Questions tagged [median-filter]

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The Logic Behind Cascading a Moving Average Filter After a Median Filter

Why do we cascade a median filter and a moving average filter? I know how each filter performs, but I do not know the difference between these two filters in denoising application and what is the ...
mohammad rezza's user avatar
0 votes
1 answer

Hampel Filter and constant data

I implemented the Hampel Filter (see here) for outlier removal, however I noticed in instances when the data in the sliding window is stationary and its standard deviation is very low, the filter will ...
MilTom's user avatar
  • 101
6 votes
2 answers

How to Deal with Outliers in Measurement of a Simple Model of Kalman Filter

I am trying to find the one-dimensional velocity of a car based on position measurements, similar to the Wikipedia article. The car moves at almost constant speed and I am mostly interested in ...
Crenguta's user avatar
1 vote
1 answer

Invertibility of a system with a median filter

I know is that for a system to be invertible it should be mapping one-one, but what happens in this signal?, I feel like I need to know the value of $x[n]$ before. $y[n]= \mathrm{median}\{x[n-1],x[n],...
Pedro Errazuriz's user avatar
1 vote
0 answers

How to choose median filter width?

In my signal processing pipeline, I normally expect data sampled at 100Hz, on which I then apply a median filter of width 10. My question is: How should I change the width for data sampled at ...
Michael's user avatar
  • 151
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0 answers

Alternatives to the median filter

I have a embedded system where I get some type of sensor readings with varying frequency between 0.3 to 1 Hz. Sometimes these readings may have impulse like noise. To filter out this noise, I've ...
Şener Yılmaz's user avatar
2 votes
1 answer

Salt and Pepper impulse Denoising opencv

I am creating a generic method to work on salt and pepper noise and variants. The example images are as shown below : I tried few methods, such as ...
Lakshmi Narayanan's user avatar
3 votes
0 answers

Inconsistant Variation in BLE Beacon RSSI Values for Distance Measurement

I am developing an application to estimate the distance to a BLE Beacon using its RSSi values measured from a Mobile Phone. But when I started to collect data I could see that they varied so much that ...
Ravindu Rashmin's user avatar
1 vote
0 answers

Accounting for Mechanical Vibration in Accelerometer Readings

I am very new to DSP so please forgive any ignorance within this post. I am working on a device which has a 6-axis IMU measuring acceleration and rotation. The device itself is attached to a ...
soplu's user avatar
  • 11
0 votes
1 answer

Extract jump location in data

I would like to extract the location of data jump (see figure below), the difficulty is that the data are noisy as you can see. I try with a median filter or a other regularization and it could move ...
user3601754's user avatar
0 votes
1 answer

is there a way to apply a median filter diagonally?

For example, some studies show how to smooth a spectrogram with a 2D median filter vertically and horizontally (along time or frequency). My question is how would I apply 2D median filter along the ...
Dan's user avatar
  • 70
2 votes
2 answers

Forward/reverse median filter. Reference needed

I am using the double median filtering of my data. For this, I perform median filtering of the signal in forward direction, then in reverse direction (from end to start). Results are averaged. Example ...
zlon's user avatar
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7 votes
2 answers

Why is the median filter called 'edge-preserving'?

I want to know about median filtering. Recently, I read that it is best for preserving edges. But how does it preserve edges? I need complete knowledge of median filters. Why it is non-linear filter ...
sufi's user avatar
  • 71
1 vote
2 answers

Median filter problems about the output image

An image has an isolated cluster of dark pixels on a light background. The area of the cluster is $(n - 1)/2$ pixels where $n$ is an odd positive integer. What happens to the cluster when it is ...
jianhua guan's user avatar
6 votes
4 answers

How to build a median filter function?

What algorithms are there for 1-d median filtering (sliding median, rolling median, running median), similar to MATLAB's medfilt1? Of interest would be a reference ...
dunklevision's user avatar
12 votes
3 answers

Moving average vs. Moving median

I have read in many places that Moving median is a bit better than Moving average for some applications, because it is less sensitive to outliers. I wanted to test this assertion on real data, but I ...
Basj's user avatar
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1 vote
2 answers

Median Filter for salt and pepper noise removal

Why median filter is considered as good for removal of salt and pepper noise? What are the other filters used for the same?
Rohith K D's user avatar
9 votes
1 answer

What is a "Hampel Filter" and how does it work?

One of the new functions in the MATLAB Signal Processing toolbox for R2015b is the Hampel Filter. It appears to be used for outlier removal and from the examples, it looks like it might do a better ...
Damien's user avatar
  • 606