Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [image-processing]

The tag has no usage guidance.

1
vote
1answer
203 views

Efficient Algorithms for Destroyed Document Reconstruction

I am not certain this is the proper site for this question however I am mainly looking for resources on this topic (perhaps code). I was watching TV and one of the characters had a lawyer who ...
0
votes
0answers
13 views

How to do mathematical morphology manually? Erosion, dilation, open, close

How do you do mathematical morphology manually? If you have a kernel or structuring element B1 do you move the origin of B1 to every pixel in the matrix A1 and see if it is a perfect match, partial ...
3
votes
0answers
13 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 ...
0
votes
0answers
11 views

Similarity of images with tree shape drawn objects

I'm trying to find the best algorithm for my task. I have images looking like this one: I want to find the most similar ones from a set of such images. I tried several algorithms to compute the ...
1
vote
1answer
23 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?
4
votes
1answer
674 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
votes
1answer
27 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 ...
0
votes
0answers
17 views

Maximum response filter

I am new to the field of Image processing. I recently came across MR8 filter and it is available in this link but I could not find well written expressions for mathematical treatment of the filter. ...
2
votes
1answer
61 views

Image convolution - image darkens

I'm using kernel convolution in python to blur an image, but in addition to blurring it also turns the image darker. Could someone explain why it happens? ...
1
vote
1answer
44 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 ...
1
vote
0answers
31 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?
2
votes
2answers
32 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 ...
-2
votes
1answer
36 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 ...
0
votes
0answers
10 views

Conventional triangularization approach in computer vision?

m new in learning image processing in openCV concepts ;can somebody help me to understand "Conventional triangularization approach " in computer vision ?
0
votes
1answer
25 views

How do we fix area of detectors in object detection?

I have gone through various articles on medium and also some from other sites trying to understand SSD. I am able to figure out most of the things from articles except this one. They always say that ...
1
vote
0answers
32 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 ...
1
vote
0answers
41 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, ...
1
vote
1answer
86 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 ...
2
votes
3answers
44 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 ...
1
vote
1answer
34 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. ...
2
votes
0answers
21 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 ...
1
vote
1answer
49 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, ...
0
votes
1answer
69 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 ...
2
votes
1answer
43 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 ...
0
votes
1answer
39 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 ...
1
vote
1answer
62 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 ...
1
vote
0answers
19 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 ...
4
votes
1answer
832 views

What is the difference between luma and luminance?

I understand the following (correct me if I'm wrong): Statements Luma as the weighted sum of RGB gamma corrected components, but luminance is the weighted sum of RGB linear components. The gamma ...
1
vote
0answers
232 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 ...
0
votes
0answers
240 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 ...
4
votes
1answer
61 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. ...
0
votes
0answers
45 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 ...
1
vote
0answers
25 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. ...
2
votes
0answers
19 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 ...
1
vote
0answers
26 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 ...
2
votes
1answer
57 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 ...
1
vote
1answer
125 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). ...
0
votes
1answer
106 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
votes
1answer
126 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 ...
1
vote
2answers
128 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 ...
1
vote
1answer
307 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 ...
0
votes
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 ...
1
vote
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: ...
0
votes
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.
0
votes
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/...
1
vote
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 ...
0
votes
1answer
163 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 ...
0
votes
1answer
22 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 ...
0
votes
0answers
50 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 ...
1
vote
1answer
28 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 ...