Questions tagged [raster-image]

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7 votes
2 answers
4k views

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 ...
Ecir Hana's user avatar
  • 1,459
6 votes
2 answers
158 views

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 ...
smuseus's user avatar
  • 61
5 votes
1 answer
2k views

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 ...
Bob Burt's user avatar
  • 183
4 votes
1 answer
1k views

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,...
Charlie's user avatar
  • 161
3 votes
1 answer
2k views

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 ...
Ecir Hana's user avatar
  • 1,459
3 votes
1 answer
740 views

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 ...
Francis Moy's user avatar
3 votes
2 answers
564 views

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's user avatar
3 votes
0 answers
61 views

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 ...
Bob Burt's user avatar
  • 183
3 votes
0 answers
65 views

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

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 ...
noob's user avatar
  • 31
2 votes
1 answer
349 views

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 ...
Samuel's user avatar
  • 123
2 votes
0 answers
62 views

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 ...
interwebjill's user avatar
1 vote
1 answer
317 views

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 ...
Simon's user avatar
  • 183
1 vote
1 answer
828 views

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 ...
ivan866's user avatar
  • 111
1 vote
2 answers
836 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 ...
Christopher King's user avatar
1 vote
0 answers
286 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-...
Cicero's user avatar
  • 11
0 votes
1 answer
431 views

Screen Space anti aliasing?

I have the following challenge. I am given a black and white image with rasterized lines. Given this input, I want to extend the edges to cover more than one pixel and antialias the edges. My first ...
Makogan's user avatar
  • 1,706
0 votes
1 answer
85 views

How to identify images with similar content?

There's a set of pictures that if you take them literally, they're different. That is, there can be two images of the same thing among them, only in different hue. In addition, among these two, there ...
user309485's user avatar
0 votes
1 answer
120 views

Is it possible to convert Polar to Cartesian coordinates and map result to an image using opengl?

Is it possible to convert Polar to Cartesian coordinates and map result to an image? I want to get the output same as the distort depolar 0 from image magick. https:...
code0x00's user avatar
  • 101
0 votes
0 answers
24 views

Animated bitmaps with 2 colours only

I want to create an animated GIF, but instead of 8-bit 256 colours, my data is comprised of binary bitmaps of black/white pixels. Can GIF accommodate this, or are pixels in GIF always 8-bit indices? I ...
Bram's user avatar
  • 270
0 votes
0 answers
42 views

How to render a rotated raster image with lesser aliasing

I am wondering about techniques for rendering a rotated and or scaled raster image. Currently I use the following algorithm Render everything at double resolution and store the result in ...
user877329's user avatar
0 votes
0 answers
64 views

How is the image reconstruction filter on the path space defined in terms of the filter on the raster space?

Say we have a image reconstruction filter $h:R\to\mathbb R$ defined on the raster space $[0,w]\times[0,h]$, where $w,h\in\mathbb N$ define the width and height of the image plane in pixels, ...
0xbadf00d's user avatar
  • 203