Questions tagged [reconstruction]

The tag has no usage guidance.

33 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
180 views

Stochastic process inference from partial observations

Consider a set $U$. My signal is a piece-wise constant "function" $Sig: t \mapsto s$, i.e. the signal at time $t$ equals to some subset $s \subset U$. One can see $Sig(t)$ as a stochastic process. ...
196 views

31 views

What is the best way to separate data using compressive sensing?

In the book Compressed Sensing by Kutyniok et al, the author talks about data separation using sparse representation. In summary, if we have a signal vector $x = x_1 + x_2$ Then, it would be ...
91 views

Recreating an image from random samples?

Assume that I have samples from an image, but the samples aren't on a grid, but instead there are multiple lowres versions of the original where the sampling locations are slightly jittered, so the ...
56 views

How to reconstruct 2D flat image from a series of pictures of a tube

I have pictures of an oesophagus (ie a tube) taken under standard white light looking down the tube. I have about 10 images taken over 20cm in series. The image looks forward down into the tube and ...
256 views

How to reduce reconstruction noise from a filtered back-projection reconstruction of a circularly symmetric image?

I need to perform tomographic reconstruction of an axially symmetric object. Because of the axial symmetry only one projection of the object (one angle) was taken. I implemented the filtered back-...
165 views

Calculate the intersample peak of a periodic sequence?

Similar to Calculating the PDF of a waveform from its samples, but for periodic sampled signals, and I just want the peak. Is there a way to calculate the highest inter-sample peak of the ...
26 views

Sampling with Rectangular Pulse and Nyquist Condition

The classical Nyquist theorem assumes that the sampled signal is obtained by multiplying the signal with dirac-delta functions separated by width 1/f_sample or less. Given such sampling we can ...
37 views

Convolution of a discrete continuous function for reconstruction

From chapter 9 page 198 of https://github.com/t4world/Computer-Graphics/blob/master/Fundamentals-of-Computer-Graphics-Fourth-Edition.pdf I am confused as to what this book's description is saying ...
14 views

Projecting a 3D point onto Multiple Cameras in the Same Projective Frame

I need a sanity check. I think I understand the following, but I just can't get it to work. Suppose that I calculate a trifocal tensor $T$ from three sets of corresponding points in three images (...
14 views

Three Projective Cameras in the Same "Projective Frame" - What Can I Do With This Info?

[I originally posted this under Mathematics, but I didn't get any replies. I thought I'd try here.] In Hartley & Zisserman's Multiple View Geometry in Computer Vision, in the chapter on trifocal ...
86 views

Power Spectral Density Reconstruction

I am from an ML background and I am working on MP3 audio reconstruction and I have managed some amount of spectrogram reconstruction but I have noticed that the higher frequency end of the generated ...
78 views

Reconstruct a signal via continuous wavelet transform (CWT)

I want to use the continuous wavelet transform (CWT) to modify the amplitude of a signal in the frequency domain (in a specific frequency band) and then reconstruct the signal. I want to do it by ...
38 views

2D IFFT implementation

I have a problem where I need to obtain 2D IFFT of a $81\times64$ signal. However, if we denote the reconstructed image $I_{m,n}$, its coordinates will be $M\times N$ but the k-space signal is sampled ...
120 views

Reconstruction of sampled band-pass signal

I am pretty new to signal processing. I am currently trying to reconstruct a sampled band-pass signal created with the filtfilt and ...
47 views

What are the constraints in design of discrete orthogonal wavelets?

Can anyone point me to literature that explains a quote from here : Why is a wavelet transform implemented as a filter bank? So not all wavelets can be implemeted perfectly (invertible) with ...
734 views

Recover Audio from Spectrogram Image

I have applied transformation(Constant Q Transformation) to my audio time domain signal, this gives me Frequency vs Time representation. Now, the CQT values consists of complex values(84*260), but ...
143 views

Construct a signal that is multiplied by a white noise?

Can we reconstructs a signal after it is being multiplied (not added) by a random noise (not with the normal distribution)? Lets say I have S=10*sin(2*pi*5*t) for t=[0:.001:1] and I have a random ...
910 views

What are the frequency components of a sampled signal after low-pass filtering?

A continuous signal $x_a(t)$ is a linear combination of sinusoids of frequency 250 Hz, 450 Hz, 1 kHz, 2.75 kHz and 4.05 kHz. The signal $x_a(t)$ is sampled at $f_s=$1.5 kHz, and the resulting digital ...
78 views

Reconstructing a partially deleted image through wavelets

I am trying to form an approximation of the wavelet transform from a partially sampled image. Reconstruction in the 1D case is easy. We have $w = h x$, with $w$ as the wavelet coefficients, $h$ as ...