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Define a 3D AOI as a frame
==========================
When an 3D AOI of the scene contains others coplanar 3D AOI, like a screen with GUI elements displayed on, it is better to described them as 2D AOI inside 2D coordinates system related to the containing 3D AOI.
## Add ArFrame to ArUcoScene
The [ArFrame](../../argaze.md/#argaze.ArFeatures.ArFrame) class defines a rectangular area where timestamped gaze positions are projected in and inside which they need to be analyzed.
Here is the previous extract where "MyScreen" AOI is defined as a frame into [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) configuration:
```json
{
"name": "My FullHD camera",
"size": [1920, 1080],
...
"scenes": {
"MyScene" : {
"aruco_markers_group": {
...
},
"layers": {
"MyLayer": {
"aoi_scene": {
"MyScreen": [[2.5, 2.5, -0.5], [37.5, 2.5, -0.5], [37.5, 27.5, -0.5], [2.5, 27.5, -0.5]]
}
}
},
"frames": {
"MyScreen": {
"size": [350, 250],
"layers": {
"MyLayer": {
"aoi_scene": {
"BlueTriangle": [[100, 50], [250, 50], [175, 200]]
}
}
}
}
}
}
}
...
}
```
Now, let's understand the meaning of each JSON entry.
### *frames*
An [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) instance can contains multiples [ArFrames](../../argaze.md/#argaze.ArFeatures.ArFrame) stored by name.
### MyScreen
The name of a 3D AOI **and** of an [ArFrame](../../argaze.md/#argaze.ArFeatures.ArFrame). Basically useful for visualisation purpose.
!!! warning "AOI / Frame names policy"
An [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) layer 3D AOI is defined as an [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) frame, **provided they have the same name**.
!!! warning "Layer name policy"
An [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) frame layer is projected into [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) layer, **provided they have the same name**.
!!! note
[ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) frame layers are projected into their dedicated [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) layers when the JSON configuration file is loaded.
## Pipeline execution
### Map ArUcoCamera image into ArUcoScenes frames
After camera image is passed to [ArUcoCamera.watch](../../argaze.md/#argaze.ArFeatures.ArCamera.watch) method, it is possible to apply a perpective transformation in order to project watched image into each [ArUcoScenes](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) [frames background](../../argaze.md/#argaze.ArFeatures.ArFrame) image.
```python
# Assuming that Full HD (1920x1080) video stream or file is opened
...
# Assuming that the video reading is handled in a looping code block
...:
# Capture image from video stream of file
image = video_capture.read()
# Detect ArUco markers, estimate scene pose then, project 3D AOI into camera frame
aruco_camera.watch(image)
# Map watched image into ArUcoScenes frames background
aruco_camera.map()
```
### Analyse timestamped gaze positions into ArUcoScenes frames
[ArUcoScenes](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) frames benefits from all the services described in [gaze analysis pipeline section](../gaze_analysis_pipeline/introduction.md).
!!! note
Timestamped gaze positions passed to [ArUcoCamera.look](../../argaze.md/#argaze.ArFeatures.ArFrame.look) method are projected into [ArUcoScenes](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) frames if applicable.
### Display each ArUcoScenes frames
All [ArUcoScenes](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) frames image can be displayed as any [ArFrame](../../argaze.md/#argaze.ArFeatures.ArFrame).
```python
...
# Display all ArUcoScenes frames
for frame in aruco_camera.scene_frames:
... frame.image()
```
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