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1.ABSTRACT:-
In the present scenario, bomb blasts are rampant all around the world. Bombs went of in buses and underground stations, killed many and left many injured. Bomb blasts can not be predicted before hand. This paper is all about the technology which predicts the suicide bombers and explosion of weapons through IMAGING FOR CONCLEAD WEAPON DETECTION, the sensor improvements, how the imaging takes place and the challenge And we also describe techniques for simultaneous noise suppression, object enhancement of video data and show some mathematical results.
The detection of weapons concealed underneath a persons clothing is very much important to the improvement of the security of the general public as well as the safety of public assets like airports, buildings, and railway stations etc. Manual screening procedures for detecting concealed weapons such as handguns, knives, and explosives are common in controlled access settings like airports, entrances to sensitive buildings and public events. It is desirable sometimes to be able to detect concealed weapons from a standoff distance, especially when it is impossible to arrange the flow of people through a controlled procedure.
Imaging techniques based on a combination of sensor technologies and processing will potentially play a key role in addressing the concealed weapon detection problem. Recent advances in MMW sensor technology have led to video-rate (30 frames/s) MMW cameras. However, MMW cameras alone cannot provide useful information about the detail and location of the individual being monitored. To enhance the practical values of passive MMW cameras, sensor fusion approaches using MMW and IR, or MMW and EO cameras are being described. By integrating the complementary information from different sensors, a more effective CWD system. .
2.INTRODUCTION:
Till now the detection of concealed weapons is done by manual screening procedures. To control the explosives in some places like airports, sensitive buildings, famous constructions etc. But these manual screening procedures are not giving satisfactory results, because this type of manual screenings procedures screens the person when the person is near the screening machine and also some times it gives wrong alarm indications so we are need of a technology that almost detects the weapon by scanning. This can be achieved by imaging for concealed weapons. The goal is the eventual deployment of automatic detection and recognition of concealed weapons. it is a technological challenge that requires innovative solutions in sensor technologies and image processing.
The problem also presents challenges in the legal arena; a number of sensors based on different phenomenology as well as image processing support are being developed to observe objects underneath people’s clothing.These imaging sensors developed for CWD applications depending on their portability, proximity and whether they use activs or passive illuminations.
The detection of weapons concealed underneath a person’s clothing is very much important to the improvement of the security of the general public as well as the safety of public assets like airports, buildings, and railway stations etc. Manual screening procedures for detecting concealed weapons such as handguns, knives, and explosives are common in controlled access settings like airports, entrances to sensitive buildings and public events. It is desirable sometimes to be able to detect concealed weapons from a standoff distance, especially when it is impossible to arrange the flow of people through a controlled procedure. 
3. INFRARED IMAGER:
Infrared imagers utilize the temperature distribution information of the target to form an image. Normally they are used for a variety of night-vision applications, such as viewing vehicles and people. The underlying theory is that the infrared radiation emitted by the human body is absorbed by clothing and then re-emitted by it. As a result, infrared radiation can be used to show the image of a concealed weapon only when the clothing is tight, thin, and stationary. For normally loose clothing, the emitted infrared radiation will be spread over a larger clothing area, thus decreasing the ability to image a weapon.
4. PMW IMAGING SENSORS:
4.1FIRST GENERATION:
Passive millimeter wave (MMW) sensors measure the apparent temperature through the energy that is emitted or reflected by sources. The output of the sensors is a function of the emissive of the objects in the MMW spectrum as measured by the receiver. Clothing penetration for concealed weapon detection is made possible by MMW sensors due to the low emissive and high reflectivity of objects like metallic guns. In early 1995, the MMW data were obtained by means of scans using a single detector that took up to 90 minutes to generate one image.
Following figure1 (a) shows a visual image of a person wearing a heavy sweater that conceals two guns made with metal and ceramics. The corresponding 94-GHz radiometric image figure1 (b) was obtained by scanning a single detector across the object plane using a mechanical scanner. The radiometric image clearly shows both firearms.
As a result, infrared radiation can be used to show the image of a concealed weapon only when the clothing is tight, thin, and stationary. For normally loose clothing, the emitted infrared radiation will be spread over a larger clothing area, thus decreasing the ability to image a weapon.
4.2SECOND GENERATION:
Recent advances in MMW sensor technology have led to video-rate (30 frames/s) MMW cameras.This system collects up to 30 frames/s of MMW data. Following figure shows the visible and second-generation MMW images of an individual hiding a gun underneath his jacket. It is clear from the figures 1(b), 2(b) that the image quality of the camera is degraded.
5.CWD THROUGH IMAGE FUSION:
By fusing passive MMW image data and its corresponding infrared (IR) or electro-optical (EO) image, more complete information can be obtained.The information can then be utilized to facilitate concealed weapon detection.
Fusion of an IR image revealing a concealed weapon and its corresponding MMW image has been shown to facilitate extraction of the concealed weapon. This is illustrated in the example given in following figure 3a) Shows an image taken from a regular CCD camera, and Figure3b) shows a corresponding MMW image. If either one of these two images alone is presented to a human operator, it is difficult to recognize the weapon concealed underneath the rightmost person’s clothing. If a fused image as shown in Figure 3c) is presented, a human operator is able to respond with higher accuracy. This demonstrates the benefits of image fusion for the CWD application, which integrates complementary information from multiple types of sensors.