**Geometry Reconstruction**

A hidden object in [the standard setup](/doc/setup) is to be reconstructed from a single transient image.

We consider geometry reconstruction the most important challenge, as it is not only the focus of most of the previous work, but also the most general problem with the highest number of degrees of freedom. In most scenarios, once a full geometric scene model has been reconstructed, derivative information such as object positions can be obtained more easily from 3D geometry than from from raw transient images.

The challenge is focussed on reconstructing a single, solid object inside an empty scene.


![Some objects of the geometry dataset](/images/GeometryObjects.png)

The test scenes are split into a total of five categories that test different capabilities of solvers:

Category 1
:  2D shapes. This category contains two-dimensional objects of a certain thickness that are placed perpendicular to the wall. This category is closely related to the texture reconstruction challenge.

Category 2
:  Simple geometric shapes. Objects with simple mathematical descriptions without additional surface details.

Category 3
:  Simple objects. Everyday objects from the real world, with limited geometric detail. Objects in this category are not easily approximated by the shapes of the previous category.

Category 4
:  Complex objects. Highly non-convex objects with complex shape but without fine surface details.

Category 5
:  Difficult objects. Objects with thin elements, fine structures and complex topology (e.g. many holes).

The challenge contains a total of sixteen objects:

Category | Name                 | Material
1        | **`LetterK`**        | diffuse
1        | `LetterQ`            | diffuse
2        | **`Box`**            | diffuse
2        | `Cone`               | diffuse
3        | **`StanfordBunny`**  | diffuse
3        | **`UtahTeapot`**     | diffuse
3        | `Ax`                 | diffuse
3        | `Hammer`             | diffuse
3        | `Cup`                | specular
4        | **`StanfordDragon`** | specular
4        | `Dinosaur`           | diffuse
4        | `FlyingDragon`       | diffuse
4        | `IndoorPlant`        | diffuse
5        | `Chair`              | diffuse
5        | `Bike`               | specular
5        | `Greenhouse`         | specular

[  ](/database/Geometry/Geometry.7z)**Database**

For the five objects marked with bold font in the table, ground truth information is available for testing purposes.

[  ](/database/Geometry/GeometryGT.7z)**Ground truth models**


Solutions must be submitted as triangle meshes stored in `wavefront obj` files. Please note that not the full `obj` feature set is supported, the files should only contain a single, triangulated mesh (using `v`, `vn`, and `f` instructions). Please test your models with the newest version of the [evaluation tools](/toolbox) to ensure compatibility.