# Questions tagged [image-processing]

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

471 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
0answers
234 views

### VLFEat: How to extract the SIFT descriptor without SIFT feature detection?

I am using the MATLAB interface to the VLFeat toolbox in order to calculate a SIFT descriptor for image patches extracted around key points. Due to the greater framework of what I'm doing, I cannot ...
0answers
94 views

### Shot boundary detection using SVM's

I'm trying to do shot boundary detection using SVM's. I'm differentiating between 3 shots, cut, fade and dissolve + (normal frames). I had used two features, shannon's entropy and variance, it gave ...
0answers
59 views

### Position vector of Lukas-Kanade optical flow algorithm

The classical optical flow equation by Lukas-Kanade can be simplified as follow: $$\frac{\delta I}{\delta x}\triangle x+\frac{\delta I}{\delta y}\triangle y + \frac{\delta I}{\delta t}\triangle t=0$$...
0answers
13 views

### is there upper limit on averaging window size for images?

An amateur question. I take an image and average pixels over a window 3 by 3, thus obtaining a smoother image. Then I increase the averaging window size - obtain an image with even less details, but ...
0answers
2k views

### Image preprocessing for facial detection->embedding->clustering pipeline

I am trying to implement an end to end pipeline for facial clustering so that it can group people with the same faces. This will be quote a long post as I know that this is a very broad topic, so I ...
0answers
46 views

### Get slopes of integer shift of an image in radians

I tried to reproduce the result from this paper, However I'm stuck at the Section III of the paper which involve integer shift. Two images which their phase correlation $\theta(k_1,k_2)$ was ...
0answers
397 views

### Intensity Transformation using Fuzzy sets

I'm doing a project on intensity transformation using fuzzy sets. In the book Digital Image Processing by Rafael C. Gonzalez. The author says this Consider the general problem of contrast ...
0answers
329 views

### Difference between Gabor filters, Gabor wavelets and Log-Gaber wavelets

I am a beginner in the field of image processing, and I am trying to understand Gabor transform but the more I read, the more I get confused. So I wish to find someone who can help me answering this ...
1answer
176 views

### 2D DWT computation order

In 2D the discrete wavelet transform (DWT) of an image using lifting based 5/3 filter, if I perform a row-wise operation first then perform column-wise operation then I will get 4 sub-band LL, LH and ...
0answers
54 views

### Locate first minima in signal

I have many datasets which all looks roughly like this: All the datasets have this in common. First there is an artifact around 0 with an unknown (but likely very high) intensity. Then there is some ...
1answer
589 views

### How to get the scale bar of an FFT for a 2d image

I've been analyzing some images from a transmission electron microscope, including their FFTs, and I'm not sure how to apply a scale bar to the FFT images. I have calibrations for the real space image,...
0answers
57 views

### Watermark insertion process in image

I'm new in the field of image processing and I'am trying to implement a watermarking algorithm (for medical images in DICOM format) based on this paper. As written in the paper, this algorithm is ...
0answers
82 views

### Image Processing: 360x180 panorama from discrete images

I'm coming from math as I was told that this would be a more fitting place for this question. For the last few weeks, I have been trying to create a full 360°x180° spherical panorama from distinct ...
0answers
369 views

### Gaussian Mixture Model-UBM based for image recognition

Scenario: Open set recognition: Unknown individuals may appear on scene (CCTV). Gallery = 10 individuals with a mug-shot image per individual. Approach: Gaussian Mixture Model-UBM based Use video ...
0answers
93 views

### Optical realization of the Radon Transform

I am trying to reproduce this paper concerning the Optical realization of the Radon Transform, especially the simulation (section 3). Shortly, the experiment is just a "Fourier filtering" with a 4F ...
0answers
1k views

### Line Detection with OpenCV

I'm trying to use the native functions of OpenCV HoughLines and HoughLinesP to detect the lines from an image. The Canny edge output of that image is the folllowing: The problem is that the OpenCV ...
0answers
89 views

### Extrinsic Camera Parameters without introducing control points?

I am new to the field of Camera Calibration. We have successfully calibrated our camera through classic method (using checkerboard etc). I recently realized there is a field of research for Automatic ...
0answers
120 views

### Wiener filter with no WSS process

I'm trying to learn something more about Wiener Filters and I can't find anywhere what happens when I feed a Wiener Filter with a non WSS process. Could anyone give me an explanation or any book (...
2answers
2k views

### Binarization of image for varying background and foreground colors for OCR

I am trying to develop an automated OCR system for images obtained from the internet. The images mostly consist of computer generated text imposed on a background, so the OCR should produce near ...
0answers
150 views

### Image Segmentation based on coordinates from reference points

I have a set of colors in a card, as below (I can modify the card as required) I have 4 reference points at four corners. I have a bunch of colors at known coordinates (in mm) from these reference ...
1answer
147 views

### Obtaining the size of objects from an image

My objective is to be able to obtain the size, in pixels, of objects in images I'm receiving from a camera. I've tried two approaches thus far, both working to some extent, and I'm wondering if there'...
0answers
105 views

### Fast greyscale image segmentation on 16x16 image

I have a 8-bit greyscale 16x16 image where I want to extract coherent shapes with a more or less consistent pixel arrangement if possible (like: a rectangle, staircase, line). Currently, I'm doing ...
0answers
1k views

### Measuring sharpness/contrast for autofocus

For the implementation of an auto-focus for the raspberry cam I need some measure of image sharpness. I used the following sample picture: The first approach was to compute the shannon entropy of the ...
0answers
80 views

### Anti tremor motion detection

I'm programming in c# using opencv (emguCV). I use motion detection approach to detect some changes in a paper wall. For example it's may be colored by a laser pointer. My problem is that when I use ...
0answers
86 views

### Target detection for UAV landing

I would like to detect and track the following target to land an UAV. Target size is $1\rm m \times 1\rm m$. I have tried SIFT + FLANN but there is too few keypoints to have a good match. Have you ...
0answers
53 views

### Annotate a dataset of images

I'll be recording a new dataset using a couple of sensors: kinect, stereovision cameras.. for a project for people detection using only depth information. But I don't know yet how can I annotate the ...
0answers
94 views

### Is there a way to detect ambiguous edges?

I'm writing a program that can detect veins(the dark lines) on an arm. When looking at the image at full size, you can easily make out where they are. But when zoomed in around a vein I get ...
0answers
53 views

### How to use Mikolajczyk evaluation for detectors/descriptors?

I want to compare different detectors/descriptors (both binaries and not) for my application and I want to use the Mikolajczyk evaluation framework, which is became a standard in the community about ...
0answers
265 views

### Why pixels on image edges are shifted when using Wiener filter?

I implemented a Wiener filter using Matlab and i noticed that both functions(mine and matlabs) are creating an image with shifted pixels on the edges. Class teacher said it will happen. Is there a ...
0answers
35 views

### Analytical expression for salient Blob detection in scale space

I am working on exact mathematical expression which can be obtained in image processing tasks.(I do not know much about image processing but my work is more mathmatical) In Gaussian scale space, we ...
0answers
83 views

### processing photo diode array data

We have designed a system which has an 8X8 array of photo diodes, we sense 10ns pulses of laser falling on those photo diodes with a repetetion rate of maximum 50Khz i.e. 20us, we were successfully ...
0answers
79 views

### How to classify images based on the amount of colors in the image?

I have a problem where all images have the same object; however, these objects can either have number_of_colors<=3 OR number_of_colors>3 and images are not labeled. My attempt starts by ...
0answers
43 views

### How to specify 2-D coordinates of an object in matlab?

This is the scenario: I marked two axes (figure below) on a board and a camera(global vision system) sees the board. I want to make the vision system to recognize $X$ and $Y$ axes and specify ...
0answers
47 views

0answers
257 views

### How to match a thumbnail to an area in the original image?

Suppose that you have a thumbnail and the original image from which it was generated. You need to match the thumbnail to an area in the original image that represents the original selection from which ...
0answers
726 views

### How can I improvise matlab code from GLCM to CLCM(Color Level Co occurrence Matrix) for feature extraction in texture analysis?

Currently I am doing my project on SKIN DISEASE DIAGNOSIS USING TEXTURE ANALYSIS in IMAGE PROCESSING domain.In this project,the histopathological image of diseased skin image is given as input and the ...
0answers
136 views

### What does 'correlation' and 'de-correlation' mean in image-processing?

Here are some problems: Does it mean these is some relationship among neighboring pixels? And I've read about DCT has a property of de-correlation,I have a doubt whether it means DCT neighbor ...
0answers
13 views

### Acoustic characteristics of thoracic diaphragm

I am looking for any kind of information about the acoustic characteristics of the thoracic diaphragm. In particular, I'm looking for characteristics which will allow to differentiate it from other ...
0answers
904 views

### Why correlation coefficient template matching perfoms better than cross-correlation and square-differences method

I am using this template in OpenCv's match template function by converting all images to grayscale. Here are my result using sum of square differences,cross correlation and correlation coefficient....
0answers
86 views

### Application of BIC, MDL, AIC

I understand that mathematical motivation behind Bayesian Information Criterion (BIC), Minimum description length (MDL), Akaike information criterion (AIC) are different but I am assuming that there ...
0answers
194 views

### Where to get an image dataset for sports?

I am doing a project on classification of sports images,for which I have not found a proper dataset on the net. I am working on sports namely cricket, basketball, soccer, hockey, baseball and tennis. ...
0answers
90 views

### Segmenting simple objects without shadows

I am trying to segment very simple objects like boxes and bottles. I am using GrabCut and it works extremely well when there are no shadows or when the shadows are soft - but as soon as there is a ...
0answers
28 views

### How to get an objects dimensions from video

I want to be able to measure an object using the camera on my phone. How would I go about getting an objects width and height from a video? My first thought was some type of 3D tracking of the video. ...
0answers
67 views

### Comparing the spatial frequency between groups of images

I have 2 groups of images, and I want to compare these groups based on the spatial frequencies of the images. In the end, I'd like to be able to say "group A is/is not significantly different from ...
0answers
123 views

### Image Subtraction using Pre-bayer data (.pgm)

Not sure if this is the best stack exchange but I'll give it a shot. I am performing background subtraction to collect Electroluminescent emission (i.e image w/ emission - image w/o emission = ...
0answers
273 views

### phase shift between two images (matrices)

I'm trying to find the phase shift between two 100x100 matrices, s and p. To start with I'm using two sine waves (2D) slightly shifted. I manage to compute the correct amplitude spectrum (using the ...
0answers
67 views

### Understand about registration between spatial prior and original image

I am working in level set/active contour method using spatial prior information . The main papers that I am focusing:"Automatic segmentation of neonatal images using convex optimization and coupled ...
0answers
76 views

### Are there any other libraries for Image Processing using hadoop?

I have been looking for libraries for Image Processing using hadoop, but by now, only have been able to know about hipi, and to some extent hadoopy. Are there any other libraries for the same? Hipi ...