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High-level python implementation

The Python OpenCV library exposes an API for the entire Canny edge detection algorithm. The Canny algorithm issimilar to, but more nuanced than, our algorithm, substituting our selective thresholding procedure for hysteresis. However,the end results are very similar. As is evident from Listing 5, the procedure is very straightforward.

Listing 5. python implementation of canny edge detection with opencv

LOW_THRESHOLD = 100 HIGH_THRESHOLD = 200edges = cv2.Canny(img, LOW_THRESHOLD, HIGH_THRESHOLD)

Motion detection algorithm

Our motion detection algorithm compares the edges from two frames temporally separated by a small interval of time and attempts to estimate regions of the frame that exhibitmovement or motion. This process is then repeated continuously to provide a real-time visualization of the regions ofmovement in a continuous video stream. The motion detection algorithm we present is composed of the following steps:

  1. Given two frames F1 and F2 separated by a time interval of Δt, compute its edges E1 and E2.
  2. Create a strict binary difference matrix D0 between E1 and E2 whose value is high at locations at which anedge is present in frame but not the other, and low at locations at which both frames have an edge or no edge.
  3. Apply a parameter-controlled movement tolerance thresholding operation to the matrix D0 to obtainmatrix D, in order to suppress potential false positives of detected motion from incidental camera movement.

F1 and F2 are obtained by sampling frames from a continuous video stream, a task aided by the OpenCV C library.Thus, the time interval Δt will be small enough for a realtime algorithm. The edges E1 and E2 are computed with theedge detection algorithm of Section II. Below, we explore, in greater depth, the procedures for building a thresholdeddiffrence matrix and finally estimating the motion area by analyzing a spatial difference density map.

Thresholded frame-by-frame difference map

The preliminary requirement in determining areas of motion from two frames is a systematic method of determining andquantifying the differences between two frames separated by a small Δt. Intuitively, areas of motion within the time intervalΔt should exist at locations at which the difference between the two frames is large. This process is then continuouslyrepeated for every pair of input frames in order to create a realtime motion detector. In our algorithm, we quantify differenceson a binary basis using edge data from our edge detection algorithm, then determine motion locations from a thresholdeddensity map of the difference matrix D. More formally, we begin with a matrix D0 created from asimple comparison of E1 and E2. Then, for each location (i, j) in D0, a thresholded differencematrix D is created by considering a box of constant size b x b around that pixel and suppressing the value of the surroundingpixels to 0 if its value matches that at D0[i,j]. This step isdesigned to reduce false positives of motion detection arising from stray movement of the frame (e.g. camera shake). Thecomputation of D is demonstrated in Algorithm 2. The output matrix is then used as input to building a spatial differencedensity map, from which we estimate motion locations.

Questions & Answers

find the 15th term of the geometric sequince whose first is 18 and last term of 387
Jerwin Reply
The given of f(x=x-2. then what is the value of this f(3) 5f(x+1)
virgelyn Reply
hmm well what is the answer
Abhi
how do they get the third part x = (32)5/4
kinnecy Reply
can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
ninjadapaul
20/(×-6^2)
Salomon
okay, so you have 6 raised to the power of 2. what is that part of your answer
ninjadapaul
I don't understand what the A with approx sign and the boxed x mean
ninjadapaul
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
ninjadapaul
oops. ignore that.
ninjadapaul
so you not have an equal sign anywhere in the original equation?
ninjadapaul
hmm
Abhi
is it a question of log
Abhi
🤔.
Abhi
Commplementary angles
Idrissa Reply
hello
Sherica
im all ears I need to learn
Sherica
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Tamia
hii
Uday
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
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Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
y=10×
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Elec 301 projects fall 2015. OpenStax CNX. Jan 04, 2016 Download for free at https://legacy.cnx.org/content/col11950/1.1
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