Most people use a false color representation to look at luminance values. Assuming you have Radiance installed, the command looks like so:
% falsecolor -i render.pic -s auto \
> ra_tiff -z - render_fc.tif
If you have Photosphere, you can use the Command-N sequence to get a false color display. Regrettably, it won't save out with the legend (scale).
If you want to look at the values directly, the pvalue command will give you radiances, which you can convert to luminance using the appropriate efficacy value, e.g.:
% pvalue -h -H -b render.pic \
> rcalc -e '$1=$1;$2=$2;$3=179*$3'
The first and second columns in the output are the x and y pixel positions, measured from the lower-left corner of the image.
I was curious to see what a 3-D rendering would look like, so I used the command:
% pvalue -h -H -b -d render.pic \
> gensurf void picsurf t s - 254 172 -o \
> obj2mesh > render.rtm
The 254 and 172 values are the horizontal and vertical dimensions of my example image, respectively. I then used objview to render the following Radiance file:
void plastic grey
5 .5 .5 .5 0 0
grey mesh picsurf
This produced a rather bland result, so I added a pattern corresponding to the output of falsecolor:
void colorpict colorful
7 red green blue electric_x1y1fc.pic . 1.47398844*Py 1-Px
colorful plastic colored
5 .5 .5 .5 0 0
colored mesh picsurf
The 1.47398844 value is 254/172, as needed to fit the image into my square area. In retrospect, I probably should have used a wider base in the gensurf command to get a rectangular plot. I can send anyone who wants to see the images I generated.
From: panick <[email protected]>
Date: August 17, 2007 9:52:05 AM PDT
1.How can I extract results of luminance from a .pic file that I have already rendered using a grid of points?
(Because the rendering process lasts 2-3 hours)
2.Is there any command that gives a 3D presentation of the values of a grid?