All Questions
148 questions
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77
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Estimate 3D location of a tracked point with Known Camera parameters and Distance
EDIT: Camera has fixed orientation and position with respect to the world coordinates, it is not moving. Therefore, the found [R₁ ∣ t₁] extrinsics are assumed to be constant throughout the moving of ...
1
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0
answers
54
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How to improve quality of the recovered image in compressed sensing technology?
I was trying to use compressed sensing technology in image processing. Basically, I did a code in Python(Spyder IDE) which takes an image, compress the image and reconstructs it.
I tried with the ...
0
votes
0
answers
32
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How to get surface topology from fringe pattern
I'm trying to recover the surface shape of a body from fringe pattern. There's a interferometer projecting circular fringes on the body. A camera takes a picture of the reflection of these fringes. I ...
2
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3
answers
108
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What is the type of blurring in such an image?
I can't figure out what type of blur such an image has and how I would be able to generate it in python. I would be grateful for any help.
I tried Gaussian blur, bokeh blur, Wolf and Born out of focus ...
0
votes
0
answers
58
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Pixel Shift when using Fourier Downsampling
I am working on a Super-Resolution network, and want to try to use Fourier downsampling, different from the normally used bicubic downsampling as it relates to MRI imaging. I have tried using this ...
1
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0
answers
213
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Combining Two Grayscale Images Without Overlapping Using OpenCV and Matplotlib in Python
I am working on a project where I have two grayscale images of different sizes, named part1 and part2. Each image has some ...
0
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0
answers
85
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Combining Three Images into One Output Image Python
I have to combine three images that are inside one single image into one output image in Python. This has to be done using Gamma corrections, Histogram
equalization, filters convolutions (gradient, ...
0
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0
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204
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Removing dense grid lines & convert into clear image - opencv - python
I want to extract the text from this image. I'm a newbie in opencv. I've tried various opencv codes across various questions, but none is working for me.
How can I extract text from this? Or maybe ...
2
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3
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217
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How to find PSNR from two images with different size in python
I have 2 images, one original and other is reconstructed from the original via some processing. I want to find the PSNR for the reconstructed image The original has a size of ...
1
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1
answer
65
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2D Fourier downsampling to even number of points gives incorrect modes in the last column
I would like to downsample an image in the frequency domain to an even shape, similar to what is described in this post. I have been able to do this successfully with a 1D signal to both an odd and ...
1
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0
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48
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Local Binary Pattern rotation
How does LBP work? To learn that, I decided to calculate by hand for the matrix but the problem is about the rotation pixel over the image based on the radius and neighbor of LBP. I do it clockwise ...
1
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1
answer
113
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Periodicity problem with FFT for generating "starburst" from aperture
I am following a paper on computationally modeling optical phenomena within a lens. (https://resources.mpi-inf.mpg.de/lensflareRendering/)
At some point they use the Fourier power spectrum of an ...
1
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1
answer
114
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Robust method to detect pinpricks in an image?
I expose films in a jig with pin pricks as reference markers. I use these references to register the scanned images of the film to other data.
I've been using mouse click coordinates to date, but I ...
0
votes
1
answer
1k
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2D FFT Cross-Correlation in Python
How to replicate scipy.signal.correlate2d(x, h) with arbitrarily sized x and h? ...
2
votes
1
answer
519
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How to compute second order derivative of image using the integral image and box filters?
I want to speed up my blob detection function by computing the second order derivatives of the input image using the integral image and some box filters.
Initially, I used the following method, which ...
1
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1
answer
175
views
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
...
1
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4
answers
78
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How can I analyse the motion of plasma
I am currently attempting a project of plasma analysis. One of the aspects of this project is to determine the stability of the plasma, when a plasma is unstable it loses its shape partially or starts ...
2
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1
answer
3k
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Implementation of Wiener filter to deblur an image using Python and OpenCV
EDIT: I have debugged the runtime warning, and now I am able to get an output image. However, the output image is still blurry. Increasing the constant value heavily distorts the image. Setting ...
0
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0
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247
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What image similarity measure is best for measuring the structural similarity of two images?
I am looking for an image similarity measure that can measure the differences between the structural composition of two images. For example these two images have structural differences between them
...
3
votes
1
answer
409
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How is the inverse Fourier transform of a Hermitian-symmetric input efficiently calculated?
The np.fft.rfft2 function exploits the Hermitian symmetry of the transform of a real input to more efficiently calculate the transform by omitting the negative ...
1
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1
answer
628
views
Fast Way to Remove Isolated Pixels in a Highly Quantized Image
I have an image that I've quantized like so:
And I would like to get rid of pixels that aren't much like their neighbors (basically do a low-pass filter). The goal would be to get rid of isolated ...
1
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0
answers
314
views
How to Measure Image Quality in an Objective Way
I need a method to measure image quality via computer programming (like Python). I'm doing this so as to compare quality of multiple images. I have found stuff like NMSE, PSNR and SSIM, but don't ...
3
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1
answer
3k
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Removing white reflective pixels from scanned RGB image (Python - preferably OpenCV)
The images above are tiles taken from a scanned painting. It's easy to see where there are tiny reflections scattered throughout. I wish to remove (or diminish) the tiny reflections somehow, across a ...
2
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3
answers
3k
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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 ...
0
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2
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79
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Signal/image processing using python?Additional IDE must required or default pyhton IDLE is sufficent?
Can we perform signal processing and image processing using default pyhton IDLE(that is downloaded from pyhton website) for scenarios where we may also need plotting etc? or is it necesssary to ...
4
votes
1
answer
177
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Interpreting results of Sobel Edge Detection
I am implementing A No-Reference Perceptual Blur Metric paper.
Somewhere in the prep steps they mention the use of vertical Sobel filter for finding vertical edges.
The algorithm is summarized in Fig....
0
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1
answer
430
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Copy an object (along with bounding box) from one image and paste on different image (only background)
I have a dataset of images with bounding boxes.
I also have another dataset of images with different backgrounds.
I want to copy the images from one dataset (with their ground truth boxes) and paste ...
5
votes
2
answers
2k
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Can the deconvolution Wiener filter reduce noise without having a blurred image?
I am trying to denoise many several noises with several filters for a research i have, i found a deconvolution Wiener filter made by "mr.tranleanh" on Github, as you can see here .
what I ...
4
votes
1
answer
269
views
Filter Artifacts from Periodic Filtering
I have a merged image containing 20 segments. When I concatenate them directly, I have obviously observable patches in the whole image. I want to get rid of them while distorting the original image as ...
1
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1
answer
848
views
How do I get various peak values from a 2-D array or a matrix?
I'm working on 2D array analysis or an image analysis and get to know the different block of peak values marked "circle" in attached plot [e.g. 2*2 matrix] of the 2D array [as shown in Fig. ...
0
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0
answers
131
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What is the magnitude and phase of the wave represents in the k-space or Fourier space?
#Code from https://stackoverflow.com/questions/70768384/right-method-for-finding-2-d-spatial-spectrum-from-cross-spectral-densities
I've an array of seismic sensors (say, N=34). Every sensor collect ...
1
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1
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322
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Scaling of FFT2 magnitude in image-processing
I got the following code:
...
3
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0
answers
88
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Overall approach for building a footfall/age/gender counter using CCTV footage
I would like some advice to validate my approach for building a computer vision system.
Design brief:
Using existing CCTV cameras in a retail store, detect the footfall in the shop (count individual ...
2
votes
1
answer
296
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Generate a PSF based on MTF Mapper's SFR measurement
Not sure if I should post this here or on Stack Overflow
I have a .csv file from MTF Mapper with 2 columns from SFR measurement - frequency and contrast:
...
0
votes
1
answer
891
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Fourier Transform High Pass Circular Filter Intuition
The situation
I need to apply a high pass filter to an image. The approach I'm following uses Fourier transform to apply a circular filter which would eliminate low frequencies.
Say I have a frequency ...
4
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1
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339
views
4
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2
answers
3k
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Are scipy second-order Gaussian derivatives correct?
For an edge detection algorithm, I need to compute second-order derivatives of an image, and I do this with use of Gaussian derivatives. I assumed that the ...
4
votes
2
answers
1k
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Understanding the Bilateral Filter (Image Filtering)
I asked this question already on StackOverflow and was told to ask it here instead, so I will just copy the content of my question.
I do understand the general concept of bilateral filtering and I did ...
0
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0
answers
352
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Find vertical/horizontal lines
I tried everything including the Hough Transform with different inputs; Laplacian and Sobel and Canny edge detector were run on filtered image but cv2.HoughLinesP and cv2.HoughLines both give me wrong ...
3
votes
1
answer
551
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ringing artifacts using FFT-based gaussian blurring
I'm trying to do an FFT-based gaussian blur on a grayscale image, and it works, however it seems to introduce ringing artifacts to the result when compared to the expected direct filter. What can I do ...
0
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2
answers
4k
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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 ...
0
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0
answers
547
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Filter 3D volumetric image with a Butterworth filter in Python
I have been looking for a way to filter a 3D volumetric image in python with a Butterworth filter, but I haven't found any good solution.
I have tried this:
...
1
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0
answers
357
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Removing feature matched outliers within same image using RANSAC
I'm a student working on a copy move forgery detection algorithm.
I have a forged image. By far I have,
Found keypoints and descriptors from the image
Matched the descriptors using 3 Nearest ...
5
votes
1
answer
461
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How to detect rectangular images inserted into another image?
It's just for a simple binary classification, so it's not needed to find the location of the inserted image or the content. I'm only interested in checking whether something like that is present or ...
1
vote
1
answer
537
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T1 Mapping in Python?
I'm trying to write a simple program to perform T1 mapping of a few MRI Images.
My understanding is that all I need is to plot the pixel intensity values by inversion time then fit a curve. The output ...
0
votes
1
answer
420
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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.
0
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1
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2k
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Python how to detect white image [closed]
I am searching for python code or library to detect blank/white images like [png ,jpg ,bmp].
1
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1
answer
5k
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How to make a contour smooth in OpenCV
I am using OpenCV(4.5.1) and trying to extract a smooth contour of an object on my image.
Firstly I got the contour by:
...
2
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1
answer
197
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Extracting ridges in automatically in image
I am trying to extract ridges from an image, calculated using the eigenvalues of the Hessian matrix (see answer in Best way of segmenting veins in leaves?). In this image I have zeroed out the ...
0
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1
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658
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Cropping binary images based on pixel counts in python
I have a numpy binary masked image that looks like the following:
I want to automatically crop this image like the following:
Can I achieve this using some sort of image processing rather than ...