Predicting the PERFECT hairstyle from your face shape
Facial identification systems can be used to recommend the most complimentary hairstyles
for any individual's facial shape.
Machine learning systems can use basic information from your facial morphology to predict objectively
what features will best suit your face.
This can be done by evaluating many things like your ocular morphology, which is the
size and shape of your eyes determined through your skull composition, eye colour and eyelid
shape.
It can also be done through your jaw shape, looking at how it compliments your teeth and
cheekbones.
Most easily however, machine learning systems can use your overall facial shape, defined
by a facial recognition classifier, to recommend certain features that would best suit your
face.
Today we will look more closely at how face shape classifiers can be used to predict the
perfect hairstyle.
A 2018 paper by Pasupa et al outlines a support vector machine that has been in construction
which recommends a chosen hairstyle for a user based on scientific aesthetics evidence.
From there, it allows the user to ‘wear’ a certain hairstyle and see how they look.
The basis of this technology comes down to being able to divide face shape into five
main categories.
The main categories are one, an oblong shape, defined by a long thin face and an equal width
for your forehead, cheeks, and jawline.
An oblong shaped face is also defined by a chin with a very slight curve.
Sarah Jessica Parker and Alexa chung are two well known attractive individuals with this
face shape.
Looking at Alexa here, you can see that the distance between the two sides of her forehead,
the two sides of her Cheekbones and the two sides of her Jaw are a very similar length,
along with the characteristic slight curve in the chin.
Oblong shaped faces are also referred to as rectangular faces, due to the equal width
along the whole face.
The second main face shape category is the round shape, characterised by a very circular
head in which the cheekbones are the widest part of the face.
On top of that, the chin of a round face is significantly curved and the sides of your
face curve outwards, instead of being straight like they are in an oblong shape.
Jennifer Lawrence is one lady with a circular shaped face, and as you can see here, the
sides of her face extend outwards as we move from the forehead to the cheekbones, and then
back inward as we move from the cheekbone to the chin, showing that her cheekbones are
the widest part of her face.
Moving on to the next face shape, we have ‘oval shape’.
An oval shaped face is characterized by a tall forehead, cheekbones as the widest part
of your face, and an overall face that is longer than it is wide.
Oval shaped faces, whilst also having the cheekbones as the widest part of the face,
are longer than round faces and have a smaller difference in length between the forehead
and cheekbones.
If we look at Blake Lively’s face here, we can see that it is much longer than it
is wide, and the cheekbones once again are the widest part of the face.
The fourth of the five main face shapes is the square shaped face.
This shape, unlike the oval shape, has the same overall height, that is from the forehead
to the chin, as it does width, which is from cheekbone to cheekbone.
As well as this, the sides of your face are very straight, meaning there is not much difference
in width between the forehead and the cheekbone (much like the oblong shaped face).
It is also typical of square shaped faces to have sharp and angular features, like a
sharp jawline.
In this picture, Cameron Diaz is accentuating the traits of a square face, shown through
the constant width all along her face (shown by these horizontal lines across the face),
a similar width and height of her overall face, and through sharp features like her
jawline.
The final of the five main face shapes is the heart shaped face.
In a heart shaped face, the forehead is the widest part of the face, and your chin is
particularly pointed.
It is also typical of a heart shaped face to have a widow’s peak, a distinct peak
of the hairline at the centre of the forehead.
Now, of course, we cannot simplify the distinct and unique facial diversity into five main
facial categories, and there are further shapes like the diamond shape, with a narrow hairline,
high cheekbones and a pointed chin similar to the heart shaped face, as well as the triangular
face shape, which has a broad face shape tapering down to a much narrower jawline and chin.
Now, after all this description of face shapes, there is considerable scientific evidence
to suggest that each unique face shape has a set of hairstyles which best compliment
them.
Some basic geometrical rules defined through aesthetics guidelines make for objective reasoning
as to which hairstyle works for which shape.
This objectivity and geometrical application allows machine learning systems to a) identify
quickly which facial shape people are, taking specific consideration into the width and
height of the overall face as well as the width of the forehead, cheekbones and jawline
and shape of the chin and b) recommend the most suitable hairstyle based on this information
presented in A. Now, to develop the technology, the research stated that it coded a facial
shape recognition classifier using the characteristics for each face shape measured above, and trained
the system using 1000 relevant faces, simply through a google image search.
To train this system, the researchers compared the manual labelling of face shapes from volunteers
and compared them to the facial shape recognition system to ensure consistency.
After this point, a landmark localisation technique, called the ‘Active Appearance
Model’ looks at vital points on the face and skin pigmentation, separating the hair
and forehead allowing them to calculate the geometric features to represent face shape.
This Active Appearance Model technology, alongside mathematical ratios of the height to the face
to the width, the distance between the jaws, the distance between the chin and the bottom
of the mouth, the angle between the straight line from the boundary of the face at a considered
point to the chin point and many more have allowed them to recognise which hairstyles
are best, which we will get onto now.
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One of the issues in developing AI technology is the role of ethnic bias due to a lack of
training data.
This paper uses only East Asian faces for training to show that it is possible.
Our face shape classifier currently in development and virtually all of our AI tools are trained
using the Fairface dataset which has equal weightings of 7 racial groups which is the
best machine learning has currently.
We’re going to make a full video on racial bias in AI beauty because it’s a very relevant
topic to our work but I wanted to clear things up and acknowledge the current limitations
we have in the machine learning field in this video too.
The Support vector machine recommends hairstyles based on four attributes, the length, being
either pixie (which is wear the short hair sits above the head), short (which is around
ear/neck length), mid, and long.
The next attribute the system recommends based on is the style, which can be either straight,
wavy, or a mix of the two.
The third attribute is the fringe, where the algorithm decides whether you should have
no fringe, a straight fringe that goes across the lining of the eyes, or a side swept fringe
which hangs on one side of the forehead.
The last attribute is whether the hair should be layered or not, which is a hairstyle that
gives the illusion of length and volume.
After these recommendations are given, the technology can then map the hairstyle onto
the face using specific reference points related to the forehead, chin and cheekbones.
For a round shaped face, the technology suggests a medium length hairstyle, about shoulder
length, with a side swept fringe.
Both curling and straight hair are recommended, however the hairstyle should be used to create
extra height in the face, and as such, it should not be tucked behind the ears as this
will accentuate the roundness of the face, contrary to the idea of adding height.
If we look back to our image of Jennifer Lawrence, a typical example of a round face, she uses
medium length hair, a side-swept fringe on one side and a slightly curved style, and
actually does tuck behind her hair, but only on one side.
Here is a summary of the recommendations it will generally give.
These researchers are not facial aestheticians and so their advice is limited by language,
preciseness and accuracy, but their methodology is definitely robust.
For the QOVES model we intend to include more races (which is a given) and with that comes
greater inclusivity for black and arabian hairstyles which are often neglected in AI.
If you are a hairstylist or have some experience with recommending hairstyles, we’d like
to hear from you at jobs@qoves.com so that the advice our tool gives is as indepth as
possible.
It’s a community effort.
For the square shaped face, a hairstyle will be most attractive if it softens the hard
and sharp structures of the face, opposite to what is recommended with the round shape.
However, much like the round shape, the hairstyle should be used to try to add height to the
face.
To achieve this, it is recommended once again that a side swept fringe should be utilised,
as this will soften the hard and sharp corners of the face out, and it is recommended that
the style have a medium to long hair length, as this will create the perception of added
height to the face.
A strong and straight fringe is not recommended as this will accentuate the sharp elements
of the face.
As for the oval shaped face, you are the lucky ones!
With the shape being linked to a wide variety of hairstyles that can be considered most
attractive.
Unlike the round and square shapes though, it is advised against trying to add extra
height to your face shape, as the oval shape is already quite long.
For the oblong, or rectangular shaped face, curly hair is recommended as is short hair.
These features will reduce the height of the face, and will create the idea of a fuller
(defined as more surface area) face, which is recommended for facial harmony.
Finally, for the heart shaped face, a side swept fringe is suggested by the technology
to ensure width is maintained down the face (as the heart shape tends to get thinner as
it gets lower), long and layered hair is also recommended, with the option to be either
curly or straight.
Overall, the facial shape of anyone can be objectively defined by looking at the skull
morphology, with specific reference to the chin, cheekbones and forehead, with special
consideration to their relationship to each other.
From this, specific hairstyles can be recommended that focus on the length, style, fringe and
layers
of the hair such that
the specific features of the face are complimented well.