Smart Framework For Deep Facial Expressions Recognition - SkillBakery Studios


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Saturday, October 31, 2020

Smart Framework For Deep Facial Expressions Recognition

 Facial expressions are the fastest means of communication while conveying any type of information. These are not only exposes the sensitivity or feelings of any person but can also be used to judge his/her mental views. This research work includes the introduction of face recognition and facial expression recognition and an investigation on the recent previous researches for extracting the effective and efficient method for facial expression recognition. Human expressive behaviors in realistic applications involve encoding from different perspectives, and the facial expression is only one modality. Although pure expression recognition based on visible face images can achieve promising results, incorporating with other models into a high-level framework can provide complementary information and further enhance the robustness. To considered the audio model to be the second most important element and employed various combination techniques for multimodal affect recognition. Additionally, the fusion of other modalities, such as infrared images, depth information from 3D face models, and physiological data, is becoming a promising research direction due to the large complementarity for facial expressions. To design a smart framework for deep facial expression recognition using max-pooling convolutional deep belief network. To propose a hybrid algorithm for video-based emotion recognition with no manual design of features using a max pooling Convolutional Deep Belief Network. The model considered the visual modality only and achieved an excellent recognition rate for the 10 used emotions.

As we are stepping forward from one generation to another, in numerous technologies are abiding us according to our necessities. Thus, we are thoroughly dependent on these technologies as a part of human-computer interaction. And one of them is facial expression recognition. Face plays an important role in social communication, equally facial expressions are vital. Facial expressions not only exposes the sensitivity or feelings of any person but can also be used to judge his/her mental views. Facial expression recognition is a method to recognize expressions on one’s face. A wide range of techniques have been proposed to detect expressions like happy, sad, fear, disgust, angry, neutral, surprise but others are difficult to be implemented. Facial expression recognition is composed of three major steps:

(1) Face detection and pre-processing of image.

(2) Expression classification. The objective of this paper is to understand the basic difference between face recognition and facial expression recognition and to investigate the effective facial expression recognition rates by acknowledging the existing proposed models. This paper is organized in six sections and the second section includes the basic terminologies which are essential to understand both face recognition and facial expression recognition. The third section of this paper includes the difference between face recognition and facial expression recognition. The fourth section explains the procedure being followed for the recognition of facial expressions. The fifth section includes a review of ten previous researches in expression recognition using various techniques. The sixth section is a conclusion and it is about acknowledging the facial expression rate above 90%, calculated from the collected review. The final and seventh section discusses the future scope.

Face Detection:

Face detection is to determine that a certain picture contains a face we need to be able to define the general structure of face. Luckily human faces do not greatly differ from each other; we all have noses, eyes, foreheads, chins and mouths; and all of these compose the general structure of a face. It is a concept of two-class classification: face versus nonface.

Face Identification:

 In this the system compares the given individual to all the other individuals in the database and gives a ranked list of matches.

Face Verification:

In this the system compares the given individual with who that individual says they are and gives a yes or no decision.

Facial Expressions: Facial expression is one or more motions or positions of the muscles beneath the skin of the face. These movements express the emotional state of the person to observers. It is a form of non-verbal communication. It plays a communicative role in interpersonal relations.


Generally, face is a union of bones, facial muscles and skin tissues. When these muscles contract, warped facial features are produced. Facial expressions are the fastest means of communication while conveying any type of information. An implementation of facial expression recognition may lead to a natural human-machine interface. In 1978, Ekman and Frisen reported that facial expression acts as a rapid signal that varies with contraction of facial features like eyebrows, lips, eyes, cheeks etc., thereby affecting the recognition accuracy, also happy, sad, fear, disgust, anger and surprise are six basic expressions which are readily recognized across very different cultures. Facial expression recognition involves three steps face detection, feature extraction and classification of expression.

The pre-processing step for recognizing facial expressions is face detection. The steps involved in converting a image to a normalized pure facial image for feature extraction is detecting feature points, rotating to line up, locating and cropping the face region using a rectangle, according to the face model. The face detection involves methods for detecting faces in a single image.

Emotion Recognition Facial Recognition is the technology that deals with methods and techniques to identify the emotions from the facial expression. Various technological developments in the area of Machine Learning and artificial Intelligence, made the emotion recognition easier. It is expected that expressions can be next communication medium with computers. A Need for automatic emotion recognition from facial expression increases tremendously. Research work in this area mainly concentrates on identifying human emotions from videos or from acoustic information. Most of the research work recognizes and matches faces but they have not used convolutional neural networks to infuse emotions from images. Emotion Recognition deals with the investigation of identifying emotions, techniques and methods used for identifying. Emotions can be identified from facial expressions, speech signals etc. Enormous methods have been adapted to infer the emotions such as machine learning, neural networks, artificial intelligence, and emotional intelligence. Emotion Recognition is drawing its importance in research which is primary to solve many problems. The primary requirement of Emotion Recognition from facial expressions is a difficult task in emotional Intelligence where images are given as an input for the systems.

Facial Emotion

Recognition Facial Emotion Recognition is research area which tries to identify the emotion from the human facial expression. The surveys states that developments in emotion recognition makes the complex systems simpler. FER has many applications which is discussed later. Emotion Recognition is the challenging task because emotions may vary depending on the environment, appearance, culture, face reaction which leads to ambiguous data. Survey on Facial emotion recognition [2] helps a lot in exploring facial emotion recognition.

Deep Learning

Deep Learning [3] is machine learning technique which models the data that are designed to do a particular task. Deep learning in neural networks has wide applications in the area of image recognition, classification, decision making, pattern recognition etc. [4]. Other deep Learning techniques like multimodal deep learning is used for feature selection, image recognition etc.

Categorizing Facial Expressions & its Features:

Facial expression presents key mechanism to describe human emotion. From starting to end of the day human changes plenty of emotions, it may be because of their mental or physical circumstances. Although humans are filled with various emotions, modern psychology defines six basic facial expressions: Happiness, Sadness, Surprise, Fear, Disgust, and Anger as universal emotions [2]. Facial muscles movements help to identify human emotions. Basic facial features are eyebrow, mouth, nose & eyes.


Table -1: Universal Emotion Identification






Motion of facial part



Anger is one of the most dangerous emotions. This emotion may be harmful so, humans are trying to avoid this emotion. Secondary emotions of anger are irritation, annoyance, frustration, hate and dislike.


Eyebrows pulled down, Open eye, teeth shut and lips tightened, upper and lower lids pulled up.



Fear is the emotion of danger. It may be because of danger of physical or psychological harm. Secondary emotions of fear are Horror, nervousness, panic, worry and dread.


Outer eyebrow down, inner eyebrow up, mouth open, jaw dropped



Happiness is most desired expression by human. Secondary emotions are cheerfulness, pride, relief, hope, pleasure, and thrill.


Open Eyes, mouth edge up, open mouth, lip corner pulled up, cheeks raised, and wrinkles around eyes.



Sadness is opposite emotion of Happiness. Secondary emotions are suffering, hurt, despair, pitty and hopelessness.


Outer eyebrow down, inner corner of eyebrows raised, mouth edge down, closed eye, lip corner pulled down



This emotion comes when unexpected things happens. Secondary emotions of surprise are amazement, astonishment.


Eyebrows up, open eye, mouth open, jaw dropped



Disgust is a feeling of dislike. Human may feel disgust from any taste, smell, sound or tough.


Lip corner depressor, nose wrinkle, lower lip depressor, Eyebrows pulled down



Face recognition is a task that humans perform routinely and effortlessly in their daily lives. Robert Axelrod has also shown the ability to recognize those they have met before and distinguish them from strangers is one of the bases for humans to form cooperation [3]. The last decade has witnessed a trend towards an increasingly ubiquitous computing environment, where powerful and low-cost computing systems are being integrated into mobile phones, cars, medical instruments and almost every aspect of our lives. This has created an enormous interest in automatic processing of digital images and videos in a number of applications, including biometric authentication, surveillance, human-computer interaction, and multimedia management. Research and development in automatic face recognition follows naturally. Face recognition is a visual pattern recognition problem where a three-dimensional object is to be identified based on its two-dimensional image. in recent years, significant progress has been made in this area; owing to better face models and more powerful computers, face recognition system can achieve good results under constrained situations. However because face images are influenced by several factors: illumination, head pose, expression and so on, in general conditions, face recognition is still challenging. From a computer vision point of view, among all these “noises” facial expression maybe the toughest one in the sense that expressions actually change the three-dimensional object while other factors, such as illumination and position, only affect imaging parameters. To get rid of expression “noise”, one first needs to estimate the expression of an image, this is called “Facial Expression Recognition”. Another, maybe more important motivation of facial expression recognition is that expression itself is an efficient way of communication: it’s natural, non-intrusive, and  has shown that, surprisingly, expression conveys more information than spoken words and voice tone. To build a friendlier Human Computer Interface, expression recognition is essential.


Facial expression recognition system consists of following steps:

Image Acquisition: Static image or image sequences are used for facial expression recognition.2-D gray scale facial image is most popular for facial image recognition although color images can convey more information about emotion such as blushing. In future color images will prefer for the same because of low cost availability of color image equipments. For image acquisition Camera, Cell Phone or other digital devices are used.


Pre-Processing plays a key role in overall process. PreProcessing stage enhances the quality of input image and locates data of interest by removing noise and smoothing the image. It removes redundancy from image without the image detail. Pre-Processing also includes filtering and normalization of image which produces uniform size and rotated image.


Segmentation separates image into meaningful reasons. Segmentation of an image is a method of dividing the image into homogenous, self-consistent regions corresponding to different objects in the image on the bases of texture, edge and intensity.

Feature Extraction

 Feature extraction can be considered as “interest” part in image. It includes information of shape, motion, colour, texture of facial image. It extracts the meaningful information form image. As compared to original image feature extraction significantly reduces the information of image, which gives advantage in storage


Classification stage follows the output of feature extraction stage. Classification stage identifies the facial image and grouped them according to certain classes and help in their proficient recognition. Classification is a complex process because it may get affected by many factors. Classification stage can also called feature selection stage, deals with extracted information and group them according to certain parameters.

Accuracy is crucially dependant on the extraction of features which is the main methodology of Facial Gender recognition system. Optimizing the recognition rate for Facial Gender recognition system by improving LBP technique of feature extraction is the purpose of this research work. The pattern, shape and edge patterns are unique for every individual on their face. The pattern of texture in image is extracted by using LBP. But only the texture pattern and edge pattern generated by Gabor filter are generated by LBP projection.

Research show that face of each individual has unique pattern using which the persons are classified, verified and identified.

The basic methodology of facial expression recognition includes the following stages:

·       Acquisition of image

·       Pre-processing using Convolutional Deep Belief Network 

·       Extraction of features using CNN 

·       Feature reduction   v)Classification


For data collection two methods will be used:

         One (UCI Machine Learning Repository) which is publicly reachable.

    Second Approach: To collect real time dataset using real-time response by real-time video capturing.

      Facial expression datasets As the FER literature shifts its main focus to the challenging in-the-wild environmental conditions, many researchers have committed to employing deep learning technologies to handle difficulties, such as illumination variation, occlusions, non-frontal head poses, identity bias and the recognition of low-intensity expressions. Given that FER is a data-driven task and that training a sufficiently deep network to capture subtle expression-related deformations requires a large amount of training data, the major challenge that deep FER systems face is the lack of training data in terms of both quantity and quality.

     Because people of different age ranges, cultures and genders display and interpret facial expression in different ways, an ideal facial expression dataset is expected to include abundant sample images with precise face attribute labels, not just expression but other attributes such as age, gender and ethnicity, which would facilitate related research on cross-age range, cross-gender and cross-cultural FER using deep learning techniques, such as multitask deep networks and transfer learning. In addition, although occlusion and multipose problems have received relatively wide interest in the field of deep face recognition, the occlusionrobust and pose-invariant issues have receive less attention in deep FER. One of the main reasons is the lack of a large-scale facial expression dataset with occlusion type and head-pose annotations.



With the rapid development of technologies it is required to build an intelligent system that can understand human emotion. Facial emotion recognition is an active area of research with several fields of applications. Some of the significant applications are:

·       Alert system for driving.

·       Social Robot emotion recognition system.

·       Medical Practices.

·       Feedback system for e-learning.

·       The interactive TV applications enable the customer

·       to actively give feedback on TV Program.

·       Mental state identification.

·       Automatic counseling system.

·       Face expression synthesis.

·       Music as per mood.

·       In research related to psychology.

·       In understanding human behaviour.

·       In interview.

Extensive efforts have been made over the past two decades in academia, industry, and government to discover more robust methods of assessing truthfulness, deception, and credibility during human interactions. Efforts have been made to catch human expressions of anyone. Emotions are due to any activity in brain and it is known through face, as face has maximum sense organs. Hence human facial activity is considered. The objective of this research paper is to give brief introduction towards techniques, application and challenges of automatic emotion recognition system.

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