Computer vision

This category contains 6 posts

Line following with openCV

In a previous article I built a simple line following robot. I had intended to follow this article up with more about building cooperating systems, but I’m afraid I got distracted! In particular I spent some time adding openCV (the open source image processing project) to leJOS. As a result I wanted a project to explore what … Continue reading

openCV web streaming

This post is a start of a series on using openCV with leJOS robots controlled from Android phones. openCV is supported in the latest snapshot of leJOS and will be supported in the next release, which is coming soon. I will start off with a version of my Webcam HTTP streaming code. This uses openCV … Continue reading

Webcam HTTP streaming

To follow up my post on webcam streaming, here is an example of HTTP MJPG streaming. This allows you to open the stream in a browser using a URL like However, Chrome does not let you open this directly – it must be embedded in an HTML document, e.g.: Here is the EV3 code, … Continue reading

Webcam as Color Detector

You can also use a webcam to detect colors: You will need to record some mono wav files in a program such as Audacity, export them as 16-bit PCM and upload them to the EV3, in order to get the name of the color spoken when it is detected.

Webcam Streaming

Following on from Andy’s post on Webcam support, here is how to use your Webcam to stream color video to your PC. The leJOS program is: And the PC program is:

Webcam support

One of the really cool things about the EV3 is that it runs on top of a fairly standard Linux system. This means that it is reasonably easy to hack the system to do new things and support new devices. One of our users Gabriel Ferrer has been doing just that. In this thread and … Continue reading

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