Basler / Driver

The driver is based on the Pypylon Wrapper.

The source is in the camera_basler.py < file including :

CameraBasler class,
BaslerERROR class : to process low-level error when accessing the camera,
get_converter_mode(color_mode: str)
get_bits_per_pixel(color_mode: str)

Warning

The camera_basler.py must be in the same directory as the Python file containing your script.

Import the CameraBasler class

To access CameraBasler class and its functions, import the class in your Python code like this:

from camera_basler import CameraBasler

Initialize a camera

Device object

First of all, you need to create a device from the pypylon module like this:

from pypylon import pylon
my_cam_dev = pylon.InstantCamera(pylon.TlFactory.GetInstance().CreateFirstDevice())

This script gets the first Basler connected device. If no device is connected, it returns an error.

You can also use the CameraList class, as shown in the previous section. The get_cam_device() method returns a device object that is the same type as the pypylon module.

Camera object

An instance of the CameraBasler class creates an object able to communicate with the device.

To use our driver, you have to create an instance of the CameraBasler class like this:

my_cam = CameraBasler(my_cam_dev)

When you use this constructor, a well-initialized message is written in the console (if the camera is correctly connected and recognized by the system.

>>> my_cam = CameraBasler(my_cam_dev)
Device is well initialized.

Connected camera

The is_camera_connected() method returns the status of the camera, in other words it says if the camera could be opened or not.

To check if the camera is well connected, you can use this command:

>>> my_cam.is_camera_connected()
Device is well initialized.
True

If the camera is well initialized, you will obtain a success message in the console, following by True.

Get information from the camera

Different kind of informations are available on Basler camera. You can get the name, the serial number, the frame rate, the exposure time… of the camera.

Camera general informations

Serial Number and name

The get_cam_info() method returns a tuple with the serial number (str) and the name of the camera (str).

>>> my_cam.get_cam_info
('40282239', 'a2A1920-160ucBAS')

>>> my_cam.get_cam_info
('40282239', 'a2A1920-160ucBAS')

>>> my_cam.get_cam_info()
('40282239', 'a2A1920-160ucBAS')

Sensor size

The get_sensor_size() method returns a tuple with the width (int) and the height (int) of the sensor.

>>> my_cam.get_sensor_size()
(1936, 1216)

Camera parameters

Color mode

The color mode corresponds to the format of the image data transmitted by the camera. There are different pixel formats depending on the model of your camera and whether it is a color or a mono camera.

Four color modes are implemented in this driver :

‘Mono8’ : monochromatic mode in 8 bits raw data
‘Mono10’ : monochromatic mode in 10 bits raw data
‘Mono12’ : monochromatic mode in 12 bits raw data
‘RGB8’ : RGB mode in 8 bits raw data

The get_color_mode() method returns the color mode of the camera (str).

>>> my_cam.get_color_mode()
'Mono8'

For more informations about the color mode of Basler camera, you can check on the Basler Website.

Exposure Time

The exposure time of a camera specifies how long the image sensor is exposed to light during image acquisition.

The get_exposure() method returns the exposure time of the camera (float) in microseconds.

>>> my_cam.get_exposure()
5000.0

Frame Rate

The frame rate specifies the maximum value of images per second collected by the camera. This factor depends on the exposure time (and other parameters).

The get_frame_rate() method returns the frame rate of the camera (float) in frames per second.

>>> my_cam.get_frame_rate()
100.0

Area of interest (AOI)

The AOI camera feature lets the user specify a portion of the camera’s sensor array to use. Only the pixels contained in this area are transmitted.

The get_aoi() method returns the position and the size of the area of interest (AOI). It gives a tuple of 4 integers : x, y, width, height. All these values are in pixels. x and y are the coordinates of the upper-left corner.

>>> my_cam.get_aoi()
(0, 0, 1936, 1216)

Black Level

The Black Level camera feature allows you to change the overall brightness of an image. Adjusting the camera’s black level will result in an offset to the pixel’s gray values output by the camera.

The get_black_level() method returns the black level of the camera (int) in ADU (analog-to-digital units).

>>> my_cam.get_black_level()
0.0

Setup a camera

Color mode

The color mode corresponds to the format of the image data transmitted by the camera. There are different pixel formats depending on the model of your camera and whether it is a color or a mono camera.

Four color modes are implemented in this driver :

‘Mono8’ : monochromatic mode in 8 bits raw data
‘Mono10’ : monochromatic mode in 10 bits raw data
‘Mono12’ : monochromatic mode in 12 bits raw data
‘RGB8’ : RGB mode in 8 bits raw data

The set_color_mode(value) method changes the color mode of the camera (str). The parameter is a str value corresponding to one of the four available modes.

>>> my_cam.set_color_mode('Mono12')

Exposure Time

The exposure time of a camera specifies how long the image sensor is exposed to light during image acquisition.

The set_exposure(value) method changes the exposure time of the camera. The parameter is a floatting number corresponding to the value of the exposure time in microseconds.

>>> my_cam.set_exposure(20000)

Frame Rate

The frame rate specifies the maximum value of images per second collected by the camera. This factor depends on the exposure time (and other parameters).

The set_frame_rate(value) method changes the frame rate of the camera. The parameter is a floatting number corresponding to the value of the frame rate in frames per second.

>>> my_cam.set_frame_rate(20)

Area of interest (AOI)

The AOI camera feature lets the user specify a portion of the camera’s sensor array to use. Only the pixels contained in this area are transmitted.

Set a new AOI

The set_aoi(x, y, w, h) method changes the position and the size of the area of interest (AOI). It requires four parameters (integers) : x, y, width, height. All these values are in pixels. x and y are the coordinates of the upper-left corner.

>>> my_cam.set_aoi(16, 32, 500, 600)
True

Caution

x and y coordinates must be dividable without rest by 4.

If the coordinates or the sizes are out of the range of the sensor size, the function returns False and no changes are applied.

>>> my_cam.set_aoi(10, 12, 522, 600)
False

>>> my_cam.set_aoi(-2, -3, 522, 600)
False

Reset AOI

The reset_aoi() method forces the position to 0,0 and the size of the area of interest (AOI) to the width and the height of the sensor.

>>> my_cam.reset_aoi()
True

Black Level

The Black Level camera feature allows you to change the overall brightness of an image. Adjusting the camera’s black level will result in an offset to the pixel’s gray values output by the camera.

The set_black_level(value) method changes the black level of the camera. The parameter is an integer number corresponding to the value of the black level in ADU (analog-to-digital units).

>>> my_cam.set_black_level(50)
True

Get and display images

The main purpose of a camera is to capture images and transmit the data to the computer.

Images format and display

Each image is stored in a numpy.ndarray. Depending on the color mode, this array is a two-dimensional (‘MonoXX’) or three-dimensional array (‘RGB8’ - two-dimensional array per color).

Each pixel is encoded in 8 bits (‘Mono8’ or ‘RGB8’) or in 16 bits (‘Mono10’ or ‘Mono12’).

The next table gives an overview of the images format depending on the color mode.

Images format
Color Mode	Numpy.ndarray shape	Pixel type	Pixel Range Value
Mono8	(H, W)	numpy.uint8	0 to 255
Mono10	(H, W)	numpy.uint16	0 to 1023
Mono12	(H, W)	numpy.uint16	0 to 4095
RGB8	(H, W, 3)	numpy.uint8	0 to 255

The simplest way to display images in Python is to use Matplotlib library, as it shows in the next exemple.

from matplotlib import pyplot as plt

plt.imshow(image, interpolation='nearest')
plt.show()

Get one image

The get_image() method configures the camera to capture one image and to store it in a numpy.ndarray.

The array has the same shape as the AOI.

>>> image = my_cam.get_image()

Get a set of images

The get_images(value) method configures the camera to capture a set of images and to store them in a list of arrays. Each array corresponds to an image. The parameter is an integer number corresponding to the number of images to capture.

Without any parameter, this method return only one image.

>>> images = my_cam.get_images(10)

You can then access to one of the image like this:

>>> image1 = images[0]

Complete example

from matplotlib import pyplot as plt

    my_cam_dev = pylon.InstantCamera(pylon.TlFactory.GetInstance().CreateFirstDevice())

my_cam = CameraBasler(my_cam_dev)

# Check the colormode
print(my_cam.get_color_mode())

# Change colormode to Mono12
my_cam.set_color_mode('Mono12')
my_cam.set_display_mode('Mono12')
print(my_cam.get_color_mode())

# Test to catch one image
images = my_cam.get_images()
print(images[0].shape)

# display image
plt.imshow(images[0], interpolation='nearest')
plt.show()

Start a continuous shot

Coming soon…