Advanced Use

The Quickstart guide made use of a special class called PyWunderCamAuto. That class provides two functions (.single_shot(), .continuous_shot()) that hide the details of communicating with the camera.

PyWunderCamAuto is based on the PyWunderCam class and that class is allowing much finer control over the functionality of the camera.

The objective of this section is to outline the use of PyWunderCam and the way communication is carried out between a client and the camera.

Directing the camera to take pictures / video

The most usual cycle of interaction with the hardware is as follows:

0. Ensure that the computer has joined the network advertised by the camera.

1. Connect to the camera via the PyWunderCam client.

2. Get the current camera state.

3. Ensure that it is in the desired…state, depending on what is to be carried out.

4. Trigger the action (e.g. take a snapshot, burst, video, etc)

So, to take a single 360 picture:

from pywundercam import PyWunderCam

camera_client = PyWunderCam("192.168.100.1")
camera_state = camera_client.state
# Ensure that the camera is in single picture mode
camera_state.shoot_mode = 0
# Set the camera to the desired state
camera_client.state = camera_state
# Trigger the camera
camera_client.trigger()

Once trigger() is called, the camera will sound a beep and it will have taken a picture and stored it in its internal SD card.

To take a set of pictures in burst mode, change the shoot_mode to 3 and to start (and stop) taking a video, set the shoot_mode to 1.

Retrieving the captured images / videos

This is achieved with a few additional steps that are conceptually very similar to directing the camera to take pictures:

0. Ensure that the computer has joined the network advertised by the camera.

1. Connect to the camera via the PyWunderCam client.

2. Get the camera state.

3. Get the file system state (BEFORE the action)

4. Ensure that camera state is in the desired…state.

5. Trigger the action (e.g. take a snapshot, burst, video, etc)

6. Get the file system state (AFTER the action)

7. Retrieve the difference AFTER - BEFORE, to determine which files were generated and download them.

So, to take a 360 picture and retrieve the image data:

from pywundercam import PyWunderCam

camera_client = PyWunderCam("192.168.100.1")
camera_state = camera_client.state
# Ensure that the camera is in single picture mode
camera_state.shoot_mode = 0
# Set the camera to the desired state
camera_client.state = camera_state
# Get a "snapshot" of its file contents BEFORE the shot
contents_before = camera_client.get_resources()
# Trigger the camera
camera_client.trigger()
# Get a "snapshot" of the file contents AFTER the shot
contents_after = camera_client.get_resources()
# Create a new snapshot that only contains the image that was acquired by this action
latest_image = contents_after["images"] - contents_before["images"]

Without getting into a lot of detais at this point, latest_image will contain only one image. To retrieve it:

shot_image = latest_image[0].get()

The get() function will trigger a file transfer from the camera to the computer over WiFi and depending on the size of the file, it will introduce a small pause.

At the time of writing, PyWunderCam serves images as PIL.Image objects. Therefore, after get(), the image is already in a form that can be passed to other algorithms (e.g. machine vision) for further processing.

Trying to retrieve a video in the same way will raise an exception.

Videos can still be transferred over WiFi and stored to the local computer for further processing.

To do this:

from pywundercam import PyWunderCam

camera_client = PyWunderCam("192.168.100.1")
camera_state = camera_client.state
# Ensure that the camera is in video mode
camera_state.shoot_mode = 1
# Set the camera to the desired state
camera_client.state = camera_state
# Get a "snapshot" of its file contents BEFORE the shot
contents_before = camera_client.get_resources()
# Trigger the camera
camera_client.trigger()
# Get a "snapshot" of the file contents AFTER the shot
contents_after = camera_client.get_resources()
# Create a new snapshot that only contains the video that was acquired by this action
latest_video = contents_after["videos"] - contents_before["videos"]
latest_video[0].save_to("myvideo.mp4")