Questions tagged [image-processing]
The image-processing tag has no usage guidance.
139
questions
2
votes
1answer
26 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 ...
2
votes
0answers
50 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 ...
1
vote
0answers
29 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 ...
0
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0answers
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 ...
0
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0answers
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 ...
0
votes
0answers
20 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?
1
vote
1answer
36 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 ...
1
vote
1answer
66 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 ...
1
vote
1answer
49 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 ...
0
votes
1answer
59 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 ...
3
votes
2answers
144 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", ...
1
vote
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 ...
1
vote
1answer
30 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?
1
vote
1answer
87 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-
...
0
votes
2answers
69 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
0
votes
0answers
59 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 ...
0
votes
3answers
136 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 ...
1
vote
1answer
56 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
votes
2answers
95 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,...
0
votes
1answer
81 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, ...
1
vote
0answers
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
votes
1answer
139 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 ...
0
votes
0answers
47 views
Which method does the painting software use to deform the image so fast?
I tried to make my own painting software. I used OpenCV in my job so I use openCV here.
I want to make a image deformation function like the following : use mouse click on GUI to deform the image. I ...
3
votes
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
votes
1answer
83 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 ...
0
votes
0answers
18 views
How can you use a rectangular object in an image and use its edges as a new coordinate system?
As a quality inspection vision application, we have images of printed circuit boards. The PCBs are rectangular in shape and the distance from the camera to the PCB is fixed. The relative location of ...
0
votes
1answer
37 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 ...
0
votes
0answers
21 views
Export images in sketchup models
I built a model on Sketchup and imported png images in it to fill some faces.
At first time, I tried to fill with a texture pointing to the desired image but it wasn't centered.
Then when I export my ...
2
votes
0answers
54 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 ...
0
votes
0answers
40 views
How do I represent the grid patterns of the image in the included figure with a DITHER MATRIX?
The problem statement is:
"Represent the grid patterns in [the the figure linked below] with a dither matrix."
The figure is:
https://www.docdroid.net/d90WXko/figure.pdf
Apparently, according to the ...
1
vote
0answers
30 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 ...
0
votes
0answers
20 views
Open source tools for extracting hi-res images from video
I found recently an article in which they describe a technique to extract high resolution images from a standard quality videos.
The technique exploits the fact that in a typical video the camera ...
1
vote
1answer
75 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 ...
0
votes
0answers
259 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
votes
1answer
104 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 ...
1
vote
0answers
61 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 ...
0
votes
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
votes
1answer
148 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 ...
1
vote
1answer
522 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
...
4
votes
1answer
90 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,...
0
votes
1answer
50 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 ...
1
vote
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
votes
2answers
581 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 ...
0
votes
0answers
47 views
How to ensure that the raytrcing coordinate system is teh same as the projection one?
I have 2 shading models right now, one is using voxels the other one is the standard projection absed renderization method.
Putting them side by side I have noticed that no matter what I do one is ...
0
votes
1answer
401 views
Difference between Cropping, Scaling, Resizing & Changing Aspect Ration of an Image?
I've got a new task related to image processing in a website. I am too confused in understanding different terms used with sizing of an image. What is the difference between:
Cropping an image
...
1
vote
1answer
92 views
Quick 2-color quantization for small images
So I have a small (8x8 pixel) image in 24-bit color. I want to be able to (quickly) generate a color-quantized version of the image that only has two colors.
One naive approach is to cluster a luma ...
2
votes
2answers
111 views
What blend mode is this?
I asked this on Graphic Design but was unable to get any relevant help from them.
I'm trying to reverse engineer a blending mode I've seen on a picture:
This image was created by someone else ...
1
vote
0answers
51 views
Tanget plane of an image
My problem is about tangent plane. I have an image (m by n). I obtain surface normal vector using machine learning methods. Then i would like to obtain tangent plane for this surface normal.
To ...
2
votes
2answers
353 views
How to generate the stereographic projection of a 3D model
Given a 3D model, is there a way to stereographically project it to a 2D image? In particular, I would only need a little more than half the model (the lower half) to be mapped to the plane (mapping ...
4
votes
1answer
413 views
Creating depth map from a 2-D image?
My question is oriented towards the generation of depth map using any of the state of the art depth sensor.
However, each of these method required the presence of an 3-D object in front of the sensor....
