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.

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64 views

Mesuring the distance between a base line and an object

I am working on an image having musical symbols, like Before i reach this step i have removed the staff lines to recognize them in efficiency. but now i want to detect on which stave line they exist. ...
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337 views

Find best fitting rectangles after applying edge detection

I am trying to implement a box detection algorithm. In my pipeline, I start with image warping to simulate a frontal view of the shelf containing the boxes (assuming boxes are straight in that ...
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1answer
259 views

How can I properly detect a ball moving in a film capture?

I have problem in detecting a ball moving in a flume (image below). since converting the frames into grayscale format didn't work I converted it into rgb and make it more saturated. problems are: 1- ...
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211 views

algorithm for segmenting cheese microstructure

I'm trying to get the internal geometry of cheese from images of its microstructure: I tried the canny edge detector and otsu thresholding but neither of these worked very well. I'm guessing that I ...
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2answers
164 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'...
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280 views

Save ROI and background in two images

I'm using MATLAB Training Image Labeler app for labeling images and exporting the regions of interest (ROIs) which I save in .jpeg files.The ROIs are exported as a structure $1\times 430$ with two ...
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1answer
1k views

How does image masking work?

I am new to image processing and I am interested how image masking can be used to extract a portion of a image. Have a look at this OpenCV tutorial. In the section Application of Mask, they say that ...
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164 views

How to properly detect segments in a LCD segment display

I have been given the task to develop a code which checks if the display of a device is showing information correctly (i.e. any segments are activating when they are not supposed to). To meet this ...
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473 views

Web Online tools for feature detection methods in image processing

I'm doing a research about image processing, I would like to access common feature detection methods online, ex: Blob detection: Laplacian of Gaussian (LoG), Difference of Gaussians (DoG), ...
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1k views

Edge linking using local processing - why is this criterion imposed

I'm reading Digital Image Processing by R. Woods and R. Gonzalez. In it, a section on edge linking using local processing in an image details a simplified algorithm, that imposes a criterion on the ...
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92 views

Classify areas of an image based on color

I have some tree canopy images that I would like to process, but not sure how to get started as image processing is a little outside my area of expertise. Any help would be appreciated. I have tree ...
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154 views

What is the image power law?

What exactly is the image power law mentioned at page 15 in here: Is it related to Gamma correction or the statistical power law Or anything to do with PSF of a camera?
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what is in intuitive explanation of local derivative pattern (LDP)?

Zhang et al. proposed the LDPs for face recognition . They considered the LBP as the nondirectional first-order local pattern operator and extended it to higher orders ( th-order) called the LDP. is ...
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1answer
294 views

Haralick features, am I approaching this correctly?

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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3k 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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450 views

Efficient Hessian-Laplace blob detector implementation

As it is mentioned in a paper for SURF, it is possible to approximate hessian determinant using integral images. If I want to implement Hessian-Laplace detector, is it feasible to also approximate ...
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423 views

How to implement HOG with trilinear interpolation by Matlab?

I am studying HOG. I have find the code code1 and code2 about HOG. However, both of them don't implement trilinear interpolation. I have also read some websites, including web1 and web2. I still don't ...
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76 views

Normalized cut segmentation output correct or not?

I have implemented "normalized cut" segmentation. The change here is that, instead of giving an image as input, I have given an matrix of image. As my output looks odd to me. I need to know whether my ...
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2k views

MPEG-7 descriptors' implementation in OpenCV

I'm looking for implementation of MPEG-7 descriptors which are compatible with OpenCV's recent versions and containing "region-based shape descriptor ART(Angular Radial Transformation)". I ...
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642 views

No proper kmeans clustering of images in matlab

I am having 1200 face images in my training set.There are 2989 test face images. I am using eigen faces (PCA) for feature extraction. I am using kmeans clustering. I even tried all 2989 test face ...
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519 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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108 views

How to quickly calculate all the line segments when their coordinate in the Hough transform is given

Hough transform is a very powerful tool to find dominant straight lines in a black-and-white image. A very common practice of analyzing Hough transform result is to find some local maximum points in ...
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223 views

Realtime image-stitching using a CMOS camera array

I am very new to DSP so please excuse any brevity... I have to design a 4x4 CMOS camera array and stitch the images together for further processing... I have tried doing that with opencv but the ...
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179 views

Region growing Vs Clustering

In image processing, how do region growing and clustering differ from each other? There are many papers like clustering based on region growing. I couldn't able to draw a fine line between these two ...
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339 views

Artifacts in image after super resolution using delaunay triangulation in MATLAB

i have to do super resolution of two low resolution images to obtain a high resolution image. 1st image is taken as base image and the second image is registered with respect to it . i used SURF ...
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259 views

Landmark Extraction via Kinect

I am working on a SLAM algorithm as part of my research and I am having issues reliably extracting landmarks from sensor (Kinect) data. (I've never dealt with machine vision before.) I am looking ...
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1answer
269 views

Image watermarking in wavelet domain (data hiding in images)

I am working and researching on Image watermarking/steganography and I'm stuck at a point and want to know which technique is better in image processing for data hiding. Bit Plane Complexity ...
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3k views

Phase of an image in the frequency domain

The following picture is amplitude and phase of an image filtered using Gabor filter in the frequency domain. I'm trying to reproduce the results, I'm getting valid results for the amplitude I think, ...
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40 views

Finding areas covered by features

I have an image as attached The blue to yellow to red points are the points of interest the algorithm found, while the pink points are the radius per point. This maps pretty fine, but the issue I am ...
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177 views

Affine detector + SIFT descriptor

I am approaching to the Oxford Buildings dataset which contains already computed SIFT descriptors from affine detected keypoint locations. Usually SIFT detector provides to its detected keypoints ...
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1answer
1k views

Finding circle in binary image (R, not matlab)

How would I go about extracting the circular area of a binary image which looks like: The two rods emerging from the side of the circle are noise. I know of the hough transform in Matlab. However, I ...
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114 views

Could someone please explain to me about Directional Filter Bank?

I'm learning about Directional Filter Banks for my Thesis about Image Enhancement. I read it from some papers (Bamberger(1992) and Park(2004)) but I still cannot understand it clearly in detail. Could ...
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251 views

Evaluation of Keypoint Detector and Feature Descriptor Combos for Vehicle Detection

I am currently doing a research project into the effectiveness of different keypoint detector and feature descriptor combinations for the task of vehicle detection. At the moment I am using a SVM for ...
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45 views

Compare luminosity beetween groups of images

We have a set of images which are immunofluorescence stainings of mice brain slices. These image show the expression level of a marked protein. We have two groups of mice, which underwent behavioral ...
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763 views

Why do object-boundaries look better on a badly rectified image?(openCV stereo correspondence)

I got 2 pictures which is almost parallel, and not positioned very far from each other. I'm using OpenCV to try to create a disparity map (Stereo correspondence). Because I'm trying to use it in a ...
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107 views

Phong Reflection Model Parameters

Question: Can anyone refer me the Phong reflection model parameters for a face image taken for web-cam? Details: I am doing 3D reconstruction of 2D images using 3D Morphable Model as in this paper ...
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206 views

There are other shape properties scale-rotation invariant except HuMoment?

There are other shape properties scale-rotation invariant except HuMoment? There are example that show me how can i implement them? I find this example in c++ https://stackoverflow.com/questions/...
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80 views

Fourier transform of images and phase filters

What are the known possibilities to date for filtering the phases of an image and what are they used for? Phases are used in some edge detection algorithms. They are also used for cross correlation of ...
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1k views

How to recognize a zebra crossing from top view using OpenCV?

How to recognize a zebra crossing from top view using OpenCV? It is not a straight zebra crossing - it has some twists and turns. I have some ideas: parallel line detection, but the available ...
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0answers
451 views

STASM or AAM which is more efficient

I am working in face detection and recognition project. I am using STASM for face detction and locating face landmarks. On googling I found AAM (Active Appearance Model) and found that it is also used ...
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1k views

OpenCV detecting elbow

I have to detect my elbow. I'm able to produce an image in which I'm facing the camera, standing before it and my arms are in my body plane(body plane is plane containing my head,chest,and legs)(i.e. ...
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1answer
594 views

KLT tracker implementation

I'm working on a object tracker based on KLT algorithm using matlab. Can anybody guide me how I can find the features and calculate the distance in the sequence of the frames? Thanks.
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12 views

How to distinguish the same object entering the camera field of view

We want to set photo cameras in the field and capture images of insects that visit flowers. We want to place these cameras above the flowers and then they should get triggered whenever an insect lands ...
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30 views

Compressed Sensing in DOA processing

I'm trying to apply the compressed sensing theory (CoSaMP algorithm) to the DOA estimation in FMCW ULA (made of 48 elements). In the dechirped signals processing I use a first FFT to solve the range ...
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17 views

Feature extraction for IRIS recognition

What are types for feature extraction in iris recognition? How can I divide it on types which detect phase, edge, etc.?
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17 views

LPF and HPF filters in ENVI

Since we know about convolution filter in image processing, it is basically a matrix applied to an image and a mathematical operation comprised of integers and it works by determining the value of a ...
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1answer
47 views

Meaning of lines on x- and y-axis of a centered FFT-spectrum of an image

I am currently learning about the Fourier transform of digital images, but I am wondering about one aspect. In most visualisations of fourier transforms of images, a horizontal and a vertical line in ...
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1answer
15 views

Extracting color information from lit regions to adjust shadow regions, HSV space

If I wanted to match the color of a shadow region to the color it is supposed to be in the lit region, would this, purely color information, be preserved in the hue of the HSV space of the image?
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29 views

Can you do temporal frequency filtering for a spatially moving signal in image sequence?

Context : A static camera captures video footage of a still indoor environment at given framerate (1080p@30fps or 720p@60fps) A low power line laser projects a line shaped beam in the camera field of ...
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Thresholding algorithm for separating skin from clothes in python

I have an several images that look like the following: I would like to separate the skin from the trousers here without specifically training a segmentation model. Can anyone suggest any such ...

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