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‎docs/agisoft_metashape.md

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# Agisoft Metashape
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In order to import the matches and the camera poses into Agisoft Metashape, you must first run a reconstruction with COLMAP or pyCOLMAP (recommended, as it is already integrated into DIM).
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Then, you can export the solution into a [Bundler file format](https://www.cs.cornell.edu/~snavely/bundler/bundler-v0.4-manual.html), which can be imported into Agisoft Metashape.
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## Running the reconstruction
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To perform an automatic incremental reconstruction with pycolmap, you must first install pycolmap (see [Installation](installation.md)) and then run DIM omitting the `--skip_reconstruction` flag (see [Getting started](getting_started.md)).
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```bash
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python main.py --dir ./assets/example_cyprus --pipeline superpoint+lightglue
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```
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This will generate a `reconstruction` folder with the necessary files to import into Agisoft Metashape.
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## Importing the solution into Agisoft Metashape
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To import the solution into Agisoft Metashape, you have to first load the images into the software (`workflow`-> `add photos`).
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Then you can import the solution by importing the camera poses with `File` -> `Import` -> `Import cameras`.
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Here you have to select the `bundler.out` file and the `bundler_list.txt` file, and then click `OK
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![](./assets/metashape_import_1.png)
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![](./assets/metashape_import_2.png)
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Then you should see the camera poses and the matches between the images.
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Note, that the reconstruction is upside down because the Bunlder format uses a different coordinate system than Agisoft Metashape (with the z axis of the cameras pointing backwards).
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Therefore, you may have to rotate the reconstruction or to use Ground Control Points (GCPs) to georeference the model.
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![](./assets/metashape_reconstruction.png)
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Opening an image, you can also see the keypoints and the matches between the images.
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Note, that the Bunlder camera model is a simple pinhole camera model, so the radial distortion is not taken into account.
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Therefore, you may see large reprojection errors in the images.
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To fix this, you should import your camera calibration according to the Metashape camera model and run the bundle adjustment (optimization) again.
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![](./assets/metashape_keypoints.png)
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## The Bundler file format
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The Bundler format is composed of two files: `bundler.out` and `bundler_list.txt`.
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The file `bundler.out` contains the camera poses and the matches between the images and it has the following format:
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```math
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# Bundle file v0.3
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<num_cameras> <num_points>
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<camera1> [two integers]
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<camera2>
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...
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<cameraN>
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<point1>
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<point2>
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...
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<pointM>
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```
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Where `<camera>` is defined as:
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```math
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<f> <k1> <k2> [the focal length, followed by two radial distortion coeffs]
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<R> [a 3x3 matrix representing the camera rotation]
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<t> [a 3-vector describing the camera translation]
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```
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The `<point>` is defined as:
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```math
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<position> [a 3-vector describing the 3D position of the point]
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<color> [a 3-vector describing the RGB color of the point]
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<view list> [a list of views the point is visible in]
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```
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The `<view list>` is defined as:
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```math
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<track_length> <camera1> <key1> <x> <y> <camera2> <key2> <x> <y> ...
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```
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where `<track_length>` is the number of cameras the point is visible in.
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The list is then followed by the camera index, the keypoint index, and the 2D coordinates of the point in the image.
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Both indices are 0-based.
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The pixel positions are floating point numbers in a coordinate system where the origin is the center of the image, the x-axis increases to the right, and the y-axis increases towards the top of the image. Thus, (-w/2, -h/2) is the lower-left corner of the image, and (w/2, h/2) is the top-right corner (where w and h are the width and height of the image).
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The Bundler format uses a pinhole camera model; the parameters we estimate for each camera are a focal length (f), two radial distortion parameters (k1 and k2), a rotation (R), and translation (t), as described in the file specification above. The formula for projecting a 3D point X into a camera (R, t, f) is:
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```math
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P = R * X + t (conversion from world to camera coordinates)
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p = -P / P.z (perspective division)
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p' = f * r(p) * p (conversion to pixel coordinates)
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```
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Refer to the [Bundler file format](https://www.cs.cornell.edu/~snavely/bundler/bundler-v0.4-manual.html) for more information.
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The camera index in `<view list>` is given by the order in which the cameras are listed in the `bundler_list.txt` file, that contains the list of the path of the images used in the reconstruction.
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For example:
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```math
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DSC_6470.JPG
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DSC_6474.JPG
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DSC_6472.JPG
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DSC_6475.JPG
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DSC_6469.JPG
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DSC_6467.JPG
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DSC_6466.JPG
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DSC_6473.JPG
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```
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Note, that if the images are not located in the same folder Agisoft Metashape `.psx` file, you must change the paths in the `bundler_list.txt` file before importing the solution into Agisoft Metashape.
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Also, check that the file names in the `bundler_list.txt` file match the actual name of the images (including the extension, with or without capital letters).
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An example of the `bundler.out` file is shown below.
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<details>
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<summary>bundler.out</summary>
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```
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# Bundle file v0.3
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8 5068
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1286.7991243248962 0 0
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0.99996278884580203 -0.0013121224216955584 -0.0085263860149726069
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-0.80777295444200337 0.57663840260582766 -0.15525511334915454
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1286.7991243248962 0 0
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0.9944298422387321 0.007496545077315649 0.10513368003144505
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0.99931655217167026 0.006691041857979663 0.036354621639898832
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1286.7991243248962 0 0
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0.99967307085130896 -0.017983902425688095 0.018175001190014438
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0.020134745213698173 0.11558611363823715 -0.99309337041850598
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1.7882607148764738 2.141918008889161 0.056122945527972187
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1286.7991243248962 0 0
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0.85443322001495281 0.036474729613622636 -0.51827933263298509
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4.0136035947712356 -0.24890319703929475 -2.2211101146350618
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1286.7991243248962 0 0
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0.9977349416959288 -0.01781447706336892 0.064866251055384697
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-0.023079383925901007 -0.9964189037647786 0.081343163559071466
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0.063184872846452397 -0.082655989662913668 -0.99457310400805732
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4.744331912881119 -0.67485373536633497 0.50235653241970457
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1286.7991243248962 0 0
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0.85052582171050761 -0.081299479583431727 0.51961160612820134
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-0.076379298718601996 -0.99659964940906087 -0.030908599531384154
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0.52035759755279865 -0.013399008067766919 -0.85384333296681514
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-2.2708756404217185 0.73112594627182004 -0.97801981077545186
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-5.3552997586126736 3.9693405899589074 17.493979792539214
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214 196 176
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11 0 2597 -460 -250 2 3174 -542 -230 3 2736 -29 -155 4 3531 -250 -282 7 1696 137 -230 0 3358 -465 -253 1 2367 -582 -191 2 3161 -546 -233 3 3431 -33 -156 4 2278 -254 -284 6 2214 33 -227
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-12.097171629638927 3.302074646768081 30.280100026537617
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227 202 180
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2 1 2418 -555 -46 7 4066 113 -101
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-5.8312471874484419 -1.9822562893941618 14.437672933948106
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116 80 51
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3 0 3207 -598 226 2 2420 -722 245 7 3861 35 212
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0.46832749086366926 4.3310105451941983 16.298232232524828
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198 180 153
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...
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```
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</details>
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‎docs/assets/metashape_import_1.png

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‎docs/assets/metashape_import_2.png

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‎docs/assets/metashape_keypoints.png

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‎docs/assets/metashape_reconstruction.png

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‎mkdocs.yml

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- COLMAP: colmap.md
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- OpenMVG: openmvg.md
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- MICMAC: micmac.md
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- Agisoft Metashape: agisoft_metashape.md
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- API Reference:
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- Image_matching: image_matching.md
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- Configuration: config.md

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