Questions tagged [image-processing]

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3
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0answers
18 views

impact of the single pixel in disparity

Disparity essentially means the distance of a corresponding pixel in another image ( in pixels). This is clear and understood. When I looked after how the depth is related to disparity, then I found ...
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1answer
30 views

Image segmentation generates inclusions and is not smooth

I am performing segmentation using opencv, but the segmented image has regions with breaks and also the border isn't smooth. How can I handle this problems?
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1answer
730 views

How does a predictive coding aid in lossless compression?

I'm working on this lab where we need to apply a lossless predictive coding to an image before compressing it (with Huffman, or some other lossless compression algorithm). From the example seen ...
2
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1answer
29 views

Given two data feeds, find out if they capture the same information

Say, there are two camera feeds, how can I establish if they were filming the same scene? It seems plausible that there are algorithms that somehow calculate mutual information and detect "causality ...
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1answer
46 views

what is meant by support of a filter?

what is meant by support of a filter in context of image processing? In the attached link of a short tutorial for detecting bar in an image by gabor filter,it is said that γ=1 helps in finding the ...
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0answers
51 views

Why is sparsity useful in dictionary learning?

What is the particular reason for which we use sparse matrix X in dictionary learning equation Y=DX where Y is the signal matrix, D is dictionary and X is the coefficient matrix?
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2answers
46 views

identify abrupt frame changes in a video

The frames of live streams or videos, in general, do not flow smoothly. A sports game would have multiple cameras recording the game and hence, there will be camera switches in the stream. I am ...
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1answer
97 views

what the mean and median filters with an n x n kernel (neighborhood) do to the grey-levels of the image? [closed]

sorry i haven't found a good title for these three questions i'm wondering if someone could give me explaination with proof (if possible ) of these three questions : Given a grey-level image stored ...
3
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2answers
914 views

Extracting features for texture classification

I'm a beginner in the field of pattern recognition and computer vision. I'm working on a project right now to classify t-shirt patterns into three categories i.e. solids, stripes and checks. I have ...
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1answer
38 views

Matching/finding mathematical plot images

I'm trying to come up with a method to match a given mathematical plot against a database of other plots. To make it more specific: plots are generated in R as PNG and might have different dimensions. ...
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0answers
110 views

Transform Image Point to Azimuth and Elevation

I'm working on an object tracker where I need to report the azimuth and elevation of targets. Both values should be scaled from degrees to unsigned 32-bit integers. For now I can ignore lens ...
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0answers
53 views

How to find corresponding points between two photos when there's a repeated pattern?

Suppose that I have two photos, I1 and I2 and I want to find a set of corresponding points between the two photos to define a homography between them. There are many algorithms for this purpose, ...
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1answer
73 views

Data structures that store efficiently detected features of an image

I struggle to find this, suppose I apply any feature detection algorithm. From my references it seems to me it's not usually explained what kind of data structures would be suitable for storing such ...
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1answer
114 views

(OCR ) How to Recognise Handwritten fractional numbers using Neural networks

I want to be able to recognise handwritten math numbers using images of the numbers , i was able to do create a ANN model for recognising simple decimal numbers , but i have no idea on how to ...
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3answers
68 views

How to prove that the erosion of a convex set by a convex set will result in a convex set?

How to prove that given convex sets A and B, the erosion of A by B will result in C - a convex set, too? I was given this question as a test-preparation, and I think it shuold be a proof, but I don't ...
2
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1answer
2k views

What is the appropriate means of bias field in image processing?

I want to do image segmentation. In (Li, C. et al, 2011) article about A Level Set Method for Image Segmentation I saw that the authors use bias field estimation. I searched a lot but I couldn't ...
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1answer
972 views

Using landmark points on the face for face recognition

I am currently working in area of computer vision for my master's thesis and am trying to use distances between landmark points on the face for recognition. My question is this: What landmark points ...
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0answers
22 views

Evolving zero level set in images

I'm trying to implement a simple image segmentation application that accepts an initial contour and evolves it to compute a refined contour in successive iterations. I'm taking some inspiration from ...
3
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1answer
111 views

Interpreting camera matrix

I'm having some trouble interpreting the camera matrix $K = \begin{bmatrix} f_x & s & x_0 \\ 0 & f_y & y_0 \\ 0 & 0 & 1 \end{bmatrix}$ after it multiplies some 3D vector. ...
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1answer
117 views

Sample K representative frames within a video

I have an image-based processing module that takes photos for some computer vision processing. I have many videos, but I need to sample representative frames as its inputs, preferably those frames ...
2
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1answer
46 views

The task of recognizing game units in the screenshot

I'm new to computer vision and I want to solve the task of recognizing the game units of the game Clash Royale in the screenshot. Briefly, there are about 70 different types of gaming units belonging ...
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1answer
76 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 ...
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0answers
21 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 ...
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0answers
505 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 ...
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0answers
369 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 ...
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0answers
52 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 ...
5
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2answers
8k 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 ...
2
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1answer
66 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 ...
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0answers
29 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. ...
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1answer
407 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 ...
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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 ...
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1answer
246 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). ...
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0answers
36 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 ...
0
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1answer
253 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 ...
2
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1answer
455 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 ...
2
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1answer
972 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 ...
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2answers
838 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 ...
3
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1answer
275 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 ...
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0answers
26 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 ...
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2answers
21 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: ...
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0answers
18 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.
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0answers
3k 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/...
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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 ...
3
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3answers
189 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 ...
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2answers
139 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 ...
12
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1answer
258 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 ...
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1answer
24 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 ...
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0answers
57 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 ...
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5answers
609 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, ...
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1answer
73 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 ...