B Can I Use GIMP to Edit My Checkerboard Images for Synthetic Schlieren Imaging?

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GIMP can be effectively used to edit checkerboard images for synthetic Schlieren imaging, as demonstrated by a user who adapted a method from a research paper. They displayed a checkerboard image on a monitor and captured it with a camera, experimenting with image subtraction techniques to visualize convection currents. The discussion highlights the importance of optimal checkerboard pitch to avoid aliasing and suggests improving image contrast through adjustments and Gaussian blur. Users also share tips on file formats and image hosting for better processing results. Overall, the conversation emphasizes the potential of combining techniques from astrophotography and Schlieren imaging to enhance visual outcomes.
  • #31
sophiecentaur said:
This is very encouraging. Have you considered do a bit of tiffling with 'curves and levels' on Photoshop (or equivalent) to make the image more visible to the eye? It's not cheating and would make the results much more accessible. Increase the gain / slope a bit but keep the blacks black.
Your program could easily identify the brightness range and do some useful scaling on its own, without human intervention.
Thank you for your interest and observations of my maximum entropy noise reduction (MENR) hobby project. I don't have Photoshop. I use OpenCV and program subroutines in C++. I have to figure out how to implement histogram equalization of the histogram of the entire image coupled with a local stretching function. I have, however, developed an alternate technique which I call "semi-holographic contrast enhancement"(SHCE).
For your amusement, I processed the two images recently posted by @Keith_McClary using both MENR and SHCE. For Keith's image
47.JPG

MENR yields
47me.jpg

I processed this image with SHCE to get
47holo.jpg


For Keith's image:
candle.JPG

MENR yields
candleme.jpg

Processing this image with SHCE yields
candleholo.jpg
 
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  • #32
Fred Wright said:
I don't have Photoshop. I use OpenCV and program subroutines in C++.
Great result. It's not necessary to choose between approaches. The high level packages are brilliant but you will, no doubt, be frustrated at what they won't do but don't discount them.

Don't go for Photoshop (£££) unless you are a photography enthusiast but there are many free image processing apps which work at a high level and are easy to interact with. GIMP is an open source package which has been around for years. It's very easy to do what you want with images because its UI is pretty much intuitive. Imo it would certainly be worth while to try it and possibly get a subjectively optimum result. There are a range of filters and other controls which are easy to tinker with and rapidly get to know.