Computer Graphics Stack Exchange
Computer Graphics Stack Exchange

Questions tagged [raster-image]

21 questions
7
votes
2 answers

Image rotation using FFT

I'm not sure how practical this might be but is it possible to use Fast Fourier Transform to rotate a raster image? To be honest, I never really understood FFT, but I saw it being used for JPEG, for example. What I try to say is let's pretend I can…
Ecir Hana
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6
votes
2 answers

Is there a image-format that support an array per pixel?

For a project dealing with deep semantic labeling of images I need a format that supports arrays of arbitrary length for each pixel of the image. The array is an array of integers. Which image formats support this?
smuseus
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5
votes
1 answer

Draw angles lines in raster graphics using bresenham line algorithm

I at the moment trying to draw some angled lines using bresenham line algorithm which can circulate a 2d array of size 21x21, as a line angled from 0 - 2pi. So the idea is that the program has to output the values which the lines pass through in…
Bob Burt
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4
votes
1 answer

Triangulated model rasterization: light-weight Python library

I have a 3D model, which consists of ~50 thousand vertices and 100 thousand triangles. Format is: there's array of vertices' coordinates and array of triangles, which has numbers of vertices (e.g., [1, 2, 5] -- triangle, which consists of first,…
Charlie
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3
votes
1 answer

Wrong color in .ppm file

I'm going through the rasterizer tutorial from Scratchapixel, but I encountered a problem with the generation of the .ppm file. Since something was off, I reduced the example to the bare minimum, so I currently simply generate a 512x512 image of a…
Francis Moy
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3
votes
1 answer

Image rotation algorithm

I would like to rotate a raster image by an arbitrary angle. I don't really care for speed: the rotation should be of highest quality possible. Could someone please suggest a suitable algorithm? I'm familiar with the rotation by three shears but I'm…
Ecir Hana
  • 1,459
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3
votes
2 answers

How is Raster and Random Scan Display different?

Raster scan display forms an image with pixel whereas a Random scan display works with Geometric primitives, but even a geometric primitve( a line) is made up of pixels so what is the difference?
pratik watwani
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3
votes
0 answers

Compute angles and thereby endpoints in a raster grid?

I am at the moment having some issues with computing an endpoint in a raster grid that is also a valid position in a graph. I am trying to draw a line between these two points, but as the point I am computing becomes negative, its position becomes…
Bob Burt
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3
votes
0 answers

Draw lines angled from 0 to 2 pi in a raster grid

I am trying to draw an angled line in a raster grid. The idea is to create a function that given a start point, a length and an angle, would give me the pixel positions that combined would give me a line at the specified angle, in a raster grid. I…
noob
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2
votes
0 answers

Normalization technique to increase spread of data in rgb space

I am visualizing a dataset. My technique is to encode the data into a rgb image with the channel range [0, 255]. The data clusters in a narrow range relative to [0, 255], however, so I'm not getting enough spread in the data to get a legible…
interwebjill
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2
votes
1 answer

Image saved as DDS with 16f format in photoshop has strange FOURCC text

I am analyzing the hex code for DDS files which are compressed via Nvidia's dds plugin in photoshop. I noticed something strange when having a 16 bit float file. This is the dialog: When I look at the header of this file it appears to not follow…
Samuel
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1
vote
0 answers

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-YPhrPu1APaRmYLKmCSx6pxbIUkaoQzOgM So far I've been…
Cicero
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1
vote
2 answers

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 the whole 3D model would be impossible, since the…
PyRulez
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1
vote
1 answer

How to use maximum resolution (pixel density) with OpenGL in MS Windows

CodeBlocks offers an example program in C, that uses OpenGL. It draws a single multicoloured rotating triangle. I have been building on this example. I am a novice in C and in OpenGL. I believe that I am using an old style of OpenGL coding (possibly…
Simon
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1
vote
1 answer

How to calculate spatial frequency of an image just in one direction?

FFT spectra is not what is needed; what I need is a histogram showing which frequencies are there in image in horizontal direction, and which one is dominant Such spatial frequency is usually known for a sinusoidal grating; I need the same property…
ivan866
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1
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