.\" RCSid $Id: evalglare.1,v 1.2 2016/04/10 04:08:19 greg Exp $ .TH EVALGLARE 1 7/30/15 RADIANCE .SH NAME evalglare \- determines and evaluates glare sources within a 180 degree fisheye HDR image .SH SYNOPSIS .PP .nh .B evalglare [ .BI \-s ] [ .BI \-y ] [ .BI \-Y \ value ] [ .BI \-B " angle" ] [ .BI \-b " factor" ] [ .BI \-c " checkfile" ] [ .BI \-t " xpos ypos angle" ] [ .BI \-T " xpos ypos angle" ] [ \-d ] [ .BI \-r " angle" ] [ .BI \-i " Ev" ] [ .BI \-I " Ev yfill_max y_fill_min" ] [ .BI \-v ] [ .BI \-V ] [ .BI \-g " type" ] [ .BI \-G " type" ] [ .BI \-u " r g b" ] [ .BI \-vf " viewfile" ] [ .BI \-vt t ] [ .BI \-vv " vertangle" ] [ .BI \-vh " horzangle" ] .RI [ hdrfile ] .hy .SH DESCRIPTION .PP .B Evalglare determines and evaluates glare sources within a 180 degree fisheye image, given in the RADIANCE image format (.pic or .hdr). If .I hdrfile is not given as an argument, the standard input is read. The image should be rendered as fisheye (e.g. using the .BI \-vt a or .BI \-vt h option) using 180 degrees for the horizontal and vertical view angle .RB ( -vv .IR 180 , .B -vh .IR 180 ). The recommended size of images input to .B evalglare is 1000x1000 pixels; the computations become very long when the image is more than 1200x1200 pixels. .PP The calculation of glare proceeds in two steps: .IP 1. 3em In the first step, the program uses a given threshold to determine all glare sources. Three different threshold methods are implemented. The recommended method is to define a task area by .B \-t or .B \-T option. The average luminance of the task area is calculated. Each pixel exceeding this value multiplied by the .B \-b factor, default 5, is treated as a potential glare source. The other two methods are described below, see .BR \-b . .IP 2. In the second step, the program tries to merge glare source pixels to one glare source, when they are placed nearby each other. This merging is performed between search areas, given by an opening angle .BR \-r , default 0.2 radians. If a check file is written, .B \-c .IR fname , the detected glare sources will be colored, each with a different color, and the rest of the image will be set to gray. The luminance values of all pixels are kept to the initial value. The color is chosen by chance, no significance is given by the color. To enable unform coloring of all glare sources, the .B \-u option can be used. Luminance peaks can be extracted to separate glare sources by using the .B \-y or .BI \-Y " value" option. The default value .B \-y is 50,000 cd/m2, which can be changed by using the .B \-Y value. A smoothing option, .BR \-s , counts initial non-glare source pixels to glare sources, when they are surrounded by a glare source. .PP The program calculates the daylight glare probability (DGP) as well as other glare indices (DGI, UGR, VCP, CGI) and writes them to the standard output. The DGP describes the fraction of persons disturbed caused by glare from daylight as a number from 0 to 1, where 0 is no-one disturbed and 1 is everyone. Values lower than 0.2 are out of the range of the user assessment tests which the program is based on and should be interpreted carefully. A low light correction is applied to the DGP when the vertical illumiance is lower than 500 lux. By the use of .B \-g or .B \-G .\" Citation? the field of view is cut according the the definition of Guth. The option .B \-B angle (in radians) calculates the average luminance of a horizontal band. In the case of non-180 degree images, an external measured illuminance value can be provided by using the .B \-i or .B \-I option. The use of the .B \-I option enables the filling up of images, which are horizontally cut. If the option .B \-d is used, all found glare sources and their position, size, and luminance values are printed to the standard output, too. The last line gives following values: (1) DGP, (2) average luminance of image, (3) vertical eye illuminance, (4) background luminance, (5) direct vertical eye illuminance, (6) DGI, (7) UGR, (8) VCP, (9) CGI, (10) average luminance of all glare sources, (11) sum of solid angles of all glare sources, (12) Veiling luminance (disability glare), (13) x-direction of glare source, (14) y-direction of glare source, (15) z-direction of glare source, and (16) band luminance. .SH OPTIONS .TP .BI \-B \ angle Calculate average luminance of a horizontal band. The angle is in radians. This calculation does not affect glare source detection. Output only when using the .B \-d option. .TP .BI \-b \ factor Threshold factor; if factor is over 100, it is used as constant threshold in cd/m2, regardless if a task position is given or not if factor is less than or equal to 100 and a task position is given, this factor multiplied by the average task luminance will be used as threshold for detecting the glare sources if factor is less than or equal to 100 and no task position is given, this factor multiplied by the average luminance in the entire picture will be used as threshold for detecting the glare sources, default\ 5. .TP .BI \-c \ fname writes a checkfile in the RADIANCE picture format .TP .B \-d enables detailed output (default: disabled) .TP .BI \-g \ type cut field of view according to Guth, write checkfile specified by .B \-c and exit without any glare evaluation. Type 1: total field of view. Type 2: field of view seen by both eyes .TP .BI \-G \ type Cut the field of view according to Guth, perform glare evaluation. Type 1: total field of view. Type 2: field of view seen by both eyes .TP .BI \-i \ Ev The vertical illuminance is measured externally. This value will be used for calculating the dgp. .TP .BI \-I \ Ev \ y_max \ y_min The vertical illuminance is measured externally. This value will be used for calculating the DGP. Below .I y_min and above .IR y_max , the picture is filled up by the last known value. This option should be used, when the provided picture is cut horizontally. .TP .BI \-r \ angle search radius (angle in radians) between pixels, where .B evalglare tries to merge glare source pixels to the same glare source (default value: 0.2 radians) .TP .B \-s enables smoothing function (default: disabled) .TP .BI \-t \ xpos \ ypos \ angle definition of task position in x and y coordinates, and its opening angle in radians .TP .BI \-T \ xpos \ ypos \ angle same as .BR \-t , except that the task area is colored bluish in the checkfile .TP .BI \-u \ r \ g \ b color glare sources uniformly when writing check file (implies .B \-c option). Color given in r g b. .TP .B \-v show version of .B evalglare and exit .TP .B \-V Just calculate the vertical illuminance and exit .TP .B \-x disable peak extraction .TP .B \-y enables peak extraction (default: enabled) .TP .BI \-Y \ value enables peak extraction with .I value as threshold for extracted peaks. .PP .I "If the view settings in the image file" are missing or are not valid (e.g. after the use of .BR pcompos "(1) or " pcomb (1)), the view options can be set by command line options. If view options are set on the command line, view options in the image file header are ignored. The view options are implemented according to the RADIANCE definition; please read the .BR rpict (1) man page for details. .sp .TP .BI \-vt t Set view type to t (for fisheye views, please use .BI \-vt \ a or .BI \-vt \ h preferably) .TP .BI \-vf \ viewfile Get view parameters from file .TP .BI \-vv \ val Set the view vertical size to val .TP .BI \-vh \ val Set the view horizontal size to .I val .SH AUTHOR Jan Wienold. .SH SEE ALSO .BR rpict (1) .SH REFERENCES .B Evalglare is based on the studies by J. Christoffersen and J. Wienold (see \*(lqEvaluation methods and development of a new glare prediction model for daylight environments with the use of CCD cameras and RADIANCE,\*(rq .IR "Energy and Buildings 38" , 2006, pp. 743\-757, doi:10.1016/j.enbuild.2006.03.017. More details can be also found in following dissertation: J. Wienold, .IR "Daylight glare in offices" , Fraunhofer IRB, 2010, available online at .nh . .hy .SH ACKNOWLEDGEMENTS The evalglare program was originally developed by Jan Wienold at the Fraunhofer Institute for Solar Energy Systems in Freiburg, Germany. It is being further developed and maintained by the same author at EPFL, Lausanne, Switzerland. .PP The author would like to thank C. Reetz for his generous help and his support of providing libraries for the program. The EU Commission supported this work as part of the EU project \*(lqEnergy and Comfort Control for Building management systems\*(rq (ECCO-Build, Contract ENK6-CT-2002-00656). .PP German Research Foundation (DFG) contract WI 1304/7-2 supported the research for the extension of evalglare for low light scenes.