# Gpu acceleration of edge-based motion detection and machine learning  (Page 4/13)

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where Gx and Gy are the values of the partial derivatives along the x and y directions, respectively, at the pixel located at (i, j)of the image A.

A variety of different discrete differentiation operators exist to approximate the gradient of the image. The operator we choose in our implementation is the Sobel operator.

Like our Gaussian kernel, the Sobel operator (in both the x and y directions) is separable:

Thus, we perform two separable convolutions with the separated Sobel filter on the Gaussian-filtered image to obtaingradients in the horizontal and vertical directions, and determine the magnitude and angle matrices G and Theta fromequations (5) and (6).

## Non-maximum suppression and selective thresholding

Given the gradient magnitude and direction of the Gaussianfiltered image, the final step of the edge detection algorithm isto determine which pixels should be selected as edge pixels, and which should be rejected. We define two procedures, nonmaximumsuppression and selective thresholding, to gain a reasonably accurate edge map from the gradient.Non-maximum suppression selects and rejects edge pixels according to the following criteria:

1. Pixels whose gradient magnitude is below a userdefined low threshold, tl, is immediately rejected
2. If the gradient magnitude of a pixel is greater than that of the pixels in either direction of the gradient angleof that pixel, then the pixel is accepted if its gradient magnitude is greater than a user-defined high threshold,th

The selective thresholding technique extends on the procedure of non-maximum suppression. For any pixel that passes crtiteria(2) (maximized, relative to the neighboring pixels, along the gradient direction), consider an a x a box around the pixel.If any pixel within the box exceeds the low threshold tl, then the pixel is accepted. This technique attempts to catch pixelsthat might “connect” ridge pixels identified by criteria (2) but fail to satify the criterion themselves, in order to create morecontinuous edge lines.

## Gpu parallelization and cuda implementation

We begin with a parallelized implementation of separable convolution, since the same convolution operation is applied for both the initial Gaussian low pass filter and the edge detectingSobel filter. Our parallel implementation involves first independently computing the convolution with the horizontalfilter (h2 in Equation (2)), then convolving that result with the vertical filter h1. In computing the output y[m; n]at every index (i, j), we launch a kernel with 16 threads per block,where the total number of blocks along one dimension is equal to the size of that dimension divided by 16. For our5312 x 2988 test images, this corresponds to 332 blocks in the horizontal direction and 186 blocks in the vertical direction,each with 16 computational threads.

#### Questions & Answers

where we get a research paper on Nano chemistry....?
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
what about nanotechnology for water purification
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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