If you are looking for some sort of image processing approach for generating statistics, this is not it.
This has only been tested on Debian 10, with a little ingenuity I'm sure that it could work on other platforms which I'm less interested in.
You will need python, python-matplotlib and Octave.
This looks complex but really only takes a couple of minutes once you are used to the process.
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Obtain a new target face.
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Shoot some arrows at it.
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Take a picture of the target face with your mobile phone, try to keep the phone vertical and ensure that the outer circle of the target is completely within the frame.
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By downloading from Google Photos, or by other means, get the photograph into this directory.
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From a command prompt in this directory, run the following command but use your own target JPG file in place of mine
python picker.py IMG_20200614_122251650.jpg > IMG_20200614_122251650.jpg.points -
The picker program will display your target photograph in a window. It's best to maximise that window before you go any further.
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It's important that the program understands the dimensions of the target. In order to inform the program left click first on the precise center of the target, then at the point on the outer circle directly above that, then on the point on the outer circle to the right of the center, then the point at the bottom of the outer circle then at the left.
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That's center, top, right, bottom, left. Essentially center then clockwise around the outer ring.
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If you make a mistake at any point, it seems as if you can press delete to undo.
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Having made an accurate selection of the first three points, click on every arrow hole in the target. The numbers in the diagram above show the order - it is important to get that right.
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You should end up with something like this:
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Press [Enter], then close the Matplotlib window - I do that by pressing 'q'
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If you cat the .points file then it should contain two columns of numbers.
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Again from a command line prompt in this directory, type this but with your newly created .points file:
octave post.m IMG_20200614_122251650.jpg.points -
This will create two new files in the directory, in my case:
IMG_20200614_122251650.jpg.points.png IMG_20200614_122251650.jpg.points.stats
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The first of those is a plot of the target with the arrow marks, the title summarises the stats. There should be a green dot at the mean position, a blue ellipse for the standard deviation and red dots for the arrow holes.
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The second is just a dump of the octave variables, in case you'd like to do some more maths.
I hope you are better at archery than I am.