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Questions tagged [luminance]

64 questions
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3 answers

What exactly is the need for gamma correction?

I have problems to fully understand the need for gamma correction. I hope you guys can help me. Let’s assume we want to display 256 neighboring pixels. These pixels should be a smooth gradient from black to white. To denote theirs colors, we use…
user1494080
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How to get colors with the same perceived brightness?

Is there a tool / program / color system that enables you to get colors of the same luminance (perceived brightness)? Say I pick a color (determine RGB values) and the program gives me all the colors around the color wheel with the same luminance…
user936774
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How to determine luminance %?

According to http://www.workwithcolor.com/color-luminance-2233.htm, RED (#FF0000) has Luminance: 54%. and light pink (#FF8080) has Luminance: 89%. Our designers like it but how is it determined? Try here:…
Henry
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1 answer

How do I adjust the luminance in a section of an image in OpenCV

I have the following image. If I plot the average luminance as a function of x-pixel location I can see that the image is bright along the center than at the edges. I would like to correct this using OpenCV so that the luminance is the same…
nickponline
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1 answer

How to Generate Material 3 Color Palettes in JS/SCSS?

Background: I'm trying to generate a color palette in SASS/JS based on Google's Material Theme Builder 3 which requires tonal palette's to be generated based on relative luminance and not lightness/brightness function. Problem: I can get the…
Arslan Akram
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4
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1 answer

What's the formula to increase the luminance in an image in a similar way how the L component in Photoshop does it?

For example I have a pixel with these values: CGFloat red = 34 // 0 - 255 CGFloat green = 128 CGFloat blue = 190 and I want to increase luminance so that blue is 255. NOTE: With "Luminance" I mean the L-component of Photoshop in LAB color space.…
openfrog
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Histogram: RGB to Luminosity

In the histogram display I am implementing, I managed to successfully display RGB histogram. When compared with Photoshop's, it seems right-on! (All screenshots below are from same image) Now, for Luminosity histogram, I used the following…
Gizmodo
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How to convert HSL (hue, saturation, lightness) to HSLum (hue, saturation, luminance) and HSLum/RGB?

I want to convert some color values from well know HSL to less known HSLum how to do it? hsl(0, 1.0, 0.5) - rgb red is hslum(0, 1.0., 0.54) hsl(120, 1.0, 0.5 - rgb green is hslum(0, 1.0, 0.80) hsl(240, 1.0, 0.5) - rgb blue is hslum(0, 1.0,…
Chameleon
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How to check brightness of a background color to decide text color written on it

I have a simple question, but I wasn't able to find an answer to this. Note, that I'm almost a complete beginner. So I have an app (it's not mine, but I'm contributing to it), and in there is writing on a color background, which can be changed by…
RedyAu
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Luminance Matching Two Colors

This will likely seem like a very easy thing I'm trying to do but Google search has not turned up exactly what I'm looking for and I'd like to do this correctly. Essentially I need to luminance match two bmps. They are simple circles (125x125…
chainhomelow
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How to get luminosity of Mat image from opencv?

I'm doing an image processing on iOS using OpenCV in c++. Sometime the ambient light is not enough and the image cannot be processed properly. I did not found any suitable way to detect the ambient light so trying to detect the luminosity of the…
Protocole
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Equalizing luminance, brightness and contrast for a set of images

I use MATLAB for a series of experiments where each eye gets stimulated with a different motiv from the images (binocular rivalry), like on the one is a bottle, on the other a watch. There is a Toolbox to adjust the luminance and spatial frequency…
dalibor
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iPhone camera Brightness... How is it physically measured?

I hope someone can answer this question, its been bugging me for a while now and I can't seem to get a solid answer. How exactly does the iPhone measure scene brightness (or luminance if you prefer) through its camera? Does it measure it off the…
Chris
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android camera preview screen intensity

I am using the custom camera application with preview, using the sdk example on nexus s (2.3) everything works fine, including taking sharp picture, but the preview does not seem to adjust his level (intensity) like the built in camera does: when I…
user1267111
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How to get luminance gradient of an image

Iam working on understanding the image with image luminance check and i tried to find the brightness of the image by the code below def brightness( im_file ): im = Image.open(im_file) stat = ImageStat.Stat(im) r,g,b = stat.rms return…
user11840960
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