Questions tagged [spectral]
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12 questions
3
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1
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Wavelength to RGB conversion issue. Average RGB result is yellow tinted instead of white
I'm currently implementing dispersion in my RGB path tracer.
How I do things:
When I hit a glass object, sample a wavelength uniformly between 360nm and 830nm and assign that wavelength to the ray
...
- 301
2
votes
2
answers
262
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Does CIE XYZ preserve spectral accuracy when used for progressive rendering?
How accurate it is to estimate rendering equation using wavelengths and then convert result to CIE XYZ to accumulate samples temporally by averaging them over time?
- 125
1
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1
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182
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Is spectral response curve and spectral power distribution the same thing?
I'm reading section 5.2 of pbrt 3rd edition and came across the part where they explain the concept of RGB colors.
When we display an RGB color on a display, the spectrum that is
actually displayed ...
- 113
3
votes
2
answers
1k
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How to determine RGB values given a display spectral response curve?
I am reading Physically Based Rendering section 2.2.2 on RGB color.
I am trying to understand how, given a display spectral response curves for rgb intensities, we can choose the intensities so that ...
- 131
4
votes
0
answers
522
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Hero wavelength multiple importance sampling
I want to add spectral rendering and dispersion to my pathtracer. I found the Hero Wavelength paper but I have trouble implementing this. This is how I understand the process and where I am stuck:
...
- 233
3
votes
2
answers
423
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Determining input color space primaries from spectrum data
If I have an output device, for which I have a known spectrum data for each of it's primaries, I should be able to calculate the CIEXYZ of its primaries using using the integral equations together ...
- 131
1
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1
answer
1k
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How to calculate spatial frequency of an image just in one direction?
FFT spectra is not what is needed; what I need is a histogram showing which frequencies are there in image in horizontal direction, and which one is dominant
Such spatial frequency is usually known ...
- 111
2
votes
1
answer
223
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Reddish tint with spectral renderer
I'm trying to implement a spectral path tracer and comparing results from my program with renders of the same scene done with pbrt and ...
- 145
2
votes
1
answer
513
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Computing sRGB color from SPDs
I'm trying to write my own spectral path tracer and a bit stuck with converting computed SPDs to LDR RGB values. What I'm doing right now is convert sampled SPDs (in ...
- 145
4
votes
1
answer
263
views
Generating and Combining Spectral Colors
I have two somewhat related questions to ask:
What is the most accurate way to get the colors of a spectrum, without having to go deep into physics and simulating the universe? ;) Right now, I'm using ...
- 577
4
votes
1
answer
286
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Does a constant reflection over the light spectrum lead to grayscale value?
I'm currently fighting with the spectrum->RGB color conversions, my algorithm seems to make an error somewhere, e.g. I get values >1 for some spectral responses.
Now there is a way to calculate an ...
- 1,638
3
votes
1
answer
469
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How is Iridescence handled in a Path Tracer?
I have little knowledge of this topic but from what I gather in a Ray Tracer each ray is given its own wavelength as opposed to an RGB value. This automatically simulates Dispersion and Fluorescence. ...
- 2,501