10 votes
Accepted

Number of dimensions? Color image vs gray scale image? Colour video vs gray scale video? Especially in the context of MATLAB

Color images are usually modeled as a vector valued function of 2D: $$ I : \mathbb{R}^{2} \to \mathbb{R}^{3} $$ Namely for 2D coordinates input it outputs 3 values (RGB). Hence images are 2D functions....
  • 42.4k
5 votes

Slicing an Image into Tiles According to Content

Under the following assumptions (Written for the vertical lines, same for the horizontal): The background is uniform. There at least a gap of 2 background pixels between the closest objects on ...
  • 42.4k
4 votes

How to Draw a Line at Non Integer Pixel Coordinates on an Image

A long time ago I wrote an article on drawing lines with the Wu-Line algorithm. This can be used to draw lines from non-integer coordinates. The effect is very nice to see when animated. You can still ...
4 votes

Number of dimensions? Color image vs gray scale image? Colour video vs gray scale video? Especially in the context of MATLAB

My answer became quite long. So normally a digital signal is 1D, a digital image is 2D, a video is 3D. But it can get complicated. Long introduction on mathematics for the start. In mathematics, the ...
3 votes
Accepted

Math for projecting 3d world point to VR image coordinates

Your images look like being shot with an angular fisheye projection . Also, to account for epipolar geometry of stereo images, you should include the fundamental matrix into the transform engine of ...
  • 1,425
2 votes

What helped you in reading and implementing papers and coming up with original ideas in computer vision/graphics?

People working in computer vision/graphics may have very different backgrounds: computer programming, high-performance computing, signal processing, image analysis, optimization, machine learning, etc....
2 votes

Number of dimensions? Color image vs gray scale image? Colour video vs gray scale video? Especially in the context of MATLAB

Depends what "dimension" means, but I'll say 2D, and interpret in context of convolutions. A convolution operates on 1D: (channels, time) 2D: ...
1 vote

Slicing an Image into Tiles According to Content

Thanks to user Ash for giving me a key insight: Measuring the HSL (hue, saturation, and lightness) of the pixels can help detect where the gaps are. If I take one horizontal row of pixels that goes ...
  • 181
1 vote
Accepted

Relation between ppi and screen(icon) size?

I would suggest that this question is related to spatial resolution and therefore a very basic Image Processing question. The way it is stated however, does make it sound off-topic for the DSP board. ...
  • 10.1k
1 vote

How can I graph the amplitude for a given frequency window over time?

Do you have access to MATLAB or Octave or similar? In general, I would: - Compute the spectrogram (STFT) of the signal you're interested in. - Perform any required scaling to get a good amplitude ...
  • 63
1 vote

How to perform 2D image rotation by FFT based image translation using matlab?

The following is the completed code that yields the expected result: ...
  • 27.1k

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