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0
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1answer
21 views

Getting 16 bit image statistics in Photoshop

The histogram in Photoshop for a 16-bit image downsamples to 8 bits, showing a tonal range of 0 to 255. I appreciate to show tonal ranges for a 16 bit image a horizontal zoom function would be ...
1
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0answers
35 views

Gonzalez question solution

If I have the histogram of an input image as Gaussian probability density function of the form: $$P_r(r)=\dfrac{1}{\sqrt{2\pi}\sigma}e^{-\dfrac{(r-\mu)^2}{2\sigma^2}} $$ where: $\mu$ and $\sigma$ ...
1
vote
1answer
47 views

Histogram Intersection with two different bin sizes?

I have two images: A and B. Image A is a screenshot of image B, the original image. While there is noise in image A, the original features are still distinguishable. Histogram intersection tells us ...
0
votes
1answer
20 views

float image to integer type image

I have a multispectral satellite image and I would like to "transform" each of the image bands into one with integer values. For example to stretch? the image between 0 and 255. Not sure how to ...
0
votes
1answer
97 views

Histogram matching of two images using cdf

I have already calculated the cdf values of each image now i have to map the reference image values to target . I cannot use histogram equalization or interpolation I simply have to map them . ...
0
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0answers
47 views

linear contrast stretching based on minimum and maximum calculation from image histogram

I'm studying Gonzalez image processing book and under the topic linear contrast stretching based on minimum and maximum calculation from image histogram has been ...
0
votes
1answer
157 views

Histogram and binary image in opencv? [closed]

I would like to compute how many zeros and ones (e.i. 255) in a binary image. The following code to generate a binary image by using Matlab. ...
1
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0answers
97 views

GLOBAL THRESHOLDING using histogram

There is a recursive way of finding threshold in the image using histogram that are biomodal, and is as follows: An automated procedure for bimodal histograms : Select an initial estimate of T ...
1
vote
1answer
91 views

What steps come after finding the gradients of the SIFT key points?

I am using a SIFT algorithm to extract features from an image. I understand that the SIFT descriptor first finds the extrema and then finds the gradient and direction of each of these interest ...
0
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0answers
44 views

Distance-metric for SIFT descriptors matching

Will using Cosine-Similarity or Histogram Intersection as distance-metric, for matching SIFT descriptors, help to get better results? Anybody tried on that ever?
0
votes
2answers
85 views

How to create a band limited signal of sine waves that is nearly uniform distributed

I would like to create a signal that is nearly uniform distributet (as depicted in Figure 1). It must consist of some single sine waves (e. g. 400 Hz, 430 Hz, 500 Hz) or a random band limited signal ...
0
votes
0answers
46 views

Encoding the HOG features

I have got a video containing 200 frames and i am extracting low level features at pixel level. Then i am dividing the entire frame in to small spatial patches (say of size 7x7) and creating a feature ...
4
votes
4answers
649 views

Why is histogram equalization called as “equalization”?

When output histogram is not same as reference histogram, why is the method called histogram equalization? For example below are two figures from http://en.wikipedia.org/wiki/Histogram_equalization. ...
3
votes
1answer
221 views

Image Contrast Enhancement based Sub-histogram Equalization Technique without Over-equalization Noise

I'm a computer science student and I have an assignment requiring me to implement the algorithm proposed by this paper but I'm hitting a roadblock trying to understand the implementation of one of the ...
0
votes
1answer
148 views

Calculating an HSV histogram

I have to compute an HSV histogram of a colored image. Is it same as an H-S histogram? I have found H-S histogram computation code everywhere. What is the method to change an H-S histogram to an ...
2
votes
1answer
98 views

Histogram evaluation for image quality concerning illumination

I'm currently trying to develop an algorithm to control the camera characteristic of a camera (the camera characteristic can be controlled to adopt it to the different lightning situation which can ...
2
votes
1answer
66 views

Histogram operation for improving visual object tracking

I'm developping a people tracking with nearest neighbour data association technique and kalman filter for smoothing/predicting. The tracker works quite good but sometimes it mismatch objects if they ...
2
votes
1answer
1k views

What is use of a gaussian filter over histogram?

I am working in the field of digital image processing and currently i am reading this paper and I have two questions about it.... After applying a gaussian filter to a histogram, will the pixel ...
2
votes
0answers
70 views

Optimal image histogram for Human eye

I need to visualize some data as gray-scale images after contrast enhancement. The processing algorithm must be built on few samples, and then it will be applied on unseen images (suppose, the [min, ...
2
votes
1answer
193 views

Histogram of signal with a time shift added

One of the problems in Proakis's signal processing book using Matlab asks to plot the histogram of x3(n) = x1(n) + x1(n-1) where ...
2
votes
1answer
532 views

Interpolation in Contrast Limited Adaptive Histogram Equalization

I have been trying to implement the CLAHE algorithm and came across this page which states step by step procedure for the algorithm. I understand the initial steps to perform HE of tiles in the ...
2
votes
1answer
159 views

Lesser bins histogram looks more equalised than higher bins histogram after histogram equalisation?

I tried to do a histogram equalisation on an image, and then display its histogram. I realise that when I show the histogram with 10 bins, it looks more "equalised" than when I show the histogram with ...
1
vote
0answers
102 views

Why histogram equalization fail in ehnanche images for bimodal hisogram?

I'm on histogram equalization process. I have quite well understood the math but i don't understand why an histogram on bimodal image fails in image enhancment and what tecniques can i use in this ...
1
vote
0answers
141 views

Local histogram equalization

I want to learn computer vision and so I downloaded image processing slides from my university archive. I'm on histogram equalization. Learning about local histogram equalization points me out to this ...
3
votes
1answer
317 views

Relation between histogram equalization and 'Auto Levels'

I need to enhance an image using only global linear adjustment of intensity, i.e.: $$I'=aI+b,\qquad a,b\in \mathbb{R}$$ where $I$ and $I'$ are input and output (enhanced) image. I already know how ...
5
votes
1answer
598 views

importance of using histogram equalization

I'm reading opencv tutorials and I'm diving into histogram equalization. i have looked in wikipedia, there is a nice example that sums up exactly the problem: original: equalized: but for getting ...
8
votes
1answer
3k views

Opencv calcHist and calcBackProject in plain english

i've started experimenting with c++ and opencv because of i want to learn image processing. Now, my first exercise is to create a skin detector with calcHist and calcBackProject. But i don't ...