A Survey on an Intelligent System for Persons with Visual Disabilities

According to the World Health Organization (WHO), At least 2.2 billion individuals worldwide have near or far vision impairment out of 7.9 billion populations. In at least 1 billion cases, or about half of them, vision impairment might have been prevented or is currently untreated. The primary causes of vision impairment and loss are uncorrected errors and eye disorders. The majority of persons over the age of Fifty have visual impairment or blindness. Visual impairment or visual misfortunes are two terms that might be used to describe visual handicaps. This impairment makes it difficult for them to go about their daily activities such as shopping, strolling, mingling, and driving. The white stick is regarded as a symbol of opportunity, liberty, and security. In this paper, we attempted to discuss a comprehensive study of all the equipment and systems related to the simplification of visually impaired people's daily lives. Those devices can be portable or wearable or could be a system to detect objects. The emphasis was on the striking characteristics of that equipment, as well as the analysis was conducted predicated on a few variables such as power usage, mass, economics, and client. The aim was always to lay the groundwork for future researchers in the area by developing a handheld device or an efficient algorithm to protect visually impaired people.

The most popular solution to provide accessibility to Visually Impaired people by helping them in traveling from one place to another is the Smart Stick that uses a GPS module to track the user's location and various sensors and a microcontroller to alert users about the obstacles on the way (Subbiah et al., 2019). The problem with this system is that it works in less crowded areas and does not provide details about the surrounding. Another solution is the one that helps the visually impaired with reading using Speech Syn-thesis Technology. It is an application that recognizes the text from a PDF document and reads it for the user (Sumathy et al., 2021). It uses a camera to take an image and convert it into a document. However, it requires an Internet connection and cannot work offline as it also provides Chabot functionalities such as light conversations.
Electronic Travel Aids (ETAs): It collects data from the environment and sends it to users using sensors such the Ultrasonic Sensor (Subbiah et al., 2019), Ultrasonic transducers (Nabiha et al., 2020), I.R. Sensor (Patel et al., 2018), LDR Sensor (Chiranjevulu et al., 2020), Accelerator Sensor (Yohannes et al., 2020), TCS3200 color sensor (Johari et al., 2020), Water sensor (Gbenga et al., 2017), and so on. These are the most typical visual substitutes employed by visually challenged people. According to National Research Council (Bledsoe et al., 1997), the rules for ETAs are: 1) Identifying obstacles near the client's body, from the beginning the head; 2) Finding things around the impediments; 3) Informing users of the distance between them and obstacles with the necessary directions; 4) Giving someone instructions on the surface's gap and roughness.

Issues and challenges
Knowledge of the snags and issues that an outwardly disabled individual has in regular daily existence can help located individuals get what an individual with vision hindrance goes through. Natural Obstacles visually impaired individuals struggle to explore the outside. Going to jam-packed places like business sectors, train stations, etc., is much harder for them. Therefore, daze individuals look for help from relatives or assistive innovation. Social Obstacles Visually hindered individuals might encounter feelings of inadequacy since they can't take an interest in certain exercises that located individuals can. They additionally experience issues playing outside games. Innovative Obstacles When utilizing the web for study, joy, or business, dazzle people face difficulties. A blind individual will find it difficult to gather information from online pages. Despite the fact that numerous gadgets have been invented for the aim of extracting information; it is not widely used among blind people of all ages. Others Blind person's encounter numerous problems and differ from sighted people in a variety of ways. There are numerous other difficulties that blind people experience, including conducting home tasks, applying make-up, recognizing cash denominations, detecting obstacles, navigating, crossing the road, and so on.

Existing Surveys
The record (Elmannai et al., 2017) examines arrangements produced for outwardly weakened individuals up until the second from the last quarter of 2017. In a plain way, the general investigations, just as the advantages and negative marks of those arrangements, have been shown. Another investigation paper (Dakopoulos et al., 2009) characterized gadgets dependent on their provisions and execution boundaries. The advancement of material and sound-based assistive innovation for dazzle individuals has been point by point in the examination (Csapó et al., 2015) to give an outline of those arrangements.
The authors of (Proulx et al., 2016) took a gander at the exploration to check whether tactile replacement could consider online control of activity utilizing visual data seen through strong or contact. The current situation with the craftsmanship for tangible replacement strategies to protest acknowledgment, restriction, and the route has likewise been tended to, just as the opportunities for these ways to deal with give a Meta modular social and neurological supporting for the online control of the activity. These survey papers aided in the comprehension of the method and flow of producing a survey study in this subject area. Although devices have been thoroughly documented and contrasted, little attention has been paid to the methods used in their development. In recent years, Artificial Intelligence-based products have been produced that were not included in prior survey reports.

METHOLODOGY:
To begin, we've compiled a list of terms that will be useful in looking for survey studies. For finding relevant publications, the Google Scholar web search engine was used in conjunction with IEEE and Research Gate databases. After year-by-year filtering, the papers were divided into two categories: survey and regular. The articles were then scrutinized, and data was retrieved in Excel/Word format for additional investigation. They were separating notes and related data into different files aided in the effective exploration and tracking of previous work. Each time another archive was considered, another watchword was added to the bunch of catch phrases. It was a clear system. The cycle we have embraced for making this outline paper has been portrayed in Fig 1. Assistive technology methods for visually challenged As recently said, the need is to help the outwardly impeded by offering assistive innovation in their regular assignments, simplifying their life, more secure and more liberated. For quite a while, specialists have been dealing with creating this kind of arrangement that might help them in hindrance recognition, route, object I.D., transportation, etc. A couple of these gadgets have been analyzed widely in this segment to give an outline of the present status of the craftsmanship for this subject. As our studied papers were totally distributed between 2016-present so, we will talk about them year-wise. We gathered several projects and publications from a variety of Journals and search engines, including Google Scholar, Re-search Gate, and MDPI. The majority of the papers we surveyed were from IEEE and Springer periodicals. We attempted to locate the majority of the documents that are directly related to our convenience. like YOLO, SSD, and others RCNN for object detection and found a SUS score of 86%. There are several sensors used, including Camera and micro-processor modules. Table 1 Here are the objectives of all the papers we have surveyed. When we surveyed our paper, we can see most of the papers are real-time object detection in outdoor or indoor. Some papers using voice commands to recognize objects in the surrounding. Some are using Android Smartphone's with a camera and network connection. In the Priority Analysis Table here, we covered all objective parts of our paper.  A minimal expense, lightweight framework utilizing a microcontroller that examinations flags and informs outwardly disabled individuals of any snags, water, or dim spots by means of blaring sounds. (Jain et al., 2018) A visual guide for outwardly impeded individuals in whom discourse orders are acknowledged from the client tends to recognizable proof of articles and billboards. (Johari et al., 2020) The keen stick is highlighted with snag identification, traffic signal shading discovery, ringerbased ready framework, area sharing. (Krishnan et al., 2016) The system works reliant upon the development of echolocation, pictures dealing with, and a course structure.

Solution Based on Sensors
Sensors are the essential gadgets that are frequently used to gather ecological information, and most Travel Aids normally include sensors. A few sensors that have been utilized in the past and are presently being employed by researchers in this field are included. Ultrasonic sensors are the most often used sensors because they are affordable and are un-affected by object color or transparency. A transducer is utilized in an ultrasonic sensor to communicate and get ultrasonic heartbeats that send information about the closeness of an article. This sensor uses an ultrasonic wave that reflects upon colliding with any objects in front. It estimates the time between transmission and receiving to estimate the distance to the object. However, it is incapable of detecting obstructions at ground level. Because of its large field of view but limited range, the Wide-angle Camera is used for surveillance. Monocular Vision Camera offers high-goal far-off detecting pictures for a minimal price. It is, notwithstanding, contrary to the natural eye visual framework. The Binocular Vision Sensor records pictures at a foreordained recurrence, taking into account 3D vision. It is very exorbitant and has a particular core interest. An infrared sensor is a kind of electrical gear that produces light to identify certain components of its current circumstance. It is a radiation-sensitive optoelectronic module having infrared wavelength sensitivity ranging between 780 nm and 50 µm. An I.R. sensor can distinguish movement just as to quantify the warmth of a thing. These sensors simply screen infrared radiation instead of transmitting it, which is named a detached I.R. sensor. Commonly, everything in the infrared reach produces a type of warm radiation. Such radiation is imperceptible to human sight, yet an infrared sensor can recognize them. The producer is only an infrared LED (Light Emitting Diode), and the locator is basically an infrared photodiode receptive to infrared light of a similar frequency as the IR LED. The Proposed brilliant stick is planned with a deterrent identification module, heat location, water discovery, light recognition, pit, and flight of stairs identification. (Moharkar et al., 2020) A framework for outwardly tested individuals that utilize OCR and A.I. to identify text from manually written archives. (Mule et al., 2020) In-house object recognition (Nabiha et al., 2020) Prototype for analyzing images and convert them into text (Parikh et al., 2018) Android cell phone with a camera and organization association (Patel et al., 2018) Object detection in the indoor environment (Pathak et al., 2020) Real point when light beams on the LDR, the obstruction brings down and increments in obscurity. When an LDR is set to indefinite quality, it has a high resistance, but when it is cared for in the light, it has a lower resistance. At (Rahman et al., 2021), a gas pedal sensor that identifies movement levels is remembered for the recommended design. In case the outwardly debilitated individual falls, the gas pedal sensor will distinguish the incident and pass on the pertinent data to the microcontroller. The microcontroller will then establish a connection with the permitted supervisor over a cloud specialist. Then, at (Johari et al., 2020), they used a Color Sensor. The TCS3200 chip is intended to detect the color of light that reaches it. It also has a photodiode array. These photodiodes are protected by four different types of filters. Sixteen sensors are fitted with a RED filter, allowing them to measure just the component of red in the incident light. And there are water sensors used at (Rahman et al., 2021) and (Gbenga et al., 2017) for detecting water for blind people. The sensor-based system can be a good solution for blind people is because it can detect obstacles and also can detect some other elements too. But there still are some detecting problems. Like those systems can't detect the exact structure of that object and can say what it is. A sensor-based system can be a good solution for blind people but not the best one.

Solution Based on Image Processing and A.I.
Picture preparing is additionally one more procedure utilized by numerous innovations to identify pictures caught by cameras. Picture handling is an approach to lead procedure on a picture to separate significant information from it. It is a type of sign preparing in which the information is a picture and the yield maybe a picture or picture attributes. For this reason, it utilizes an assortment of approaches, including picture division, profundity map assessment, and synchronous limitation or planning. Picture division is the way toward partitioning a picture into unmistakable segments known as super pixels. The goal of the division is to redo the image with the objective that it ends up being more enormous and less difficult to review as time goes on. The term "image segmentation" refers to the process of separating the region of an image that contains objects and edges.  Water Sensor empower P.C.s to learn without the requirement for unequivocal programming. It is the assessment of assessments and certain models to do a given errand. Huge Learning is a piece of A.I. assessments that pulls highlights from input information.  Here most of the papers we have surveyed are sensorbased. So, they don't have any particular accuracy rate there. There are different object detection methods used in the others, which are using cameras and camera modules. We can see a comparative Table 3 of the accuracy and models of our surveyed paper.

App-based Solution
There are a couple of invigorating application-based applications expected for the vision crippled that probably go as an extra course of action of eyes for them. People living with a visual lack or a visual handicap have discovered that applications have simplified their lives.

TapTapSee by CloudSight Inc -(TapTapSee, 2021)
TapTapSee is smartphone camera software designed for visually impaired and blind people that use the Cloud Sight Image Recognition API. TapTapSee takes a photo or video of anything and detects it for the user using the device's camera and Voiceover. Clients must double tap the right half of the screen or the left half of the screen to take images. TapTapSee examines and recognizes any a few dimensional thing at any point right away. The character is then recited for all to hear by means of the gadget's Voiceover.
Be My Eyes -(Be My Eyes, 2021) Be My Eyes is an application that associations outwardly disabled and low vision individuals with found volunteers and corporate specialists through live video gatherings for visual assistance. Regular schedule, located volunteers offer their eyes to finish exercises huge and minimal to help visually impaired, and low vision people is turning out to be more independent. As a person who is blind or has limited vision, their volunteers are pleased to assist people who require visual aid. Users and a volunteer may connect directly and fix a problem via a live video conversation. The volunteer will assist in determining which way to point the user's camera, what to focus on, and when to switch on the torch.  Table 4 records the entirety of the gadgets and classifiers them into five classifications: gadget name, examination type, inclusion, object type, and conveying mode. The "Analysis Type" category is further split up into two subcategories: online and offline mode. The "Coverage" category is further divided into three sub-categories: indoor, outdoor, and both. The term "Object Type" is further split into three subcategories: static, dynamic, and both. "Carrying Mode" is further split into two categories: Wearable and Hand-held. The "Online" category indicates devices that require an internet connection to function, whereas the "Offline" category indicates gadgets that do not require an internet connection to function. The term "indoor" refers to equipment that can only execute its functions inside.
The "Outside" category de-notes that the item is only suited for use in an outdoor environment. The category "Both" implies that the gadgets may function both indoors and outside. The "Static" category indicates that the device can only identify static objects, whereas the "Dynamic" category indicates that the device can only detect moving things. Again, the category "Both" indicates that the gadget can identify both static and dynamic items. The "Wearable" category includes gadgets that may be worn, whereas the "Handheld" category includes nonwearable equipment that must be handled in the hands.

Architecture
Different authors used different equipment and technology to build their proposed system for the blind, like Raspberry Pi, Arduino, etc. The Raspberry Pi is an expense proficient, little chip that utilizes a P.C. screen or T.V. and works with a customary console and mouse. It is a minuscule contraption that permits people, everything being equal, to explore different avenues regarding registering and figure out how to write in dialects like Scratch and Python. It does all that a P.C. does, from perusing the web and observing top quality recordings to making work-sheets, word handling, and playing P.C. games. In addition, the Raspberry Pi can talk with the remainder of the world and has been utilized in a wide extent of cutting-edge maker projects, including music machines and parent pointers, similar to environment stations and tweeting aviaries with infrared cameras (Raspberry Pi, 2021    Sensor-Based Arduino Uno microcontroller, I.R. and Ultrasonic Sensor (Suraj et al., 2019) Sensor-Based Microcontroller, three ultrasonic sensors, two vibration engines, a ringer, power source, a GPS module, and a GSM Module. (Vaidya et al., 2020) YOLOv3-tiny OpenCV, TensorFlow, Darknet, Smartphone. (Yohannes et al., 2020) Sensor-Based Ultrasonic sensor, I.R. sensor, accelerator sensor, and LDR sensor (Appendix I) This work can additionally be progressed for face affirmation to learn regular appearances experienced by the outwardly hindered person.

Ref
We can utilize high-velocity complex calculations for expanding precision. The present work identified hospital signs; however, signs seem to be considerably more than just detecting and recognizing.
Will make an interpretation of a clinic sign into a more significant expression. We will widen our rundown of objects to incorporate lifts, snags, and lifts to resolve the issue of constant multiobject location or distinguishing numerous things in a solitary picture. Picture text-to-sound interpretation and the improvement of correspondence and customer level advances will likewise be incorporated. Home automation module will be developed through server for real-time test; app will be available for all users not for authorized user. (Gbenga et al., 2017) This technology, as well as the nature of the impediment, cannot identify holes.
A worldwide situating approach that utilizes GPS to decide the client's area and GSM modules to impart the area to a family member or parental figure. It ought to likewise have the option to oblige a wide scope of grasps for adaptable dealing with. Outwardly debilitated individuals just pay attention to a screen peruse perusing the text shown on the screen. They don't typically get the opportunity to know the right spelling of a specific word, particularly when it's clinical terms and so forth.
Utilizing the GPRS innovation, this framework would be refreshed to an electronic checking framework, permitting clients to get to the framework distantly through the Internet. In addition, an improvement would be made to allow for the surveillance of a greater area. Furthermore, sensors like a barometric pressing factor sensor, a gas indicator for air quality observing, and a web interface would be fused into a solitary framework that couldn't just gauge yet additionally assess temperature and moistness factors. (Parikh et al., 2018) -Outdoor obstacle photos from a wider range of sources can be utilized. Here are the network types, models, and advantages of all the papers we have surveyed. (Patel et al., 2018) It is not tested in outdoor environments. - (Pathak et al., 2020) -By joining cards with GPU in the equipment and cloud-based organization execution, the to some degree daze individual will actually want to accomplish total autonomy both inside and outside. (Rahman et al., 2021) There are only a few sensors and devices in the model. Another requirement is that, in view of the assortment of things, the model uses a connected model in object recognizable proof with a foreordained number of genuine pictures.
A couple of kinds of sensors, for instance, the M.Q. gas sensor and the fire sensor, will be merged, and the arrangement will be ready in the object area using a tremendous picture dataset to ensure an optimal result. (Subbiah et al., 2019) -Applying different types of sensors to increase decision-making capabilities (Sumathy et al., 2021) The MEMS (Micro Electro Mechanical System) accelerometer will respond to even minor shocks, making the difference output or error difficult to estimate.
As an expansion of this work, in case of a mishap or crisis, similar data might be shipped off the closest emergency clinic/wellbeing office, permitting them to act rapidly to save the existence of the people in question. In addition to the latitude and longitude information, future works will include the correct address. (Suraj et al., 2019) Recognizing just the closest deterrents yet at the same time can't tackle the outwardly disabled individual's concern in seeing the climate.
The proposed framework comprised of a small example size, and the test climate was restricted to a school ground or a few restricted destinations that they knew about. In the future; we ought to incorporate more examples with that framework. (Vaidya et al., 2020) Things should not be placed too close to the camera chart and should be placed further away than the length of the assembly mark. For situations where the thing is exceptionally far and too small to even consider evening con-template evening considers being gotten, this judgment has a low Mean Average Precision. Because the authority module of the remote isn't used, the presence of sound has no effect on the region.
The accuracy of identification in murkiness should also be increased when distinguishing things that are stowed away by impediments in front of them; the distance of the article from the camera is also a factor that can be combined.

RESULTS AND DISCUSSION:
As indicated by the writing audit, sensor-based frameworks were made to help outwardly debilitated individuals in route and impediment location (Preceding, 2000). Ultrasonic sensors and radar sensors were joined into the stick or other wear able/handheld contraptions to make them more pleasing to use. Then, until 2015, camera composed contraptions were made using diverse picture taking care of methodologies, which achieved devices that were to some degree heavier than prior ones as a result of the weight of cameras. Individuals have begun utilizing profound learning calculations for obstruction recognition over the most recent quite a while, which requests a great deal of processing power. A couple of normal contraptions are displayed in Table 8 alongside their provisions. It has been shown that most gadgets don't need a web association with work. Web access is required for contraptions that consolidate a GPS) and different applications planned for obviously obstructed people. Besides, most of the gadgets are appropriate for both indoor and outside use and can distinguish both static and dynamic obstructions. Since the start, there has been a pleasant harmony among wearable and handworked contraptions created. The practicality of proposed ways to deal with help dazzle individuals can be surveyed utilizing boundaries like force utilization, weight, cost, and ease of use. It has been found that if the gadgets are basic and depend simply on sensors for preparing, they are lightweight, powerproductive, economical, and easy to use. In any case, as more limits are added to those devices, similar to camera coordination and figuring power, they become heavier, eat up more power, and become all the more exorbitant.

Future Direction
In the wake of perusing the papers and surveying the gadgets constructed so far for outwardly hindered individuals, the accompanying focuses have been separated that can help scientists working in this subject later on:  We need to add to our gadget and the assets we require, like force and cost. It is dependent upon the client to choose if they need to keep it savvy, light, and compactor spotlight on the gadget's provisions and functionalities.  As a rule, a precise and multi-highlight gadget won't be lightweight or savvy since equipment prerequisites will increment, maybe expanding the gadget's general weight/dimensionality. A lightweight and practical arrangement will likewise be inadequate in highlights. Accordingly, accomplishing harmony among elements and assets in a continuous gadget is an assignment that scholastics may seek after as a significant future region.  This paper discusses a range of devices that provide a variety of functions to the user, but they are either expensive or heavy, making them unsui-table for visually impaired people. Therefore, the time's necessity is for an answer that is savvy, lightweight, convenient, and include rich, just as fit for working progressively.  An assortment of gadgets for the outwardly weakened has been developed, each with its own objective and answer for the issue of the outwardly weakened in some structure.
However, there is no one-stop solution designed to assist them that meets practically all of their needs.

Current Research Stage
At present, we're chipping away at a keen visually impaired stick with a camera and a Raspberry Pi. Before hand, Arduino was incorporated with the stick, yet we changed over to Raspberry Pi since we required a camera and quick handling for conveying the item discovery model. For general snag recognition, a pre-fabricated item location model, the SSD Lite Mobile Net model, has been utilized, which furnishes clients with a voice-based yield by means of Bluetooth headphones. This was just a model to perceive how the gadget capacities progressively with a sent model. We are zeroing in comprehensively on two classifications:

Traffic light detection
Outwardly hindered individuals struggle exploring uninhibitedly in the rest of the world, particularly in jam-packed regions. We will probably make traffic signal recognition for better and more secure development.

Currency Denomination Detection
An individual experiencing vision disability ought to have the option to identify the cash category, so it's not possible for anyone to swindle them, all things considered.

CONCLUSION:
The paper survey of past turns out accomplished for the outwardly disabled. We attempted to describe the beneficial technologies designed for the visually handicapped, focusing on their operation, utility, and characteristics. We attempted to make it more intuittive and justifiable by looking at the gadgets dependent on various boundaries ( Table 8). The interface between the client and the framework, just as the plan by which data is communicated to the client, are basic provisions in the improvement of an assistive gadget. Clients ought to have the option to use the thing with little exertion in case it is basic, wearable, and easy to use. Albeit a ton of exertion has been done as of late to help the outwardly impeded, there is as yet a requirement for a financially savvy arrangement with more elements to help the outwardly weakened become more proficient and autonomous. The savvy stick ought to be easy to work and low in weight, with the capacity to perform well progresssively and with high exactness. There are numerous basic smart sticks available now that are simple to use, but as technology advances, more advanced devices are being produced. These devices have a lot of features, but not all of them work in real-time.
Moreover, most contraptions are substantial, making them hard to move and illogical for constant use. The emphasis ought to be on working on the precision of these gadgets, bringing down their force utilization, and making them lightweight, easy to utilize, versatile and proficient continuously. In contrast with the current gear, a solitary gadget with these components would make the existence of outwardly debilitated people more helpful.

ACKNOWLEDGEMENT:
First of all, I recognize the aid of Allah since, without Allah's help, it was unachievable. Moreover, my thanks go to the co-authors and respected professors of the Dept. of Computer Science and Engineering, Bangladesh University of Business and Technology (BUBT), for supervising me and for providing me with the appropriate assistance to finish the research work.

CONFLICTS OF INTEREST:
The authors state that they have no conflicting interests in the paper's publication.