Questions tagged [image-processing]
The image-processing tag has no usage guidance.
146
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29 views
Are there algorithms besides Canny edge detection that can create consistent width edges?
Sobel edge detection is pretty much the quintessential way to get edges out of an image. It however suffers from certain quirks.
One example is, because it's gradient, based certain surfaces exhibit ...
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1answer
33 views
Interpreting Image Processing Math Equation
I am reading "Image Processing and Analysis" by Chan and Shen, c 2005 SIAM. They introduce some notation I'm not 100% sure how to interpret:
$$ u_0(x)=u(x)+n(x), x=(x_1,x_2) \in \Omega $$
They ...
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45 views
What modern C++ Unit Testing Framework do you use for highly parallel image, 3D and higher dimensional matrix processing workloads? [closed]
Most of the existing open-source libraries such as OpenCV, Tensorflow, and Pytorch use Google Test. I would like to know about strong alternative testing frameworks that thrive under a similar ...
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31 views
HSI color space and RGB color space relationship in Steganography
I need to embed text in an image, research papers say HSI produces better mse and psnr therefore are better for steganography. I have RGB values(69,223,90) and its corresponding HSI is (127.223,0.458 ,...
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17 views
How Quantum works exactly in MagickCore?
It's been long I have been trying but I guess I will give up now, I am not able to understand some stuffs + documentations seem wrong. For example, In Magick++, the QuantumRange equations they ...
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23 views
What technique should I use to animate a summer picture to its winter version: linear interpolation, or opacity?
I've used a CycleGAN to generate the winter version from a summer picture (https://github.com/junyanz/pytorch-CycleGAN-and-pix2pix).
An example of the output can be seen in the top right corner:
...
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30 views
How to filter a photo to look like a cartoon / anime?
I am interested in reverse engineering a video effect, that is composed of different parts.
I'll try to split it into different questions as advised on StackExchange Meta.
Part 1: TV-Noise effect
...
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15 views
Create a TV noise effect
I am interested in reverse engineering a video effect, that is composed of different parts.
I'll try to split it into different questions as advised on StackExchange Meta.
This is the example image: ...
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45 views
What fast algorithms can generate not-realistic but quite handsome animated landscapes?
I was looking for algorithms that quickly compute quite nice realistic, or not realistic, animated landscapes, in video format ("animated" = the camera moves, or the water is animated, etc.) But all I ...
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31 views
Is it possible to develop this image generator from randomly redrawn detected edges or am I going straight to the wall?
Aim
I would want to procedurally generate totally new images from a set of thousands of images of a given category (simple landscapes for example). Deep-learning won't be used for this purpose. This ...
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1answer
53 views
Given a background image B and a composie image of A OVER B, can we somehow recover image A?
I often find myself in the situation where I have some old image where I composed a translucent overlay on top of a background, but then lost (or more likely discarded) the overlay. I still have pre-...
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84 views
Visualize the variance of an image
Let $h_j$ denote the image reconstruction filter of pixel $j$.
I'm estimating the color value $$I_j=\int h_jf\:{\rm d}\mu$$ of the $j$th pixel (see [Veach, Section 8.2]) by an asymptotically ...
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1answer
35 views
Controlling “zoom” and “position” of a cubemap in shaders
I am trying to mimic reflections in image composition using shaders.
I have gotten this far:
In this image the floor is "reflecting" the back wall, however the reflection is uncanny because the ...
3
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0answers
73 views
Upscaling screenshots with subpixel rendered text
Upscaling a screenshot with subpixel antialiased text produces unpleasant color fringes, e.g. why does black text have orange and blue pixels This is especially annoying when trying to show an ...
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30 views
Extract object from image and apply it to different image
SHORT BACKGROUND:
I am developing a neural network based model to differentiate benign and malignant ovarian tumors. I am working with transvaginal ultrasound images, some of which contains yellow ...
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24 views
What's the most efficient way to extract the information from Shipping Labels?
I'm currently using Google Cloud Vision API to extract shipping information from shipping labels. While, OCR accuracy is not the issue here, the problem is that the data extracted from the label is ...
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22 views
GIMP's Additional blending formula
I try to implement GIMP's the Additional blending mode for layers in my application.
I've found the formula:
E = min((M+I), 255)
I think, that if I blend ...
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22 views
Convolution of multiple gaussian filters with different sizes
What is the size of the final filter after implement convolution of multiple gaussian filters with different sizes?
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1answer
49 views
Extracting information from EXR Files
I am relatively new to computer vision and image processing. I have a single EXR file with 7 channels: 1-3 give me the RGB values, 4-6 give me the surface normals coded as RGB values and 7th channel ...
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1answer
69 views
How do you add text dynamically to an image and export it?
Apologize for crossposting, but I posted this in Stack Overflow and thought it might be a better post here.
Recently, Spotify released their 2019 Spotify wrapped web application, which is essentially ...
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1answer
52 views
What kind of denoising must follow locally adaptive binarization?
I am experimenting with local (adaptive) grey threshold for the binarization of B&W photographs of yellowed manuscripts:
I got adaptive thresholding working in both scikit-image and cv2. In both ...
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1answer
66 views
How RGB images are formed when normalized between 0 and 1
There is a popular technique of normalising images by dividing each pixel with 255 so that it comes in the range of 0 and 1.
But, then how the same colours are formed when we normalize images.
for ...
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2answers
213 views
What does texture resolve mean?
In the context of render targets or textures, what does "resolve" mean?
For example: To resolve a color texture.
From my understanding, it seems to mean, "copy but process/convert at the same time", ...
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0answers
30 views
Fuse 3D-Points in Bundle Adjustment? [closed]
(Crossposting from here: https://softwareengineering.stackexchange.com/questions/399331/fuse-3d-points-in-bundel-adjustment)
I'm actually implementing my own Pose-Estimation/- and -Refinement ...
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1answer
31 views
How to create static alpha masks of an image
I have an image of following type-
I want to create mask of the following type where the inside area is white and rest of it is black. How to do it?
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1answer
94 views
Artificially increase the region of interest of an image
I am solving an image segmentation problem. To increase the accuracy of the model, I came across the following preprocessing step-
First, the set of pixels of the exterior border of the ROI is de-
...
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2answers
76 views
Is there way for polygon decomposition by thickness?
Here is an example
dots representing coordinates of pixels
added more representative example
added real example
added main problem
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77 views
Converting one png file into multiple SVG files
I have the following image which I would like to turn into a font:
I can easily turn it into an svg with pngtosvg.com, but the result is only a single group. I'd like the result to be multiple groups ...
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3answers
227 views
Blurring image with RGB values without convolving it with a kernel
I'm using an app for face redaction that doesn't allow access to the source code but only allows me to pass pixel values for red, green and blue channel upon which it creates a matrix with the same ...
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1answer
64 views
Estimating the position of vertexes in a 3D model
Introduction to my project:
We are machine learning scientists and working on a biomedical system for tracking tongue for speech pathology using a technology called EMA (Electromagnetic ...
0
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2answers
96 views
How RGB images are formed
I have a noob level question about RGB images-
Pixels in RGB images are in the range of (0-255), so technically each channel ranges from 0(black) to 1(white), then why we say that each image has a Red,...
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1answer
90 views
Want to study computer graphics
I want to study computer graphics but I don't have a strong foundation in mathematics. I am doing a computer science degree that doesn't cover computer vision, image processing or computer graphics, ...
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29 views
Deskewing and Cropping Scans using ImageMagick
Attempting to deskew and crop scans of a CD booklet using ImageMagick.
Here's one image which I've been using as an example on which to build my one-liner - https://mega.nz/#!jIQD3aqC!PbjG4_Xaq-...
2
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1answer
192 views
Downscaling texture via mipmap [DirectX 11]
I am implementing a post-processing effect in my DirectX 11 pet renderer. The post-processing pass is implemented by rendering a full-screen quad covered with texture containing original rendered ...
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0answers
72 views
How to separate, modulate, and reassemble spatial frequencies?
Background
I am trying to create a node in Blender that would allow me to do what you would do with an audio equalizer but on the spatial frequencies of an image: A sort of panel with eight ...
3
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1answer
85 views
Origin of blurring and colour distortion in monochrome diagrams
I am analysing a large number of PDF files from scientific articles, all of which contain images which (I think) were originally monochrome ( black/white).
The images have been extracted with Apache ...
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1answer
41 views
How to make the lines of a (binary) image dotted or dashed?
Let's say I had a binary image (i.e. only contains black and white pixels).
For example, this one:
How would I make all the lines in this image dotted or dashed?
In other words, the eyes would be ...
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0answers
60 views
How to project an image on spherical surface with least possible distortion
I did not know where to ask, I will try it here. I work in a local planetarium and I wonder if it is possible to edit an image in such way, that when projected on spherical cupola (diameter 8 m), it ...
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0answers
31 views
Are there some methods of preventing tools like FotoForensics from detecting manipulations?
I am asking this question purely our of curiosity. I do not look for step-by-step tutorial on how to manipulate a photo and making sure that it will be hard to detect it.
I was wondering, because ...
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1answer
106 views
How to translate the center of an equirectangular projection?
I'm trying to perfectly align two or more equirectangular photos of the same place taken from slightly different positions.
Using an example provided by openMVG I managed to get the relative position ...
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0answers
300 views
Lanczos filter implementation issue
I tried to follow Nathan Reed post Antialiasing: To Splat Or Not to implement splat method. The image I am getting thorugh the Lanczos filter is very different than Nathan. I do not understand where ...
3
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1answer
113 views
Tiled Image Palettization Algorithm?
In most cases today, image palettization consists of reducing the overall number of colors in an image to some fixed number globally. This is typically solved as a straightforward but computationally ...
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0answers
62 views
Why don't discretization errors occur with compute-shaded kernel filters?
An efficient compute-shaded image filter would be emitted with (screenX / [kernel width], screenY / [kernel height], 1) groups and one kernel in each group, allowing texels to pass into groupshared ...
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1answer
29 views
Can you generate your own HDRI maps without using photos?
For example, preparing a scene in Maya using standard lights and rendering out a panorama?
Could they also be made from scratch in photoshop using 32bit color?
Is there a reason why people don’t ...
3
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1answer
179 views
Adding noise to gradient
I found this picture
When you zoom in to any part of the image, the background looks a bit noisy/grainy. See pixels around "violent violet" label:
I'm trying to understand how to achieve the same ...
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1answer
715 views
Convert RGB image to YUV420 using a hlsl shader
I am new to shaders and I need to convert efficiently an RGB image to YUV420.
I can convert the RGB image to YUV420 with a simple c++ program that uses the
...
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1answer
98 views
How to shift color values of a single RGB channel
I’m a weaver and textile maker with no prior coding or programming experience. In researching and reading through posts on this and other message boards, I was able to find a lot of useful information,...
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1answer
54 views
Resolution issue of generating a PNG icon for macOS menu bar
Wonder if anyone has experienced this. When generating png image icons for macos. its recommended at 19x19 pixels. However, based on that, the icon (shield) that is generated is pixellated compared ...
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1answer
38 views
How to blend a segment of an image with another image
I want to put a segment of an image to another image. But to make it realistic I applied poisson blending. But the output is not good at all.
Output without poisson blending. The kid was cropped ...
3
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2answers
673 views
Calculate the average color of an image
I want to calculate the average color+opacity of an image. First I thought about just averaging all ARGB values component-wise, but this got really dark on images with a lot of transparency. I also ...
