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Calibrated HDRI's (EXPERIMENTAL)
🕑 Added 2021-06-21 05:57:58 +0000 UTCDisclaimer: This is something rather new to me and I'm not very experienced with color science. To someone more experienced than myself, this post might make me sound stupid. How would I know? :-)
Hey,
So I've spent quite some time the past week experimenting with a very quick way of shooting HDRI's and evaluating its output. To be more precise, shooting HDRI's with a Theta 360 Camera.
It's certainly NOT a perfect way of shooting HDRI's. The time it takes to shoot is way longer than it should be, meaning that we're getting a lot of ghosting in the final output as leaves and clouds have moved between the different shots.
Then there is the resolution. It's not really sufficient if you want to use the HDRI as a visible backplate, but for lighting or blurred out view, it works just fine.
However, the benefit if this approach is that it's extremely convenient. The camera fits in my pocket and I can easily carry it around when walking or hiking.
In this past week I've been experimenting with calibrating the HDRI's to make sure that colors are accurate. I've learned that it's not as easy as it sounds, as there is ALWAYS some color science going on in every bit of the process of making 3D Rendered images. The camera we shoot HDRI's with have it's own color handling, which we can compensate for. But then our renderer has its own tonemapper, which is harder to compensate for without rendering a color checker card in our images. Then there's white balance and exposure, which basically nothing to do with color accuracy or calibration, as this is something done on top of everything else. Our eyes and brain are constsantly white balancing and exposing what we see, and therefore even the best color calibrated image may not look at all like what we see with our own eyes. Adding to that, the dynamic range of our eyes many times higher than what a computer monitor can display.
In 3D, the final output ultumately depends on our renderer, its tonemapper and the settings we provide it. And then finally, it all breaks apart if your monitor isn't perfectly calibrated as well. In other words, even with perfectly color calibrated HDRI's, there's no guarantee what so ever that the result you see on screen is what you see in real life.
However, having color calibrated HDRI's makes it a little bit easier for us, at least, knowing that we're one step closer to a proper result.
In an upcoming video I'm showing you the whole process of creating and calibrating these HDRI's as well as how I like to use them.
I also want to let you know that I've been working day and night for the past week building a machine that will automatically capture high res HDRI's (25k+ px) really quickly and without any ghosting. The resolution of these is well good enough to use as visible backplates too. And this machine will offer another great perk that I'll talk about once I have it properly working and can show some results :-)
I'm having some more parts to manufacture, but I should be ready to show you some first results later this week.
With all this being said, I'm now sharing a few of my (EXPERIMENTAL) calibrated HDRI's captured with the 360.
PLEASE NOTE: These are only my tests from different stages of my testing process. Some are pretty good, others are not. Some have crappy stitching with visible seams, others are perfectly stitched. Some are super noisy, others are pretty clean.
These are merely the result of my learning process (including my fails) and they can't be concidered any kind of final production ready HDRI's, but feel free to use them for whatever you want.
Comments
Absolutely! Wanted to make a better one, but happy to share this for now :-)
c widd
Could you share the teapot scene and necessary dependencies (if possible), please?
