In general, image processing is any form of signal processing for which the input is an image, such as a photograph or video frame.

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41 views

Limitations of the Fourier Domain?

I am fond of Fourier Theorem (series &transform). In Fourier domain we can come to know what frequency components are present and the contribution of each component in forming the given signal. ...
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1answer
7 views

Adaptive Sampling of Videos and Interpolation

I need to sample a video using adaptive sampling using MATLAB, sampling rate dependent upon rate of change of pixel values and then reconstruct the video using interpolation.I need to attach time ...
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12 views

What does visual clue means ?

Given a keypoint p detected in an image I . What does visual clueof the keypoint p mean ? ...
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6 views

What does darktable noiseprofiling read_pfm parameter mean?

I'm trying to analysis the darktable noiseprofile.c What does -c a1 b1 paramertes mean? If you can please let me know the meaning of 2.0f* sqrt(a[0]*1.0f+b[0])/a[0]. I assume that a is poisson ...
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21 views

Suggested books for Digital Image processing

Ok, I'm trying to get my concepts clear in this subject. Well, as per my course ware at college, the recommended books are "digital image processing- By Rafael gonzalez" and "fundamentals of image ...
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1answer
19 views

How does kernel work in unsharp masking?

I applied the kernel below to the picture for unsharp masking k = [-1 -1 -1; -1 8 -1; -1 -1 -1] I got ! Then I changed 8 to 14. And I got How does kernel work ...
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8 views

get convex hull of isolated shapes with openCV/C++

I have segmented CT images, something like the following one: I would like to get a convex hull that contains all the white regions. Something like this circle, but more fitting, and of course not ...
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33 views

Opinion about this aproach on Machine Learning

I have a question for you that maybe you could give me a clue. I'm trying to make a CBIR (Content-Based Image Retrieval), so I query an image and I get the most similar, not classified within a ...
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11 views

How does the clipped observation model plot?

I'm trying to plot the clipped observation model as following a paper. http://www.cs.tut.fi/~foi/papers/Foi-PoissonianGaussianClippedRaw-2007-IEEE_TIP.pdf I succeeded to got a solid line plot from ...
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5 views

Canny QR code detection on Wood

I have been trying to use Canny to detect the 3 QR code markers on the following picture. But to no avail. (using the countour hierarchy method) I have tried so many different paramters, but I always ...
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1answer
38 views

How to estimate the noise of an image?

I want to know how to estimate the noise of an image? Also is this represent the camera's noise? Does anyone know how to estimate the noise of an image or camera? Update: Especially, I want to ...
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0answers
16 views

How to estimate noise level and actual intensity of image from a noisy image?

The image I have is corrupted with random (natural) noise. So I would call it Gaussian noise. I am thinking of the following approaches for denoising: Mean filter Non-local means filter Averaging ...
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12 views

Implementation of grayscale area opening [on hold]

I am looking for an implementation of grayscale AREA opening (algorithm described in "Grayscale area openings and closings, their efficient implementation and applications" by Luc Vincent). Ideally ...
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0answers
14 views

How to represent the relationship of pixels within a cluster

I have a question about image processing that need your help. I have an image I that includes foreground (FG) and background (BG) regions. I want to represent the relationship of pixels within these ...
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1answer
32 views

How to make a plot of noise standard deviation sigma vs. brightness from a images?

Hi I don't know where to start from. I'm trying to implement a plot of noise with Matlab. I have found a plot of noise standard deviation sigma vs. brightness from a images like this. ...
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16 views

Large scale consecutive matrix multiplication applications

I am running some experiments with matrix multiplication and I am looking for applications (preferably signal processing applications) where multiple input matrices A(i), [i=0,1.....] are multiplied ...
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2answers
40 views

Has this 2D filter for enhancing circular dots in images a name?

I came across this 2D filter for enhancing circular dots in images, for example to enhance a dot with a diameter of 5 pixel, the filter is: $\frac{1}{336}\left( \begin{array}{ccccccc} 0 & 0 ...
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0answers
11 views

Sound Manipulation and Playback [closed]

Implement the echogen function using following parameters and write down the differences which you find in audio output. a. Att=0.5, td=0.5 b. Att=0.3, td=1 c. Att=0.1. td=2 2.Take the audio ...
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0answers
18 views

How to calculate Dot Pitch for a device? [closed]

Okay I am trying to figure out how to calculate the dot pitch for a monitor. For example a 14inch monitor with a display area of 9.875inch and a height of 7.125inch and a diagonal 12.25inch with a ...
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1answer
22 views

differences between 2D and 3D Medical Images

i have two questions: 1)what is the difference between 2D and 3D medical images? 2)assume i have a 2D image and for example it contains 1000 ROIs. each ROI is a matrix and we can convert it to a ...
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23 views

Distance Transformation in image processing

What is the exact purpose of distance transformation in image restoration. Is it a way to restore or only a step towards restoration of a blur image?
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2answers
36 views

cause of adaptive threshold poor result

I try to run text cleaning process based on the camera captured image. By using OpenCV adaptive threshold method with parameter ...
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0answers
45 views

How to detect nuclei in cell

I want to detect the nuclei in this picture. Anyone know the Matlab code? Because I use watershed it's not performing well.
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17 views

frequency domain image analysis for recognition purposes

There are many areas like, gait analysis, where we recognize persons by analyzing their silhouettes taken while they are at different stages of their walking where analysis also carried on in ...
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2answers
231 views

Fourier Decomposition

Hello everyone have a look at this video of Fourier Decomposition of an image(otherwise you can also refer the image which shows few plots of different extracted waves from an image) . We also know ...
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1answer
30 views

Lane detection and tracking using B-snake?

I am truly sorry if my question sounds little bit stupid, but I am getting stuck at this part for a long time. I am currently working for my final year project of lane detection for curved road using ...
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16 views

Optical Flow Problems

I was wondering if any of you guys could help me with the next 3 problems. They're about estimating the lamda on the Optical Flow equation $E = E_s + λE_c$, for different situations that try to ...
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2answers
118 views

Finding the Harmonics contained in an Image?

I am beginer in image processing. Any signal whether it is 1D,2D or any multidimensional signal can be represented using combination of number of sine and cosine wavesforms (harmonics). Similerly any ...
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21 views

Finger Detection on various backgrounds

I tried tracking down the finger placed in the frame. Constraints: Algorithm works in live streaming of USB Camera, so there will be a lot of background changes. Algorithms tried: Tried ...
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1answer
58 views

Why different smartphones with same Megapixel camera have different quality of image?

I am image processing student. Nowdays there are different brands of smartphones available. But the common thing is two different big brand smartphones with same Megapixel camera have different ...
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1answer
36 views

How to choose between taking the real part or the absolute value of an inverse discrete Fourier transform?

I kind of expected this to of been asked before, so if this is duplicate please point me in the right direction, however I couldn't find anything. I am currently experimenting with low pass ...
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4answers
91 views

Noise Removal from an image using Opencv

I tried removing noise from the image shown below using Median Blur in OpenCV. But i'm not able to remove the colour noise completely as it is done in Neat Image. Any suggestions.? 1. Original Input ...
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7 views

Looking for a better way to posterize or normalize the colors of an image

I have very little experience with image processing or signal processing in general, but I'm willing to learn. I've been experimenting with a way to, uh... "flatten" the colors of certain kinds of ...
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1answer
33 views

Image processing for eye movements

I have series of images extracted from a eye tracker video for both eyes. is there any image processing algorithm/method/technique available to find the following from those images: Horizontal eye ...
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1answer
12 views

Difference Between monocular video and stereo video?

What is the difference between monocular video and stereo video ,as i am studying about motion tracking i need to know the meaning of these two things.
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1answer
16 views

Why does cel-shading sometimes look similar to rotoscoping?

Why does cel-shading sometimes look similar to rotoscoping? Rotoscoping: A Scanner Darkly: Cel-shading: Wikipedia: Cel-shading, Teapot Example:
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1answer
21 views

How to plot ROC curve for weka multilayerperceptron?

I am working on an image classification project I use multilayerperceptron,how do I plot ROC curve.I use weka's perceptron.
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20 views

Filtering an image with a helmholtz-type equation

I'm attempting to apply the following PDE as an image filter to smooth a discrete heightmap with a helmholtz-type equation as described in this paper. It seemed like an interesting alternative to a ...
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1answer
30 views

How to Linearise an Input Image before applying Color Correction?

I'm doing color correction on Raw images taken from Camera directly. I want to make my Camera reproduce same colors as my Target camera. Here are the steps I'm following: Take Target Color values ...
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1answer
20 views

Haralick features, am I approaching this correcly?

I'm trying to personalise a custom CBIR by adding more features not only based on colour, but based on textures' features. What I don't know is if I'm approaching this well with Haralick's features. ...
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3answers
69 views

Is there a method to compute an average amplitude for 2D sinusoids using the F.C.'s?

I am working on FFT analysis AFM like the one shown below. I am currently at a point where I understand fairly well what an FFT does, and how to think about the information it gives. I currently have ...
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1answer
40 views

Images to signal intensities

I have a series of images captured using an eye tracker to detect the eye movements. Is this possible to convert these images to get intensity signals?
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47 views

Is it possible to have negative PSNR?

I have been working on image processing. I have an image and then add it a Gaussian noise with standard deviation=0.005. then using averaging filter to denoise it (I know it is not a good idea). then ...
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0answers
17 views

Algorithm to find similarities on a huge database querying one image [duplicate]

After days trying to look to some algorithms, I haven't found any good for my approach. My problem is the following one: I have a large dataset, for example of 2.000 images and I'm trying to query ...
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2answers
67 views

Matching two very similar images

I have two images for the same object from the almost same perspective (no more than 1-2 degrees or 1-2 mm is acceptable). I want to change the perspective of one of them to match exactly the other so ...
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2answers
147 views

Physically what is phase term means for multidimensional signal?

I want to ask very basic question related to multidimensional signals like an image or a video signal. What is phase term means for multidimensional signal like an Image or video signal(like for ...
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2answers
170 views

Whether phase congruency and phase coherence terms are same or different?

I am beginner in Image processing.I am studying the importance of phase in signal.Can anybody explain what is phase congruency ? Also,I am confused between terms i.e. phase congruency and phase ...
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14 views

Granulometry by morphological opening and closing

I am trying to understand granulometry. I understand that it deals with determining the size distribution of particles in an image and uses the principles of opening and closing. I have a smoothed ...
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1answer
61 views

Applying Gaussian Blur in frequency domain

Please see second update I'm trying to implement gaussian blur in frequency domain using c#. Those are steps that I'm doing: Load bitmap. Split bitmap into separate color channels. Convert every ...
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22 views

How to threshold medication boxes against black background?

Some medication boxes contain black patches on them, which make it difficult for me to extract the whole box from the black or almost black background (due to variance in illumination). For example ...