Signal Processing Stack Exchange
Signal Processing Stack Exchange

Questions tagged [detection]

86 questions
17
votes
2 answers

Detection of a Circle in Noisy Image Data

I have an image that looks like the one below: I'm trying to find the radius (or diameter) of the circle. I have tried using circular Hough transform (via matlab's imfindcircles(bw,[rmin rmax],'ObjectPolarity','bright')) , and by fitting to a…
bla
  • 576
  • 1
  • 3
  • 14
9
votes
0 answers

Help in Retraining a HOG Descriptor using SVMLight

I am currently trying to count cars using OpenCV 2.4.4 with a HOG descriptor. Because a model for car detection is not available in OpenCV, I am creating my own model using SVMLight and a dataset of cars from the INRIA car dataset here (positive and…
bonchenko
  • 201
  • 1
  • 3
8
votes
1 answer

Suggested Preprocessing methods for OCR on Circular Images

Hello this is my sample image I am going to do real time character detection on images like that. I've tried SURF, SIFT, MSER and template matching on original image without any preprocessing. I can detect characters but when the image changes this…
Anar Bayramov
  • 247
  • 1
  • 4
7
votes
3 answers

How to classify accelerometer data?

I am trying to detect if a car did accelerate or did brake by using the accelerometer of the iPhone. In the figure below I plotted the collected data. (To collect the data the phone was laying flat in the car facing the top of the phone to the…
riik
  • 171
  • 3
6
votes
3 answers

How detect signal from noise?

I'm trying to detect when a signal is "on" from samples I have. Those samples come from a software defined radio, if that matters, and the signal i'm trying to detect is a WiFi signal. The problem is separating "noise" from "signal", as I did by…
user35067
  • 61
  • 1
  • 2
6
votes
2 answers

What Is the Best Color Space to Work with for Hand Detection: RGB, HSV, or YCrCb?

I'm working on hand gesture recognition using C#. I'm using OPENCV for skin detection but its performance is not optimal. So I decided to do some filtering based on color space, but I do not know what color space is the most suitable for this…
The Beast
  • 161
  • 2
5
votes
1 answer

Detecting the original bandwidth of upsampled recordings

I have a set of recordings sampled at 16khz, but some of them are upsampled from 11khz and some from 8khz. Quite some of the recordings are noisy. What is the best way to classify the recordings according to the original bandwidth? I know some…
Nikolay Shmyrev
  • 1,099
  • 5
  • 11
5
votes
0 answers

Filtering Corners Detected on Multiple Scales

I made a multi-scale Harris corner detector (inspired by MOPS) which is simply a Harris corner detector performed on several scales (i.e. subsampled versions of the same image). This effectively make the detector more robust to noisy/blurred images…
Libor
  • 4,135
  • 21
  • 37
5
votes
0 answers

detect what is noise in audio signal

I'm trying to filter noise from an audio signal. The signal was and is going to be recorded in a city environment which always contains some white/pink noise. At this moment I'm using two options to filter the noise. Spectral Subtraction algorithm…
Carlos_Rei
  • 51
  • 3
5
votes
4 answers

Note Recognition Software

I'm wondering if anyone knows of any open source solutions to note recognition. I'm planning on building a program for online sheet music, which recognizes your notes, and tries to tell you what you can improve, and how. However, for piano for…
Marianos
4
votes
1 answer

How to detect underdamped harmonic signal?

I would like to ask what could be the easiest way to detect the presence and beginning (no more, no less) of under-damped harmonic signal in a collect of ultrasound data. I have some acquired data which is presented in 2-D image form, where vertical…
Specku
  • 141
  • 2
4
votes
1 answer

How to detect the presence one- and two-dimensional patterns in distributions of spatial points?

I have many point patterns, and I want to detect those patterns that have points arranged in lines that may be curved, intersected or broken. For example, on the following picture, the upper left pattern is not interesting but other three patterns…
Vladislav Gladkikh
  • 155
  • 5
4
votes
2 answers

Detect a Frequency Change in a Step Wise Frequency Chirp

I am driving a system with a step-wise frequency chirp from 50-400 hz with a frequency step of 0.01 hz. I am having difficulty identifying the points of frequency change as the data collected has an indeterminate amount of time at 50 Hz and an…
Jon
  • 41
  • 1
4
votes
1 answer

Radar signal processing flow chart

I'm new to Radar in general, and I'm studying RADAR using online resources. I came across the following slide which shows the process flow of the Radar signal processing. The thing I don't get in the figure is the signal processing block and the…
Jung_Zheng
  • 41
  • 2
4
votes
1 answer

Should I Use a High Pass Filter (HPF) or Low Pass Filter (LPF) to Enhance the Features for Image Splicing Detection?

I'm recently learning image splicing detection. I've already known image splicing can bring some abrupt changes to an image,which generate the sharp edges.And sharp edges correspond to high frequency. And I want to extract features from images for…
Vivian Lee
  • 131
  • 1
  • 6
1
2 3 4 5 6