# Alternative Open-Source Stereo Pipelines

Comparisons of ASP with other widely used open-source stereo photogrammetry pipelines, using the [SpaceNet UCSD WorldView-3 example](https://asp-plot.readthedocs.io/en/latest/examples/notebooks/worldview_spacenet_ucsd_stereo.html) as a common test case.

```{note}
This is not a comprehensive comparison of processing parameters between ASP, CARS, and SETSM. We make no quantitative ranking between DEM outputs.

In these sections, we seek to:

- document the processing setup for the pipelines,
- briefly discuss some key differences,
- and demonstrate reasonable, comparable results for the same stereo scenes from each tool.

We encourage end users to make their own comparisons, with these notes providing promotion and helpful guidance for the tools.
```

::::{grid} 1
:gutter: 3

:::{grid-item-card} SETSM
:link: setsm
:link-type: doc

Surface Extraction with TIN-based Search-space Minimization (Ohio State / PGC).
:::

:::{grid-item-card} CARS
:link: cars
:link-type: doc

CNES open-source stereo pipeline with Pandora dense matching.
:::

::::

## Key Differences

ASP is general purpose software for geodesy and stereogrammetry. It contains tooling for alignment of point clouds, structure-from-motion, jitter solving, camera intrinsic refinement, and more beyond DEM generation from stereo-pairs.

Our comparison focuses only on the standard stereo pipeline for the three tools.

| Feature | ASP | CARS | SETSM |
|---|---|---|---|
| Language | C++ | Python + C++ (pybind11) | C++ |
| Dense matching | NCC, MGM, SGM, etc. | Pandora (Census + SGM) | TIN-based NCC |
| Bundle adjustment | Separate tool (`bundle_adjust`) | Separate tool (`cars-bundleadjustment`) | None (RPC bias comp. only) |
| Install | Pre-built binaries | pip / Docker | Build from source |

```{toctree}
:maxdepth: 1
:hidden:

setsm
cars
```