.. include:: <isonum.txt>

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Example for users to understand how to use the library
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Different methods have been written for interconversion between different mappings related to omnidirectional cameras.

1. `Equirectangular image to fisheye or pinhole camera image <Equirectangular-to-fisheye.html>`_
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**Possible areas of application**

* Generate images with different focal length and distortion coefficients.
* Generate synthetic images for the training of various deep learning models.
* Image augmentation
* Creating interesting visual effects with 360 |deg| videos.
Some of the above-mentioned applications have been discussed in detail in the application notes sections.

.. figure:: eqrect2fisheye.*
   :align: center
   
   Example of conversion of equirectangular image to fisheye image


2. `Fisheye image to equirectangular image <Fisheye-to-equirectangular.html>`_
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**Possible areas of application**

* Used for stitching and creating a 360 |deg| video from two fisheye cameras facing away from each other.
* To upload omnidirectional camera videos to youtube which can support the 360 |deg| viewer GUI.
* Used as an interconversion step

.. figure:: fisheye2eqrect1.*
   :align: center
   
   Example of conversion of fisheye image to equirectangular image


3. `Equirectangular image to cubemap image in horizontal or dice format <Equirectangular-to-cubemap.html>`_
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**Possible areas of application**

* Useful to create cubemap environment textures, for video games or VR application, from a given equirectangular image.
* To remove distortions generated due to the fisheye lens.
* Used in visual SLAM methods where omni directional cameras are used.

.. figure:: equirect2cubemap_dice.*
   :align: center
   
   Example of conversion of equirectangular image to cubemap image


4. `Cubemap image to equirectangular image <Equirectangular-to-cubemap.html>`_
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**Possible areas of application**

* Create a compressed equirectangular form of texture maps which can be later converted to cubemap and used as texture maps.
* Intermediate step when using omnidirectional cameras.
* Convert cubemap based images into a format that can be uploaded to a 360 |deg| image/video viewer.

.. figure:: cube2eqrect_dice.*
   :align: center
   
   Example of conversion of cubemap to equirectangular image


5. `Convert equirectangular image to perspective image with desired field of view and viewing angles <Equirectangular-to-perspective.html>`_
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**Possible areas of application**

* Creating different perspective views in a 360 |deg| video/image.
* Object detection in 360 |deg| videos with existing pre-trained models.
* Creating a GUI to view 360 |deg| videos and images.
* Surveillance robots using omnidirectional cameras.

.. figure:: eqrect2persp.*
   :align: center
   
   Example of conversion of equirectangular image to perspective image


6. `Convert cubemap image to perspective image with desired field of view and viewing angles <Equirectangular-to-perspective.html>`_
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**Possible areas of application**

* Create different perspective views in a 360 |deg| video/image.
* Creating a GUI to view 360 |deg| videos and images.
* Simulate and analyze a texture map in a video game.

.. figure:: cubemap2persp_dice.*
   :align: center
   
   Example of conversion of cubemap image to perspective image


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