Image 22

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 02:45:55
# Resolution   : 1280 x 960 in jpeg (1424x1076 in pgm/22.pgm)
# Focal length :  9.4mm  (35mm equivalent: 64mm)
# CCD width    : 5.32mm
# Exposure time: 2.000 s 
# Aperture     : f/2.8
# ISO equiv.   : 200

# Selected image percentils         L=(1.730*0.35*R+1.000*0.65*G+1.570*0.00*B)* 1.66E-4
# %    R     G1    G2    B readings  R        G        B        L / cd/m2
  1   -33   -29   -30   -45        -0.00948  -0.00490  -0.0117  -0.00650
 10    10     6     7    -8         0.00287   0.00108  -0.00209   0.00171
 50   227   199   200    52         0.0652   0.0331   0.0136   0.0444
 90  1818  1364  1365   221         0.522    0.227    0.0576   0.330 
 99  4207  3203  3211   547         1.21     0.533    0.143    0.769 
100 15869 15866 15866 15867         4.56     2.64     4.14     3.31  
# flux from 0.241*0.95 sr ( 3.16E-7 sr/4px) is  0.0292 lx ( 0.0300 lx tilewise);
# tilewise luminance  0.127 cd/m2 with rel. SD  106 % (summing pixels below 15850 and with non-zero green: there is 94.8 % of them)
# Fuji Devignetting: 2 # dark frame dark/43.pgm subtracted from all values
# Red  average= 693.4  minimum= -125  maximum=15869   over 15850: 1307 zero:  3.6 %
# GrUp average= 548.3  minimum=  -99  maximum=15866   over 15850: 1127 zero:  5.2 %
# GrDw average= 548.4  minimum= -119  maximum=15866   over 15850: 1105 zero:  5.1 %
# Blue average= 106.4  minimum= -205  maximum=15867   over 15850: 288 zero: 11.5 %

End of results of "raw2lum" (version 1.22) with parameters:
  -c fuji -fa -d dark/43.pgm -sm100 -nh -nt -i 22.txt -e 22.eps -n 22.ppm -t 118 -s71:76 pgm/22.pgm
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)