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Questions tagged [image]

This tag covers signal processing where input is an image, such as a photograph or video frame and the output could be an improved or altered image, parameters related to the image or information about features within the image.

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22 views

Dirty Image Quality Assesment Measure

I was looking for a way to measure how dirty is the document in image processing. Example images below: a. Dirty Backgrounds b. Dirty Backgrounds with Text Can someone give me an initial idea to ...
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66 views

IQ to RF conversion

I appreciate any help: I wanna convert IQ data to its RF data, representing an image. The centre frequency and sampling rate are available. What I do is: First I do up-sampling in MATLAB by ...
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1answer
99 views

Generating spectrogram for band-pass filtered wav file python

I have some .wav files of heart sounds. I want to apply band-pass filter [20Hx 100 Hz]. Then generating PCG images size of 560x420 pixels and RGB format. How could i do this? Any help will be highly ...
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1answer
68 views

Localized Gamma Correction

Question: Is there an algorithm that does (what I would call) "localized" gamma correction? That is, applying different gamma corrections on different parts of an image, using a masking filter or ...
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1answer
167 views

Algorithm/Code for finding surface shape of an image?

Is it possible to find the surface shape of an image as mentioned in the reference question ? If I find the unknowns of the equation , then what should be my next step in determining the shape of the ...
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1answer
44 views

Why we need Laplacian for edge detection?

I am studying some trivial computer vision processing techniques and I came across edge detection algorithms. IMO sharp changes in the gradient are enough indications to detect the edges in an image ...
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1answer
48 views

How to compute an old style shore line drawing?

I wish to represent a shore line, old-style, as in the following image (city on the left, water on the right): UPDATE: new image for another example of what I'm after, namely the thin lines (given ...
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15 views

Grading Images According to the Noise It Contains

I have collected a lot of dirty blank pages and each image is varied in the noise it contains. How will I grade images according to the noise it contains in terms of amount, and other aspects? What ...
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13 views

Overlaying A Distorted Text According to its Background

I have several dirty background images, sample image is below: I want to overlay a text on it but I want the text to be as distorted as the background. Example, if the background is a bit wavy, I ...
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11 views

Measure that Compares an Actual Old Document from a Synthetic Old Document

I have collected dirty background images, below is the sample: I have also a collection of an actual image of a dirty document with text on it, just like below: My problem with my actual image of a ...
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2answers
277 views

Easy way to get rid of noise in a hand drawing

I would like to take a user's hand drawn input, and filter out "noise", aka small sketches or blobs, where the user might have screwed up and accidentally touched his hand to the drawing device, or ...
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2answers
842 views

Which Transformation, Or Similarity Metric, Is Rotation, Shift and Scale Invariant?

I have an algorithm to to detect copy-move forgeries in images. I used block matching to detect regions of an image that were forged with copy-move forgery and highlighted the alleged areas. For block ...
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11 views

active contour without edges

i am new to image segmentation.i am studying chanvese ACWE paper1.This is level set equation of chan vese paper ACWE. Above, μ,ν,λ1,λ2 are real parameters, c1,c2 are constants determined for ...
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2answers
332 views

Anisotropic Diffusion Filter - Intuition Behind Parameters

I need to know what is iteration and divergence in anisotropic diffusion filter technique. Isotropic diffusion $$\frac{\partial I(x, y, z)}{\partial t}={\rm div}\left[c\cdot \nabla I\left(x, y, ...
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1answer
41 views

Comparing spectra from hyperspectral images

I extracted the mean spectra of regions of interests of different tissues from hyperspectral images. How to compare those spectra by the difference of their reflectance and their spectral behavior (...
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1answer
33 views

Fixing edge/pixel defects in image

I have a large number of images that are supposed to look something like the top part of the image: Instead, some have defects in them, as in the bottom part of the image. As you can see, there are 2 ...
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67 views

How to improve interpolation for chroma upsampling (4:2:0 to 4:4:4)?

I am trying to perform the best possible interpolation in order to perform proper chroma upsampling from 4:2:0 YCbCr to 4:4:4 YCbCr. I have implemented the improved interpolation proposed at this ...
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1answer
590 views

How do I measure the amount of information within an image?

I'm trying to find some information threshold that is required for performing detection of objects in images. However, I'm not sure how exactly to quantify the amount of information contained within ...
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17 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 ...
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1answer
347 views

Generating Kawase Blur Kernels to Approximate a Gaussian Blur on an Image

Is there an algorithm to generate the Kawase Blur Kernels to approximate the actual Gaussian Blur (of a specific kernel size, and if possible, a sigma)?
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178 views

What is the definition of the bsd68 dataset?

If I just google "bsd68 dataset", I find this page which allows to download the whole BSD dataset, with all 300 images (potentially 500). However, I have no idea which of the 100 test images are ...
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1answer
4k views

How to Estimate the Noise of an Image / Estimation of the Noise in an Image?

I want to know how to estimate the noise of an image? Also is this represent the camera's noise? Does anyone know how to estimate the noise of an image or camera? Update: Especially, I want to know ...
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0answers
46 views

Randomly Generate Synthetic Noise in an Image Text Document

I'm working on denoising dirty image document. I want to create a dataset wherein synthetic noise will be added to simulate real-world, messy artifacts. Simulated dirt may include coffee stains, faded ...
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2answers
7k views

How does salt and pepper noise occurs in an image

How does salt & pepper noise occur? And, what are some techniques to remove it?
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1answer
540 views

Amplitude of an Image

If I take a two dimensional image and conduct a fourier transform on it, I would get a two dimensional matrix of complex values. If I want to find the amplitude of each value, is that the same as ...
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31 views
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2answers
12k views

Measuring the contrast of an image

For a project, I want to measure the contrast of a global image. I want to compare different images to get the image with the best contrast. I know about the Weber contrast, but I need a normalized ...
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2answers
61 views

What are the measurable factors of image sharpness?

I need a way to present data on an essay written about image sharpening algorithm. So I've thought that if I measure a factor of sharpness from image or relative sharpness (between test img and ...
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0answers
79 views

Image Compression (JPEG) - Show the Effect of Number of Coefficients on Quality

write an m-file that will take the"cameraman" and produce a image quality or difference matrix for spectral selection method.The image properties are a sfollowings: For spectral selection: image1:DC ...
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2answers
725 views

How to Create Image Editing Filters

I am trying to make filters for days but now I just want to know the experience of others rather than go on to wrong way and finally decided to put my query over ...
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0answers
10 views

Want to create a function that calculates the ISO and Shutter speed based on the brightness of previous image

I want to calculate the shutter speed and ISO of Picamera using the brightness information of the previous image I captured. I have already calculated the brightness of the previous image but I am ...
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1answer
140 views

What Is the Difference Between MRF and Total Variation in Noise Removal?

I have a general question in image processing. I have a noisy image. I would like to classify the noisy image into some regions. Two famous approaches I can use are: MRF/Gibbs MRF: Model the spatial ...
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1answer
187 views

Estimate Variance of Additive White Gaussian Noise (AWGN) Given Multiple Realizations with Different Mean

Given $ N $ images of the same scene, where each image is corrupted by additive white Gaussian noise of the same variance $ {\sigma}^{2} $. How can $ {\sigma}^{2} $ be estimated? So we have an Image $...
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1answer
447 views

How to remove striped noise from this image. Which filter or algorithm use better?

I need to process a gray scale image. The task is to remove the stripes, which constitute some noise. I have next origin image: This image received many channels ADC(Y) in moment of time (Xn) from ...
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1answer
200 views

Strong (0,0) pixel among an otherwise normal cross correlation peak

I am working on an imagery registration problem via cross-correlation and am seeing a weird phenomena sometimes. First, I am pre-processing each image by subtracting the mean image brightness from ...
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2answers
25 views

Recommended Order of Performing Denoising, Deblurring and Super Resolution on an Image

In the normal workflow of image processing, there are multiple operations, increase image contrast, image denoising, image deblur and image super-resolution. What are the sequence/order of performing ...
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41 views

Matching Coordinates between two images

I am using images and corresponding lidar values for depth estimation CNN. I have RGB images. Corresponding to each RGB images, there is another image representing a subsets of pixels and distances to ...
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1answer
108 views

Optical realization of the Radon Transform

I am trying to reproduce this paper concerning the Optical realization of the Radon Transform, especially the simulation (section 3). Shortly, the experiment is just a "Fourier filtering" with a 4F ...
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0answers
75 views

Combining two images with different resolutions?

I am attempting to combine two radar images, each of which is a 3-dimensional cube with a range dimension, an azimuth angle dimension, and an elevation angle dimension. One image has high azimuth ...
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0answers
49 views

Face image quality assessment

I'm trying to filter out bad face images (with artifacts) generated by StyleGAN. Is there a good image quality measurement mechanism in python for doing this? I've tried using BRISQUE but it is not ...
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1answer
308 views

Which Approach Is Better for Decomposing an Image into High Frequency and Low Frequency Components?

Which approach is better or there is mathematical justification for using Bilater filter and Fourier Transform to decompose a image into High Frequency and Low Frequency Component. Both Bilateral ...
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1answer
222 views

How are line pairs and pixels related in image resolution?

I hope this is the correct place to ask this. If not, please refer me to a better place, thanks. Now to my question, I am learning about digital image processing, and the book I am reading is ...
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1answer
32 views

Understanding the resulting image matrix when differentiating image

Let $A$ be a image matrix and let $P(i,j)$ be the gray level of pixel $i,j$. Let $0$ be black and $255$ be white Assume I want to differentiate this image with respect to the columns $(x)$ as in I ...
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4answers
2k views

what is the difference between YUV format and HSV format?

i wonder why HSV and YUV are different formats, even though they both works similarly (based on the brightness), if not what is the difference and i have confusions with YPbPr and YCbCr , can anyone ...
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2answers
1k views

Is It Possible to Reconstruct the Original Image from Laplacian Pyramid?

In our computer vision course, my professor said we can reconstruct the original image from the Laplacian pyramid. It just feels to me that information is lost after doing subsampling and upsampling. ...
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1answer
543 views

`SSIM(YUV)` vs. `SSIM(Y)`: Values Are Very Different

I'm seeing some weird results when trying to compare image qualities in a few different color spaces. Have a look at my graph: I want to compare with another publication, which reported PSNR(YUV) and ...
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1answer
1k views

What's the Difference Between UQI and SSIM Measures for Image Similarity / Quality?

I'm studying image quality assessment (IQA) problem and I'm currently learning about quality measures UQI and SSIM, I know UQI is a predecessor of SSIM, but they look exactly the same for me...
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2answers
76 views

Digital Image Processing Textbook with Specific Topics

I am looking for a Digital Image Processing and analysis textbook, but there are specific topics that I would like the book to cover. Among other topics, I would like it to include a discussion of: (...
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1answer
26 views

Gender classification using Periocular Region [closed]

I have a dataset of the periocular region, I have images of the male and female periocular region but they are only labeled as left and right periocular region, Folder is a mixture of male and female ...
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5answers
1k views

Auto Detection of Rotation Angle on Arbitrary Image with Orthogonal Features

I have a task at hand where I need to detect angle of an image like the following sample (part of microchip photograph). The image does contain orthogonal features, but they could have different size, ...

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