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Questions tagged [image-processing]

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1 answer
83 views

Performing semantic segmentation on images on word documents

At the moment, I'm making a comparative analysis between two different neural networks for a class. The problem they are both trying to solve is detecting tables on documents. Below is an example of ...
0 votes
1 answer
254 views

Tapered Quantization

In Gonzalez et al it is mentioned that Tapered Quantization is I am unable to figure this thing out. I have searched the whole internet, but nothing of the same appears. I need a help in ...
0 votes
2 answers
167 views

Interpreting results of Sobel Edge Detection

I am implementing A No-Reference Perceptual Blur Metric paper. Somewhere in the prep steps they mention the use of vertical Sobel filter for finding vertical edges. The algorithm is summarized in Fig....
1 vote
1 answer
120 views

Comparing variable image to static image

What are Levenshtein distance algorithms, but for images? I will have one static image (the target: what it should look like) and one variable image (actual: what the user has created) For example, ...
1 vote
0 answers
24 views

Algorithm to find most likely continuation of image over border from set of possible next images

Is there an algorithm that would fit in the following situation: I have a sub image A of a larger image, and a set of sub images B that could (but not necessarily) share border with A. Now the ...
21 votes
3 answers
25k views

What is the difference between the fundamental matrix and the essential matrix?

Could someone, in plain english, explain the distinction between the fundamental matrix and the essential matrix in multi-view computer vision? How are they different, and how can each be used in ...
1 vote
1 answer
114 views

How are epipolar lines useful in computer vision?

Why do use epipolar lines and what are it's benefits in computer vision ?I am unable to find the uses of epiploar lines and how they are helpful although i am aware of epiploar geometry concepts. I ...
0 votes
0 answers
9 views

Partial derivatives wrt input and weights in CNNs

I'm working on understanding the backpropagation process in convolutional neural networks (CNNs) and am having some trouble comprehending how to calculate the partial derivatives of the output of a ...
2 votes
1 answer
126 views

How to jump directly from level 0 to level 5 in a Gaussian pyramid without having the levels 1, 2, 3, and 4?

I am current studying the Laplacian Pyramid as a compact image code by Peter J Burt and Edawrd Hudson. I understood all the concepts but I am having trouble with the equivalent weighting function. I ...
2 votes
1 answer
316 views

How many pixels support each neuron in multi-layer CNN?

I'm studying for a computer vision module and I'm on the deep learning topic, in one past paper we have the following question: Given that a convolutional neural network has five convolution layers (...
-2 votes
1 answer
70 views

$N \times N$ Image Processing Time Complexity: Grayscale to Binary using Median Step Function

In an image processing system, an algorithm processes an $N \times N$ image with each pixel being a number between $0$ and $255$. It finds the median value $M$ in the $N \times N$ image and applies ...
-1 votes
1 answer
91 views

Accuracy of Digit Recognition with Template Matching

I have designed a C++ program to recognize the digits on an ID card based on OpenCV. First I preprocess the ID card image and then segment it based on contours. The segmentation results are as ...
0 votes
2 answers
39 views

How to unscramble an RGB image 1024x1024

I have a colored image 1024x1024 whose rows and columns were randomly shifted, how would I unscramble it without having any information about the original image?
0 votes
0 answers
38 views

Reading and answering a text question from a image?

I wanted to see what models would be best suited for providing a image (see the link below) and having the model perform a image to text (OCR of some kind) and laying out the contents of the image in ...
2 votes
1 answer
269 views

Contrast vs. Brightness question

As part of my homework I need to prove (or disprove) that changing the contrast and, then, changing the brightness is (or isn't) the same as changing the brightness and, then, changing the contrast. ...
0 votes
0 answers
11 views

What is a good appropriate algorithm for localization for images?

Assume that you have an image that you going to classify its class ID. One good option is to use interest points e.g FAST that can find coners/edges inside an image. From these points you could ...
1 vote
0 answers
69 views

Detecting thin lines in binary images

I want to find areas in a binary image that correspond to long and thin curves. In the example below, structures thinner than 3 pixels but longer than 20 pixels are highlighted. Observe that the ...
0 votes
1 answer
587 views

Inverting an image, as a matrix

I am curious about something pretty simple, though I have never heard, read and more sadly seen any example of it. Take any image, represent it as a matrix, invert the matrix (assuming the inverse ...
0 votes
1 answer
110 views

Determining all pixels of a specific color directly bordering on another color

I need a data structure/algorithm to efficiently retrieve borders and update changes. There may be many (unconnected) regions of the same color. The shape of regions changes frequently over time and ...
2 votes
3 answers
119 views

Slicing clusters of non-black pixels from an image into separate images

The backstory I have spectrograms of certain repeating sounds. The background of the spectrograms are black and could easily be made transparent if that would help. The sounds are easily distinct from ...
0 votes
3 answers
132 views

Given two sets of coordinates, find out neighboring ones

I have two sets of 2-dimensional coordinates on an integer grid, $A$ and $B$ $A = \{(x_{A1},y_{A1}), (x_{A2}, y_{A2}), (x_{A3}, y_{A3}), \dots\}$ $B = \{(x_{B1},y_{B1}), (x_{B2}, y_{B2}), (x_{B3}, y_{...
2 votes
2 answers
41 views

What is an algorithm to do this binary image segmantation task?

What I need to do is go from a binary image like this: to a segmented structure like this: because I have a program that operates on those separated line contours after. As you see, those contours ...
1 vote
1 answer
36 views

Does flipping the kernel in image processing only help maintain mathematical symmetry?

So I've been really confused about the act of flipping a kernel in image processing. Is there any intuitive way to think about it or does it only help computing efficiently and maintain the ...
1 vote
0 answers
62 views

Details about KNN based background segmentation

I build a python script which uses OpenCV implementation of KNN Backgroud Segmentation/Remover. I know the basics of how KNN works, but not how the background segmentation works. For the MOG algorithm ...
0 votes
1 answer
87 views

How can I find a Stable Diffusion program?

Well, I know that I'm going to ask too much. So, I really want to ask you a totally (powerful (!)) free completely off-line code to generate prompt-based images like midjourney. I want to run with my ...
0 votes
0 answers
19 views

Calculating the Correct Translation and Scaling Transformations for Segmentation Polygons

I have an image with a list of segmentation polygons. Getting the bounding box with the polygons is easy enough. I used the bounding box to crop out the objects of interest. Now, I want to scale the ...
0 votes
1 answer
154 views

Finding whether a point lies on the boundary of an geometrical object or not?

Suppose I have the mesh of an geometrical object (Interval in 1d, Region in 2d, Volume in 3d). How can I find out whether a point lies on its boundary or not? I am looking for algorithms with ...
0 votes
1 answer
43 views

2D fourier transform

I an new to image processing and I have some questions I want to understand: What is the meaning of the imaginary and real part of the 2d fourier transform? What can it tell me about the image it ...
0 votes
1 answer
258 views

Count the number of lines in binary image

Consider I have the following binary image (each pixel is either 0 or 255). How to count the number of lines (they could be straight or a little curvy). For example, in the picture, there are six ...
1 vote
2 answers
936 views

What is the best way to compare two images for similarity if the brightness of the second image was changed?

I calculate similarity percent between two images. Another image is the same with changed brightness. I've already tried comparing by pixel (euclidean distance for grayscale and 0/1 values), comparing ...
2 votes
0 answers
30 views

Algorithm to find best alignment of one curve onto another

So I've boiled a certain problem I have down to the point where I have two images of (approximately) the same scale. One which contains a closed curve, and one which is a partial curve. I want to ...
6 votes
2 answers
326 views

Why is Scale Space Needed to Detect Scale Invariant Features?

I have been doing research on the SIFT (scale invariant feature transform) algorithm, and while I have repeatedly read that in order to detect image features that do not vary with respect to scales of ...
0 votes
0 answers
26 views

What is the best way to predict a continuous score based on image characteristics(pixels)?

I have a dataset with 9912 images, what is the best way to train them based on the pixels and features of the images to be able to predict a continuous target ranging from 1 to 100? The goal is to ...
1 vote
0 answers
28 views

What is "energy" in computer vision

I keep seeing the term "energy" used in computer vision literature, specifically when speaking about Image Segmentation. For example on this page on Graph-Cut. I'm just wondering if someone ...
0 votes
0 answers
64 views

Fast Algorithm To Compute Gradient Of Gaussian Blur

what is the fastest algorithm to compute the gradient of the Gaussian blur of a (grayscale) image, with a blur radius of around 100 pixels, where smoothness of the result is important to me, i.e. no ...
0 votes
1 answer
14 views

preprocessing or real time for magnification of portions of video

Im new at CS and would like to gather preliminary information to approach an interactive art project. I want to construct a grid of videos - think about a matrix M = m x n where Mi,j is a video that ...
1 vote
0 answers
43 views

RGB synthesis in pixels in a computer

A pixel is contained of 3 ranges of RGB color synthesis to add colors into a tiny-square small box, as I learned (correct me if I am wrong). But, through these 3 colors admixture can we create any ...
1 vote
2 answers
405 views

Which algorithm is most suitable for comparing two images to find differences?

I have two images of two objects that are suppose to be exactly the same. I use one for reference and one as my model. I want to find an algorithm that will help me find on which areas these images ...
1 vote
0 answers
155 views

Computational complexity of median filter in image processing

I found this paper http://nomis80.org/ctmf.pdf, that describes an efficient algorithm for applying a median filter to an image. Though this works for non-HDR images, I am not sure how well it scales ...
0 votes
1 answer
420 views

How many unique Huffman codes can you make. Image I has size 256x256 and has pixels of values 50,100 and 200

Let I (M x N) be an image made only of 3 pixels, how many unique Huffman code can you make (example: Image I has size 256x256, and has pixels of values 50,100 and 200). If someone can help me how to ...
1 vote
1 answer
179 views

Predicting continuous variables using image and text input to neural network

I am looking to create a neural network architecture that takes two kinds of inputs: image and text, and outputs a predicted continuous variable. More specifically, I will have multiple images of a ...
0 votes
0 answers
24 views

point of view of each pixel with regard to the whole image

I am looking for a technique or an algorithm that outputs a unique number/vector for each pixel of the image. I want to give the pixel a perspective so the neighboring pixels have more visibility and ...
0 votes
1 answer
87 views

Which pretrained model will be best for my dataset?

I am trying to build a classification algorithm having 28 classes. These classes consists of Logo of companies like adidas , Nike etc. I have very low dataset below than 100 images and greater than 70 ...
1 vote
1 answer
50 views

What is a task type?

I have an unlabeled dataset: 500 X-rays of seeds in husk. In each image there are different number of seeds, for instance, from $10$ to $50$. A seed has some features. The main features are a seeds' ...
1 vote
2 answers
478 views

An algorithm to find the closest match between 2 arrays of RGB pixel tuples

So I'm looking for a bit of an abstract algorithm and I'd appreciate any references to read up on. This is a bit tough to explain but I'll try my best. Suppose we have 2 arrays of ...
0 votes
0 answers
43 views

Affine transformations for twisting and pinching

In image processing we can use affine transformations for translation, rotation, shear and scaling of pixels. But what kind of transformations are used for twisting and pinching of image pixels? Or ...
0 votes
0 answers
38 views

Inability to understand local fourier analysis in the given link

https://www.researchgate.net/publication/235662494_On_separating_overlapped_fingerprints [Paper name-"On separating overlapped fingerprint", author-Fanglin Chen,Jianjiang Feng,Jie Zhou] I ...
6 votes
1 answer
2k views

circle packing algorithm used by Percolator

I was admiring this rendition of the Mona Lisa from quasimondo's Flickr account. He says: Combining circle packing with data visualization. The pie charts show the distribution of the dominant ...
2 votes
0 answers
35 views

approximate line segments from array of unsorted points

The polygon above is actually a collection of a lot of black points closely packed together. I want to approximate these black points as straight line segments. The black points are not sorted in any ...
1 vote
1 answer
525 views

A pretrained model for mathematical equations characters detection

I am working on a project to convert equations to LaTeX code. After segmenting out the characters, I got stuck on the detection part and was looking for some pre-trained model that could detect ...

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