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Touchless Writer provides a new way of interaction between computers and humans. Each generation of computer is characterized by a major technological development that fundamentally changed the way computers operate, resulting in smaller, cheaper and more powerful devices. Touchless Writer provides the interaction with computers by means of tracking pointed colored marker through a web camera. Using a pointed colored marker user draws a character within the frame of the web camera. The frame here refers to the limit to which the web camera can capture the character entered by the user. The images of pointed colored marker are captured continuously and movement of pointed colored marker is analyzed and tracked. According to the movement of pointed colored marker, the pixels will be plotted on the screen. It represents the character entered by the user and it is compared with the predefined character set (A-Z, a-z and 0-9). The best possible matching character is displayed on the screen. Touchless writer enables the user to enter the text without use of regular input devices such as keyboards or on screen keyboards.
IndexTerms-Touchless Writer, Character recognition, object tracking, image processing, pattern matching
The technological development has brought a significant and fundamental change in the computers resulting in cheaper and smaller devices. Touchless writer is one of such significant development that provides humans the comfort and convenience to enter the character into computers without even touching the keyboard or onscreen keyboard or any other input device.
Following are some of the existing systems which provide user with facility to interact with the system without use of regular input devices such as mouse and keyboard with Touchless technology:
1.Touchless Capacitive Sensor for Hand Gesture Detection 
It uses a capacitive motion-tracking sensor system including the electrodes and interface electronics.The experimental results were obtained which demonstrated the capability of the sensor system to track a human's finger within a 10cm range from the electrodes' plane. In this system, the motion tracking sensor and electrodes are used for tracing the path of the object.
2. Touchless interactive screen 
The aim of this project is to develop a touchless interactive screen which helps to ease the controlling of any kind of monitors such as PC monitor, TV screen without a stroke or touch. The objective is to apply image processing techniques to track the movement of the finger gestures which is captured by a webcamera and that will be converted into mouse movements to control the screen.
3. Handwritten Digits Recognition 
It implements a classification algorithm to recognize handwritten digits (0-9). The implementation of the Principal Component Analysis (PCA) is combined with 1-Nearset Neighbor to recognize the numeral digits and discusses the other different classification patterns.
4. Microsoft TouchlessSDK 
It's an unusual way of interacting with the computer by using Text-based User Interface. This is the replacement of the traditional input devices. This is the replacement of the traditional input devices. User only needs the camera. By tracking multiple moving objects with web camera; the Touchless SDK obtains a number of position data in real-time, which simulates a multi- touch positioning device. It is based on the image processing.
In the touchless capacitive sensor, for hand gesture detection, the motion-tracking sensor system including the electrodes and interface electronics are used, which makes the system more costly. For use of touchless writer, there is no need of any special type of hardware other than a web camera and a colored pointed marker.
Touchless interactive screen moves the mouse cursor with motion of object using MATLAB, Touchless writer also show the entered character to the user.
Limiting factor of Handwritten Digits Recognition is that it recognizes only digits and not characters.
In touchless SDK, it is assumed that the color of a certain object seen by web camera is recognizable and remains the same when the object moves, it is not always true in reality.
The color of the object must be contrasting to make it easily distinguished from the environment. The color response is heavily influence by the ambient light conditions.
To overcome all above drawbacks and to provide a touchless experience to user for entering the characters as well as digits, Touchless writer is introduced.
Touchless Writer is a new way of interaction between computers and human beings. The user enters the character into the computer without the use of keyboard or on-screen keyboard or any other input device. This is done through a web camera by using a pointed colored marker. The entered character is recognized by the touchless writer and displayed on the screen. In this way touchless writer provides convenient andcomfortable way of entering characters into the system.
The Touchless Writer allows the user to enter the character in the frame of the web camera using the pointed colored marker. The frame here refers to the limit to which the web camera can capture the character entered by user. The web camera continuously tracks and analyzes the movement of the pointed color marker and accordingly captures the character. The captured character is then compared with the existing character set in the system. This character set is predefined (A-Z, a-z and 0-9).The best possible matching character is displayed on the screen. The display screen shows two images, the one that the user enters and the other is the character from the predefined character set that matched with the pixels of the entered character. If the captured character does not match any of the characters in the predefined character set, an alert message is shown, stating 'No such character found'.
Touchless writer does not require expensive hardware and software. Touchless Writer can be used by disabled people who know English language but are unable to work on computer. They just need to manage to hold the marker and write.The user need not know the standard format of the keyboard that is the key arrangement or the location of keys for using touchless writer. The software can recognize a character entered in any handwriting by the user.Also, the typing speed doesn't matter here, since the software eliminates the use of keyboard. This makes Touchless writer more convenient to use than traditional input devices. The objective of project is to provide convenient way of entering character into system by using a colored marker through a web camera.
ARCHITECTURE OF PROPOSED SYSTEM
Architecture of proposed system
Fig. 2 shows the architecture of Touchless Writer.
Following are the components of Touchless Writer:
A. I/O Unit
B. Capture a video
C. Color Filtration
D. Tracking object movement
E. Feature Extraction
G. Resultant Character
A. I/O Unit:
The web camera is an input device for the Touchless writer. The web camera acts as an interface between the user and the software. The user is given a choice to select a web camera (internal and external). The display unit displays the entered character and the resultant character.
B. Capture a Video:
As the camera starts, all the motion within the frame of the camera is captured. The frame of the camera is predefined as 320x480px.With the help of the pointed colored marker, the user enters the character. This is known as the video capturing. Video capturing is done using aforge.net framework.
C. Color Filtration:
The motion of the marker specifies the character entered by the user. So we have to eliminate the background and trace the movement of the marker. The first step is to perform color filtering, keeping only the color of the marker we are interested in and removing all the rest. To filter the color of the pointed marker, Euclidean Color Filtering algorithm will be used.
D. Tracking Object Movement:
Once the marker is detected, its movement is tracked. This is done by getting the co-ordinates of the marker and putting pixels on the corresponding co-ordinates of the white panel. Now, the entered character is tracked on the white panel. This is done using aforge.net libraries. Fig. 3 shows the user interface which contains two displays. White panel display is used to show the entered character. And other display screen is used to display the captured video.
E. Feature Extraction:
In Feature extraction, the image is scanned to find the boundary of the character. These boundary pixels are used to compare the entered character with existing character set. The entered character is now ready for comparison.
The character entered by the user is compared with the predefined character set. This is achieved using back propagation algorithm of neural networks. It gives the highest and lowest possible matching character.
G. Resultant Character:
The resultant character is the comparison result of the entered character and the existing character set. The best possible matching character is displayed.
In this proposed system user has to write in air interface which is bit complex and tedious for user to write. In some cases due to environmental conditions the character entered by the user is not recognized correctly. To achieve the better performance,
Following conditions should be met:
The color of the marker which is used to enter the character should contrast with the background or environment.
Sufficient amount of light must be provided so the colors get detected properly.
The intensity of light should be constant enough so that the color is not changing.
Camera's resolution and capturing capacity should be high enough to get a clear image.
The proposed system provides easy way of interaction of human being with computer. Touchless Writer is cost effective since it does not require expensive hardware. It is useful and more advantageous for those users who cannot use the keyboard properly and users with slow tying speed.