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Questions tagged [image-processing]

The tag has no usage guidance.

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1answer
30 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 ...
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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 ...
3
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0answers
68 views

What are some research papers or techniques that deals with fitting clothes on a human?

Given an image of a dress (from different angles), what could be ways to fit it on a human image (again multiple angles corresponding to dress)? Any link to research papers or tutorial regarding this?
5
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1answer
171 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 ...
5
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1answer
241 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: $$...
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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 ...
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0answers
45 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 ...
0
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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 ...
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2answers
85 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.
3
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1answer
459 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 ...
1
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1answer
55 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 ...
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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....
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0answers
32 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 ...
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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. ...
1
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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 ...
0
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2answers
53 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 ...
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0answers
350 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{equation} \begin{split} f(x+u, y+v)\approx (...
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0answers
59 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 ...
2
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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. ...
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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 ...
2
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0answers
45 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 ...
0
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0answers
36 views

What is the best way to find similarity between two bodies?

Suppose we have two human bodies. We need to find some number that represents a similarity score between the two bodies. However in order to achieve that we need to find the similarity between the ...
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0answers
347 views

Why are SIFT features significantly different after simply re-sizing image?

I'm new to SIFT and was surprised by how much the features changed after resizing an image. Here's the images I used for testing: Original: Resized: Cropped: After running SIFT on those 3 images, ...
2
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1answer
338 views

Algorithms to correct misspelled word?

At present, I am doing a project on Optical Character Recognition (OCR). I am looking forward to improve the results by checking the output words of my OCR code with existing words from a text file. ...
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0answers
50 views

How to detect if objects are on top of each other?

Lets say we know the co-ordinates of each object in a camera co-ordinate systems. How do we find out if some object is on top of each other? My idea is: Compare each object and point with one another....
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0answers
64 views

Up to what extent the hypothesis of piece wise constant intensity values is valid in ocean images?

Usually, in MR images one hypothesis research communities are making is, " the spatial intensity distribution is piecewise constant and that each tissue corresponds to a unique grayscale level. Based ...
2
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1answer
67 views

Color Filler Algorithm

Is there an algorithm that fills the area outside the edges? e.g.: From this to this
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0answers
36 views

Gradient Direction Equation: Color Value

I've been trying to implement this paper from Boris Epshtein, Eyal Ofek, and Yonatan Wexler, the pioneers of Stroke Width Transform . On computing the gradient direction, given the equation: theta = ...
1
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1answer
284 views

Stroke Width Transform: Gradient Direction Computation

I've been trying to implement this paper from Boris Epshtein, Eyal Ofek, and Yonatan Wexler, the pioneers of Stroke Width Transform . Having a simple image with random texts, that underwent gray ...
3
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1answer
247 views

Stroke Width Transform: Gradient Direction and Rays

I've been trying to implement this paper from Boris Epshtein, Eyal Ofek, and Yonatan Wexler, the pioneers of Stroke Width Transform . Having a simple image with random texts, that underwent gray ...
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1answer
777 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 ...
3
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1answer
36 views

Any ideas on implementation of a certain image process?

I recently found this music video. While the music is mislabeled, the video part caught my eye. It seems to be transitioning between two images based on shape? I think its a fade-in/fade-out with the ...
1
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1answer
215 views

How does an image classifier select relevant features?

I am trying to understand cascade classifiers for computer vision. I use OpenCV Traincascade for now and successfully trained some cascades. However I am trying to grasp the whole process. One thing ...
1
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1answer
162 views

Basic queries for Object Detection using deep learning

I have recently started working on the Object detection using deep learning. I have understood the basic steps of object detection are: Input Image -> Object proposals -> Feature Extraction -> ...
1
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1answer
183 views

Coordinates of the center and the radius of the circle on the image

What is the simplest possible way to calculate the coordinates of the center and the radius of the circle on the image (for example BMP and I'm interested in image of the Sun included below)?
3
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1answer
46 views

Simple Recognition Algorithm, How Does It Work?

I am trying to understand how a simple image recognition of an image with dynamic size could work. What I have seen is that parts of the images are taken and evaluated. For example a simple finger ...
3
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1answer
190 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 ...
2
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1answer
313 views

How to use PHOG and LPQ features for Emotion Recognition?

I have a database that consists of PHOG and LPQ features for each image. Now, I wish to train an SVM on these features for emotion recognition i.e SVM classifies the images on basis of emotion in the ...
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0answers
59 views

Metrics for image/visual complexity in computer vision/graphics?

Could anyone kindly point me to revenant literature in computer vision/graphics that detail on metrics for image/visual complexity and how to regularize that? More specifically, I am trying to design ...
3
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1answer
76 views

Applicability of Machine Learning on Images.

I am trying to use machine learning to detect and locate an object in a greyscale image. I have about 700 images which are 360x360 pixels in size. See below for an example of the object and image: ...
3
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1answer
255 views

Rearrange pixels to maximize visually distinguishable pattern

I have a dataset full of 0s and 1s, and when I visualize it with t-SNE, which does dimensionality reduction. There is clearly some structure in it as shown below. Each color corresponds to a ...
0
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1answer
76 views

Derivative for x-direction for image

I want to ask, consider we want to compute the slope of x-direction of the following step . The slope for it would be $m =\frac{0}{m_2 - m_1} =\frac{0}{5 - 2}$ which is 0. But the derivate for ...
2
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1answer
468 views

Where I can I find Pre Trained CNN Datasets for Facial Emotion Recognition?

I am working on a project that involves recognising emotion from images. There are two parts in the project: One where I will generate features from images using API's and then classify the emotion ...
5
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1answer
215 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 ...
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0answers
127 views

Image sharpening : Adding prewitt's filter resulted images. Is it correct?

I'm reading that 'Prewitt' filter is high-pass filter, which means that it can sharpening the image (via edge highlight). But I'm not sure to implement the sharpening process (not just edge detection)...
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0answers
76 views

Reduction of flow-shop scheduling to a real-world computing problem

Consider the following well known flow-shop problem: We are given a set of jobs $J=\{J_1,\ldots,J_n\}$ and a set of resources $R=\{R_1,\ldots,R_m\}$. Each job $J_i$ consists of a set of operations $...
1
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1answer
554 views

Circle Hough Transform. Improvement by knowing edge direction

I'm studying Hough Transform. I have fully understood the HT for detecting lines and successfully implemented it. I have more problems with the circle detection HT. Given a circle, if the radius is ...
2
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1answer
58 views

Extracting intersecting objects of the same colour from an image

What is the good way to extract the objects(circles) from image as shown in picture below? respectively create two images one with lines and one with circles from source image. I started with ...
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1answer
105 views

Is there any good way to judge whether the rectangle is inside the point cloud? [closed]

How to judge whether a rectangle in the figure is inside the given point cloud? For example, in this figure, the red rectangle is outside the point cloud and the green rectangle is outside the point ...
7
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1answer
2k views

Computer vision: object detection with labels that are single coordinates

Are there papers in the literature that address the following object detection task ? The task can be described as follows: Given a set of images, the labels are just coordinates (x,y) that ...