Irradiance spherical view¶
Description¶
This instrument creates a spherical image of scene irradiance, showing how much light is incoming over the surrounding visible surfaces. Depending on sensor type, the computed value may be scene illuminance (Y), spectral irradiance, …
The projection is equirectangular projection, as for the Spherical camera.
This camera send rays isotropically. As equirectangular projection is not area preserving, some parts of the image (top and bottom, resp. zenith and nadir) will receive much less samples than others. Consequently, these areas will be much noisier. For this reason, the Equirectangular smooth filter filter was created for restoring uniform noise level over the image. It ensures that the image once reprojected on a sphere has uniform resolution and uniform noise.
Note
Using this feature requires a Lighting or Advanced Edition license
Children Nodes¶
This node may have a variable number of output children with custom names.
List of channels defined by a sensitivity spectrum |
|
First output preset |
|
Second output preset |
|
… |
Parameters¶
name |
type |
description |
---|---|---|
xresolution |
integer |
Horizontal buffer resolution |
yresolution |
integer |
Vertical buffer resolution |
pixelfilter |
list |
The ray pixel filter |
shutter |
real |
Shutter time or exposure, in seconds |
wlmin |
real |
Low bound of simulation wavelength range |
wlmax |
real |
High bound of simulation wavelength range |
pos |
vec3 |
The camera center position |
forwards |
vec3 |
The viewing direction corresponding to the center of the generated spherical image. Should be orthogonal to up |
up |
vec3 |
The zenith direction, corresponding to the top of the generated spherical image. Should be orthogonal to forwards |
focusdistance |
real |
The lens focusing distance in meters. Set to zero for infinite focus distance |
autofocus |
boolean |
Set to true for setting the focus distance to the first geometry met in the forward direction |
fnumber |
real |
The lens aperture F-number |
radius |
real |
The spherical lens radius. Affects depth of field, not image brightness |
Ocean XML 5.0 example¶
<instrument type="spherecam" name="spherical">
<prm xresolution="1024" yresolution="512"/>
<prm pixelfilter="bilinear"/>
<prm shutter="0.8"/>
<prm wlmin="380E-9"/>
<prm wlmax="780E-9"/>
<prm pos="0.278 0.273 -0.8"/>
<prm forwards="0 0 1"/>
<prm up="0 1 0"/>
<prm autofocus="true"/>
<prm fnumber="5.6"/>
<prm radius="1E-4"/>
<sensor type="ciexyz" name="sensor"/>
<output type="channelimage" name="irradmap">
<prm quantity="sceneradiance"/>
<prm channel="Y"/>
<prm colors="thermal"/>
<prm rangemax="200"/>
<prm logarithmic="true"/>
<prm logdecades="2"/>
<prm info="false"/>
<prm legend="true"/>
<prm grid="false"/>
<prm gridx="30"/>
<prm gridy="30"/>
<filter type="sphereresolutionfix" name="filter1"/>
</output>
</instrument>