Orthographic camera

Description

../../../_images/orthocam.jpg

Cornell box rendered with an orthographic camera

Instrument This instrument is an orthographic camera featuring orthographic projection. It provides images similar to a standard rectilinear camera placed very far away, with a very long focal length, or to an object-space telecentric lens. This camera is not physically plausible, as it collects only light coming from a single direction, which means the amount of collected light is zero. This is equivalent to a zero aperture object-space telecentric lens. For this reason, the amount of light collected on the sensor is not in lux·s as with real cameras, but in lux·s/sr (equivalent to cd·s/m²). This means that this instrument measures luminance directly and can be used as an exact luminance sensor.

Children Nodes

Sensor sensor List of channels defined by a sensitivity spectrum
Postprocessing postprocessing The post-processing filter chain

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 position : center of principal points
forwards vec3 The camera direction (all sampled rays go in that direction). Should be orthogonal to up
up vec3 The camera up direction. Should be orthogonal to forwards
width real The camera field width in meters. Must be greater than 0
height real The camera field height in meters. Must be greater than 0

Ocean XML 3.0 example

<instrument type="orthocam" name="orthocam">
   <prm xresolution="512" 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 width="0.6"/>
   <prm height="0.6"/>
   <sensor type="ciexyz" name="sensor"/>
   <postprocessing type="" name="postprocessing">
      <filter type="xyztorgb" name="filter1" enabled="1" xwhite="0.3127" ywhite="0.329"/>
   </postprocessing>
</instrument>