Blog of things

OpenCV baby steps 5: Tracking multiple colours

2018-7-17

Sorry, its been a while since I took my last baby step. I have been in the midst of a few things and funnily enough, as I start typing this, I am actually holidaying in Canada. The drive from Vancouver to Kamloops is very very scenic :D. Eitherways, learning never stops, holidaying or not. I have been struggling to go ahead with my plans to track multiple coloured objects in the same frame. I mean in the last post we saw how we can identify four coloured balls using HSV masking. Also in step 3 we saw how to detect circles using OpenCV's HoughCircles function. What I wanted was a combination of the two - Detect position of a ball of my choice e.g. Red ball is placed here (x,y,radius). Turns out it was my lack of Python knowledge than OpenCV that got in the way. OpenCV continues to amaze me for its versatility and ease of use.

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OpenCV baby steps 4: Building a HSV calibrator

2018-6-26

So far we have taken small bits of OpenCV goodness and explored them independently. Today we are going to see how we can combine a few things together and build ourselves a small app that helps us convert a coloured image into its Hue, Saturation and Value equivalent, and then adjust the HSV range to isolate one or more colours in the image.

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Open CV Baby steps 3: Circle detection

2018-6-19

So far we have seen how to install OpenCV and capture images from a video stream. Today we'll see how we can detect circles (or balls) in an image. Last year, the biggest challenge of PiWars was to be able to detect coloured balls kept on four corners of an arena and drive a robot towards it. Now I don't know if they will have the same challenge this year, however we can use this as a starting point to use a few more OpenCV tricks. Today we'll learn about how to use Hough transforms in OpenCV and how we can use it to detect balls in an image.

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Open CV Baby steps 2: Capturing video frames

2018-6-18

In the introductory post we saw how to setup OpenCV on a Raspbian (Desktop) and run a small sample application to convert an image into greyscale. Today we'll see how easy it is to capture frames from a camera and write some text on to each frame and save them.

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Open CV Baby Steps 01: Installation

2018-6-14

I always wanted to learn OpenCV, because it was a massive step up from my Computer Graphics theory class back in the University days. Also I dream that all my the pictures I have ever taken will one day be collated, indexed and searchable with context like place, scene, people in the image so on and so forth. So learning OpenCV is the natural first step towards that (no, I will not use a my images as training material for some corporate AI engine, I wear a tin-foil-hat, sue me!). Of course everything had to run off (one or more) RaspberryPi!

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PiWars 2018: Team Pi-O-Steer's day out

2018-5-9

Finally managed to collate all the images from friends and family who had come along to PiWars 2018. Here's a glimpse of Team Pi-O-Steer's action packed day at PiWars 2018.

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