Processed images from London, 2003

The first image in a row is a standard jpeg as stored within the original raw file (*.raf, for Fuji S5000) -- a scene as processed by the own camera software.

Each second image in a row shows luminance coded by colours (each colour corresponds to another power of ten, scale is logarithmic; mean red is 1 cd/m² or one nit (1 nt), mean green is 10 cd/m²)

Each third image has a grid overlay. Average luminance of each tile is written at its bottom (in cd/m²). (The middle number in each tile is a median value of green pixels.) Each fourth image has the same grid overlaid on colour-coded lumiances.

Further three images in a row code similarly a ``circadian'' (melatonin production affecting, non-imaging visual subsystem) luminance, from the B pixels of the image. (See a poster from Graz conference, g_camer.pdf for its definiton.) In fact, eye sensitivity is far from being uniform for this radiation, maxima being in upper outer quadrant as seen by each eye (see Melatonin Suppression by Light in Humans Is Maximal When the Nasal Part of the Retina Is Illuminated -- Visser et al. 14 (2): 116 -- Journal of Biological Rhythms). Real scenes photographed with a fish eye lens should take it into account in the future.

Indoor ones, from the Childhood Leukaemia conference, lecture by Richard Stevens

London at twilight

Westminster bridge over Thames, Parliament and Big Ben are shown. Glare from the lamps on the bridge becomes prominent already. (Vignetting far from the image centre is not corrected, and becomes very apparent in images with colour-coded luminance.)