Questions tagged [histogram-equalization]
23 questions
36
votes
10 answers
OpenCV Python equalizeHist colored image
I need to do a histogram equalization for a colored image.
First I convert the colored image to gray and give it to the equalizeHist function:
image = cv2.imread("photo.jpg")
image = cv2.cvtColor(image,…
Fariss Abdo
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32
votes
3 answers
Histogram equalization not working on color image - OpenCV
I am trying to perform a histogram equalization using OpenCV using the following function
Mat Histogram::Equalization(const Mat& inputImage)
{
if(inputImage.channels() >= 3)
{
vector channels;
…
user349026
5
votes
1 answer
Adaptive Histogram Equalization (AHE) Algorithm
I've been trying to figure out the algorithm to perform full adaptive histogram equalization (without interpolating).
However, I still seem to be missing a piece and haven't managed to get the result image right.
Here are the steps that I followed,…
Elia
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5
votes
1 answer
Histogram equalization for python
I have this routine to do histogram equalization of a photo:
def histeq(im,nbr_bins=256):
#get image histogram
imhist,bins = histogram(im.flatten(),nbr_bins,normed=True)
cdf = imhist.cumsum() #cumulative distribution function
cdf = 255…
Nick
- 9,285
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5
votes
3 answers
I need to do a histogram stretch
I have an array of BitmapFrames and need to do a histogram stretch. I know this is different from a histogram equalization, and what the final outcome is... sorta. the problem is I have absolutely no idea what to do after I get the histogram.
So far…
dabonz413
- 69
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3
votes
1 answer
Histogram Equalization on specific area using mask
I am working with images that I need to process. However, only specific areas of these images are of interest so for each image I have a corresponding mask (that can be of any shape, not a bounding box or anything specific). I would like to do…
arnino
- 441
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- 14
2
votes
1 answer
How to do histogram matching with normal distribution as reference?
I have an image and I want to do histogram matching with normal distribution as reference. I've seen this link: Histogram matching with OpenCV, scikit-image, and Python. According to this link, the reference must be an image. But I don't have any…
Mina
- 327
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2
votes
2 answers
local histogram equalization in matlab / python
i am very new in matlab. i want to write the code for local histogram equalization . i have been written code for global histogram equalization and i know that local equalization means do equalization for each part of image seperately but my…
taranom
- 153
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2
votes
1 answer
Histogram Equalization Results
I am trying to code histogram equalization by my self, but the results are different from the built in function in matlab histeq. Any suggestions why is this happening?. I attached the code and the results.
%% Histogram Equalization
close all
clear…
Fadwa
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1
vote
0 answers
Color enhancement using PIL: How to compute color value?
I am using these functions to modify the values of brightness, contrast and sharpness. My default values are 128, 24, 4 respectively. I extracted these values. I don't know how to extract the value of the color to modify it in the same way.
import…
Andrea Vergine
- 11
- 3
1
vote
0 answers
Histogram Equalization: Converting histogram to 32 bins
I'm doing image histogram equalization . The code works fine for an image with 256 bin histogram, but, when I try to convert histogram to 32 bin,the image quality detoriates. Any ideas how to fix that?
My…
user3830162
1
vote
1 answer
Using histogram equalization for 3 regions in histogram
I'm trying to develop an application that will stretching the histogram for each region..
In one picture, the histogram will be divided into 3 region which are dark, mid and bright region.
the range will be: [0 85], [85 171] and [171 255]
my problem…
Sumi
- 21
- 1
0
votes
0 answers
Special criteria for histogram equalization measure
let us consider following code -which reads image, applies histogram equalization procedure and display both result :
import cv2
import numpy as np
img = cv2.imread('original.png', cv2.IMREAD_GRAYSCALE)
assert img is not None, "file could not be…
neural science
- 81
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0
votes
0 answers
CLAHE Implementation produces unexpected output
I am trying to implement CLAHE(contrast-limited adaptive histogram equalization) algorithm using python3, numpy and cv2. I am using the slower non-interpolation method. Just dividing image to tiles and trying to equalize histograms of sub-images to…
tohajiile
- 11
- 4
0
votes
1 answer
Histogram Matching on Sentinel 2 satellite images
I try to apply histogram matching based on OpenCV and Scikit image on Sentinel 2 data, similar to https://www.geeksforgeeks.org/histogram-matching-with-opencv-scikit-image-and-python.
Sentinel 2 bands have a value range between 0 and 10000, also…
MikeHuber
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