Introduction

A generic camera interface that allows Python developers to easily grab frames from multiple types of cameras and write them to disk.

Camera Support

• usb cameras
• compressed video files
• raw video files

• basler pylon cameras

  pylon SDK and pypylon package must be installed.

• ids ueye cameras

  ueye SDK must be installed.

Modules

Input objects obtain data from a data source, such as a usb camera, pylon camera, or video.

Output objects write data to a file, such as a raw video file or a compressed video file.

Stream objects link a single input and output.

Input Types

Supported input types can be found under the create_input function docs.

Using Inputs

Input objects obtain data from a data source. They can be created by using the create_input function.

All Inputs support the open and read functions.

The open function initializes the Input object.

The read function returns data from the Input in a tuple with the format: (data, timestamp).

data is typically a numpy array obtained from the Input object.

timestamp is a unix timestamp that records when the frame was obtained.

Here’s a simple example that opens and reads from a usb camera.

from senseye_cameras import create_input

# initialize and open a usb camera
camera = create_input(type='usb', id=0, config={})

# print documentation for the CameraUsb module
# docs will show what key/value pairs can go into the config dictionary
print(camera.__doc__)

camera.open()
frame, timestamp = camera.read()

print(frame)

More examples can be found in the senseye_cameras/examples/input folder.

Output Types

Supported output types can be found under the create_output function docs.

Using Outputs

Output objects put data into a file. They can be created by using the create_output function.

All Outputs support the write and close functions.

The write function writes data, typically in the form of numpy arrays, to the Output object.

The close function gracefully closes the Output object.

Here’s a simple example that creates and writes to a file Output object.

import numpy as np
from senseye_cameras import create_output

# supported extensions
# FILE_PATH = './tmp/usb.avi'
# FILE_PATH = './tmp/usb.mp4'
# FILE_PATH = './tmp/usb.mkv'
# FILE_PATH = './tmp/usb.yuv'
FILE_PATH = './tmp/usb.raw'

data = np.random.rand(256, 256, 3)

# create a raw video Output object that points to the path1.raw file.
output = create_output('file', path=FILE_PATH)

output.write(data=data)
output.close()

More examples can be found in the senseye_cameras/examples/output folder.

Streams

The Stream module is a high level module that links a single Input and Output.

Here’s a simple example that creates a stream that opens a usb camera and writes frames to a file:

import time
from senseye_cameras import Stream

'''
Takes a usb input and writes to a file.
The input_type can be easily switched to ffmpeg/pylon/ueye/raw_video.
'''

SLEEP_TIME = 5
CAMERA_ID = 0

# supported file extensions
# FILE_PATH = './tmp/usb.avi'
# FILE_PATH = './tmp/usb.mp4'
FILE_PATH = './tmp/usb.mkv'
# FILE_PATH = './tmp/usb.yuv'
# FILE_PATH = './tmp/usb.raw'

s = Stream(
    input_type='usb', id=CAMERA_ID,
    output_type='file', path=FILE_PATH,
    reading=True,
    writing=True,
)
time.sleep(SLEEP_TIME)

s.stop()

More examples can be found in the senseye_cameras/examples/stream folder.

Error handling

Inputs/Outputs will fail loudly when initialization fails.

If initialization succeeds but a read/write fails, an Input/Output will typically catch the error and log it instead of erroring out.