Irradiance spherical view

Description

../../../_images/irradsphereview.jpg

Cornell box rendered with an irradiance spherical view, illuminance(Y) displayed in false colors with a log scale

Instrument 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.

Sensor sensor

List of channels defined by a sensitivity spectrum

Output user-defined

First output preset

Output user-defined

Second output preset

Output user-defined

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>