Image 08

original 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    : 2005:08:05 00:34:25
# Resolution   : 2048 x 1536 in jpeg (2064x1540 in pgm/08.pgm)
# Focal length : 11.2mm
# Exposure time:10.670 s 
# Aperture     : f/7.8
# ISO equiv.   : 100

#c li count  min  Yav  max  ovf   min  Cav   max  ovf   min  Gav   max  ovf   min  Mav  max  ovf
# Image percentils         L=(1.000*1.30*Y+1.060*0.00*C+1.240*-0.30*G+1.310*0.00*M)* 3.65E-4
# %    Y     C     G     M readings  Y        C        G        M        L / cd/m2
  1   -22   -28   -35   -29      -0.0080  -0.011   -0.016   -0.014   -0.0057
 10     0    -7   -10    -5       0.0     -0.0027  -0.0045  -0.0024   0.0014
 50    66    29    32    45       0.024    0.011    0.015    0.022    0.027 
 90   279   110   125   188       0.10     0.043    0.057    0.090    0.12  
 99  1465   575   647   995       0.54     0.22     0.29     0.48     0.61  
100 16319 16316 16321 16329       6.0      6.3      7.4      7.8      5.5   
# flux from 5.55 sr ( 8.71E-6 sr/4px) is  0.264  (summing all pixels below 16380)
# dark frame dark/1m.pgm scaled by  0.1780 (after subtracting an offset frame dark/off.pgm from both images) subtracted
# Yell average= 147.1  minimum= -141  maximum=16319   over 16380: 332
# Cyan average=  62.3  minimum= -142  maximum=16316   over 16380: 490
# Gree average=  68.4  minimum= -331  maximum=16321   over 16380: 638
# Mage average= 101.2  minimum= -460  maximum=16329   over 16380: 302

End of results of "raw2lum" (version 1.07) with parameters:
  -c YCGM -fa -w 7.3 -fc0.214 -o 16380 -o dark/off.pgm -d dark/1m.pgm:0.178 -sm200 -i 08.txt -e 08.eps -n 08.ppm -t156 -c 3412 -s32 pgm/08.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)