Authors: Diego Royo, Jorge Garcia, Adolfo Muñoz, Adrián Jarabo and the original Mitsuba 2 authors.
Mitsuba 2, extended for transient path tracing and non-line-of-sight data capture.
See tal python library, with utilies to execute mitsuba and visualize its results.
We provide the transientpath, transientstokes and streakhdrfilm plugins. There is an example scene below.
<scene version="2.2.1">
<!-- Use transientpath integrator -->
<integrator type="transientpath">
<!-- Discard paths with depth >= max_depth -->
<integer name="max_depth" value="4"/>
</integrator>
<!-- Use transientstokes integrator -->
<!--
<integrator type="transientstokes">
<integrator type="transientpath">
<integer name="max_depth" value="10"/>
</integrator>
</integrator>
-->
<!-- Geometry, etc. -->
<sensor ...>
<!-- Sensor configuration etc. -->
<!-- Streak (transient) film with dimensions width x height x time -->
<film type="streakhdrfilm" name="streakfilm">
<integer name="width" value="1024"/>
<integer name="height" value="1024"/>
<integer name="time" value="400"/>
<float name="exposure_time" value="8"/>
<float name="time_offset" value="500"/>
<rfilter name="rfilter" type="gaussian"/>
<boolean name="high_quality_edges" value="true"/>
<!-- NOTE: tfilter is not yet implemented -->
<rfilter name="tfilter" type="gaussian"/>
</film>
</sensor>
</scene>We provide the nloscapturemeter plugin. See nloscapturemeter for additional details. There is an example scene below.
Note that variables that start with $ should be changed
<scene version="2.2.1">
<integrator type="transientpath">
<!-- Recommended 1 for progress bar (see path integrator) -->
<integer name="block_size" value="1"/>
<!-- Discard paths with depth >= max_depth -->
<integer name="max_depth" value="4"/>
<!-- Only account for paths with depth = filter_depth -->
<!-- <integer name="filter_depth" value="3"/> -->
<boolean name="discard_direct_paths" value="true"/>
<!-- Next event estimation for the laser through the relay wall (recommended true) -->
<boolean name="nlos_laser_sampling" value="true"/>
<boolean name="nlos_hidden_geometry_sampling" value="false"/>
<boolean name="nlos_hidden_geometry_sampling_do_mis" value="false"/>
<boolean name="nlos_hidden_geometry_sampling_includes_relay_wall" value="false"/>
</integrator>
<!-- Relay wall and hidden geometry materials -->
<bsdf type="diffuse" id="white">
<rgb name="reflectance" value="0.7, 0.7, 0.7"/>
</bsdf>
<!-- Hidden geometry -->
<shape type="obj">
<string name="filename" value="$hidden_mesh_obj"/>
<bsdf type="twosided">
<ref id="white"/>
</bsdf>
<transform name="to_world">
<scale x="$hidden_scale" y="$hidden_scale" z="$hidden_scale"/>
<rotate x="1" angle="$hidden_rot_degrees_x"/>
<rotate y="1" angle="$hidden_rot_degrees_y"/>
<rotate z="1" angle="$hidden_rot_degrees_z"/>
<translate x="0" y="0" z="$hidden_distance_to_wall"/>
</transform>
</shape>
<!-- Relay wall -->
<shape type="rectangle">
<ref id="white"/>
<transform name="to_world">
<rotate z="1" angle="180"/>
<scale x="$relay_wall_scale" y="$relay_wall_scale" z="1"/>
</transform>
<!-- NLOS capture sensor placed on the relay wall -->
<sensor type="nloscapturemeter">
<sampler type="independent">
<integer name="sample_count" value="$sample_count"/>
</sampler>
<!-- Laser -->
<emitter type="projector">
<spectrum name="irradiance" value="400:0, 500:80, 600:156.0, 700:184.0"/>
<float name="fov" value="1.5"/>
</emitter>
<!-- Acount time of flight for the laser->relay wall and relay wall->sensor paths -->
<boolean name="account_first_and_last_bounces" value="$account_first_and_last_bounces"/>
<!-- World-space coordinates -->
<point name="sensor_origin" x="-0.5" y="0" z="0.25"/>
<point name="laser_origin" x="-0.5" y="0" z="0.25"/>
<!-- alternative to laser_lookat_pixel -->
<!-- <point name="laser_lookat_3d" x="0" y="0" z="0"/> -->
<!-- Screen-space coordinates (see streakhdrfilm) -->
<point name="laser_lookat_pixel" x="$laser_lookat_x" y="$laser_lookat_y" z="0"/>
<!-- Transient image I(width, height, num_bins) -->
<film type="streakhdrfilm" name="streakfilm">
<integer name="width" value="$sensor_width"/>
<integer name="height" value="$sensor_height"/>
<!-- Recommended to prevent clamping -->
<string name="component_format" value="float32"/>
<integer name="num_bins" value="$num_bins"/>
<!-- Auto-detect start_opl (and also bin_width_opl if set to a negative value) -->
<boolean name="auto_detect_bins" value="$auto_detect_bins"/>
<float name="bin_width_opl" value="$bin_width_opl"/>
<float name="start_opl" value="$start_opl"/>
<rfilter name="rfilter" type="box"/>
<!-- NOTE: tfilters are not implemented yet -->
<!-- <rfilter name="tfilter" type="box"/> -->
<boolean name="high_quality_edges" value="false"/>
</film>
</sensor>
</shape>
</scene>Refer to the original Mitsuba 2 repository for additional documentation and instructions on how to compile, use, and extend Mitsuba 2.
See the original repository. Additionally, if you are using this code in academic research, we would be grateful if you cited our publication:
@article{royo2022non,
title = {Non-line-of-sight transient rendering},
journal = {Computers & Graphics},
year = {2022},
issn = {0097-8493},
doi = {https://doi.org/10.1016/j.cag.2022.07.003},
url = {https://www.sciencedirect.com/science/article/pii/S0097849322001200},
author = {Diego Royo and Jorge García and Adolfo Muñoz and Adrian Jarabo}