Stack Overflow
Stack Overflow

Questions tagged [luminance]

64 questions
2
votes
4 answers

Find sequential smallest sums of the multiples of three different numbers, javascript

On this post I found an algorithm to determine the luminance of an RGB color: Luminance (standard for certain colour spaces): (0.2126*R + 0.7152*G + 0.0722*B) I want to use this equation, starting at rgb(0,0,0), to generate all RGB colors in order…
AustinPhillipTaylor
  • 190
  • 3
  • 15
2
votes
1 answer

fixing (with ffmpeg) the chrominance position on a video after capturing

I'm trying to convert some video from VHS to digital using an (old) video capture card (and obviously an old VHS player). Due to the input from my video capture card and the output available from the VHS, I have no other choice than capture with an…
APLU
  • 99
  • 1
  • 8
2
votes
0 answers

What are some methods to measure luminance of image using opencv c++

I need to measure luminance of image with opencv c++ in different ways. One way is converting image to YUV ,then calculating luminance. Is there any other way you suggest? Thanks in advance.
ort23
  • 83
  • 2
  • 10
2
votes
2 answers

CIAreaHistogram + CIHistogramDisplayFilter to get Luminance ONLY Histogram

I believe this could be relative to Core Image in iOS as well as in Mac OS. I am able to get a RGB Histogram to show up using CIAreaHistogram + CIHistogramDisplayFilter in Core Image. Is there a way to get just LUMINANCE instead of RGB separately?
Gizmodo
  • 3,151
  • 7
  • 45
  • 92
2
votes
1 answer

How to retrieve the luminance channel from an rgb image in MATLAB

I'm trying to retrieve the luminance component of a set of 'tif' images in matlab. The code is bellow: function [defaultImages] = readImgLum(nFiles) % readImgLum reads a specified number of images in 'tif' format % and retrieves the luminance…
Sebi
  • 4,262
  • 13
  • 60
  • 116
2
votes
2 answers

Given hue and saturation of a color, how to generate colors in evenly spaced relative luminance level?

Given hue and saturation of a color (H & S of HSL), how to generate colors in evenly spaced relative luminance level? E.g. Source: http://www.workwithcolor.com/hsl-color-schemer-01.htm If I give it a pure Red @ 50 relative luminance, how can I…
Henry
  • 32,689
  • 19
  • 120
  • 221
2
votes
1 answer

Linear interpolation with GL_FLOAT and GL_LUMINANCE?

I'm developing an app using OpenGL ES 2.0 on an iPad 3. I'm attempting to switch from GL_UNSIGNED_BYTE when calling glTexImage2D() to GL_FLOAT for "type", with GL_LUMINANCE as the "internalFormat" and "format" parameters. (formerly GL_RGBA) The…
Vern Jensen
  • 3,449
  • 6
  • 42
  • 59
2
votes
2 answers

Calculate scene luminance using the back camera

I'm building an application on Android using a Samsung Galaxy Tab 10.1". I want to get the value of the scene luminance using the back camera of the device. Unfortunately I could not find a way to access readings from the light sensor on the back…
3arbouch
  • 43
  • 9
1
vote
1 answer

make a lightness histogram with luminance, Lab and sRGB space in Java

I have to create a lightness histogram of an image. I have already maked a RGB Histogram On Internet i found these values: Luminance (standard, objective): (0.2126*R) + (0.7152*G) + (0.0722*B) Luminance (perceived option 1): (0.299*R + 0.587*G +…
postgres
  • 2,242
  • 5
  • 34
  • 50
1
vote
0 answers

Get EXR image luminance

As far as i know, I think to get an image.exr luminance we have to render the image in different exposure and gather them into one ? Here is my image made in Adobe which have different luminance from 0(left) to 10 (right) in exr…
huangkaiyi
  • 73
  • 2
  • 9
1
vote
1 answer

Setting the luminance of an image in skimage does not return constant luminance

I have an rgb image (rgb), and I want to set the luminance to make sure that it's constant. I first check the luminance of the original image (greyrgb). I then convert the image to Lab, then setting the L value to 50 (lab50), before converting back…
Mubaraka
  • 69
  • 9
1
vote
1 answer

Image processing: luminance weighted

I would like to weigh values of luminance. Example: I have a vector of luminance values: vector lum {50,100,150,200,250); I have a vector of coefficients: vector coef {5.1 , 2.55 , 1.7 , 1.275, 1.02 } I create an empty image: Mat1…
Guillaume Andreani
  • 27
  • 7
1
vote
1 answer

Getting maximum/minimum luminance of texture OpenGL

I'm starting with OpenGL, and I want to create a tone mapping - algorithm. I know that my first step is get the max/min luminance value of the HDR image. I have the image in a texture in FBO, and I'm not sure how to start. I think the best way is to…
MikeFadeCrew
  • 107
  • 2
  • 11
1
vote
1 answer

Extracting the Y, Cb, Cr from a Mat in c++ and create a Mat with only the Y values

I have two videos which I want to fuse. I plan to take the visible light video, capture frames, and convert the frames to YUV. Before fusing this with the IR video, I want to extract the Y component, put it in another image(variable) of type Mat of…
st1046
  • 23
  • 1
  • 6
1
vote
3 answers

Luminosity from iOS camera

I'm trying to make an application and i have to calculate the brightness of the camera like this application : http://itunes.apple.com/us/app/megaman-luxmeter/id455660266?mt=8 I found this document :…
user1833903
  • 187
  • 3
  • 16
1
2
3 4 5