Tracking Migratory Birds Around Large Structures by Arik Brooks and Nicholas Patrick Senior Design Project Bradley University Department of Electrical and Computer Engineering

Outline 1.Background 2.Project summary 3.Previous Work 4.Detailed description 1.System block diagram 2.Subsystems 3.Modes of operation 4.Design equations

Outline Preliminary design work Datasheet Schedule Standards/Patents References Equipment List

Background Every year, many birds are killed when their migration path takes them near tall structures. This usually occurs on overcast nights, and one widely accepted theory on why these bird kills happen is that the birds do not want to leave the lighted area near a structure and end up running into it.

Project Summary The purpose of this project is to implement a system to track the trajectories of birds flying within the field of view of a set of cameras mounted on a rotatable boom in realtime. The positions of the birds are determined using stereoscopic vision by placing the two cameras a known distance apart in parallel with each other.

Project Summary The system output is a display depicting a three dimensional representation of the trajectories, and data relating to the trajectories. Inputs to the system include the position of the boom, images detected by the cameras, calibration information, and confidence level threshold.

Previous Work Seniors Brian Crombie and Matt Zivney worked on a senior project in Spring 2003 with the goal of tracking birds around tall structures via stereoscopic imaging. They achieved basic object tracking in a laboratory environment with major limitations. The groundwork laid out in their project (algorithms, design equations, software organization, etc.) will be used as a starting point for our system.

Detailed Description

System Block Diagram System

Hardware Block Diagram

Subsystems Cameras Boom Frame Grabber PC Display and Interface

Camera Subsystem The camera subsystem includes two cameras mounted in parallel a known distance apart allowing objects to be located in space. Inputs –Photons -- Images from the environment within the field of view of the cameras –Synchronization signal -- Signal from an external source (frame grabber) to coordinate the capturing of images Outputs –Data -- Image data transmitted to the frame grabber Operation in Modes –The cameras capture images continuously

Boom Subsystem The boom subsystem holds the cameras in parallel and rotates via a stepper motor. The position of the boom is determined from the output of an encoder. Inputs –Stepper Motor Control Signal -- Rotates the boom in two directions Outputs –Encoder Output -- Signal to the PC to determine the current angle of the boom Operation in Modes –The boom operates (changes position) only in Setup mode

Frame Grabber Subsystem The frame grabber simultaneously captures images from both cameras and supplies the data to the PC. Inputs –Data -- Image data from the cameras –Setup -- Information from the PC Outputs –Image Data to PC –Synchronization Signal -- Signal to the cameras to coordinate the capture of images Operation in Modes –The frame grabber operates continuously along with the cameras

PC Subsystem Inputs –Image Data -- Arrays of intensity information from the frame grabber representing the collected images –Encoder -- Angle information from the boom encoder –Desired Boom Position -- Input from the user for desired boom position –Real-time/Delay -- Input from user determining whether or not to calculate and display the trajectory information in real-time –Calibration Input -- Calibration data for the cameras being used –Confidence Level -- User defined level of non- linearity in trajectories allowable for consideration

PC Subsystem Outputs –Display -- Trajectories displayed in a three dimensional representation and graphical user interface –Statistics -- Pertinent information about the objects locations and trajectories (e.g. Number of birds within x distance of the cameras, maximum velocity, etc.) –Raw Data -- Data file containing all position data for later analysis Operation in Modes –The PC is continuously operating in every mode

Display and Interface Subsystem The trajectories will be displayed on a standard computer monitor. The user will interface with the system using a standard computer keyboard and mouse. Inputs –Display Information –User Inputs Outputs –Image Display –User Data Operation in Modes –The Display and Interface will be used in Setup and Display modes

Modes of Operation Setup Monitoring Data Acquisition Display and Computation

Setup Mode

Monitoring Mode

Data Acquisition Mode

Display and Computation Mode

Design Equations

Preliminary Design Work Based on preliminary work performed in the laboratory, it was determined that a better method of transient object correlation needs to be implemented to achieve the tracking of a large number of objects at one time. When objects cross paths or get close to each other, the current transient correlation algorithm fails to differentiate between those objects accurately and errors occur.

Preliminary Design Work

The basic flow of the software to be designed including better organization and correlation method was determined. Preprocessing –Read in image, record initial time stamp and time between frame grabs –Discard areas that are not within field of view of both cameras –Perform a background subtraction to extract moving objects –Threshold and convert each image to B/W –Apply filters –Find areas/centroids of all objects

Preliminary Design Work Correlation/Trajectory –Input areas/centroids found in preprocessing –Save data for later use –Find every “possible” 3d position for the objects in the present frame to be “possible”, must be within 30 pixels of each other between cameras in horizontal position –continued...

Preliminary Design Work Correlation/Trajectory (continued) –Search for closest position to predicted position, within the user defined threshold, for each object based on its previous two locations –Search for objects that were first detected in the previous frame based on closest position and area within a threshold (Different from the user defined threshold) –Correlate any remaining objects between two cameras based on closest horizontal distance and area –Calculate new predicted positions for any object with two or more data points in time –Display

Datasheet Average Migratory Bird Size (AMBS): TBD Max # of Objects Tracked Simultaneously: TBD Max Distance from Cameras: TBD Min Distance from Cameras: TBD Max Location Error: TBD Light Level Sensitivity: –Lab Cameras: 0.22 Lux –Low Light Cameras: Lux Max Framerate: TBD System Latency: TBD Max Trackable Bird Speed: TBD Total Volume of Space Observed: TBD Boom Rotation Step Resolution: TBD

Test Plan There will be four primary test procedures that will be performed to verify the system specifications: Location Accuracy –track an AMBS object in known trajectories (including trajectories proceeding primarily towards and away from the cameras) and compare the measured and actual locations Max/Min Distance from Cameras –track an AMBS object in known trajectories and check accuracy/ability to track Max # Objects –TBD Contrast Resolution –track objects of various known intensities in front of a variety of backgrounds

Schedule Week beginningTaskAssigned to 1/22Research/Develop algorithms to improve tracking and correlation Determine final output to the user and layout of the user interface Both 1/29Implement final preprocessing code in C++ Implement improved algorithms in MATLAB for testing Nick Arik 2/5ContinuedBoth 2/12ContinuedBoth 2/19Integrate new cameras to system Port MATLAB to C++ Nick Arik 2/26Develop Graphical User Interface for system and continue other software development Both

Schedule 3/4ContinuedBoth 3/11Test system in near real environmentBoth 3/18Attend wet T-shirt contest in CancunBoth 3/25Develop and implement final boom system and stepper motor Both 4/1Continued and create test plan and final specifications Both 4/8Test systemBoth 4/15Continued and make any necessary changes Prepare for Expo presentation Both 4/22Prepare final report and presentationBoth 5/6Give presentationBoth

Standards There are no overarching standards that apply to bird tracking, but several standards are used to interface cameras to the PC. NTSC –The cameras selected produce NTSC compatible signals, which is the standard in North America –The Frame Grabber converts NTSC inputs to digital images DirectX –DirectX is a defacto standard for Microsoft Windows which includes a programming interface to video capture devices such as frame grabbers –DirectX was chosen over proprietary APIs to maintain a maximum amount of hardware independence

Patents Patent #6,366,691 –Stereoscopic image processing apparatus and method Patent #6,028,954 –Method and apparatus for three-dimensional position measurement Patent #6,035,067 –Apparatus for tracking objects in video sequences and methods therefor Patent #5,812,269 –Triangulation-based 3-D imaging and processing method and system

References Pinhole camera model, image processing reference. Equations relating focal length to zoom Light levels for various time of day and weather conditions. Estimating position when synchronized cameras are not available. Using line lock cameras. Equation relating focal length to target object size, distance, and CCD width. Measurements for various CCD sizes. Project proposal from previous group Chen, Tieh-Yuh; Bovik, Alan Conrad; Cormack, Lawrence K. “Stereoscopic Ranging by Matching Image Modulations,” IEEE Transactions on Image Processing. Vol 8, # 6, June 1999, pg

Equipment List Cameras and Lenses –Lab Sanyo VCB-3444 Rainbow L8DC4P Auto Iris Lens –Low Light Hitachi KP-200E –$920 at DV10x7.5A-SA2 Auto Iris Lens –$273 at

Equipment List Video Capture Card –Data Translation DT3132 Dual Frame Grabber Supports simultaneous acquisition of images from two sources. Programmable through DirectX

Equipment List PC –Windows 2000 or higher OS –DirectX 8.1 or higher installed –One PCI slot for frame grabber –Enough processor power for real- time operation –Development software DirectX 8.1 SDK Microsoft Visual Studio 6.0 MATLAB 6.5 with image processing toolbox

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