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Distinguishing the best smile from a set

Using several more images of Danny, we can determine which image of him has his best smile.

Figure 1: Input images for distinguishing the best smile of the set

When determining the best smile from this set of given photos, the following calculated data is used in the code’s decision tree.

Image Corner Density Mouth Curvature
1 63 0.0043
2 78 -0.0010
3 24 0.0045
4 6 -0.0010

Table 1: Corner Density and Mouth Curvature Parameters for Images 1-4

Photos one and two both contain high numbers of corner points, but number one has a greater curvature. Photo four does not meet the minimum threshold number of data points, so its curvature is irrelevant. Since photo three meets the minimum threshold and has the greatest curvature, it is selected as the best smile photo of the set.

Distribution of our smile detection parameters

We wanted to run more extensive tests to see if our determination of smiling subjects works on a large set of subjects. We obtained the FEI face database ( Link )[6] , which has images of 200 subjects. In one image the subject is smiling, and in the other the subject maintains a neutral expression. We gathered results on the distribution of each parameter, and also whether the program correctly predicted which image of the two was a smile.

Figure 6: Corner Density distributions for the 200 Non-Smiling and 200 Smiling photos from the database. (NOTE: The x-axes have significantly different scales)

Figure 8: Mouth Curvature distributions for the 200 Non-Smiling and 200 Smiling photos from the database. (NOTE: The y-axes have significantly different scales)

One important trend noticed in the distribution is that the concavity parameter has a high probability of being positive when analyzing a smiling photo. The parameter is negative less than 5% of the time for analyzed smiling images. We used this to validate our requirement that the curvature of an image must be positive to be identified as the most smiling photo of a set.

Another thing that we notice is while a neutral photo will not always provide line a predictable curvature parameter, there will often be a lack of detected edges. We confirmed discarding images with a low number of detected mouth corners was also a good strategy. At the threshold of 10 that we used (must have greater than 10 corners), about 78% of smiling photos will be kept as candiates for the most smiling photo, while 81% of non-smiling photos will be eliminated as candidates. Using both terms, we see the separation at there is relatively high separation that can be achieved from using both the corner density and mouth curvature parameters.

Corner Density Mouth Curvature
Smiling Face 16.3 0.0124
Unsmiling Face 7.7 0.0016

Table 2 : Mean Corner Density and Mouth Curvature for images from the FEI database.

The final step of if multiple images are able to pass all thresholds, is selecting the image with the highest mouth curvature. As seen in Table 2 , the average mouth curvature of a smiling face is over 7 times that of an unsmiling face.

Performance analysis

Number (of 200) Total % Procedure Accuracy
Correct Recognitions 121 61% 93%
False Positives 9 5% 7%
Inconclusive 70 35%

Table 3 : Percentage out of total database images from the FEI database, as well success and failure rate of the images the program attempted to analyze.

Using the decision tree outlined in Section 4.2 , we got the result in table 3 . Of the 200 subjects analyzed, 70 were deemed inconclusive because they could not be properly analyzed as either the face or mouth detection algorithm didn’t work properly, or less than 11 corners in both images. The remaining 130 photos were analyzed with only 9 false positives, and a 93% success rate of those analyzed.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
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
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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Source:  OpenStax, Smile identification via feature recognition and corner detection. OpenStax CNX. Dec 17, 2012 Download for free at http://cnx.org/content/col11469/1.1
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