This tag covers signal processing where input is an image, such as a photograph or video frame and the output could be an improved or altered image, parameters related to the image or information about features within the image.

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49 views

How to improve an FFT AM demodulator for NOAA APT satellite imagery?

My question involves proper FFT Technique for AM demodulation, in the special case where the modulation rate exceeds the carrier frequency. This question has a specific hobbyist application, the ...
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1answer
15 views

A question about image compression with SVD - MATLAB

I have to compress an image by using svd. I did a few things but all of them produced gray image. However, Output must be rgb. How can i compress an image without changing its original format?
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1answer
65 views

Who is Barbara (test image)

In recent years I've started doing work in image analysis and have used the Barbara and Lena images. Early on I became aware of the interesting history surrounding the Lena image and that got me ...
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23 views

High Pass Filter, effect of applying it on this image.

I am having question about the HPF. In particular, it is having a high pass guassian filter which is applied to the original image below. High pass filter should only detect edge (lots of change in ...
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1answer
12 views

compute image contrast

I need to get information about contrast of an image, and I compute its value in this way: contrast=Pmax/Pmin where Pmax is ...
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1answer
50 views

Avoiding edge repeats in a FFT convolution

I am trying to use FFT as a fast way to convolve a image, however one of the downsides of this is that the "kernel" image will repeat when reaching the edges of the sample. Is there a way to avoid ...
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1answer
50 views

Explain Shift property of DFT

Please check the link What effect does a delay in the time domain have in the frequency domain? Here it is said that if you delay your input signal by D samples, then each complex value in ...
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49 views

Radon Transform Implementation In Matlab

I know MATLAB has a built in Radon function, but I am working on implementing the radon transform in order to perform filtered back projection. As I started, my idea was multiple nested for loops for ...
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28 views

How to display images with log axes? [on hold]

I'm trying to plot few points on existing log-log graph, for comparison. I've saved the existing graph as .png image then I plotted the points on the image!. The difficulty I'm having is how to ...
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14 views

Using morphological operations for color images processing

Have you ever seen any articles about using morphological-like technique for denoising color images?
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12 views

Image Registration Accuracy

I am doing image registration of aerial images with ground reference image. To extract the accuracy measure, one would have to obtain some sort of ground truth manually via selecting tie-points ...
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2answers
103 views

Calculation of sampling rate and its effect on an Image?

I know that for a given signal, the sampling frequency $F_s$ must be twice or more than maximum frequency of the signal $F_m$. It is easy to understand the concept for a 1D signal. But I don't know ...
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1answer
24 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 ...
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36 views

What filters used in this picture?

What filters are used to get an image like one on the left? I need to find body pose of a person in a picture.
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2answers
76 views

2D-otsu algorithm in Digital image processing

I'm working on image project using Matlab & I heard about 2D-otsu algorithm as effective segmentation with low SNR and low contrast images, but I can't find enough information about it or how to ...
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0answers
8 views

image recording

Can I know the delay between the time the PC receives the image and the time when it was acquired? I will record video with time stamp, which software it better for recording? Thank you!
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2answers
55 views

Ship detection from aerial image

I have an aerial image, like this I want to detect the outline of the ship without shadow. How can I do it? I tried threshold in both graylevel, RGB and HSV. It doesn't work perfectly.
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3answers
74 views

How to filter noise from continuous path in image

Problem statement In the dataset above, you can notice a continuous path and then a noise-band at around 320-400 on the x-axis. I want to be able to apply a filter that amplifies the continuous ...
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1answer
51 views

How to detect a inhomogeneity region in image

I have an image that includes object and background. However, the object appears some inhomogeneity region due to illumination. My work is that how to detect inhomogeneity region. Which is feature can ...
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2answers
105 views

Draw outline of a text in an image

I need to draw an outline of text in an image. Consider the below image as an example. Can anyone suggest me a direction to achieve this? I don't have experience in image processing. Any tools/lib ...
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0answers
27 views

Affine Parameter Optimization using simulated annealing

I am working on a project to compare images in the database. I use color and gradient orientation as features of the image and these features are not rotation invariance, therefore to compare well I ...
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1answer
129 views

An alternative algorithm for blob detection

Here's a sample image of my experiment which is to be processed for finding the information of all the blobs (centre, dimension etc.). Basically the image contains some noise, few bold lines, and of ...
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1answer
51 views

Longest line inside of 3D object

I have a 3D object which I have segmented and represented as a 3D binary array. I need to find the longest line which fits inside of the object in three dimensional space. What would be an efficient ...
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1answer
30 views

which spatio-temporal properties does dynamic textures exhibits?

know that dynamic textures are spatially repetitive and temporally varying patterns. 1.I read one sentence in one paper i.e. They are sequences of frames exhibiting certain stationarity properties ...
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0answers
33 views

Impact of different padding schemes in Frequency domain image filtering

I understand, that image padding is necessary in order to prevent wrap-around effects due to circular convolution. My set of questions are related to different padding schemes. Zero Padding is easy ...
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2answers
108 views

How can I go forward with this image processing task?

0 down vote favorite I am totally new to Image processing. I just started my Master thesis in the area of Computer vision and Machine learning. My background is Informatics. Now, my first task is to ...
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0answers
38 views

what is the starting time of FRAME VALID in CMOS MT9V131 Sensor?

I am going to start my project with CMOS MT9V131 Image sensor. In that, data output timing diagram, I have some doubts. Actually, I am going to interface this sensor with LPC1768 by the use of I2C ...
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1answer
83 views

What is the Difference between Texture and Image?

I am beginner in the image processing I want to know what is difference between Texture and Image? or whether they are same? can anyone explain it. Also,if i want to do texture segmentation,can i ...
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29 views

What is weakness of entropy image

I often see that entropy is used in image segmentation area. Hence, I have a question about entropy. What is weakness of entropy image. Which case is fail when apply entropy image? Thank you so much
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1answer
44 views

Thresholding a difference image with a very high kurtosis

I have an difference image produced by substracting two images of a certain location taken a two different time steps. The resulting image of this operation shows a histogram with a very large peak ...
2
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1answer
76 views

Dynamic Textures

i know that texture refers to surface characteristics and appearance of an object given by the size, shape, density, arrangement, proportion of its elementary parts. But i am more interested in ...
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0answers
54 views

Box filter approximations for oriented gabor filters

I'm currently working on a library to generate synthetic fingerprints using the SFinGe method (by Maltoni, Maio and Cappelli) link ...
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2answers
50 views

Image warping - how to proceed

I'm studying image warping and I'm unsure how to warp a starting rectangular image into another image where the box corner points have been changed as I want: (image from ...
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0answers
20 views

image restoration using known noise variance

I want to design filter for image restoration. The noise varince of the noisy image is estimated by me. Which method can I use to de-noise the image so that the filter passes only the pixels having ...
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0answers
33 views

How many way to reduce overfitting problem of Linear classificationH

I am working in linear classification such as y=ax+b. where x={x1...xn}. But the method has weakness that is overfitting problem. Could you suggest to me one method or one way to reduce overfitting ...
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1answer
33 views

Linear classification and overlapping problem reduction

I am study linear classification(Y=aX+b) But it is still weakness that is overlapping problem. Could you suggest to me how to reduce overlapping problem in linear classification or how to find these ...
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1answer
50 views

Image and video processing in matlab

I have been working on Digital signal processing since Feb-2013. I have good command over it. Now I want to expand work in field of IMAGE and Video processing. Please suggest me best practical guide ...
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2answers
55 views

Adaptive gaussian filter for noise image

I am looking for methods to enhance noisy images, where: some pixels in the image are very noise, some other pixels do not contain so much noise. My first thought is to build an adaptive Gaussian ...
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0answers
25 views

How many features of given image

assume that I have a set of image and segmented image of a object in image (training set). Now, I want to measure features of object in image based on the training data. But I don't know how many ...
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1answer
164 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 . ...
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2answers
79 views

how to make image editing filters

I am trying to make filters for days but now I just want to know the experience of others rather than go on to wrong way and finally decided to put my query over ...
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0answers
32 views

How to apply dictionary learning to several images?

I'm implementing a dictionary learning algorithm for doing sparse coding on images and I have a problem how to learn a dictionary corresponding to several iamges. Let’s say X is the data matrix. If I ...
0
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1answer
108 views

Computer Vision Libraries for PHP

Are there any computer vision libraries in PHP, or any server-side programming languages? If not, maybe we can make a list of some -already implemented- methods (Viola Jones face detector, landmark ...
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0answers
37 views

Fourier Transform in 2D? (image processing) [duplicate]

In audio signal processing, Fourier Transforms are widely used to convert the mono-dimensional signal, expressed in time, into the frequency domain. It is not clear to me how this is extended to the ...
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38 views

Image processing(JPEG)

write an m-file that will take the"cameraman" and produce a image quality or difference matrix for spectral selection method.The image properties are a sfollowings: For spectral selection: image1:DC ...
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2answers
110 views

Poisson noise and curve fitting - denoise first?

If I have an image that is severely corrupted by Poisson noise, and I want to fit a function to the image, is it "better" to attempt to denoise the signal first before fitting, or should I move ...
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1answer
134 views

Drawing in images

I want to develop a procedure to remove some inpainted text from images, i.e. I have to estimate the inpainted pixels. I will do that with first an imputation step and then applying SVD (and perhaps ...
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0answers
30 views

Spatial Expectation Maximization matlab

I am looking for the way to implement spatial Expectation Maximization matlab code. Because traditional EM cannot handle with noise image. Hence, I want to find improved EM matlab code. Could you ...
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1answer
207 views

Which method to remove small unwanted region and fill holes

I have a hard problem that need your help. I have a binary image that maintains some unwanted region (small white dot) and hole regions (in figure 1).My idea is that the first I will remove unwanted ...
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174 views

How to make color balance of photoshop using opencv

I want to make the same thing programmatically like Color balance in Photoshop , like in below image if we have same bar ...