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pfsview(1)						      General Commands Manual							pfsview(1)

NAME
pfsview - Viewer for high-dynamic range images in pfs format SYNOPSIS
pfsview [--window_min <log_lum>] [--window_max <log_lum>] DESCRIPTION
pfsview is a QT application for viewing high-dynamic range images. It expects pfs stream on the standard input and displays the frames in that stream one by one. pfsv script can be more convienent to use if hdr images are to be displayed without any prior processing. DYNAMIC RANGE WINDOW
To show high-dynamic range data on a low-dynamic range monitor, pfsview uses concept of a dynamic range window. The dynamic range window is the highest and lowest value that should be mapped to black and white pixel. Values above or below the window are clipped (see clipping methods below). The dynamic range window is displayed in pfsview as a blue area on the dynamic range scale (second toolbox from the top). The window can be moved, shrunk and expended using a mouse or a keyboard. CLIPPING METHODS
Currently, two clipping methods are available (see View menu): Simple clipping The values above and below the dynamic range window are displayed as black or white. Color-coded clipping The values above the dynamic range window are displayed as yellow and below the window as green. This is helpful to see which parts of the image do not fit into the selected dynamic range. Keep brightness and hue This method tries to preserve brightness and hue while sacrificing color saturation when the colors exceed the RGB color gamut. Col- ors are desaturated in the RGB color space towards the neutral color (D65) of the corresponding luminance. MAPPING METHODS
High-dynamic range data are usually better visualized using non-linear scale, for example a logarithmic or a power function. pfsview offers several such scales, shown in View menu. Gray-scale values for each mapping method are computed by the formulas: LINEAR: y = (x-min)/(max-min) GAMMA: y = [ (x-min)/(max-min) ]^gamma LOGARITHMIC: y = (log10(x)-log10(min))/(log10(max)-log10(min)) where y is the gray-scale value after mapping, x is an input HDR value, min and max are lower and upper bounds of the dynamic range window. OPTIONS
--window_min <log_lum> Lower bound of the values that should be displayed or minimum value of the dynamic range window. The value should be given in log_10 units, for example -1 if the lower bound should be 0.1 (10^-1). --window_max <log_lum> Upper bound of the values that should be displayed or minimum value of the dynamic range window. The value should be given in log_10 units, for example -1 if the upper bound should be 0.1 (10^-1). EXAMPLES
pfsin memorial.hdr | pfsview See the memorial image. pfsv memorial.hdr The same as above, but using the utility script 'pv'. SEE ALSO
pfsv(1) pfsin(1) BUGS
Zomming in may sometimes show artifacts. Please report bugs and comments to Rafal Mantiuk <mantiuk@mpi-sb.mpg.de>. pfsview(1)

Check Out this Related Man Page

pfsabsolute(1)						      General Commands Manual						    pfsabsolute(1)

NAME
pfsabsolute - Convert luminance in images to absolute measure SYNOPSIS
pfsabsolute <dest Y> [<src Y>] [--verbose] [--help] DESCRIPTION
pfsabsolute applies all necessary operations to convert an image from relative luminance (tag LUMINANCE is RELATIVE) or display-dependent luma (tag LUMINANCE is DISPLAY) to absolute luminance values. When the luminance in an image is absolute (tag LUMINANCE set to ABSOLUTE), the Y channel represents physical luminance in cd/m^2. Absolute luminance levels are useful for some tone mapping algorithms and also for image or video compression. The argument <dest Y> denotes the level of luminance that relative luminance <src Y> should be rescaled to. The luminance is in fact multi- plied by the ratio <dst Y>/<src Y>. <src Y> is normally relative luminance checked with pfsview in the spot where the absolute luminance <dest Y> is measured, known or guessed. If <src Y> is omitted, the value 1 is assumed, so <dest Y> is just a scaling factor. In case if display-depended luma (tag LUMINANCE is DISPLAY), the inverse gamma correction is applied (assuming sRGB color space). In such case <dest Y> is usually the maximum luminance of a display (e.g. 80 cd/m^2). This command always sets LUMINANCE tag to ABSOLUTE. EXAMPLES
pfsin memorial.hdr | pfsabsolute 20 0.04 | pfsview Multiply luminance in memorial image, so that relative luminance 0.04 becomes 20 cd/m^2. Normally, the value 0.04 is check using pfsview in the spot, where the absolute luminance (which equals in this case 20 cd/m^2) is known. pfsin lena.png | pfsabsolute 80 | pfsview Convert lena image from sRGB color space to absolute XYZ, assuming maximum luminance of the monitor 80 cd/m^2. SEE ALSO
pfsgamma(1) pfsinppm(1) BUGS
Please report bugs and comments to Rafal Mantiuk <mantiuk@mpi-sb.mpg.de>. pfsabsolute(1)
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