Abstract:
A synthetic underwater visualization system (SUVS) comprising a real-time graphics software engine, a sophisticated underwater environmental sensor, a fixed-base database, and a retrieval system designed to accept and assimilate into a common database bathymetric and environmental information acquired from around the world by components of other deployed SUVS sensing systems. SUVS is capable of sensing, modeling, and realistically displaying underwater environments in real-time, and will foster widespread utilization in the areas of homeland security, commercial and recreational maritime navigation, bathymetric data collection, and environmental analysis. The technology will also be readily adaptable and highly desirable in non-marine applications.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to the field of bathymetry, and specifically to a system for creating a detailed synthetic visualization of an underwater environment. 
         [0003]    2. Description of the Related Art 
         [0004]    Current technology used for bathymetry and underwater visualization is deficient in two critical areas: sensors are incapable of high-resolution three-dimensional measurement, and software is incapable of realistically representing large, complex, dynamically changing underwater environments in real-time. As a result of these deficiencies, it has not previously been possible to develop and commercialize low-cost, high-resolution, real-time, three-dimensional underwater visualization systems. 
         [0005]    Current State-of-the-Art Underwater Sensors: 
         [0006]    Objects on the ocean floor that threaten navigation or national security in coastal waters, such as bottom-mounted mines, and other objects of military or commercial interest, are often obscured due to turbidity in the water column. Standard camera systems, operating passively with ambient sunlight or in combination with flood and strobe lights, can typically image through one to two optical attenuation lengths (1/k; where “k” is the diffuse attenuation coefficient). 
         [0007]    Light is attenuated as it passes through water. That is, light gradually lessens in intensity as it passes through water (as well as other mediums, including air) as it is scattered and or absorbed. In clear water, light with the longest wavelengths are absorbed first, so red, orange, and yellow light is absorbed in shallow water than is blue and violet light. It is this fact that gives clear ocean waters a deep-blue appearance when viewed from above. Other material suspended in water, such as dirt from the bed of the body of water, chemicals, and other detritus, can drastically increase the amount of absorption and scattering of light particles and cause the light to be attenuated faster. 
         [0008]    In the 1990s, new imaging systems based on laser illumination, (synchronous laser scan and imaging LIDAR approaches), have increased the imaging range to four to five attenuation lengths. However, light attenuation in very turbid water, such as associated with river plumes and suspended bottom sediments, render even these systems ineffective due to the limited stand-off range necessary for generating high quality imagery and the associated decrease in survey rate. Therefore, the need remains to develop compact optical systems capable of imaging through greater ranges and deployable on a variety of manned and unmanned platforms. 
         [0009]    No low-cost, commercial, three-dimensional bathymetric LIDAR systems currently exist. However, there are a number of commercially deployed high-cost Airborne LIDAR Bathymetry (ALB) systems. ALB is an airborne survey methodology utilizing an aircraft-mounted LIDAR system to rapidly and accurately measure seabed depths and topographic elevations. These systems utilizes two wavelengths of laser light, one to measure the surface of the body of water and the other to penetrate into the body of water to measure the depth of the water. 
         [0010]    Probably the most advanced ALB system is the SHOALS system. The SHOALS technology is owned and operated by the Joint Airborne LIDAR Bathymetry Technical Center of Expertise (JALBTCX), which is a unique partnership between the South Atlantic Division of the US Army Corps of Engineers (USACE), the Naval Meteorology and Oceanography Command/Naval Oceanographic Office, and USACE&#39;s Engineer Research and Development Center. 
         [0011]    Although the technology is quite advanced, only a few systems exist and they are extremely expensive to own and operate. The SHOALS system utilizes very high power YAG lasers, expensive photomultiplier tubes, and stabilization systems that are intricate and expensive. These systems utilize complex algorithms to deal with surface reflection and light dispersion. 
         [0012]    In addition to bathymetric applications, three-dimensional scanning LIDAR has recently been developed for acquiring high-density environmental ranging information on land (in air). An example of this type of system is the DeltaSphere-3000 Laser 3D Scene Digitizer being marketed by 3rdTech, Inc. This system is based on technology developed by Dr. Lars Nyland at the University of North Carolina at Chapel Hill. The system is capable of taking millions of range measurements using scanning 3D LIDAR in order to create a three-dimensional graphic image of the scanned space. 
         [0013]    Terrain Rendering State-of-the-Art: 
         [0014]    The state-of-the-art in visual, computer generated terrain rendering varies from simple graphics depictions created on personal computers (PC) to sophisticated, very expensive real-time simulators. In general, real-time rendering of detailed terrains poses a significant problem due to the vast amounts of data and large number of computations that are required to accurately represent complex terrain models. 
         [0015]    On the low end of the complexity scale are graphics generated by PCs, principally used for computer gaming. Modern PCs use dedicated graphics processing units (GPU) to help offload real-time graphic rendering related work from the CPU. However, due to memory storage and computational limitations, the PC is inadequate when it comes to rendering large, highly-detailed terrain models that require a large number of polygons to accurately represent the 3D image. In an effort to overcome this problem and still maintain highly-realistic computer-generated terrains, the gaming industry has implemented a distributed computing model for delivering new and improved content to multiple clients. This content is created and processed on a centralized server, which offloads the massive storage and computational work from the PC, and is used in today&#39;s Massively Multi-player On-line Games (MMOG). 
         [0016]    The rendering of large, detailed terrains for military simulations is accomplished using large and expensive image generator (IG) systems, such as the Harmony Military Simulator System developed by the Evans and Sutherland Company. 
         [0017]    In addition to the hardware limitations described above, there exist significant software challenges to depicting large, moving terrains in real-time. To address some of these problems, Level of Detail (LOD) algorithms have been developed. These algorithms lower the amount of detail in terms of triangles drawn to the screen in regions which are farther away from the operator, or in areas where the number of triangles can be reduced without causing much loss in detail. By so doing, these algorithms provide high detail for objects that are in the main field of view, while limiting the overall number of triangles displayed, thereby reducing graphics-related computations. Popular LOD algorithms in use today include ROAM, SOAR, Adaptive Quadtree, and Chunking. 
         [0018]    Although surface terrain information databases have improved as more of the world is mapped in increasing levels of detail and accuracy, underwater bathymetric databases are much further behind and for the most part remain woefully out of date. In waterways, where there are high currents such as rivers and coastal areas, the underwater landscape is in a constant state of change and not regularly measured and corrected. Furthermore, present systems do not learn about these changes and automatically update a common national or international database, nor is this information gathered from a number of geographically displaced systems and annotated for storage and redistribution. 
         [0019]    What is needed in the art is a system that solves these problems by providing and combining new-to-the-world technologies in underwater environmental sensing and real-time underwater graphics and terrain visualization software. 
       BRIEF SUMMARY OF THE INVENTION 
       [0020]    The present invention is a modular, mobile synthetic underwater visualization system (SUVS). SUVS is a commercially-viable, augmented reality (AR) system made possible by the development of a highly-sophisticated and innovative real-time graphics software engine and a sophisticated new underwater environmental sensor. Mobile components of the system will be complimented by a fixed-base data storage and retrieval system designed to accept and assimilate into a common database bathymetric and environmental information acquired from around the world by the mobile SUVS units. SUVS is capable of sensing, modeling and realistically displaying underwater environments in real-time. This technology will foster widespread utilization, and will play an important role in areas of homeland security, commercial and recreational maritime navigation, bathymetric data collection, and environmental analysis. The technology is also readily adaptable and highly desirable in non-marine applications. 
         [0021]    The SUVS underwater visualization system is based on two innovations. The first innovation is an advanced terrain rendering graphics software engine capable of acquiring and incorporating large amounts of streaming real-time data into preprocessed terrain maps, and capable of generating geospatially-synchronized, highly-detailed, three-dimensional images. This rendering engine is designed to run on a very low-cost hardware platform. 
         [0022]    The second innovation is an advanced three-dimensional underwater sensor incorporating time-of-flight (TOF) LIDAR with self-adjusting beam convergence, a SONAR transceiver, a dual-axis scanning platform, and advanced MEMS (micro electro-mechanical systems) attitude sensing elements. This sensor is capable of acquiring high-fidelity data from marine environments in real-time, preprocessing the data, and passing it along to the graphics software engine for display to an operator. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a block diagram showing a high-level view of the synthetic underwater visualization system of the present invention. 
           [0024]      FIG. 2  is an illustration of the synthetic underwater visualization system of the present invention as it might be used in an operational scenario. 
           [0025]      FIG. 3  is a block diagram of one embodiment of an underwater component of the synthetic underwater visualization system of the present invention. 
           [0026]      FIG. 4  is a block diagram of one embodiment of an above water component of the synthetic underwater visualization system of the present invention. 
           [0027]      FIG. 5  illustrates one embodiment of a display featuring a graphical visualization of an underwater environment, augmented with expert knowledge by the present invention. 
           [0028]      FIG. 6  illustrates how information tags can be added to a displayed object on the present invention to provide additional information about each detected object. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0029]    For the purposes of this specification, the following terms have been defined:
       3D Three Dimensional   AI Artificial Intelligence   IG Image Generator   ALB Airborne LIDAR Bathymetry   APD Avalanche Photodiode   API Application Program Interface   AR Augmented Reality   ASIC Applications Specific Integrated Circuit   CPU Central Processing Unit   DARPA Defense Advanced Research Projects Agency   Eutrophic Shallow, warm, mud bottom lakes with high sediment levels and which are high in nutrients   FAA Federal Aviation Administration   FCS Future Combat Systems   GIS Geographic Information Systems   GNSS Global Navigation Satellite System   GPS Global Positioning System   GPU Graphics Processing Unit   IG Image Generator   JALBTCX Joint Airborne LIDAR Bathymetry Technical Center of Expertise   LIDAR Laser Identification Detection and Ranging   LOD Level of Detail   MEMS Micro Electro-Mechanical Systems   MMOG Massively Multi-player On-line Games   Nd:YAG Neodymium—Yttrium Aluminum Garnet (Laser)   OEM Original Equipment Manufacturer   Oligotrophic A newly formed lake that is poorly nourished, with small quantities of nutrients that plants need to grow   PC Personal Computer   PIN PIN Photo Diode   SHOALS Scanning Hydrographic Operational Airborne LIDAR Survey   SONAR Sound Navigation and Ranging   SUVS Synthetic Underwater Visualization System   TAWS Terrain Awareness and Warning   USACE US Army Corps of Engineers   WAAS Wide Area Augmentation System   YAG Yttrium Aluminum Garnet (Laser)       
 
         [0065]    SUVS Operation Overview: 
         [0066]    Augmented reality (AR) is a created environment that includes elements of both virtual reality and the real world. A simple example of this is the yellow first-down line that is artificially created and “painted” on top of the field in televised football games. The synthetic underwater visualization system (SUVS) of the present invention combines real-world data, including sensed terrain and underwater objects, with virtual elements, such as predefined library graphics and animations, to create an unparalleled real-time graphic depiction of sensed underwater environments. 
         [0067]    The principal components of the SUVS system are an advanced, miniaturized, underwater scanning LIDAR/sonar sensor and a high-resolution display console. SUVS can manipulate existing bathymetric data in real-time, transforming it into a very realistic three-dimensional view of the underwater environment in the immediate vicinity of the system, using information acquired from the advanced sensor system. The operator console displays this image on a daylight-readable, color liquid crystal display or any appropriate display type. The operator is able to view the rendered scene from virtually any “camera” angle, and discern vehicle location and orientation very accurately in relation to the actual environment. The operator&#39;s location and position in space are determined by components within the advanced LIDAR sensor, which include an augmented location sensor (such as a global positioning system, or GPS, sensor, or other global navigation satellite system (GNSS) augmented with a supplementary signal from a wide-area augmentation system, or WAAS) and MEMS-based attitude sensors. 
         [0068]    SUVS acquires real-time data from a newly-created, innovative, underwater sensor. In one embodiment, this sensor uses LIDAR adapted for use underwater to very rapidly scan the environment by sending out millions of pulses of light in a hemispherical pattern and measuring the light returning to the system. Pulsed sonar is used to acquire additional information, including current depth and the type of the bottom surface soil. 
         [0069]    As this high-resolution data is received, the on-board processing unit uses artificial intelligence (AI) algorithms to identify objects based on various sensed attributes. When the objects are identified, SUVS loads graphics elements from a predefined library of known underwater objects and displays these elements with the proper location, size, animation and orientation relative to the environment so as to create a highly realistic image. Terrain information that is acquired by this system that differs significantly from pre-existing bathymetric information will be used to correct information for subsequent use. 
         [0070]    The major elements of the present invention (SUVS) are identified in the following paragraphs. 
         [0071]    Display Console: 
         [0072]    In one embodiment, the Display Console consists of a daylight-readable color display, computing platform, non-volatile storage, and short and long-range wireless transceivers. The short-range transceivers will be used to communicate with the SUVS Sensor (described below), while the long-range transceiver will be used to communicate from vessel to vessel and to access the bathymetric database. In one embodiment of the invention, the display console may be a dedicated, information display designed specifically for use with SUVS. In an alternate embodiment, an existing mobile device, such as an iPad or a smart phone, may be used as the display console. Some embodiments may utilize both a dedicated display and a mobile device in cooperation. 
         [0073]    Bathymetric Database: 
         [0074]    A database and learning software suite will receive data gathered from all over the United States and/or the world by SUVS-enabled systems and use this data to update existing bathymetric information so that the national and world underwater terrain accuracy increases over time. This data can then be redistributed to deployed SUVS systems and other targeted recipients so that each system gains knowledge from the sum of these inputs. In some embodiments, this bathymetric database may be centralized, hosted on a primary server, while in other embodiments the bathymetric database may be distributed across a cloud-based server. Occasionally, throughout this specification, the term “centralized” will be used to describe the database, and, when it is, the term shall be defined to mean “a server or collection of servers and/or other storage and processing components that are tied together logically to perform a single primary function.” That is, whether the database described is located on a single physical server or distributed over various resources in a cloud, the term “centralized” is not meant to limit the physical implementation of the database. 
         [0075]    SUVS Sensor: 
         [0076]    An innovative, unique, technically-advanced 3D sensor is the heart of the invention, and, in one embodiment, comprises the following individual elements: scanning bathymetric LIDAR, sonar, MEMS attitude sensors, a location sensor (such as a GPS receiver or similar GNSS receiver), and a magneto-resistive flux sensor. The information gathered from these components is combined through a process of sensor fusion to produce a homogeneous output rich in environmental information. This sensor enables the SUVS system to create an augmented reality depiction of terrain detail unattainable in any commercially-available underwater visualization system, and is seen as one of the key technical innovations in the SUVS system. 
         [0077]    3D Rendering Augmented Reality Software: 
         [0078]    Another key component of the SUVS system is an advanced graphics-rendering engine that operates on sparse data (containing little detail in some locations and rich detail in others) and displays it in three dimensions on the display console. This graphics-rendering engine uses data acquired from the SUVS Sensor to augment preexisting terrain maps in real-time. This software works with large, detailed datasets representing terrains in the range of several hundred thousand square kilometers on a low-cost hardware platform designed to be affordable to most users. 
         [0079]    It is only due to relatively recent developments in MEMS technology and advanced laser research that it has become possible to create the SUVS sensor. The overall architecture of the SUVS invention is shown in  FIG. 1  and the operational concept in  FIG. 2 . 
         [0080]    Turning now to  FIG. 1 , we see a high-level diagram of one embodiment of the synthetic underwater visualization system, or SUVS, of the present invention. The main functional component of the full visualization system described herein is the primarily mobile component called the “SUVS reporting unit”  600 . A SUVS reporting unit  600  is typically a watercraft equipped with the sensors and other components needed to sense the underwater terrain, flora and fauna, and other objects. However, a SUVS reporting unit  600  may also be a buoy or other floating platform that contains similar sensors, and which has provides the same function. A buoy of floating platform may be positioned in a harbor or near important infrastructure on or near water, tethered or anchored in location to continuously monitor the underwater environment for threats. These types of SUVS reporting units  600  would be largely non-mobile units. For the purposes of discussion in this specification, many of the examples given will describe the embodiment of the SUVS reporting unit  600  based on a mobile watercraft, but the use of this type of example should not be considered limiting to the implementation of the invention. 
         [0081]    Looking now at the expanded view of a SUVS reporting unit  600 A in  FIG. 1 , we can see the subcomponents that make up a typical SUVS reporting unit  600 . The main components will be mounted to or used in or near a watercraft or other floating platform  300 . The floating platform  300  in  FIG. 1  is shown as a dashed line for two reasons: (1) to allow the description of the components mounted in or on the floating platform  300 , and (2) to emphasize that the floating platform  300  may be a watercraft (as shown) or it may be any other appropriate type of floating platform. 
         [0082]    The SUVS system has an above-water component  200  containing electronic circuitry and sensors that do not need to be under or in contact with the water. The details of the above-water component  200  are illustrated in  FIG. 4  and the corresponding text description. There is also a below-water component  100 , detailed in  FIG. 3 , containing circuitry for controlling the underwater sensors, including the LIDAR  340 , and the sonar  330 . The above-water component  200  and the below-water component  100  communicated with each other over communications pathways  215  and  235 . Communications pathway  215  is used in this embodiment to bring compass and GNSS values from the above-water component  200  to the below-water component  100 . Communications pathway  235  brings data from the below-water component  100  to communications circuitry of the above-water component  200  for transmission to external systems. 
         [0083]    It should be noted that, in other, alternate embodiments of the present invention, the above-water component  200  and the below-water component  100  may be combined into a single enclosure, or that the circuits and sensors shown housed in each different component (as shown and detailed in  FIGS. 3 and 4 ) might be divided between the two components ( 100  and  200 ) differently than shown in this example embodiment, without deviating from the intent of the present invention. 
         [0084]    Finally, the SUVS reporting unit  600  ( 600 A) contains a display  500  for showing the underwater environment as detected by the system sensors and as augmented with additional detail supplied by the system. The display  500  is connected to the above-water component  200  by communications means  510 , which may be a wired connection or a wireless connection. The display  500  may be a dedicated, special purpose computer display, or it may be a mobile device such as an iPad, smart phone, a tablet computer, or a laptop, or any other appropriate device with a suitable display. 
         [0085]    One or more SUVS reporting units  600  may be deployed in a body of water, or dispersed over different bodies of water. Each SUVS reporting unit  600  connects data, such as bathymetric data and data describing flora, fauna, and other underwater objects, and transmits this data to a centralized database  400 . This data is transmitted over a wireless two-way communications path  450 , and is processed and assimilated by the centralized database  400  into a global repository. Data contained in the centralized database  400  can be transmitted back to each SUVS reporting unit  600  in the form of updated bathymetric maps and other data. 
         [0086]      FIG. 2  describes the SUVS invention of  FIG. 1  in an example operational scenario. 
         [0087]    The below-water component  100  is directly mounted to the bottom of a watercraft (or fixed buoy) or other floating platform  300 , or, in alternate embodiments, can be connected to the floating platform  300  by a tether and otherwise allowed to be free-floating. A scanning LIDAR system  330  is used to acquire data about the underwater environment  305  immediately surrounding the below-water component  100 . The fusion of this information with that from other sensor elements within the SUVS enables the creation of extremely detailed graphic renditions of underwater features, including manmade objects and marine life. Movement of the floating platform  300 , such as rocking caused by waves or movement within the floating platform  300 , is detected by the SUVS system and can be accounted for in the resulting displayed images in some embodiments of the present invention (that is, the display of the images can be presented such that the moments of the floating platform  300  or of an operator holding the display can be taken out of the visual presentation.) 
         [0088]    The sonar component  340  of the SUVS sensor will be used to calculate depth and bottom type. This information will allow for dynamic calibration of the LIDAR sensor  330  so as to assist in compensating for water turbidity, and as a means for the graphics software to determine what bottom type is to be displayed. 
         [0089]    The sonar  340  and LIDAR  330  are used in conjunction to create a clear sensory image of the underwater environment  305 . The sonar  340  typically uses a relatively focused (narrow) “beam” of sound waves  340 A directed at the underwater terrain  310  to aid in the detection of the shape and distance of the terrain  310 . The LIDAR  330  is directed in a scanning pattern  330 A that is broad (nearly hemispherical) in the area just below and around the floating platform  300  (or just below the LIDAR  330  if the LIDAR is suspended or tethered to the floating platform  300 . The scanning pattern  330 A of the LIDAR  330  allows the SUVS to acquire detailed images of the area captured within the scanning pattern  330 A, while the sonar  340  is used to capture data about the terrain  310  and typically has more range than the LIDAR  330 , especially in turbid, murky water. Data from the two sensing systems are combined to create a more complete picture of the surrounding environment  305 . 
         [0090]    The creation of a lightweight, low power, and affordable bathymetric scanning LIDAR system  330  with capabilities similar to the SHOALS systems is a significant development. In one embodiment, the LIDAR  330  may utilize a solid-state diode pumped laser, emitting light at a wavelength of 532 nanometers (the wavelength that is least attenuated by water). The LIDAR  330  is designed so as to avoid eye injury to marine life and human divers. Because the SUVS LIDAR  330  is mounted underwater, not on an aircraft, and because the target depth for operation is 50 meters or less, the very high-power YAG lasers and expensive photomultiplier tubes used by the SHOALS system will not be required. Rather, the present invention, in one embodiment, uses solid state avalanche photodiodes (APDs) as light detectors. 
         [0091]    Returning to  FIG. 2 , the combined data received from the LIDAR  330  and sonar  340  will be used to detect and track objects within the underwater environment  305  surrounding the floating platform  300 . Examples of these objects include marine animals  320 , marine plants  310 A, objects of unknown origin  310 B (for example, a bottom-mounted sea mine, a shipping container, a sunken watercraft, etc.), rocks  310 C and other natural outcroppings, and debris  310 D. These objects are detected and recognized by the SUVS, and used to compare to previous scans of the area to detect differences that may exist in the data. 
         [0092]      FIG. 3  shows a detailed block diagram of one embodiment of the below-water component  100  of the present invention (some references in the following paragraphs also appear on  FIG. 2 ). A CPU (central processing unit)  128  controls the operation of most of the functionality within the below-water component  100 . The CPU  128  receives inputs from horizontal sense  104  and vertical sense  108  blocks, with information from the sensing systems (LIDAR  330  and sonar  340 ). In response, the CPU  128  commands the horizontal drive  102  and vertical drive  106  function blocks to direct the positioning of the LIDAR component  330 . 
         [0093]    In one embodiment of the SUVS, the control circuitry of the LIDAR component  330  includes an induction generator  110 , a power supply  112 , a solid state laser  114 , a frequency converter  122 , a beam splitter  120 , and transmission optics  116 . This circuitry is used to generate and transmit a laser pulse  118 . 
         [0094]    Outputs form the beam splitter  120  are also directed into a receiver channel  124  and fed into a time-to-distance converter (TDC)  126 . The output from the TDC  126  is fed back into the CPU  128 . 
         [0095]    The CPU  128  transmits information over an output communications pathway  235  to communications circuitry ( 230 , see  FIG. 4 ) in the above-water component ( 200 , see  FIG. 4 ). The CPU  215  also receives data over an input communications pathway  215  from the compass ( 210 ,  FIG. 4 ) and the GNSS receiver ( 220 ,  FIG. 4 ). 
         [0096]    The below-water component  100  also contains attitude sensors  130 , for sensing the geospatial position and orientation of the SUVS, memory  132 , and a temperature sensor  134 . Finally, the below-water component  100  contains a sonar transducer  136  for creating and sending sonar directives  138  to the sonar component  340 . 
         [0097]      FIG. 4  details one embodiment of the above-water component  200 , including a compass  210 , a GNSS receiver  220  (likely augmented by a supplemental system to provide a more accurate location), and communications circuitry  230 . The compass  210  provides directional information to other system components over communications pathway  215   a  and the GNSS receiver  220  provides location information over communications pathway  215   b . Pathways  215   a  and  215   b  combine to form the input communications pathway  215  as previously shown in  FIG. 3  and described in the corresponding text. The communications circuitry  230  receives data from the CPU ( 128 ,  FIG. 3 ) over communications pathway  235  (the same 235 as shown on  FIG. 3 ). 
         [0098]    The commercialization of the SUVS system will utilize lightweight, low-power, low-cost components throughout the design. In some embodiments of the present invention, major elements of the scanning bathymetric LIDAR  330  may be incorporated into custom ASICs, including the Time to Distance Converter and the precision receiver circuits. Beam steering will be accomplished through the utilization of custom designed low cost mechanical components. The remaining sensor elements may be designed and integrated, along with the scanning LIDAR  330 , into a small, ruggedized, lightweight, portable sensor. The principle components of this sensor will be reconfigurable for use in free air applications such as aviation and land vehicles. 
         [0099]    Terrain Rendering: 
         [0100]    In coastal marine navigation, the SUVS system is required to render very large terrain areas. Data for these types of terrains is most commonly stored today using heightmaps, a method of storing terrain data in which data is stored using a fixed-resolution grid. Using heightmaps, a terrain with one elevation point every 300 millimeters using 2 bytes of data each would require approximately 22 megabytes of data per square kilometer. A typical terrain in the range of several hundred thousand square kilometers, say 800 by 800 kilometers (640,000 square kilometers), would require in excess of 14,000 gigabytes using heightmaps. Current technology does not allow this amount of data to be effectively stored and rendered on a low-cost hardware platform, and since the SUVS system will be required to work with terrain areas of this magnitude, some method other than traditional heightmaps must be developed for representing large terrains. 
         [0101]    To address this problem, one embodiment of the present invention uses a revolutionary new software concept whereby the terrain is represented by a sparse dataset. The system allows for the storage of large amounts of data in areas of high detail where it is needed and minimal data in areas of low detail, such as flat ground, where it is not. A sparse dataset allows for a more efficient method of modifying and adding detail when new terrain information is acquired via the SUVS sensor. Without the fixed resolution and size of a heightmap, detail can be added as needed to areas as new information arrives. This sparse dataset will be stored with regional and detail indexes, allowing terrain data to be quickly accessed by the terrain-rendering engine. 
         [0102]    The rendering of large, sparse data on low-cost hardware requires the use of “level of detail” (LOD) software algorithms (explained in further detail later in this specification) in order to reduce the number of vertices/triangles rendered. Applying dynamic LOD will result in the need to create dynamically changing Triangular Irregular Networks (TINs). The processes of creating these TINs (vertex LOD and TIN building) are slow and additive (cannot be done in parallel), which can result in a low rendering frame rate. Further compounding the problem is that today&#39;s LOD algorithms work with traditional heightmaps, and are not designed to work for sparse data. Consequently, the present invention uses unique LOD and TIN building algorithms to achieve the objectives for the SUVS system. 
         [0103]    To address these issues, the present invention advances the state-of-the-art of graphics rendering software in the following ways:
       New LOD algorithms for large sparse datasets. These algorithms previously existed for height map data, but not for large sparse datasets.   A new TIN building algorithm based on the well-known Delauney algorithm capable of executing at a much higher speed than current implementations.   The use of bump mapping texturing techniques to add high frequency detail, giving the terrain a realistic look without adding additional detail to the underlying terrain.   A vertex and triangle caching mechanism, such that the vertex LOD algorithm sends only new and to-be-removed vertices to the TIN builder. Therefore the TIN builder only needs to add and remove triangles from a cached TIN.       
 
         [0108]    All of the functions required to render the terrain, such as operating system eccentricities, file input/output, LOD algorithms, TIN building, object loading and rendering, caching, operator input, and real-time sensor input make for a potentially unpredictable system, which results in unpredictable frame rates. In one embodiment of the invention, a supervisory algorithm is used to monitor and adjust system performance so as to accommodate processing time surges between frames and smooth out system performance. 
         [0109]    Storage of surface texture information can also be very memory intensive. Unfortunately, representing textures as sparse sets of data, the same concept proposed for addressing the heightmap issue, cannot be used with surface texture information. This is due to limitations in graphics application program interfaces (APIs), which require that surface textures have detail that meets or exceeds the detail of the underlying terrain surface if they are to look good. The present invention solves this problem by loading tiles of very low detail texture across large areas of the terrain, swapping out tiles as needed as operator perspective changes. High-detail textures are loaded at the locations perceived to be close to the operator, then swapped out with low-detail textures as the operator&#39;s view travels across the terrain. In one embodiment of the present invention, the algorithms required to accomplish this are based on the SOAR algorithm for rendering large scale terrains, but applied to textures rather than terrain height maps. 
         [0110]      FIG. 5  provides an example of one embodiment of the display module  500  of the SUVS invention. The display module  500  has a display screen  505  for presenting information to the operator of the system. An example of the types of information that might be shown is provided. A three-dimensional depiction of the terrain  515  surrounding the SUVS is displayed. The terrain depiction  515  is displayed in accurate virtual detail, including features such as terrain outcroppings  520 , trenches or gullies  520   a , rocks and other natural formations  530   a , and unknown objects  530   b . As shown in  FIG. 5 , newly discovered features (such as the rock  530   a  or unknown object  530   b ) which did not show up on a previous scan of the terrain may be shown highlighted or in a different color to indicate to the operator that the features were previously undetected. In addition to terrain features, the screen  505  may show plant life  525  and animal life  535  and their current position in the water relative to the SUVS. 
         [0111]    In one embodiment of the SUVS, the SUVS software will contain animation models of typical marine plant and animal life that can be displayed to represent detected plants and animals. For example, if something is detected by the SUVS that matches the qualities of a typical plant such as kelp, an animated graphical representation of kelp, previously loaded into the SUVS, can be displayed on the screen  505 , so that the image of kelp moving back and forth in the water can be shown to the operator, creating a more realistic visualization of the underwater environment. The animated graphic can be sized accordingly such that it is the size and rough shape of the detected plant as sensed by the SUVS. Additional detail on this concept is provided below in the discussion of terrain rendering. 
         [0112]    The display module  500  may be a custom display created specifically for the SUVS application, or it may be an existing or off-the-shelf display. In some embodiments, a mobile device, such as an iPad, table computer, laptop computer, or a smart phone may be used as the display module  500 . 
         [0113]    The present invention is novel and non-obvious in that it addresses several technical barriers that have previously not been addressed by solutions in the prior art. Table 1 below summarizes these technical barriers, and how they are addressed by the present invention. 
         [0000]    
       
         
               
             
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Technical Barriers Addressed by Present Invention 
               
             
          
           
               
                 Technical Barrier 
                 New Technology 
               
               
                   
               
               
                 Today&#39;s bathymetric scanning LIDAR 
                 One embodiment of the present invention uses a new ruggedized, complex 
               
               
                 systems are too heavy, consume too much 
                 scanning LIDAR sensor combining an ASIC laser, attitude and geospatial 
               
               
                 power, are too fragile, are too complicated 
                 sensors, and traditional SONAR, the outputs of which are fused and acted 
               
               
                 to operate, and are too expensive for wide 
                 upon by sophisticated advanced artificial intelligence software in order to 
               
               
                 spread commercial use 
                 provide a compact data rich stream of information describing the underwater 
               
               
                   
                 3D environment 
               
               
                 Light attenuates quickly in turbid water, 
                 One embodiment of the present invention will use monochromatic 532 nm 
               
               
                 limiting the usefulness of optical marine 
                 radiation from a frequency doubled solid state laser, a dynamically focused 
               
               
                 sensing systems 
                 beam, a very short pulse high power transmitter and an ultra high sensitivity 
               
               
                   
                 receiver will extend imaging capabilities over any existing prior art systems 
               
               
                 Time required to perform the millions of 
                 One embodiment of the present invention generates real-time data from 
               
               
                 scans necessary to generate a detailed 
                 incoming sensor information and uses it to augment pre-existing bathymetric 
               
               
                 LIDAR image prohibits real-time 
                 data, rather than attempting to create entire new scenes from incoming data 
               
               
                 commercial utilization 
                 alone. Software are dynamically adjusted so that the scans required are 
               
               
                   
                 optimized for vehicle speed and detail of image generation 
               
               
                 Current low-cost mobile hardware 
                 One embodiment of the present invention uses an innovative sparse dataset 
               
               
                 platforms are incapable of rendering large 
                 based terrain rendering engine using new LOD algorithms, an innovative 
               
               
                 3D terrains while simultaneously processing 
                 new TIN building process, and bump mapping texturing techniques that add 
               
               
                 complex, incoming sensor data in real-time 
                 high frequency detail, giving the terrain a realistic look without adding 
               
               
                   
                 additional detail to the underlying terrain 
               
               
                 Lack of algorithms and sensors for 
                 One embodiment of the present invention utilizes fuzzy logic algorithms 
               
               
                 detecting and identifying underwater 
                 based on unique signature characteristics of the SUVS sensors that enables 
               
               
                 objects in real-time, including terrain 
                 the identification of classes of objects and the intuiting of other classes 
               
               
                 features 
               
               
                   
               
             
          
         
       
     
         [0114]    There are many key design factors that must be considered in order to create a commercial version of the present invention. Table 2 below identifies these factors by the SUVS component with which each one is associated, and lists suggested technical “targets” as well as proposed commercial requirements required for a commercially successful SUVS as described herein. 
         [0000]    
       
         
               
             
               
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Key Factors/Technical Targets Chart 
               
             
          
           
               
                 SUVS 
                 Key Factors 
                   
                 Commercial 
                   
               
               
                 Component 
                 (Variables) 
                 Technical Targets 
                 Requirement 
                 Prior Art Practice 
               
               
                   
               
               
                 Scanning LIDAR: 
                 Light collection 
                 360 degrees horizontal, 
                 180 degrees horizontal, 90 
                 None 
               
               
                 Collection Optics 
                 ability 
                 90 degrees vertical 
                 degrees vertical 
                   
               
               
                 Scanning LIDAR: 
                 Pulse width and 
                 1 nanosecond pulse, 
                 5 nanoseconds, 40 watts, 
                 10 nanoseconds, 30 
               
               
                 Solid State Laser 
                 energy 
                 100 watts, eye-safe 
                 eye-safe final output 
                 watts 
               
               
                   
                   
                 final output 
                   
                   
               
               
                 Scanning LIDAR: 
                 Attenuation of 
                 7 optical attenuation 
                 5 optical attenuation 
                 4 optical attenuation 
               
               
                 Imaging range 
                 Light in Water 
                 lengths 
                 lengths 
                 lengths 
               
               
                 Sensor Fusion: 
                 Accurate, real-time 
                 32,400 results per 
                 16,200 results per second 
                 None 
               
               
                 Gathering and 
                 acquisition and 
                 second 
                   
                   
               
               
                 Correlating Data 
                 calculations on 
                   
                   
                   
               
               
                   
                 multiple data 
                   
                   
                   
               
               
                   
                 points 
                   
                   
                   
               
               
                 Rendering 3D 
                 Frame rate 
                 60 frames per second 
                 30 frames per second on 
                 Currently not done on 
               
               
                 Model: 
                   
                 on low-cost mobile 
                 low-cost mobile hardware 
                 low-cost mobile 
               
               
                 Performance 
                   
                 hardware 
                   
                 hardware 
               
               
                 when rendering 
                   
                   
                   
                   
               
               
                 High-Detail 
                   
                   
                   
                   
               
               
                 terrain 
                   
                   
                   
                   
               
               
                 Rendering 3D 
                 Frame Budget 
                 16 milliseconds per 
                 33 milliseconds per frame 
                 None 
               
               
                 Model: 
                   
                 frame for 3D graphics 
                 for 3D graphics 
                   
               
               
                 Performance 
                   
                 calculations on mobile 
                 calculations on mobile 
                   
               
               
                 when rendering 
                   
                 hardware 
                 hardware 
                   
               
               
                 High-Detail 
                   
                   
                   
                   
               
               
                 terrain 
                   
                   
                   
                   
               
               
                 Rendering 3D 
                 Dataset Size 
                 90% reduction in data 
                 75% reduction in data 
                 Utilize large terrain 
               
               
                 Model: High- 
                   
                 storage while 
                 storage while maintaining 
                 databases on high-cost 
               
               
                 Detail Terrains in 
                   
                 maintaining select areas 
                 select areas of high detail 
                 platforms 
               
               
                 a Space- 
                   
                 of high detail 
                   
                   
               
               
                 Constrained 
                   
                   
                   
                   
               
               
                 Environment 
                   
                   
                   
                   
               
               
                 Real-time ID of 
                 Percent detection 
                 97% of suspended 
                 95% of suspended 
                 SONAR can detect 
               
               
                 Objects: Object 
                 of objects in 360 
                 objects, 10% of 
                 objects, 5% of predefined 
                 95% of suspended 
               
               
                 Detection 
                 degree by 80 
                 predefined objects on 
                 objects on the bottom 
                 objects in narrow-beam 
               
               
                   
                 degree space 
                 the bottom 
                   
                 cone in direction of 
               
               
                   
                   
                   
                   
                 focus 
               
               
                 Real-time ID of 
                 Percent 
                 95% of predefined 
                 50% of objects over 50 
                 SONAR which gives 
               
               
                 Objects: Object 
                 identification of 
                 objects over 50 mm 
                 mm properly identified 
                 one return echo for 
               
               
                 Identification 
                 predefined objects 
                 properly identified 
                   
                 entire beam footprint 
               
               
                   
                 in real-time 
                   
                   
                   
               
               
                 Real-time ID of 
                 Percent detection 
                 99% of new objects 
                 95% of new objects 
                 None 
               
               
                 Objects: Detection 
                 of new objects on 
                   
                   
                   
               
               
                 of new objects on 
                 pre-known terrain 
                   
                   
                   
               
               
                 pre-known terrain 
                   
                   
                   
                   
               
               
                 Create a Learning 
                 Accuracy in 
                 Eliminates 100% of 
                 Eliminates 95% of invalid 
                 Manual collection and 
               
               
                 System: Learning 
                 identification of 
                 invalid data and 
                 data and incorporate 95% 
                 correction of existing 
               
               
                 Distributed GIS 
                 valid new 
                 incorporate 100% of 
                 of new valid data 
                 data 
               
               
                 System 
                 environmental data 
                 new valid data 
               
               
                   
               
             
          
         
       
     
         [0115]    A successful SUVS system will directly and dramatically impact the knowledge base and technical leverage of the world in several ways. Because of the profound low-cost, the technical capabilities of the envisioned system, and the fact that data acquired from all systems will be combined into a single database or other appropriate centralized repository, the world will gain unparalleled knowledge of underwater environments such as lakes, rivers, and coastlines. This knowledge will be a significant step forward for maritime navigation and the generation of bathymetric data. In addition, the ability of the system to detect, identify, and store information on all types of marine plant and animal life, as well as water clarity, will add significantly to our understanding of marine biology. The information gathered and integrated by the deployed net of SUVS systems will create a dynamic database of marine life locations and migration habits and the early detection of pollution. The Coast Guard and other marine authorities will have instantaneous access to up-to-date data on the location of all underwater objects approaching our coastlines. 
         [0116]    The following paragraphs provide additional information on one embodiment of the SUVS invention, and specifically on the optical characteristics required for the invention to work efficiently. 
         [0117]    In one embodiment, SUVS will inject the beam and collect the reflected light using optics immersed in the water. The optics, light pipes, fibers, and antireflective coatings can be selected to maximize the percentage of the pulse energy to be delivered into the water. 
         [0118]    Clear water does not have a strong absorption coefficient for green light. Use of 532 nm radiation from a doubled Nd:YAG laser keeps absorption by water to a minimum. Absorption by suspended material or living organisms is also a concern. However, most photosynthetic processes utilize visible light in the red and blue regions of the spectrum. Again, use of 532 nm radiation will minimize any absorption by these processes. While absorption does attenuate the number of photons reaching the detector, it does not disturb the illumination profile of the beam and therefore does decrease the target depth resolution. 
         [0119]    The scattering of the probe pulse is the most challenging problem to overcome. Scattering has the effect of spreading the incident beam, which will cause a target area larger than is desired to be illuminated. The reflected light is also scattered on the return trip to the collection optics. Overall the effect of scattering will be to reduce the number of photons/unit time collected by the acquisition system. An additional affect will be the “blurring” of the target point, such that a larger area will be probed than desired, and the intensity of the leading edge of the return beam is attenuated, which potentially leads to loss of temporal resolution and thus depth resolution. The loss of spatial resolution is mitigated by using a focusing system on the collection optics to limit the viewed area. The size of the aperture can be adjusted to increase or decrease the resolution. The problem of the loss of temporal resolution is mitigated by using very short pulse widths. If the pulse width is limited to 1 nanosecond, for example, the entire return pulse can be collected to increase the possibility of detection, while only limiting the depth resolution to 250 millimeters. 
         [0120]    The presence of scattering particles in the water causes constant background radiation as well, which needs to be filtered out. This is done, in one embodiment, by gating the collection response. The use of dichroic notch filters allows the system to collect a very small spectral range around the source wavelength. This technique is successfully used on existing LIDAR systems to allow operation during daylight hours. 
         [0121]    The collection optics are used to define the field of view necessary for various applications. In a survey mode, optics with spherical/fisheye type collection optics will allow good signal return strength at the expense of spatial and depth resolution. However, in “imaging” mode, the field of view can be limited to a small portion of the illuminated spot size on the target. By using the signal collected from multiple pulses, the fine resolution necessary for target recognition can be realized. Even with a pulse rate of 200 Hz, 50 to 60 pulses can be incident on the target before the movement of the collection system becomes an issue. 
         [0122]    The following paragraphs provide additional information on one embodiment of the SUVS invention, and specifically on the efficient display of 3D virtual environments. 
         [0123]    The concept of rendering large-scale detailed terrain databases at an acceptable rate is possible today on large image generators (IG) commonly used by military simulators. These systems rely on memory-intensive heightmaps where every area of terrain has the exact same amount of detail, whether it is required or not. However, years of research on sparse datasets and graphic rendering concepts have shown that high-detail results can be produced on a low-cost mobile processor platform. Handheld low-memory GNSS units rely on a similar sparse terrain data concept to produce acceptable results on a low-cost platform, by displaying only the detail required for the application. 
         [0124]    The landscapes displayed by the SUVS system will need to be modified (deformed) based on the introduction of new terrain data from the SUVS sensor. For instance, sandbars are constantly reforming on river bottoms due to changes in currents and river traffic. When the SUVS sensor detects a new sandbar beneath the vessel, the terrain must be modified in real-time to provide up-to-date river bottom images to the operator. This real-time requirement adds a new level of complexity to the 3D rendering algorithms. 
         [0125]    Not only must the SUVS be able to accurately display terrain maps and detect underwater objects, but it is also required to augment this data with unique textures and graphics. For example, if the SUVS sensor detects a moving target that it determines matches the specifications of a walleye, it will call up the image of a walleye from a predefined graphics library, size the graphic accordingly, and display it in the location of the detected object. In addition to a graphical image of the walleye, the SUVS system has the option of displaying an animated image sequence of the walleye (in this example), such as a pre-recorded animation of a walleye swimming, or even an “intelligent” and interactive animation of a walleye that responds to stimuli, such as new information received from the sensors (the presence of other fish, or of an object) or an interaction with the human operator (perhaps through a touch screen interface). 
         [0126]    These animated sequences would act essentially as avatars for the object they are representing, and could be loaded with additional information that could be called up through an interaction with the display. Turning now to  FIG. 6 , we see an example of one embodiment of the display module  500  and display screen  505  as previously presented in  FIG. 5 . In this version, though, information tags  700  containing information about the various objects being displayed are shown. These information tags  700  may be displayed all the time, perhaps selected through a customization interface on the display screen  505 , or in other embodiments maybe the information tags  700  appear when an operator interacts with the corresponding object (for example, a tag  700  describing a fish may appear attached to the fish when the user taps the fish graphic). In  FIG. 6 , examples of information tags  700  are shown. The terrain  515  is marked with an information tag  700  identifying the type of the bottom surface of the body of water, as well as with a percentage of likelihood that the information is correct. The type of bottom surface can usually be determined by analyzing the return echo from a sonar pulse, as different types of bottom surface (clay, sand, mud, etc.) will give different return types. 
         [0127]    The animal life  535  shown in  FIG. 6  is marked with an information tag  700  identifying the most likely type of animal (in this example, a lake trout) with a percent likelihood of correct identification and an approximate length of the fish. It is possible to identify the likely type of fish based on an algorithm which considers the geographic location of the lake, the depth that the fish is in the body of water, the time of day, the size of the target, and the overall shape of the target. Other factors may also be included, such as a unique swimming or movement signature. For instance, if it is known that a body of water has been known to have a lot of trout and a lot of sunfish, it might be relatively easy to identify the type of fish by looking at the size and shape of the return echo and comparing that to the available types of fish known to be in that body of water. The more identifying factors available in the return signature from LIDAR and/or sonar, the higher the probability that the identification is correct. 
         [0128]    Finally,  FIG. 6  shows a piece of plant life  525  being marked with an information tag  700  identifying the most likely type of plant life (kelp, in this example) and the percent likelihood of correct identification. Similar methods to those described in the previous paragraph for identifying animal life  535  may be used to identify plant life  525 . 
         [0129]    A database of underwater terrain information discovered by a network of deployed SUVS systems. New information will be gathered constantly from the deployed systems and uploaded to this central database. Existing maps will be integrated with the updated information, and redeployed to units in the field. 
         [0130]    Business Opportunity: 
         [0131]    The commercial opportunities for accurate, real-time, underwater visualization systems that can both contribute and draw upon the collective information gathered by all systems will grow to immense proportions as the technology to enable such collaboration is developed and deployed and the cost of such systems are reduced. In the same way that having many phones adds value to a single phone, having many “learning” navigation systems deployed and sharing the results among each other will result in an unprecedented level of detailed knowledge and understanding of underwater environments and their inhabitants, and a new and dynamic source of intelligence. This new information, coupled with next-generation real-time sensors and cutting-edge visualization, will add substantial value to the economy by reducing threats to national security through the early detection and identification of water-borne threats. In addition, navigational safety will be enhanced, helping to reduce the number of accidents which occur each year that result in injury, financial loss, and/or substantial environmental impact. Finally, this technology will provide a demonstrated basis for numerous spin-off commercial, consumer, and military product applications in low-cost, lightweight navigation and visualization products. 
         [0132]    Future Users of the Technology: 
         [0133]    While the underwater environment is the initial and most obvious application for the SUVS, there are numerous non-marine applications in adjacent industries. For example, in aviation a great deal of effort is being put into creating realistic 3D visualization systems as a result of the FAA&#39;s Terrain Awareness and Warning (TAWS) mandate. These “synthetic vision” systems, as they are sometimes called, are starting to be available but cost tens of thousands of dollars and so are far from reaching broad distribution. A synthetic vision system based on the SUVS technology would be an order of magnitude less expensive, and, as a consequence, achieve wide distribution in the general aviation community resulting in safer skies. 
         [0134]    This system could fill an important role in the United State&#39;s plans for the military for the future by providing a robust low-cost navigation aid for terrestrial, air, or underwater vehicles. It would be applicable to the Navy&#39;s Autonomous Underwater Vehicle Program, the Air Force&#39;s Unmanned Aerial Vehicle Program, and the Army&#39;s Future Combat Systems Program. Currently the United States is spending millions of dollars each year on DARPA and SBIR programs exploring these areas. Rapid commercialization of this system could potentially save millions of dollars and accelerate new vehicle introduction. 
         [0135]    Economic Significance of the Invention: 
         [0136]    The United States is a highly mobile society and relies heavily on navigational aids to keep waterways, airways, and highways open and safe during all types of weather. These systems are far from perfect and transportation is often disrupted, resulting in an overall slowing of our economic engines. Significant advancements in navigational technologies, such as SUVS, will have a positive impact on the reliability of public transportation. 
         [0137]    As fundamental advancements of broad-based technologies overcome key barriers the ripple effect in products and industry is hard to predict. What is known, however, is that affordable high-definition sensors are lacking for marine and non-marine applications alike while the applications for them in navigation, security, remote sensing, and information gathering are endless. 
         [0138]    Additional Benefits: 
         [0139]    The data acquired by networked systems will aid in better understanding and management of the sensitive ecosystems of our lakes, rivers, and coastal marine areas. Parameters effecting marine life could be dynamically monitored and early action taken where needed in order to better preserve and enhance this fragile ecosystem. 
         [0140]    Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in this document. For example, and as previously mentioned, the above-water and below-water components described in  FIGS. 1-4  might be combined into a single component, or the contents and functions of each component may be redistributed from one to the other component. Also, additional features may be added to the SUVS sensor, or some functional blocks left off, without changing the overall inventive concept. 
         [0141]    One embodiment of the system may rely on sonar data only, without the addition of LIDAR, or on LIDAR only, without the use of sonar. A low-cost version of the system may use the more standard sonar technology by itself (that is, without LIDAR) to sense the position and shape of the underwater terrain, as well as the bottom surface type. 
         [0142]    Finally, it should be noted that the SUVS sensor can be used to create a bathymetric map of the area immediately surrounding the watercraft in real time, even if no pre-existing bathymetric data exists or has been preloaded into the system. The processor within the sensor can process the sonar and/or LIDAR data in real time to create a visualization of the underwater terrain and environment, including animal and plant life and other transient objects. 
       LIDAR BIBLIOGRAPHY 
       [0000]    
       
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