/
Configuring the camera sensor

Configuring the camera sensor

Owned by Sylvain Bernard
Last updated: Nov 20, 2021
2 min read

This page describes how to configure the OV5640 camera sensor.

** UPDATED for v2.x **

Table of Contents

References

Intro

There are 3 main ways of configuring the MPCam’s image sensor, i.e. OV5640:

  • using V4Linux

  • using OpenCV (limited)

  • using the PyMPCam module

While you can use V4Linux from the command line (see insert below), for ease of use, we’ve wrapped it in our PyMPCam library. The following paragraphs will detail how to use the CameraManager module in your script to configure the image sensor.

The OpenCV API relies on V4Linux for the sensor configuration. Unfortunately, the OpenCV driver is not fully implemented and there is no simple way, other than looking at the source, to know what is implemented and what is not. For this reason, we are not recommending its use to configure the sensor.

The MPCam ships with a NoIR lens, which means that IR is not filtered out (to allow for night vision when using the IR LEDs.) However, it also means that colors appear distorted!

Note: you may want to replace the S2 lens with one that includes an IR cut-out filter.

By default, the MPCam enables the automatic white-balance correction, which may affect the color rendering with the NoIR lens. If preferred, you can turn off while-balance auto-correction:

  • using V4Linux at the command line:

    v4l2-ctl --set-ctrl white_balance_automatic=0

  • then, you can manually set the blue/red balance, for example:

    v4l2-ctl --set-ctrl red_balance=1000 v4l2-ctl --set-ctrl blue_balance=1000

    note: adjust the red/blue value to your liking.

PyMPCam.cameraManager

The PyMPCam library includes a cameraManager module which exposes the V4Linux image sensor controls. For example, you can en/disable the auto white-balance function and configure the red/blue balance levels manually (see insert above), or you can change the camera up/down orientation, or change the gain, exposure, etc…

The full module API is available online: https://pympcam.readthedocs.io/en/v1.2.0/api.html#cameramanager

In your script, first import the module and instantiate a camera instance:

from pympcam.cameraManager import CameraManager camera = CameraManager()

From there, you simply call any of the CamerManager class functions.

For example:

gainLevel = camera.get_gainLevel() # disable auto-gain: camera.set_autoGain(False) # set the gain level to half: camera.set_gainLevel( gainLevel / 2 ) # disable auto-white-balance: camera.set_autoWhiteBalance(False) # configure the red/blue balance level: camera.set_blueBalanceLevel(1000) camera.set_redBalanceLevel(1000)

The API follows V4Linux’s v4l2-ctl one-to-one (it wraps it!) and consists of simple setters/getters.

 

Related content