A form of signal processing where the input is an image. Usually treating the digital image as a two-dimensional signal (or multidimensional). This processing may include image restoration and enhancement (in particular, pattern recognition and projection).

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14 views

Pseudoinverse for time series filtering

Suppose I have a few time series, that are strongly correlated to each other, and I consider this to be noisy data. How do I use the pseudoinverse technique from image processing to filter this data?
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23 views

Normalized cross correlation vs Euclidean distance in template matching

What is the difference between normalized cross-correlation and Euclidean distance in pattern recognition? -- especially if we want to do recognition with template matching. I understand about ...
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1answer
26 views

What is parameter fine tuning means in SVM?

I got this sentence in one of paper, but I dont understand what does it mean?? " Training a learningbased classifier such as an SVM on an imbalanced dataset often requires parameter fine-tuning, ...
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1answer
15 views

Distance Transform In Image?

I understand how to compute Distance Transform for BW image In BW image we can calculate the distance of the pixel with non zero pixel value using Eucledian Distance. But I dont undertand how to ...
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8 views

EnergyThe meaning of these term in Image Processing?

Im newbie in Image Processing field, and I got many term that wierd. There are : Moments Local and global characteristic Energy of Image Color Temperature What each of them represent in Image??
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18 views

Detecting noisy patterns in document images

I am looking for features to extract to distinguish between text objects and arbitrary noisy patterns in degraded document images. This is an example of a document with some parts of noise, I have ...
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14 views

Metric to show the overall similarity between two set of points obtained from handwritten word?

In my case, I would like to compare different handwriting to a template handwritten word, and return a single metric to show how closely the input matches the template's shape. The lines are the same ...
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3answers
249 views

statistical method for spatial correlation between images

I am working on analyzing a data set and I was wondering what would be the most statistically valid method of demonstrating that there is a strong spatial correlation between images. I have a data ...
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16 views

Assuming a raster image is a random vector

I am currently working in remote sensing. It is quite common to find that the beginning of the statistical descriptions of techniques used in satellite image processing begin with defining the initial ...
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2answers
113 views

k folds cross validation on a multi-class dataset

Cross validation is one of the most important tools because it gives us an honest assessment of the true accuracy of our system. In other words, the cross-validation process provides a much more ...
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19 views

Datasets representing image collections

Ive been researched Information Visualization techniques application to image collections. I need some image datasets with features. Ideally, would be good find a dataset in a file representing each ...
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0answers
7 views

Three categories of spatial relationships

In this paper, the author claimed there are three categories of spatial relations: Topological relations, which remain invariant under transformations such as translation, scaling and rotating ...
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1answer
111 views

Variational method — implementation of function gradient for image denoise

I am studying Variational Methods and decided to code a simple matlab implementation of the famous image denoise example: $E(u) = \displaystyle\frac{1}{2}\sum_{i=1}^N (u_i - f_i)^2 + \displaystyle ...
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15 views

Heat kernel and laplacian

Is there any relation between heat kernel and Laplacian? I know what each of them is but I am not sure about the relation between them.
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47 views

Training a basic Markov Random Field for classifying pixels in an image

I am attempting to learn how to use Markov Random Fields to segment regions in an image. I do not understand some of the parameters in the MRF or why the expectation maximisation I perform fails to ...
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1answer
34 views

Questions on bag of features methods

I've been studying the bag of features (BoF) methods. I understand the basics and how it's done but I think I still am not good at the details. So here's my understanding of such methods: Suppose you ...
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0answers
38 views

Classifier predicts only one class

I was trying myself in kaggle CIFAR competition, I trained lots of classifiers but get the same result/fail (don't know how to treat them), maybe someone could help me figure what i'm doing wrong. ...
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1answer
73 views

Detecting An Image is Bright or Dark? [closed]

I use Java and I have some PNG images. I want to put a caption on my images. However I want that: if an image is bright I want to put a black text on image and if an image is dark I want to put a ...
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3answers
113 views

use of t-test to compare performance of algorithms

I need a little bit guidance. I have to compare the classification performance of multiple algorithms using simple or paired t-test. Let's say I have four datasets (A,B,C) with training and test ...
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49 views

Easy to follow tutorial on using Markov Random Fields for classifying pixels in gray-scale images

I am trying to learn how to use Markov Random Fields for classifying pixels in an image. Could someone please direct me to a simple tutorial demonstrating how this is done. The tutorial needs to ...
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0answers
18 views

Appropriate bounding boxes on images for training data?

This is the first time I'm doing research in computer vision, and I'm going to be using OpenCV's cascaded training, for which I'm preparing positive samples for training data. If anyone's experienced ...
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0answers
32 views

How can i add a weight correctly in a classification algorithm created by me of handwritten sign?

I have 150 images of handwritten signs (like cross, star, circle, tridents), i extracted from them the number of branched point, ent-point and "close" a s feaetures (Having said that features are not ...
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28 views

Optimal to sub-optimal sampling patterns

In the compressed sensing (CS) framework an incoherence property $\mu$ is used to quantify the correlation between a sensing matrix $\Phi$ and a representation matrix $\Psi$. This incoherence ...
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1answer
66 views

How to calculate number of features based on image resolution?

Just covered Andrew Ng's Non-linear Hypothesis of Neural Netowrks, and we had a multiple choice question for determining number of features for an image of resolution 100x100 of grescale intensities. ...
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18 views

Intuitive difference between real and imaginary components of Gabor filter?

Can you explain intuitively what is a difference between real and imaginary components of Gabor Filter? Thanks.
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2answers
101 views

Question about Eigenfaces (PCA applied to facial images)

I've been reading up a bit on eigenfaces. I think I understand the basic concept of it - vectorize a set of facial images then reduce the dimensionality of the images using PCA. What I don't really ...
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1answer
126 views

Distance or Similarity metric for 2D frequency data maps

I want to compare the distance/similarity of 2D flood frequency data maps. The maps are square with YxY grid size and in each cell of the map is stored its flood frequency. For example in a 5x5 grid ...
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1answer
257 views

What does “Mean of each pixel over all images” mean?

I was reading a paper related to Auto encoders for my project work. It is required to input images as vectors to the neural network. I couldn't understand a certain sentence due to lack of knowledge ...
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181 views

Image Clustering using Rapidminer 5

I have a collection of color Images that I want to cluster using Rapidminer 5 and the image processing extension for it. For a start I'd like to cluster them according to the color of the picture but ...
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28 views

Db3 and Haar wavelets properties

Is there someone who can explain to me why when I apply Db3 on my Test image which contains a hole it shifts especially when I augment in the Level from 2 to 5 and when I apply the Haar wavelet the ...
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1answer
265 views

Principal component analysis with Voxels (Vector Pixels) in Matlab

I have Vectors which have a certain position (Voxels) in an image. I would like to perform a pca to cluster out all Voxels which are correlating with each other. I have for example three Voxels in ...
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1answer
125 views

How to calculate the signal-to-noise ratio for an image? [duplicate]

I've started with a “perfect” image 'without noise'. Then I added some noise to it. I've used gaussian white noise for this purpose. In = In+0.5*randn(size(Io)) ...
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1answer
178 views

Estimation of the signal to noise ratio of an image

I originally had a multispectral satellite image consisting of 5 bands. I applied principal components to these bands. So an example of the process would go something like this: reality -> satellite ...
2
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0answers
392 views

Image reconstruction using compressed sensing

This question deals with an example of image reconstruction related to this other question on signal reconstruction. I have different issues in both examples but there could be an underlying factor. ...
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1answer
116 views

How to model a multi-dimensional feature set for classification

I am new to statistical modelling and so please pardon if the question appears trivial. I have a set of multi-dimensional data ($T$) where each dimension represents features ($f_i$) obtained from a ...
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73 views

How can I prepare a feature image with uncertain values for an SVM?

I'm building a system where an user uploads an image and the system suggests 1 or 2 classes (depending on the percentage of match) to which it may belong. I chose an SVM for training my images. I ...
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236 views

Image classifier in python for few samples

I have 150 pictures that represent archeological signs and 5 categories to which they belong. These pictures have features like circularity, roughness and elongation that are expressed as continuous ...
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2answers
121 views

Application of Poisson distribution to image processing

I'm trying to write a program to detect water bubbles in heated oil. I've applied a canny edge detection filter to the image and the results look like the following: No bubbles: ...
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1answer
3k views

How to calculate the signal-to-noise ratio (SNR) in an image?

I am working with an image X, I apply the "adaptive median filter" in it and I get the image Y. I'd like to measure the SNR in both in order to evaluate the quantity of noise deleted. I know the ...
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0answers
76 views

Image similarity database

I'll preface this by stating I'm very new to computer vision. I took a Stanford Machine Learning course on Coursera, and that is the extent of my experience. I'm working on a free-time project to ...
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0answers
60 views

Markov random field and iterated condition mode

I have spent a lot of time studying MRF (applied to images) but still can't grasp the idea. Could you please clarify these ideas: What is the clique potential? What is a clique in image, and do they ...
4
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2answers
657 views

does it make sense for non-negative data to subtract the mean and divide by the std dev?

It is a very usual procedure to subtract the mean and divide by the standard deviation in a set of data. If we deal with non-negative data, i.e. image, (in [0,1] or [0,255]), does this procedure make ...
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2answers
362 views

Auto crop black borders from a scanned image by making stats about gray values

I'm writing a computer program to automatically detect black noisy borders on scanned images and crop them off. My algorithm is based on 2 variables: gray mean value (of the pixels in a rows/columns) ...
4
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2answers
352 views

Classification on principal components

For my research I am doing classification on the dataset of three variables. I run unsupervised clustering (based on a histogram peak technique of cluster analysis)and the result I evaluated visually ...
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1answer
143 views

bag of words in an online configuration, for classification / clustering

I have a set of image documents. I extract text keywords from this images using OCR to represent each image as a bag of words (a vector where each value is the number of occurrence of a word in the ...
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1answer
172 views

Suitable data preprocessing for an image recognition task: normalization ,standardization or neither?

I aim to train my classifier for an image recognition task. What kind of preprocessing steps I need to take to enhance my results? (I have >40000 images with >700 pixels so large amounts of data with ...
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2answers
448 views

Image Clustering with K-means - Postprocessing

I did some clustering on an image (each pixel is an observation that has 5 variables associated with it), I get pretty detailed results but they are a little bit noisey... I think. I used K-means. ...
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0answers
17 views

how Neural Network works on image recognition [duplicate]

Possible Duplicate: How does neural network recognise images? I am trying to learn how Neural Network works on image recognition. I have seen some examples and become even more confused. In ...
3
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4answers
3k views

How does neural network recognise images?

I am trying to learn how Neural Network works on image recognition. I have seen some examples and become even more confused. In the example of letter recognition of a 20x20 image, the values of each ...
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1answer
100 views

Document image analysis and retrieval with online incremental clustering

Is there any interesting problem in the area of "Document Image Analysis and Retrieval" which by nature needs an online/incremental clustering process ? The problem may be in the context of "Logical ...