58 zero: 41.4 %
# GrDw average=  23.8  minimum= -114  maximum=15866   over 15850:  62 zero: 40.0 %
# Blue average=  12.3  minimum= -156  maximum=15867   over 15850:  23 zero: 37.3 %

End of results of "raw2lum" (version 1.22) with parameters:
  -c fuji -fa -d dark/43.pgm -sm100 -nh -nt -i 10.txt -e 10.eps -n 10.ppm -t 118 -s71:76 pgm/10.pgm

In grid tiles, flux densities from these points and tiles are given.


  Luminance scale / 1 
cd/m<sup>2</sup>
Logarithmic luminance scale (the unit is candela per square meter) – intensities of snow illuminance in lux would be obtained by multiplying the numeric value of luminance by 3.6. For asphalt, such a coefficient is between 20 and 40 (or much less, for specular reflection of distant lamps)