All Questions
269 questions
1
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32
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Question regarding global thresholding algorithm for images
I am trying to mathematically prove that for an initial choice of threshold To, if we compute the successive thresholds as average of foreground and background means, the thresholds will follow a non-...
- 377
0
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0
answers
20
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Beginner's troubles with binary thresholding for particle tracing in ImageJ
I'm a researcher working on making crystalline microspheres (100-400µm diameter), and have recently begun taking SEM images of my samples. It would be really useful to be able to have a quantitative ...
0
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0
answers
12
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Contrast enhancing very faint extended blobs in an image
I have a series of images of the night sky and I'm looking for methods to enhance very faint structures that are barely visible. The movement of those structures is visible when you click through ...
- 19
0
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0
answers
29
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Detecting a large horizontal band in the center of an image
I have a small (228x228) grayscale image that I have created by segmenting the original image and converting it to grayscale after applying colors to the segment. I want to know possible approaches I ...
- 19
2
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0
answers
19
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Defining the PSNR for images in CIE-LUV or CIE-XYZ or CIE-HCL spaces
In image compression applications, we know that for an 8-bit 0 to 255 level grayscale image the PSNR (peak signal to noise ratio) can be defined through the MSE as:
$$MSE=\frac{1}{mn}{\displaystyle \...
- 121
4
votes
1
answer
991
views
OpenCV 2 Connect Incomplete Contours edges
I have to connect the unfinished edges of the contours in the red color bounding box.
I used distance transform, watershed, and morphology, but still, edges are not connecting.
...
- 41
2
votes
1
answer
495
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Can DFT magnitude be used to identify repeating patterns in an Image?
Given the DFT magnitude vector of an 1-D image, I want to understand if we can calculate the size and pitch of repeating patterns in the image. Is this possible? I took a few test images and ...
- 73
1
vote
1
answer
56
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Segment Image of Small Elements on Neutral Background
I have a 8 bit gray level image where if the value = 122 it means no information, value = 0 means highly negative, and value = 255 means highly positive.
I want to connect as many positive information ...
- 13
1
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1
answer
175
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Segment Hand Image into Palm and Fingers
Here is my code, i want to extract only the fingers and save them as a new image
...
- 11
1
vote
0
answers
83
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Replicating Hysteresis based Thresholding Technique to an Image from a Paper
I was reading a paper where they applied a hysteresis thresholding to help with segmentation of vessels in an image. It provided a formula to determine how to select a hard threshold (Th), which ...
- 11
1
vote
1
answer
216
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Segmenting dark spots from a light background?
I need to perform automatic segmentation of dark blue spots on light yellow paper. Here's a very simple example:
In this case, a simple threshold based on hue or brightness works well. But here are ...
- 111
1
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2
answers
1k
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What does convolving an image with kernel [1 -2 1] do? How is it different than convolving with the derivative kernel [1 -1]?
What does convolving an image with the filter [1 -2 1] do? I see that it's a form of edge detection but it's also very similar to the results I get when convolving with the derivative kernel [1 -1] so ...
- 13
7
votes
1
answer
176
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Why Is PDE Based Image Processing Not as Active as It Used to Be?
I can see from the literature that PDE-based image processing (especially inpainting) was a "hot topic" at one point. Why does it not seem to be an active area of research anymore, yet it ...
- 123
3
votes
1
answer
49
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Explain the Terms: Semantically Richer and Spatially More Precise in the HRNet Model Paper
High-resolution representations are essential for position-sensitive vision problems, such as human pose estimation, semantic segmentation, and object detection.
From HR-Nets we get semantically ...
1
vote
0
answers
72
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how to understand the gradient vector flow formula
Currently, I am learning gradient vector flow. I have one question about the calculation.
After Euler equations, the GVF can be found by solving the following formula:
Then, the paper said: "...
- 11
2
votes
3
answers
3k
views
Any good alternatives of ImageJ (Fiji)?
I worked on some medical image processing research two decades ago and I used ImageJ then. I started to pick up some medical image processing projects again (some registration and segmentation). I ...
- 43
1
vote
1
answer
496
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Removing dark borders in Image Stitching for Panorama
I am working on a Matlab code for panoramic image stitching for multiple image frames and getting satisfactory results however there are always dark regions surrounding the stitched images as ...
- 500
4
votes
1
answer
90
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Image Standardization for Image Classification (Machine / Deep Learning)
I am trying to write a program to standardize an image which I need to better perform image classification. I found the definition of standardisation which is obtained simply by subtracting the mean ...
- 141
4
votes
1
answer
457
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Rectangle Segments of Image (Rectangle Super Pixels) per Pixel
I would like to divide an image into "rectangular" components that are similar according to some visual criterion:
For example I found these algorithms :
https://scikit-image.org/docs/dev/...
- 143
0
votes
0
answers
23
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Lung Detection and Segmentation in X Ray Image
I'm a beginner in image processing and I have to create a segmentation algorithm to detect lungs from an image .
Image given :
And after removing the noise from the image and applying a threshold the ...
- 1
0
votes
1
answer
145
views
How can I segment areas, each of which has nearly same colors of pixels in an image?
For clarity, Nearly same colors of pixels belong to a category. Another nearly same colors of pixels belong to another category. The distinction depends on nearly same RGB values of pixels.
- 11
1
vote
0
answers
30
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Foreground extraction with zebra background
I am trying to classifiy grayscale images but I need to focus on a specific object on each image.
I would like to segment the object but the targeted object has the same color than the background.
And ...
1
vote
1
answer
172
views
Image Segmentation Using Deep Learning
I see in many reviews on Autonomous Car how they segment the images with person, cars, etc...
How is it achieved in Deep Learning?
Could anyone give an example of that?
How it is done?
- 144
2
votes
1
answer
145
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What exactly is "connectivity" between pixels in an image?
So, my professor says that two pixels are connected if:
they are neighbours; and
their intensities satisfy a specified criterion of similarity.
And depending on the type of neighbours they are, they ...
- 123
0
votes
2
answers
4k
views
Is there a way to find the contours of instances in a binary mask image by color?
I need to find the contours for each of the instances of microscopic cells in a binary image mask of dimensions 256 x 256 shown below.
My approach involves thresholding the image to get a binary mask ...
7
votes
2
answers
400
views
Locate Non Homogeneous Areas in an Image
I need to choose some points on an image. These points should be chosen more where there is lots of color changes, transitions and variations. Which techniques can I use for determining where most ...
- 194
4
votes
1
answer
223
views
What is Label Refinement in the Context of Image Segmentation
I have been reading the paper entitled Measures of Similarity by Unnikrishnan and Herbet, in which they discuss some metrics to evaluate image segmentation. They use the word refinement of labels/...
- 143
0
votes
1
answer
420
views
image processing find liquid level (only with images processing, no AI)
I want some ideas to get the level of a water/liquor in a cup. i tried many ideas (contours, edges,...) but nothings is working. So any ideas that i can explore.
3
votes
1
answer
588
views
Removing halo effect in image composition: Google Meet's solution
Wanted to understand how google meet is removing halo effect when composing their image. They describe their method briefly in their blog as:
"The blur shader simulates a bokeh effect by ...
- 141
2
votes
1
answer
55
views
Image noise reduction
I have an image of a cross-section of soil where the main object of interest are the plant roots.
I would like to segment or extract the roots from the background noise of the soil itself and other ...
- 121
3
votes
1
answer
57
views
How to distinguish the same object entering the camera field of view
We want to set photo cameras in the field and capture images of insects that visit flowers. We want to place these cameras above the flowers and then they should get triggered whenever an insect lands ...
- 133
5
votes
2
answers
681
views
Should Edge Detection Be Applied in Spatial or in Frequency Domain?
I want to ask why everywhere is used to do edge detection in spatial domain and not in frequency domain with FFT of image and apply HP filter. Thank you.
- 73
4
votes
1
answer
260
views
Easiest Pattern to Recognize with Machine Vision
I need to detect the exact position of some kitchen tools using machine vision. I've the possibility to label the tools with a pattern, to make the detection (more specifically the image segmentation) ...
- 141
1
vote
1
answer
2k
views
Defining the SNR or PSNR for color images (3 channel RGB files)
In image compression applications, I know that for an $8$-bit $0$ to $255$ level grayscale image the PSNR (peak signal to noise ratio) can be defined as:
$$
\text{PSNR} = 10 \log_{10} \frac{\sum_{m,n} ...
- 133
2
votes
1
answer
120
views
Thresholding Algorithm for Separating Skin from Clothes
I have an several images that look like the following:
I would like to separate the skin from the trousers here without specifically training a segmentation model. Can anyone suggest any such ...
0
votes
2
answers
137
views
Object identification based on both shape and intensity -- i.e., identify the stars and their diffraction spikes at the pixel level
Here's an example image to make the problem very clear:
I've used OpenCV's blob_log() as well as the rank.otsu threshold approaches. The problem with the blob detection is that the blob radii are ...
- 101
3
votes
1
answer
260
views
Algorithm that Fills the White Holes Within the Character Image
I have this degraded image :
Using paintbucket tool in Paint.NET Windows application, I fill the character image black.
My ...
- 127
0
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0
answers
64
views
How can I stitch bottom of some image to topside of another image by erasing as much overlapped image as possible?
I have 2 images of size 1920*1080 and I want to try image-stitching on them. These are images (images are from wind turbine blade.)
This is the first image
And the second image.
I already have ...
- 101
0
votes
1
answer
128
views
How to get the area(Pixels count) inside ring-like shape?
I have the following image, and I do like to count the pixels inside the ring to get the area.
I did some morphological operations as a kind of post-processing to make the image as much as possible ...
- 167
1
vote
1
answer
26
views
How can I implement Guided Random algorithm walker matrices?
My Question is related to the implementation of the paper Segmentation by retrieval with guided random walks: Application to left ventricle segmentation in MRI
After careful reading of the code of the ...
- 167
0
votes
0
answers
81
views
How do i calculate the accuracy of an algoruthm?
I'm doing research on an machine learning image processing algorithm (segmentation algorihtm)i.e. computer vision performs when an image takes as an input and objects in an image are segmented and ...
- 1
5
votes
1
answer
202
views
Is HSV Color Space Sufficient for Rudimentary Color ID and Edge Detection
I want to, as part of a C++ school project (no OpenCV), work with an RGB image taken from a camera filming smarties (round colored pellets) from above and extract the number of candies in each color.
...
- 53
0
votes
0
answers
122
views
Finding Duplicate Pixel/Objects along Image seams
I have a seam of two photos joined by a seam alignment algorithm that on occasion generates duplicated pixels/objects/artifacts on both sides of the seam in the final, aligned photo. The images are ...
- 101
1
vote
1
answer
133
views
Create a mask like DAVIS dataset
I am testing the dataset DAVIS from here with one of the papers it has. The codes works fine with DAVIS dataset but it does not work for my data. In particular, the code does not accept the mask I ...
- 111
2
votes
1
answer
241
views
Looking for a way to fill holes in objects, and break bridges between them
I am trying to extract building footprints from satellite images. Using a series of morphological operations i.e erosion and opening by reconstruction, I'm able to obtain the footprints, albeit with a ...
1
vote
1
answer
145
views
Improve Alpha Matting on Hair of Human Portrait
I have an image like this:
I am trying to build a semantic segmentation and matting model which currently gives an output like this:
One can see that some regions between the hair strands are fuzzy....
- 119
4
votes
0
answers
87
views
Approaches to Segmentation in images of water surface
this is my first question here. Therefore please help me inform me when I miss any good practice in asking questions here.
Given a short video sequence of an water surface, I would like to detect if ...
user44846
3
votes
1
answer
118
views
How to Make Ground Truth Images for Document Image Binarization Task?
The two images are from DIBCO (Document Image Binarization Contest). The objective is to find a solution to binarize the top image (original image) to be similar to the bottom one (ground-truth image)....
- 33
0
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0
answers
46
views
Thermal image based segmentation [duplicate]
I'm working on a project to do segmentation of thermal images. So far, the methods have produced limited segmentation performance (k-means, Otsu's Method, Sobel, Canny, LoG).
I am trying to achieve ...
- 1
1
vote
0
answers
44
views
Size filtering on binary images
I have noisy images from which I extract the contours using OpencCV's findCountours, which performs binarization internally. This results in innumerable small ...
user7657