Field of invention:
The present invention generally relates to a system and method for determining or detecting the presence of human body beneath the water bodies. Our system uses sound (acoustic signals) to find the location of the body. Only human body will reflect all characteristic frequencies. When the sound waves get transmitted one half of the signal moves through the body and other half gets reflected. The frequency change and time delay are calculated to find the location. Here signals are transmitted and received using speaker and microphone respectively.
Background of the invention and the prior art:
The Objective of this invention is to create a device that can assist to find humans in underwater during flood relief operations. A human body (180 cm) has a frequency of around 3 Hz from side, but from top (head 25 cm) the frequency is around 6 Hz. A finger from side (10cm) has a frequency of around 10 Hz. When the signal is transmitted from the speaker one half of the signal moves through the body and one half gets reflected and received at the microphone. Hence the signal is transmitted and received several times to find the exact location of the human beneath the debris.
The invention disclosed in Patent Numbered WO2016170005A1 by Redmond Shouldice et al, describes a system in which one of the sensors are designed for location of attributes of moving articles and living subjects for human recognizable proof or validation, one of the processors, for example, in an arrangement of sensors or that control a sensor, might be designed to deal with signals from the one of the sensors to distinguish an individual. The preparing may incorporate assessing highlights from the signs, for example, breathing.rate, breath profundity, level of development and pulse and so forth the sensors might be radio recurrence non-contact sensors with robotized discovery control to change location control boundaries dependent on the distinguishing proof of living creatures, for example, to evade sensor obstruction.
The invention disclosed in Patent Numbered WO2011056830A1 by Michael Bruno et al, describes a system in which a portable threat detection apparatus and method is disclosed which may include a majority of acoustic discharge sensors masterminded in a bunch, raming a polygon characterizing at least two axes of arrangement between particular sets of acoustic outflow sensors, a registering gadget in collaboration with a non-momentary PC intelligible capacity medium involving PC readable instructions for performing accepting a first sign created by a first acoustic emission sensor inside an individual pair of acoustic emission sensors, in light of the principal acoustic emission sensor distinguishing an acoustic discharge from a source, and getting a subsequent sign delivered by a second acoustic emission sensor

inside the separate pair of acoustic outflow sensors, because of the second acoustic discharge sensor recognizing the acoustic emission, deciding a cross-connection factor between the main sign and the subsequent sign, and, deciding a heading to the source dependent on the cross relationship factor.
The invention disclosed in Patent Numbered KR20070007462A by Dong-ik et al, describes a system which helps in wireless underwater communication. This system includes a voice signal amplifier, a modulator, an alectroacoutic transducer, a demodulator, a duplexer and an oscillator. This system is introduced to reduce power consumption and improves background noise characteristics by determining a carrier frequency in a frequency band. Here a voice signal amplifier for amplifying a voice signal, converted into an electric signal by a microphone {microphone) and / or amplified voice signal output to the speaker; A modulator for modulating the voice signal; An electroacoustic transducer for converting the modulated signal modulated by the modulator into an underwater acoustic signal; A demodulator for demodulating the received modulated signal into an original signal; A duplexer for selectively transmitting or receiving the modulated signal; And an oscillator providing an oscillation frequency for modulation and demodulation in the modulator
The invention disclosed in Patent Numbered W02011084483A2 by Barry Megdal et al, is about underwater positioning and tracking system using acoustic signal transmitter and receiver. The acoustic transmitters are used to transmit array of acoustic signals. The position of the object to be found underwater using global positioning system technology (GPS). The receivers present underwater find the object from the acoustic signals transmitted by the transmitter. The GPS time of transmission is synchronised with underwater receiver. The receiver calculates the position of the object is found using GPS time, transmitted signal's position and attitude.
The invention disclosed in Patent Numbered US7496226B2 by Shahriar Negahdaripour et al, is about underwater acoustic positioning system and method. The system comprises of a submersible thing and multiple cameras are coupled with it. A stereovision matching logic programmed is utilized to simulate the frontal view of the object underwater in form of photo mosaic and 3D structural map. that is simulated based on the information of the target underwater captured by the camera from various distances. Any of the optical or acoustical cameras can be used. And any of the remotely operated vehicle (ROV) or autonomous underwater vehicle (AUV) can be used for the submersible device. The apparatus further includes positioning sensors.
DETAILED DESCRPTION:
The project is used to find the human bodies easily and faster under water especially during emergency conditions like flood relief operations. The existing techniques, manpower and equipment's to search human bodies underwater are not capable enough. So, here we use acoustic signals. They are transmitted, reflected and received. According to the difference in frequencies of the transmitted and received reflected signal we can easily find there is a human body. The searching process can be further improved by using remotely operated vehicles(ROVs) or towed operated vehicles (TOVs) and other sensors. And from the

calculation of the time of transmission and reception of the signal, we can find the location of the body and recover it. This saves time, resources and prevents panic.
A. Design of the system
Electronic sensing devices are being recommended strongly to be more reliable, effective, cheap, and user-friendly to identify people buried under debris and vast water-bodies. These devices allow the rescuers to rescue the victim quickly and efficiently saving precious minutes of fruitless search. An underwater acoustic signal is obtained using devices such as Sonar device. The detector is designed with both seismic and acoustic sensors which differentiate between environmental and relevant sounds. Sonar may be used as a means of acoustic location and of measurement of the characteristic frequencies of the human bodies in the water. The acoustic frequencies used in Sonar systems vary from very low [infrasonic] to extremely high [ultrasonic].
Modern active sonar system uses an acoustic transducer to generate a sound wave which is reflected from human bodies, we should use a sonar system with lowest supported frequency to increase the range of detection. Trapped person locator is an efficient and sensitive tool which uses leading edge technology. It allows two-way communication using its waterproof communication probe up to two meters with the victims once they are found. The communication probe's microphone and speaker help communicate with buried survivors. We need a microphone that can detect very deep frequencies and a ping for everybody [multiple ping frequencies for multiple body parts], only human body will reflect all characteristic frequencies, we need a water proven speaker (send ping) and a water proven microphone (receive pong)to recognize a human body between these both frequencies. If we scan for the body parts (2- 10 Hz reflected on their projected surface) we should get a very clear response in all bands. It works like a simple detector for metals, but specialized for frequencies of human bodies.
B. Estimation of Humans inside water
To find humans in underwater, we have to detect the resting frequency of human body parts. A human body (180 cm) has a frequency of around 3 Hz from side, but from top (head 25 cm) the frequency is around 6 Hz. A finger from side (10cm) has a frequency of around 10 Hz. Only a human body will reflect all characteristic frequencies. Instead of human body if there is some other things for example, barrel having similar frequencies like our human body parts , but the higher frequencies of our arms and fingers are missing in the reflected response. Thus calculating the resting frequency of all body parts to express the characteristic polynomial. The following formula can be used to calculate the frequency,
f=SQRT((9.81 m/s2)/R)
where R is the middle diameter from observers point of view (projection area).
R = VA(l/3) = (mass / density)A(l/3)
To identify the depth of the human body in underwater we have to calculate acceleration g that should be greater than 9.8 m/s2.Therefore it can be calculated according to the amount of gravity {- pressure over body) by using the formula

g = MG/r2
Where M is the Mass of water in sea, r is the distance of sea to center of earth and
G is the gravity constant.
C. Process for Estimating Humans in underwater during flood relief operations.
This system consists of transmitter, receiver and a microcontroller (raspberry pi). Underwater acoustic communication is the wireless communication in which acoustic signals carry digital information through the underwater channel. Since there are comparatively low data rates in underwater communication we use acoustic signals.
The transmitter generates the acoustic signals. It determines pulse width, pulse reception frequency, modulation and carrier frequency. Here we use active sonar transducers which emit an acoustic signal of proper frequency or pulse of sound into the water. SONAR is a system using transmitted and reflected underwater sound waves to detect and locate submerged human bodies. The acoustic frequencies used in SONAR systems vary from very low(infrasonic) to extremely high (ultrasonic). The speed is determined by water's bulk modulus and mass density. The speed of acoustic signals in water is 1500 m/s.
When an object is in the path of the wave, the signal is reflected and received by the receiver. The frequency and time taken by the sound wave to come back is recorded. On the off chance that the transducer is furnished with the capacity to receive signals, it measures the strength of the signal, sonar is likewise utilized for the gear used to produce and get the sound. An underwater acoustic signal is got utilizing device, for example, a SONAR device that can supply the sound record of the acoustic field action in a provided guidance.
Submerged acoustic signs are utilized with numerous applications, like acoustic communication, discover)' and localization of surface and subsurface articles, depth sounders and different applications. The transmitted acoustic signals strike the body under the water. Some of the signals are absorbed by the body and remaining gets reflected. The signal is then received and processed using Raspberry pi. The Raspberry Pi is a minimal effort, small PC that connects to a PC screen or TV, and utilizations a standard console and mouse. It is a skilled little gadget that empowers individuals, all things considered, to investigate figuring, and to figure out how to program in dialects like Scratch and Python.
Raspberry pi is used to process the frequency of the received signal. Each body part absorbs different amounts of signal. So there is difference in the frequency of the received signal. Based on this difference we can identify that the signal is reflected from a human body part. So we can know that there is human body in that location and we can rescue it.

Brief description of Drawing:
The figure gives crystalline explication of the invention.
Figure 1 Transmitting and reflecting pattern of a sonar system
Figure 2 Overall detection of humans using acoustic signals in under water during flood relief operation.
Figure 3 Schematic diagram of the invention
Figure 4 Flow chart indicating overall detection of humans using acoustic signals in under water during flood relief operation.
Detailed description of the drawing:
The present invention generally relates to the system, which can be used to detect human using acoustic signals in underwater during flood relief operation. More specifically, it transmits and receive signals (Acoustic waves) to detect the human presence under the debries.
Figure 1 explains the Transmitting and refection pattern of a sonar system. The transmitted signal has some frequency that we generate. After it gets reflected from the human body underwater the frequency pattern changes as some of the signal is absorbed by the body.
Figure 2 depicts the overall detection of human bodies under water using acoustic signals during flood relief operations. Here, we use transmitter to transmit the acoustic signal which is generated by SONAR. Then the acoustic signal transmitted towards the human body. The signal is reflected back to receiver which is then processed in raspberry pi. Finally human body is detected based on the frequency.
Figure 3 depicts the schematic diagram of overall detection of human bodies under water using acoustic signals during flood relief operations. It consists of a microphone as transmitter, a speaker as receiver and a microcontroller to process the output.
Figure 4 depicts the flow chart indicating overall detection of humans using acoustic signals in under water during flood relief operation. The step by step process of detecting human body under water is been explained in the flow chart.