EYE GAZE TRACKING FOR HUMAN COMPUTER INTERFACE
Submitted by
Prajnyadeep Subhashis Patra
Dibyesh Das
Priyatosh Das
Alok Ahuti Roul
Guided by
Prof. Bibhu Prasad Mohanty
EYE GAZE TRACKING
What is it? Gaze tracking, as the name suggest, is tracking the gaze of a person.
The objective of a gaze tracking system is to track the focus of the user's vision.
So it is necessary to be able to track the eye first from which other information can be inferred.
IS GAZE TRACKING USEFUL?Gaze tracking has a number of possible applications that is beneficial for the society.
A new form of Human-Computer Interaction, that can help aiding the disabled.
The technique can be used to detect when a driver is getting drowsy.
It can be a tool for study of user’s visual behaviour when surfing the internet or for cognitive analysis.
It finds application in medical research and for surveillance purpose.
Recent application of Eye tracking involves the scrolling effect like when we move our eye up or down accordingly it will scroll up or down.
HUMAN VISUAL SYSTEM
The parts of the eye which are of interest for eye-trackers.
IMAGE FORMATION Cornea lets the light inside of the eye, which passes through pupil.
Around pupil, we find the iris. Iris controls the amount of light which passes through pupil.
The light that enters the eye is refracted by the eye lens, and then it falls onto the retina layer which covers the inner surface of the eyeball, forming the image of what is seen through the eyes.
EYE MOVEMENTS
The eye movements can be mainly classified into three categories.
Saccades:
These are rapid eye movements that are aimed at focusing the visual attention to a different object.
Smooth pursuits:These happen when the eyes are following a moving target. In
order to achieve this movement, the speed of the target should be in the range that can be handled by the human eye.
Fixations:These are the movements which stabilize the retina on the object of
interest.
DIFFERENT EYE GAZING TECHNIQUES
Electro-Oculography
Sceleral Search Coils
Infared Oculography
Video Oculography
WORK DONE SO FAR
Our objective is to track the gaze of an eye.
We have been able to detect the eye for 3 directions that is left,middle and right.
Here we have worked with still image.
The complete workflow is as follows:
ENTIRE PROCESS DONE
Input ImageImage
EnhancementImage
Segmentation
BinarizationMorphological
OpeningImage
Cropping
Iris Detection
IMAGE ENHANCEMENT
The principal objective of enhancement is to process an image so that the result is more suitable than the original image.
Here image enhancement is done using laplacian operator.
LAPLACIAN OPERATOR
The Laplacian operator is an example of a second order or second derivative method of enhancement.
It is particularly good at finding the fine detail in an image.
This Operator can be used to find edges in an image.
It can be of two types:
Positive laplacian operator
Negative Laplacian Operator
0 1 0
1 -4 1
0 1 0
0 -1 0
-1 4 -1
0 -1 0
2. Negative Laplacian Operator
1. Positive laplacian operator
INPUT IMAGE
ENHANCEMENT RESULT
(LAPLACIAN MASK RESULT) (ENHANCED IMAGE)
IMAGE SEGMENTATION
Image segmentation is the process of partitioning a digital image into multiple segments.
More precisely, image segmentation is the process of assigning a label to every pixel in an image such that pixels with the same label share certain characteristics.
Here the image segmentation is done on the enhanced image using k-means clustering.
K-MEANS CLUSTERING
Clustering is the process of partitioning a group of data points into a small number of clusters.
The k-means algorithm is an evolutionary algorithm that gains its name from its method of operation.
The algorithm involves clustering of observations into k groups, where k is provided as an input parameter.
The steps for K-mean clustering is as follows.
Take input value k
start
Select centroid for each cluster
Calculate the euclidean distance between each pixel and cluster
centroid
Group the pixel with the cluster having minimum distance
If the new observation changes
the cluster ?
END
Yes
No
FLOW CHART FOR K-MEANS CLUSTERING
OUTPUT OF KMEAN CLUSTERING
BINARIZATION
After segmentation we go for binarization of segmented image on which morphological operation will be done.
Image binarization converts an image of up to 256 gray levels to a black and white image.
The simplest way to use image binarization is to choose a threshold value, and classify all pixels with values above this threshold as white, and all other pixels as black.
BINARIZATION OUTPUT
MORPHOLOGICAL OPENING
In binarization, binary regions produced by simple thresholding are distorted by noise and texture.
Morphological image processing pursues the goals of removing these imperfections by accounting for the form and structure of the image.
Morphological Opening is same as ‘erosion followed by dilation’.
Opening removes small objects from the foreground (usually taken as the dark pixels) of an image, placing them in the background
OUTPUT AFTER MORPHOLOGICAL OPENING
IMAGE CROPPING
The image was cropped in order to find the correct iris position in both eyes.
The original image was cropped into two images-one of left eye and one of right eye.
IRIS POSITION DETECTIONThere were 8 parameters calculated, namely: (min_x, y_min_x,max_x, y_max_x, min_y, x_min_y, max_y,x_max_y).
After calculating the coordinates of the eye, a variable by the name of loc was declared to indicate the direction the user was looking.
The loc variable could take on one of three values at a single time:-
IRIS POSITION LOC VALUE
left 1
right 2
center 3
(Eye looking towards center)
(Eye looking towards right)
(Eye looking towards left)
FLOW CHART FOR IRIS POSITION DETECTION Input
cropped image
count the number of 0’s and 1’s in the region enclosing the area from min_y to max_y
If no of black
pixels >no of white pixels
loc is set to 3.iris is at
center
count white pixels(w1,w2) in region 1 and 2
Region 1:-max_y to min_x
Region2:-max_yand max_x
If W1<W2
Loc=1.Iris is
towards left
Loc=2.Iris is towards
right
YesNo
Yes No
WORKFLOW FOR 8TH SEMTill now we have been able to detect the Iris position in 3 different direction that is right,left and center. Further we will try to detect the Iris position in all possible direction.
And here we have performed the whole process on a single still image.At a later stage we will implement it for continuous images or videos .
The outputs obtained here are not accurate enough however outputs can be improved by finding better techniques through technique comparisons.
Then our ultimate aim is to implement this ideas for
developing a ‘Human-Computer Interface’.
REFERNCES
[1] Vision-Based Eye-Gaze Tracking for Human Computer InterfaceKyung-Nam Kim* and R. S. Ramakrishna*
[2] A SURVEY ON EYE-GAZE TRACKING TECHNIQUESR. Chennamma
[3] Gaze Tracking Using A Regular Web Camera Submitted in partialfulfillment of the requirements of the degree of Bachelor of Science(Honours) of Rhodes University .David Jonathan Wild
[4] Design and Impletation of A HumanComputer Interface Tracking System Based on Multiple EYE FEATURES
1Shazia Azam, 2Aihab Khan, 3M.S.H.Khiyal
[5] Digital image processingRafael C Gonzalez, Richard E Woods
Thank You
Top Related