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# Questions tagged [image-processing]

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1answer
69 views

### calculting distance between a person and the object in the image

Let's say a person took an image like this I have access to all image attributes (like for example image format, resolution and so on), and I know the location of the person - basically the place ...
0answers
20 views

### Multiphase levelset Chan Vese algorithm

I am implementing the multiphase level Chan Vese algorithm. I am using IPOL document as reference (http://www.ipol.im/pub/art/2012/g-cv/article.pdf) Everything is clear for me, except the stopping ...
0answers
344 views

### Backward mapping with bilinear sampler

I have some experiences with Convolutional Neural Networks before. I have a question regarding the Bilinear Sampler used in "Unsupervised Monocular Depth Estimation With Left-Right Consistency" (the ...
0answers
290 views

### How to recognize digits in water meter image

I need to read the digits of images like the one below: From what I understand, this will involve: Registering and segmenting the image into each individual digit Hand labeling a bunch of these ...
0answers
48 views

### 3-SAT reduction to image matching problem

I have a research paper, Elastic image matching is NP-complete by Daniel Keysers and Walter Unger, that illustrates the reduction from 3-SAT to an image matching problem in order to prove that this ...
2answers
7k views

### find the actual size of an object from pixel coordinates

I am quite new to vision and OpenCV, so forgive me if this is a stupid question but I have got really confused. My aim is to detect an object in an image and estimate its actual size. Assume for now ...
1answer
59 views

### Is it possible to transfer a point from one camera to another, given n corresponding points?

I have 2 images of a scene taken at one moment by two identical cameras (similar cameras intrinsic parameters) by to arbitrary locations and at two arbitrary orientations (different cameras poses). On ...
0answers
28 views

### Accept something with probability

I am reading the following paper https://pdfs.semanticscholar.org/5e86/db52119d2d691af0365cdba7bb27dc0dc303.pdf and trying to implement the tabu search algorithm they describe for image segmentation. ...
1answer
287 views

### How to identify object(s) in image when given a list of all images?

I see a lot of articles and topics about OpenCV and machine learning in regards to identifying general things (like cats, or alphanumeric characters) but I am wondering if something more specific is ...
0answers
20 views

### How to find the matched SIFT features that are spatially consistent?

I have extracted DenseSIFT from the query and database image and quantized by kmeans. The challenge is to find those SIFT features that quantized to the same visual ...
1answer
163 views

### Algorithm for weighted elliptic curve fit

Background: I was trying to detect a face solely on the bases of features and the confidence of the features found. I am using a method to identify the features along with the response (confidence). ...
0answers
31 views

### Open source implementation of Multiscale Combinatorial Grouping [closed]

I would like to use Multiscale Combinatorial Grouping for my PhD research. However, I am restricted to use open-source implementations and this one runs on Matlab. Does anyone know of an equivalent ...
1answer
167 views

### Face recognition on on tilted images

From what I learned, viola jones needs images with faces upfront. Tilting the head a few degrees to each side can botch the algorithm. Is it possible to take an image, take a several rotated copies of ...
1answer
199 views

### What is the significance of the imaginary parts in the output of an Inverse Fourier Transform? Can I avoid them?

Starting with an image, I have taken its fourier transform and then modified it, and finally taken the inverse fourier transform of the modified fourier transform to get my resulting image. In my ...
1answer
584 views

### Segmentation technique for handwritten text (cursive and unconstrained)

Although I am new to the computer vision domain, I am tasked with automating handwritten text recognition from bank cheques. I first did some preprocessing(blurring and binarization) and then dilated ...
2answers
346 views

### What is the best algorithm for image comparison in terms of speed?

Problem domain - I'm implementing a home monitoring system using smart phones. At regular intervals rear camera of the phone takes images and compare them for a change detection. This change detection ...
1answer
220 views

### Image registration algorithms for images with varying distances

I have two cameras side by side. I'd like to register two images taken from each camera. I think global transformation will not work for this issue since changes of distances between two images for ...
0answers
25 views

### Edge detection using Image Morphology

Is it possible to do an edge detection using ONLY opening and closing operations? Where: opening- $X\bullet B = (X \ominus B) \oplus B$ closing- $X\circ B = (X \oplus B) \ominus B$ (I know we ...
2answers
20 views

### Distinguishing between side-by-side liquid streams

I'm new to computer vision and am looking for advice. I'd like to perform computer vision on a spiral system, in this system a down flowing liquid separates into different regions based on density: ...
0answers
17 views

### what interpolation method can I use for reliefs

I need to know which interpolation method is the best for working with reliefs, that is, to know the elevations or depths of a given terrain a set of points.
0answers
2k views

### opencv measure objects by pixels

I am trying to calculate the length and width of objects using a camera. The camera (90° angle from the top) and the background is fixed. See this Link https://www.pyimagesearch.com/2016/03/28/...
0answers
1k views

### Measure objects length and width by picture (pixels)

I am quite new to image processing. I have experimented with opencv and tried to measure the lenght and width of an object from a picture using a reference object where I know the dimensions. See ...
3answers
185 views

### How center the eyes of human face at specific pixels?

I am facing a problem with processing some frontal facial images. I need to adjust the centers of the eyes (irises) to be at certain specific pixels in the image. In other words, i need to transform ...
2answers
133 views

### Digital Image Processing [closed]

I'm a Computer Science Graduate but I didn't study digital image processing during my college years. Now I'm thinking of learning it, but I'm little bit confused about where to start. Is there any ...
1answer
213 views

### Google DeepDream Elaborated

I've seen a few questions on this site about Deep Dream, however none of them seem to actually speak as to what DeepDream is doing, specifically. As far as I've gathered, they seem to have changed the ...
1answer
23 views

### How to prevent the optimization algorithm from just shrinking the image?

I'm trying to optimize a set of patterns in an image, but unfortunately they only way I have of evaluating the images results in smaller versions of the pattern scoring much better than larger ...
0answers
52 views

### Recognizing features in images (uncontrolled environment)

I have been working for some time in several kinds of image recognition. They work well. One example is , character or shape recognition. I have implemented this in an embedded processor and I can ...
5answers
600 views

### Google's Deep Dreamer

I was just wondering on a more technical side, if anyone could explain what Google does to create these amazing images from it's deep dream system. Could anyone explain to me in a step by step way, ...
1answer
42 views

### What is the Code2 and other concepts of variable encoding in Coding Redundancy?

Am learning the concept of Coding Redundancy in image compression and am finding it hard to understand the table on page 3 of this document. All other explanations seem to follow the same symbols and ...
0answers
24 views

### Want to do 3D reconstruction via simple matching

I have 2 images, called left and right images. I have some matched points $[c_l,r_l]$ and $[c_r,r_r]$ in both of them (these points are in pixel coordinates). For a 3D point in the real world, they ...
4answers
906 views

### Which algorithm for counting the occurrences of a certain pattern (spots) in an image?

The Problem : Finding the number of occurrences of a certain pattern (or shape) in an image. In my example, the problem is about finding the number of spots (in variety of sizes) in an image. See ...
1answer
208 views

### Summed-area table for circular range queries

A summed-area table is a data structure and algorithm for quickly and efficiently generating the sum of values in a rectangular subset of a grid [Wikipedia]. Is there any algorithm for quickly and ...
1answer
269 views

### Bilinear Interpolation

I am trying to implement bilinear interpolation as described in the paper Spatial Tranformer Networks by Jaderberg et. al (see link to paper). They describe bilinear interpolation in Equation 5 as: ...
0answers
27 views

### Ghost outlines in image segmentation

If you observe the results of many image segmentation algorithms, you can notice the occurrence of region borders where a human observer wouldn't draw one, for instance across slow gradient/textured ...
0answers
46 views

### Finding a line shape objects (bars) in video images using neural networks (instead of Hough transform)

I'm currently trying to learn about computer vision stuff and I want to try it on a simple project of real time tracking of figures of players in a foosball game while the camera can be moving a ...
1answer
33 views

### Feature selections : Still a high dimentionality

One of the advantage of using a features reduction/sub feature selection is to avoid a high dimentionality. The most known method is the Forward selection, where it finds the best combinations of ...
2answers
89 views

### Obtaining Image Measurements of a Known Object [closed]

Given the image of an adhesive tape as below, what would be possible method to find the tape radius? The image sepia toned with artificial background added. The tape itself is partially hidden.
1answer
581 views

### Given a low resolution video, is it possible to create a higher resolution image

This question is purely theoretical as I've not been able to find anyone who's done such a thing, so my question is - is it possible, and if not why? Say you have a short video (CCTV) of a face, or ...
1answer
70 views

### How to predict the next image in a sequence, or predict the deblurring of an image?

I have 3 versions of an image at lower resolutions - 480p, 720p, and 1080p. Is it possible to use those 3 images to predict the next highest resolution image (the 4k image)? My first guess was that ...
0answers
26 views

### Should I normalize values not bigger than 1

I have a question regarding a normalization of values especially in the case of image processing features classification. What if have a series of values that will never be bigger than 1. A = 0.004 0....
0answers
36 views

### What kind of numerical image features should I use to distinguish between the attached types of poses?

I've around $500$ binary (black and white) images, of which I attach $2$ samples. I'm working on a machine learning problem of classifying images like them. I'd like to know what image features I can ...
0answers
1k views

### Comparing pixel density and number of pixel values

I am curious about an image processing algorithm used in this code pulled from this github repo. I have posted an explanation of the code below. ...
1answer
55 views

### Can a computer differentiate a normal image and a sensitive(dirty) image? [closed]

In the image files, is it possible that a computer stores information such that it can identify which is what kind of image based on how it stores the file? Or when an image/video/file is sent or ...
2answers
56 views

### Convolutional Neural Network with constant kernels

I'm starting to learn about CNNs, and I have this question that I haven't been able to answer. Sorry if it is too basic. I know that in a CNN, the network learns to extract relevant features of ...
0answers
417 views

### Derivatives involved in Bilinear interpolation

If we choose a unit square in which the four points where the function $f$ is known are as shown in the diagram the interpolation formula for $f$ is: \begin{split} f(x+u, y+v)\approx (...
0answers
62 views

### Stroke Extraction to recreate Chinese characters

I was going through the project lists of Andrew NG from his Stanford machine learning course and I found a project based on recreation of calligraphic characters. To do so firstly we need to extract ...
1answer
92 views

### warm/neutral/cool tone of one image

I wanna determine whether an image belongs to warm/neutral/cool tone. I find Kelvin color temperature to calculate the average temperature of an image over all piexls. But the result seems not good. ...
0answers
99 views

### More Efficient Feature Method Than Haar-Feature For Face Detection

The seminal work by Viola-Jones had the most impact in face detection. It used Haar-Feature, which is fast to compute with the help of integral image method. Is there a feature method that is more ...
1answer
6k views

### 2D convolution: Flipping the kernel?

Why do we need to flip the kernel in 2D convolution in the first place? What's the benefit of this? So, why can't we leave it unflipped? http://www.songho.ca/dsp/convolution/convolution2d_example.html ...
0answers
52 views

### How the SIFT results vary by changing some parameters

I'm studying the SIFT algorithm and I have some problem understanding its operation, in particular I don't understand how the results vary according to the parameters: number of octaves, number of ...