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.
449
questions
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28 views
IQ to RF conversion [closed]
I appreciate any help:
I wanna convert IQ data to its RF data, representing an image. The center frequency and sampling rate are available. What I do is:
First I do up-sampling in MATLAB by ...
0
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1answer
20 views
Modifying sizes and thickness of letters to “embed” an image in text
I am wondering if this is defined, names and possibly solved - suppose I have a grayscale image and about one page worth of text. I would like to attempt to give the text an appearance of an image ...
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1answer
31 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 ...
1
vote
1answer
45 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 ...
2
votes
1answer
18 views
Describing a certain quality of an image
Generally I guess I’m asking for a source of image processing terminology.
Specifically here I’m trying to find the word for the quality that would identify the main difference between the Mondriaan ...
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0answers
12 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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0answers
12 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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0answers
9 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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0answers
8 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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1answer
34 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 (...
0
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1answer
23 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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0answers
19 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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0answers
13 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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0answers
43 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 ...
1
vote
1answer
346 views
Running the BM3D Denoising Algorithm in Python
I am looking for a strong baseline in image denoising and therefore wanted to have the BM3D algorithm in my benchmark.
These 2 python implementations:
https://github.com/ericmjonas/pybm3d
https://...
1
vote
1answer
86 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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0answers
21 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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0answers
19 views
What does dynamic range values in SSIM image quality technique refers and how to calculate?
http://en.wikipedia.org/wiki/Structural_similarity
Below is java implementation of SSIM.
...
2
votes
2answers
45 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
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 ...
2
votes
1answer
74 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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0answers
29 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 ...
3
votes
1answer
146 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 ...
0
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1answer
43 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 ...
2
votes
0answers
42 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 ...
0
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0answers
32 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 ...
1
vote
1answer
143 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 ...
2
votes
1answer
25 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 ...
3
votes
4answers
645 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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0answers
15 views
Efficient image matching technique for small match library set
Background
A scene captured from video frames from an Android mobile device camera are to be analyzed in real-time. The scene will contain up to 12 distinct photos. The library images to be matched ...
0
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2answers
20 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 ...
1
vote
1answer
56 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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0answers
16 views
Measures of edge image continuity and connectivity
Suppose I have a scalar image $I:\mathbb{Z}_{1,m} \times \mathbb{Z}_{1,n}\rightarrow [0,1]\subset \mathbb{R}$, where $\mathbb{Z}_{1,m} = \{1,\ldots, m\}$.
(For instance, computed as the (scaled) ...
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0answers
25 views
Deriving transformation from input and output images
I will preface this by saying that my undergrad signal processing course is very far back...
Context:
I am comparing images of global illumination (GI) passes. I want to be able to change the ...
2
votes
2answers
70 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:
(...
0
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1answer
315 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 ...
0
votes
1answer
21 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 ...
0
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1answer
268 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 ...
1
vote
2answers
65 views
Image downsampling with Haar DWT?
How can the resolution of an image in matlab be reduced by using 2D haar wavelet by downsampling-decimation? Is there any predefined code or tool within wavemenu? thanks in advance
0
votes
2answers
41 views
Camera image pixel structure origin
I am using machine vision for industry task with opencv. I have images from a camera monitoring the process. The detailed look at the small part of the image follows:
Enlarged:
In the detail, it ...
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0answers
9 views
How to warp and enlarge the center of an image?
I am trying to smoothly enlarge the center part of an image. The Skimage code that I use need an inverse map that specifies location of input pixels that will occur at the output pixel location.
If I ...
0
votes
0answers
11 views
Adjustments to get better result appyling hough circles
I have the aboveimage and wanted to detect circles spread around the image. I can detect the circles in the middle through hough circles but it does not work out for the left-most circles which exists ...
9
votes
5answers
519 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, ...
0
votes
1answer
26 views
Why does the Y component in YCbCr represent luma/intensity?
As far as I know, the RGB to YCbCr conversion is just a linear transformation, yet the Y channel successfully captures the intensity value of each pixel. How?
In other words, where do the following ...
2
votes
0answers
157 views
How do 2D DCT basis functions interact to produce 8x8 JPEG tiles?
This section is a bit of an intro. If you want to skip directly to where the problem is explicitly outlined, skip to the bottom of this post. Please note that I'm not hip with mathematical lingo, so ...
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0answers
54 views
Intuitive understanding of Fourier transform of images [duplicate]
I am trying to have an intuition about the Fourier transform of images
For example the image on the right is the Fourier transform of the image on the left,
my question is :
1)Why are the ...
0
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0answers
27 views
Elimination of image blurring using noise model restoration techniques
How can the blurring be eliminated from image using the noise model restoration process techniques?
To my knowledge the answer must be filter.If yes,then which filter is used?
0
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1answer
121 views
What is the difference between domain and range filtering?
In the context of image processing, I have heard the expressions "domain filtering" and "range filtering". What do these terms refer to? What is the difference between them?
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0answers
8 views
Why is correlation involved? - Axis Rescaling for a 2D axes - brightfield illumination microscopy of blood cells
for 1D axis rescaling, you use a FOV calculation
len_pixel=total_magnification * len_specimen_in_pixel
len_specimen_in_pixel=len_pixel/total_magnification
and then to get the axes rescaled, you do ...
0
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0answers
28 views
Texture model of Active appearence model
I am working in a face detection project and currently I am trying to understand Active Apperance Model.I have understood how Active Shape Model algorithm works which is the shape model of the AAM ...
