# Tagged Questions

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2k views

### Computational Complexity of Correlation in Time vs Multiplication in Frequency space

I am working with 2d correlation for image processing techniques (pattern recognition etc...). I was wondering if there is a theoretical approach on how to tell when to use multiplication in frequency ...
328 views

### How are dynamic images programmed?

I have two friends that want to create a jewelry store, focused on customized jewels. The core feature is the jewelry designer, based on a jewel model. Here's an example of the sort of thing I am ...
448 views

### Kth selection routine - Floyd Algorithm 489

I have recently come across a promising Kth selection routine that reportedly outperforms quickselect the Floyd, Rivest Select routine. This Wikipedia article provides a pseudocode version which I ...
151 views

### Counting Barrels / Hough Transform [closed]

i'm trying to find a way to count barrels on an image. For this I'm using Hough Transformation. I tried my code first recognising eyes and it works excellent. But now the problems is when i try to ...
328 views

### Best practice for Restful API that perform heavy calculations (Image Processing)

We are currently developing an image processing restful api. Server performs some CPU-heavy computations image processing upon request and return the image to the client. We want to make this a ...
139 views

### Can I use machine learning for screening experimental data?

I am a experimental physicist. In our research, we have our experimental data in a 400*400*400 matrix(x, y, z axis of a 3d space), each entry is associated with a value("brightness"). We expect the ...
286 views

### How to maintain standard quality of images uploaded by many users?

We're developing a site where individuals (store owners) will be able to take pictures and upload to the site. Our biggest concern is the variance in quality of pictures across the site. The options ...
74 views

### Determine how two images should be combined to produce the original image

Suppose I have two similar images as follows Image 1 (base) Image 2 (target) The second image is basically a variation of the first image, except with a green oval slapped on top (indeed, I ...
111 views

### Difference in orientation of Sobel mask gives different edge detector result

I am implementing a Canny Edge detector for a class which I have based off the code found here. For the first derivative mask that I will convolve with the image, I am using the Sobel mask, although ...
815 views

### Comparing absolute values when determining zero crossing in 2D image

I am trying to implement an algorithm for finding the zero crossing (check that the signs of all the entries around the entry of interest are not the same) in a two dimensional matrix, as part of ...
1k views

### Getting started with object detection - Image segmentation algorithm

Just getting started on a hobby object-detection project. My aim is to understand the underlying algorithms and to this end the overall accuracy of the results is (currently) more important than ...
678 views

### Stereo images rectification and disparity: which algorithms?

I'm trying to figure out what are currently the two most efficent algorithms that permit, starting from a L/R pair of stereo images created using a traditional camera (so affected by some epipolar ...
134 views

### Algorithm for deciding change in gesture

I am developing an application where I am taking dynamic gestures as input and then mapping them to keyboard controls. By dynamic gesture, I mean for example hand moving from left to right or hand ...
127 views

### What algorithms would suit image colour summarization?

I would like to analyse a set of hundreds of thousands of product images (clothing, electronic goods etc) and retrieve the dominant colours in each. I'm only interested in the top 3 or 4 colours. The ...
42 views

### Rotation logic for MNIST Handwritten Digit Dataset

I am currently applying some pre-processing to this dataset. Some of the digits are extremely rotated and I would like to know how others managed to get them 'upright'. I have implemented something ...
111 views

### How to “de-dupe” similar lines (detected using the Hough Transform as rho/theta pairs)

I'm trying to identify an object (a cube) in a set of photos. Using Canny/Sobel/Hough I've managed to get the photo down to a set of lines that are pretty accurate; however if I plot these lines on my ...
51 views

### Project a piece of image cut by N-vertex shape to a different N-vertex shape

I have an N-vertex shape that I cut out from an image, and I want to project it onto another shape with the same amount of vertices, but different. So, the image will get changed inside the projection....
180 views

### Colour curves tool for “value” channel

I'm trying to write a program to read GIMP curves files and apply them to an image. I have successfully implemented the curves for the red, green and blue channels, but I can't get it working for the ...
433 views

### Effective and simple matching for 2 unequal small-scale point sets

I need to match two sets of 3D points, however the number of points in each set can be different. It seems that most algorithms are designed to align images and trimmed to work with hundreds of ...
417 views

### Most efficient way of saving images and sending them to client browser

I'm building an app where users list items for sale and they can include up to five photos for each item. I'm using Azure Blob storage for storing the images. In my app, I'll be displaying these ...
172 views

### How to implement k-means algorithm on RGB Images?

I want to apply the k-means algorithm on an RGB image data-set. I don't know how to proceed. You can mention basic step by step flow to proceed. I do know basics of Image Processing & OpenCV.
185 views

### Store generated image in database or generate it on server/client

I have been thinking what could be the fastest way to show base64/img data to the user, i could generate the data when the user is registered and then store it to database, or generate it every time ...
249 views

### Which Computer Vision / Image Processing technique would solve light imbalance in images?

Given a colour image whose light intensity is dim at the edges and bright in the middle, such as [dim bright dim], which computer vision technique would be recommended to correct this imbalance? ...
763 views

### Algorithm for searching images within images [closed]

I can't google this question, because I can't come up with a good query, so let me describe what I want and maybe someone will be able to suggest a way forward for me. I need to solve the following ...
30 views

### File structure for storing pixels that changed from one image to another

Have two images with the same dimensions. I want to create a file that contains information on what pixels are different between the two images. The file should also tell me the value of the new ...
221 views

### Simple (hand-drawn) shape recognition

As the input, program would get a set of point (x,y), along with the time a certain point was drawn. (suppose on a tablet). Let's restrict ourselves to simple polygons. I implemented Hough transform,...
141 views

### Measure and locate areas of similar value in an image

I saw this picture online and wanted to see if I could create an algorithm to give ordinary images an effect like this: http://justinlivi.net/wp-content/uploads/2011/01/Living_In_Digital.jpg My idea ...
225 views

### image processing algorithm to find solid square vs square outline in video frames

I am working on a system to detect an "embedded" 12 bit number within a series of frames that are recorded inside an mp4 file. The point of it is to automatically identify the "take", and also trim ...
283 views

### Image segmentation - show or hide clusters

I'm trying to make a small program in c#, that will downsample image to specified amount of colors (using K-means). Then, user will be able to hide\show colored areas(clusters) in image. I've ...
77 views

### Counting lines of text and get color of a specific line in an image

check this picture out before I explain further: How can I count the amount of lines there are from the yellow line to line #5? OCR sounds like overkill, because I don't really care what the text ...
63 views

### Picking an image from a set of images that is most likely to be compelling to a typical viewer [closed]

Given a set of images on a webpage, what's a good way to pick a compelling image that is also representative of the webpage? The use case is displaying an image along with a description of a URL to a ...
58 views

### How to change an specific part of an image colour? [closed]

I'm not so sure whether this questions fits here, but I need help in this case, cause I'm searching for days to apply this. I have a website of rugs and carpets, in this website I would like ...
26 views

### perfect isolation or train with polluted data for better OCR results

This is an (in my opinion) interesting thing I'm struggling with. I am building this app which should be capable to read utility meters. As with any OCR application this means I have to isolate the ...
61 views

### Speed of image comparison using GraphicsMagick in Node.js

Trying to determine whether a single image matches one of 100 other images. I have it working, but it returns the resutl too slow to operate in our production application. Current Implementation ...
76 views

### Web App - Better to load Large, low quality image or many html elements?

I'm creating a web application that is visually enormous. I'm talking 2 million pixels wide and 2 million pixels tall (about). My goal is to show dynamically changing spots all over the site. For ...