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This module carries instructions to correctly identify and match the images from the database.

Give me your digits!: identification algorithm

Feature extraction

In general

Now that the image is in the format of the database (28 x 28 grayscale), a method to match the image to the database must be explored. To achieve a high accuracy rate in matching from the database, a feature extraction method could be employed. Three methods will be explored: pixel matching, Principle Component Analysis (PCA), and two-dimensional Fast Fourier Transform (2D FFT).

Pixel matching

Pixel matching, the first method, is not to use any feature extraction. It is meant to match the image to the database in the most obvious manner. The identifier literally compares the images pixel by pixel and computes the mean squared error (MSE, sums up all the error). In fact, the following two methods employ pixel matching after the transforms.

Pca principle component analysis

Next, the Principle Component Analysis, employs an orthogonal linear transformation that transform the matrix to a new matrix such that the greatest variance of the projection of the data comes to the first coordinate (principle component), and the second highest variance to the second coordinate, and so on. For our purposes of matching the image from the database, the PCA actually performs very poorly. This is due to the fact that because the images so closely resemble each other (same variance). This similar variance is attributed to it being so small (28 x 28) and gray scale. As a result, the PCA transform of the images are almost identical for this specific database. Experimentally, roughly a 30% matching rate was observed, which is barely better than random guessing. PCA would be much better suited for large images with great variances.

2d fft

Last, our method of choice, is the two-dimensional Fast Fourier Transform. Recall that the FFT is a form of Discrete Fourier Transform. The 2D FFT, for our purpose of image extraction, is the a frequency representation of the images. Note that the magnitude of the FFT must be used to compute the MSE. Also, the Matlab fftshift command was used shift the high frequency to the center.

The formatted images and their 2D FFT’s


In general

Once the input images are transformed, they are now ready to be matched and identified by the images in the database. Three algorithms can be used: a) finding the lowest MSE, b) finding the best averaged MSE, and c) finding the highest frequency digit from the best one hundred MSE.

Absolute nearest neighbor

The first algorithm finds the database image that has the lowest MSE from the input image out of all the randomly selected database images and declares that the input image is the digit the matched database image represents. In other words, it is an absolute nearest neighbor approach. The accuracy of this method depends heavily on the number of randomly selected database images since the bigger the database to choose from, the higher the chance that there will be a perfect match.

Averaging database per digit

Another algorithm that could be used is to average all of the MSE’s of the database of one digit with a input digit,and declare the digit with the lowest average as the input’s digit. This method, in theory, should eliminate the chance picking an outlier.

Majority of nearest neighbors

Finally, the last algorithm is a variation of the aforementioned minimum MSE approach. This method picks the one hundred lowest MSE’s observed from the selected database and tallies the frequency of digits represented and declares the highest frequency digit is the input’s digit. In other words, it is finding the digit with the most nearest neighbors. In theory, this approach should be more associated with finding common features since higher frequency of certain digit means shared characteristics. A drawback of this method could come from a particularly poor input (say a 3 that looks awfully like an 8), there is a possibly of “tying” since the digits are separated by integers.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
Nasa has use it in the 60's, copper as water purification in the moon travel.
nanocopper obvius
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
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
analytical skills graphene is prepared to kill any type viruses .
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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