Why does createsamples make images that are partially transparent
I'm 100% a rookie on this, so it might be a stupid question.
I've been following alone with this tutorial;
Creating your own Haar Cascade OpenCV Python Tutorial
All is well (except that it stops after stage 5... but it's a complex problem so should run further - not my question at the moment though). I pretty much copied the tutorial line for line and I don't understand why when using create samples it doesn't place the sample image over the background images, it kinda merges them. This is the single example used in the tutorial;
And here is an example of one of the created sample;
Now, you can just about see the outline of the watch face at the bottom left of the image (just below the leftmost person). But this is clearly not a simple paste over the background image with the positive sample. I assume this is intended behaviour but I don't know why. Can someone please explain why this is done (and if possible how it chooses which part of the positive image should be made transparent).
that is not really a good tutorial. opencv's is here
if you expect any variation in the objects you want to detect later, you should not use synthetically generated images from a single positive, but LOTS of real positive images, and an info.txt file (with filenames and bounding boxes), probably from the opencv_annotation tool