Dipan Mehta
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What Is the Relationship Between a Kalman Filter and Polynomial Regression?
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56 votes

1. There is a Difference in terms of optimality criteria Kalman filter is a Linear estimator. It is a linear optimal estimator - i.e. infers model parameters of interest from indirect, inaccurate and ...

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What are some good signal and image processing blogs worth following?
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33 votes

There are many for different subjects - Efg's algorithm collection : http://www.efg2.com/Lab/Library/ImageProcessing/index.html DSP Forum : http://www.dsprelated.com/ Data compression - http://...

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Simplest way of detecting where audio envelopes start and stop
29 votes

What you really want to do is essentially called as Voice Activity Detection or speech detection. Basically any pure speech signal (which contains no music) has three parts. The voiced sound - ...

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List of possible image features for content based image retrieval
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25 votes

The field itself is too vast. So i doubt you can have a fully exhaustive list here. However, MPEG 7 is one of the primary effort in standardizing this area. So what is included here is not universal -...

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What Resources Are Recommended for an Introduction to Signal Processing (DSP)?
18 votes

The below three are the best referred Text books on this subject. Discrete-Time Signal Processing, Prentice-Hall Signal Processing Series by Alan V. Oppenheim, Ronald W. Schafer, John R. Buck. ...

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Libraries for Voice Activity Detection (Not Speech Recognition)
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14 votes

In my answer to your that question, I had mentioned that Voice Activity Detection is a standard feature for codecs like G.729 and such others. You should look for reference encoders and decoders ...

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What does the "smoothing optical flow" mean?
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14 votes

Optical flow is an approximation of the local image motion based upon local derivatives in a given sequence of images. That is, it specifies how much each image pixel moves between adjacent images. (The ...

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Detection of circles (ellipses) in 2D point cloud
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14 votes

The best ideas that exactly tries to solve this problem is Hough Transform . Basically, the signal in hough space will be r, x, y co-ordinates. Here r stands for radius and x,y stands for center. ...

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What is the least JPG-compressible pattern? (camera shooting piece of cloth, scale/angle/lighting may vary)
11 votes

There is a difference between JPEG exploitable and Transform Compressible. Take the white grainy noise of TV set for example. A general white noise is spread maximum in the frequency and hence ...

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Filtering kinda "half-toned" image for OCR processing
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9 votes

What you really require is probably some morphological operation like dilation followed by erosion. This is called as Closing operation. May be in your case- just dilation itself might be good. ...

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How is the Laplacian used for Unsharp Mask?
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9 votes

The regular sharpening i.e. high pass filter, essentially applies the inverse filter of blurring. Basically, when you do unsharp masking - instead of subtracting the blurred image, you add the edge ...

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How to remove stains from images?
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8 votes

This is not a complete and crisp answer however, i am leaving you with at least some approach for you to fight with. (I would be very glad to know if you have results). Take a look at these questions:...

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Extremely computationally intensive image/video compression schemes which offer better compression than industry standard JPEG/H.264
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8 votes

There are various aspects of compression - whether you are referring to image or video. (May be audio is totally different so i am not referring this here). If you really look at the history of ...

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Do the DCT coefficients correspond to particular pixels?
7 votes

What I'm planning to do is to apply edge detection to obtain the locations/indices of the pixels and then get their corresponding DCT Coefficient As others stated in the comment - any pixel in ...

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Purpose of interleaving in OFDM systems
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7 votes

Interleaving is not specific to OFDM. It is an age old technique used for improving error correcting codes. Basically, most error correction coding techniques are good at suppressing bit-wise errors ...

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What Are the Best Algorithms for Document Image Thresholding (Example Inside)?
7 votes

Nikie's answer seems best and also seems to be working and producing results. So it's a clear winner. However, just to documentation i adding one more reference, that could just be very fast. This ...

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What Is the Algorithm Behind Photoshop's "Black and White" Adjustment Layer?
7 votes

Each (color) image is composed of RGB components. when you add (or reduce) a constant value to all pixels only in RED components you will see the effect equivalent to moving the RED tab towards the ...

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Lip sync over IP
6 votes

Before going to IP, I would like to draw your attention to lip synchronization techniques used in broadcast domain. This is also one of the toughest ones because here not only you want to maintain a ...

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What image-processing techniques are ideal for this particular shift/scale invariant template matching?
6 votes

Broadly speaking there are two primary approaches to solving this problem: a. template matching or b. matching with a parameterized model. Personally, given the simplicity of the model, i would ...

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Adaptive Thresholding for liver segmentation using Matlab
6 votes

I saw the link of the paper (of SS Kumar) you referred and the link where you got the code (HIPR) are two different algorithms - even though both sounds like Adaptive Thresholding First i would like ...

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What segmentation methods can be used for simple images?
6 votes

One of the simplest method you can use is "Region growing" scheme. Here the algorithm starts with a seed points, and keeps registering the pixel surrounded by it as long as the region as a whole has ...

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What Properties Make Certain Wavelets "Better" Than Others In Image Compression?
6 votes

As a very short answer - any transform is better than other transform when it has, what is known as "energy Compaction property" which is explained as below: "when only a small fraction of transform ...

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What is the optimal filter?
5 votes

The question is rather vague or inaccurate really; or I haven't understood it well. I would start with saying "there is no such a thing as a 'best' filter (for all use)". A filter is optimal only ...

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How do the motion vectors work in predictive coding for MPEG?
5 votes

To simplify your confusion - there two processes : 1. Motion estimation 2. Motion compensation Before we talk about the estimation, we should talk about the Motion compensation. Let say, the $ ...

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How should a moving average handle missing data points?
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5 votes

As a general impression, regression would work better in automatically fitting the missing points rather than a moving average filter you have chosen. If you use an AR (auto regressive filter) or ...

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Connecting edges detected by an edge detector
5 votes

This might not be complete solution, but will give you good direction. Basically, what is the key criteria of to say that edges match? That "locally" the gradient of the edge matches and to some ...

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Embedding digital ID in audio signal, and retrieving it
5 votes

You approached the problem of Embedding the ID by custom encoding. This is limiting. From the URL you send: A startup called SonicNotify embeds inaudibly high-pitched audio signals within ...

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Determining the resulting pixel value before creating a compressed JPEG image
5 votes

To give you an upfront answer your question you want to determine the $pixel-values$ from $DCT-Coefficients$ probably there is nothing on earth better than doing IDCT itself! However, leaving aside ...

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Does every 8 by 8 DCT matrix have a valid (in range) IDCT?
4 votes

All images blocks that are applied by DCT matrix have a valid IDCT - i.e. they can always bring back original pixels and in general inverse transfer is theoretically as well as computationally viable. ...

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How can I remove shadows from an image?
4 votes

There are several methods that talk about Shadow detection essentially work against known background. There is no absolute notion of what is shadow just by looking at a pixel color. However, you need ...

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