DAVID ALAN PALMER
اسلاید 1: DAVID ALAN PALMERJuly 1933 - June 2000
اسلاید 2: Christ’s College, Hendon Lane, Grammar SchoolImperial College - physics, 1952 - 1955Imperial College - PhD, 1958: supervisor W.D. WrightNational Physical Laboratory - 1958National Physical Laboratory - W.S. Stiles
اسلاید 3: NPL - general duties including photometryNPL - Brian Crawford & colour renderingNIC - chair of colour rendering committee 1965-7IoO - Institute of Ophthalmology, 1967
اسلاید 4: MESOPIC PHOTOMETRY
اسلاید 5: MESOPIC PHOTOMETRY“The equivalent luminance L of any light may beexpressed, to a good approximation, as afunction of its scotopic and photopic luminances.”The question is, “What is this function?”David measured scotopic and photopic luminances by matching test lights of different wavelengths to white light of 2042KAt match, LV, the equivalent luminance follows the relation:and the scotopic and photopic luminances can becalculated and log LP plotted against log LS
اسلاید 6: David’s plot of log LP against log LS
اسلاید 7: Palmer said that ideally the plots should show,“straight lines parallel to the P axis at very lowlevels, and parallel to the S axis at high levels.”But additivity was not perfect so there weredepartures from this especially at the endsof each curve.The data fitted adequately the expression:which is the form that the Palmer Mesopic Model is usuall set out: the figure shows how well the data fit the relation
اسلاید 8: Data from other workers fitted the model well considering the problems know to exist with additivity - here are data from Kinney, JOSA, 58:1296, 1968
اسلاید 9: Christmas CelebrationsDavid was known for celebrating Christmas in style - a chosen theme, usually Dickensian, was followed for food, drink and decorand the lab had the benefit of last years decorations, for example, celebrations with Captain Cuttle from Dombey and SonIn this David revealed high talent as an artistic draughtsman
اسلاید 10: ENTOPTIC PHENOMENA - in art the light source was seldom depicted because glare, halos and contrast ratios are not easy or possible to capture convincingly
اسلاید 11: A search for halos and glare showed many artists capturing the drama of light and shade but hiding the source
اسلاید 12: COLOUR RENDERING . . . the effects of new fluorescent lamp phosphors on clinical evaluation of patients and skin lesionsThis was the first of a long series of papers on colour rendering and . . . .
اسلاید 13: COLOUR RENDERINGAnd this was the last set of papers in the series
اسلاید 14: COLOUR RENDERINGFor this work the team were awarded the Walsh-Western Bronze Medal of the Chartered Institute of Building Services Engineers in 1993
اسلاید 15: There we had fun with sunglare protection (i.e. sunglesses)RETIREMENTIn the ninties David retired and then worked afternoons at the University of WestminsterWe evaluated sunglasses for magazines and checked for safety a whole range of toys which contained laser light sources
اسلاید 16: Traffic signal light recognition involved sorting out the infamous Q Factorand doing experiments on signal colour recognition
اسلاید 17: CHRISTMAS again....and the sloe gin recipe competitions continued as did the search for the perfect microwave oven baked Christmas PudDavid continued his work, started with Brian Crawford years before, on luminosity functions
اسلاید 18: David showed normal observers’ photopic luminosity functions for large fields fell into one of three groups
اسلاید 19: David measured protanopes’ scotopic luminosity functions and showed they were reduced at long wavelengths - evidence that scotpic vision is a mix of rod and L wavelength cone inputs
اسلاید 20: David re-analysed the original scotopic luminosity function data of Crawford which had been used to formulate the CIE internationally agreed curve and found some surprises: many curves were considerably narrower than the CIE curve and the peak wavelengths were grouped as shown below
اسلاید 21: David started to re-measure these curves with modern equipment but had to know about pre-retinal absorption so we set about measuring the macular pigmentWe made many prototypes with David’s favourite material - card & UHU glueSix instruments of the final design were made and are used across EuropeIt was whilst calibrating one of these that David was taken ill - he never worked again
اسلاید 22: PROMOTION OF SCIENCEDavid hated the way the Government treated science and scientists, and was appalled at the general lack of understanding of science, especially by those “educated” elites that made up various authoritiesHe worked to improve the understanding of science with, e.g. the Institute of Physics and the Royal Institution
اسلاید 23: James Clerk Maxwell - a model and hero
اسلاید 24: DAVID PALMER vision scientist 1933-2000
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