HDRBlur is a relatively niche little web-app tool I wrote to try to understand better what is going on when a very bright light source is blurred or has glare. Here's the basic setup in two views:
https://www.metabunk.org/HDRBlur/
At the bottom are the rendered views of two disks of the same size. You can think of them as being a flashlight pointing at the camera, the sun, or the hot parts of a jet engine. Both are perfectly evenly lit, but the one on the right is a lot hotter (high intensity) than the one of the left (low intensity)
The upper graph shows the intensity of light (or heat, but I'll use light here) across the image of the disk. The red line is 100% saturation for the sensor. Any value above that line just gets rendered as black.
The first example shows the result with no blur (or glare spread). Both discs are rendered as correct sized black discs. This would require perfect optics.
The second example has some blur. Since the low-intensity one starts out at 100%, it becomes less distinct and more grey.
But the high-intensity disc just gets bigger, with a little blur around the edges. Here it is in more detail.
With even more glare, it get's more distinct.
Now, the low-intensity object has faded away and would largely be lost in the blurry background. But the high intensity object still has a relatively well-defined border.
While this is mostly simulating blur, the effect of a Glare Spread Function (GSF) is similar (but with a much steeper drop-off across the blur radius), and playing with the parameters here might help us understand what's going on in various cases.
Again, it is of limited interest, but I'd be happy to get feedback and suggestions for improvement.
https://www.metabunk.org/HDRBlur/
https://www.metabunk.org/HDRBlur/
At the bottom are the rendered views of two disks of the same size. You can think of them as being a flashlight pointing at the camera, the sun, or the hot parts of a jet engine. Both are perfectly evenly lit, but the one on the right is a lot hotter (high intensity) than the one of the left (low intensity)
The upper graph shows the intensity of light (or heat, but I'll use light here) across the image of the disk. The red line is 100% saturation for the sensor. Any value above that line just gets rendered as black.
The first example shows the result with no blur (or glare spread). Both discs are rendered as correct sized black discs. This would require perfect optics.
The second example has some blur. Since the low-intensity one starts out at 100%, it becomes less distinct and more grey.
But the high-intensity disc just gets bigger, with a little blur around the edges. Here it is in more detail.
With even more glare, it get's more distinct.
Now, the low-intensity object has faded away and would largely be lost in the blurry background. But the high intensity object still has a relatively well-defined border.
While this is mostly simulating blur, the effect of a Glare Spread Function (GSF) is similar (but with a much steeper drop-off across the blur radius), and playing with the parameters here might help us understand what's going on in various cases.
Again, it is of limited interest, but I'd be happy to get feedback and suggestions for improvement.
https://www.metabunk.org/HDRBlur/
