William “Lee” Willcockson Science Team Paul Kolesnikoff William “Lee” Willcockson Miranda Mesloh Pascal Getreuer Keith Wayman Casey Rubin Ariel Esposito Science Jessica Pipis Mike Wong Allyson Bieryla Anders Fornberg Introduction The purpose of the science subsystem is to take stereoscopic images of clouds in order to create a topographic map from which we can determine cloud heights. There will be two camera’s mounted at specific angles on the satellite. Each camera will take an image that will contain at least one identifiable cloud feature and at least one identifiable ground feature. These images will then be sent to the flight computer where they will be overlapped and turned into a topographic map which will allow us to determine the height of the clouds. Requirements The Science subsystem shall be designed to meet all of DINO’s science objectives. It shall implement a stereoscopic imaging technique in order to measure cloud heights. Clouds imaged in the visible spectrum Field of view of 40-55 degrees. Resolution of better than 640x480 Shutter speed of 1/64th of a second or faster Ample amount of time shall be allotted for the software system to finish processing an image before another image is required Each image shall contain at least one identifiable cloud feature and at least one identifiable ground feature Each of the multiple images used to produce a topographic map of the cloud features must contain the same cloud features and the same ground features Requirements-cont. Mass- 0.56 kg on the main satellite Power- less than 11 Watts on the main satellite The Science subsystem shall operate on 5V and/or 12V lines All Science subsystem components shall comply with NASA’s safety requirements There shall be no pressurized vessels in the science subsystem, including the lens of each camera All components shall comply with NASA’s outgassing specifications Any glass components shall comply with NASA’s regulations All components shall either be contained or meet NASA’s requirements to be a low-released mass part Block Diagram The Camera Basic Information AIPTEK Pen Cam 1.3 Mega 41.5 degree field of view Maximum resolution of 1248x960 Electric variable shutter speed Needs 5 Volt line to each camera At maximum resolution, each picture is about 200K. Takes about 10-15 seconds for each picture to store. Takes a couple minutes to retrieve pictures. Time is dependent on software. Needed Flight Preparations Replace current lens with Jam Cam lens. Remove springs on circuit board. Conformal coat entire board. Build another casing for Jam Cam lens. Make sure that lens is bolted securely to circuit board. Decisions Not Yet Made Camera angle on structure Time between pictures Yaw control needed How to determine when to take pictures Determining if it is a good picture Commands and Sensors Commands from C&DH Turn on/off camera #1 Turn on/off camera #2 Take a picture Retrieve pictures Clear memory Sensors Possible Thermistor Parts List 2 Camera’s - Approx. $60 each USB Cables PC Board Multiplexer Components Test Plans Find a camera that will work Make sure that components are flyable Do STK simulations Test with C&DH to make sure commands work Create a stand alone test that tests the cameras ability to respond to commands without C&DH. Vibration testing to make sure lens will not break (not fracture critical) Issues and Concerns Camera Problem The camera that we are currently using has a lens casing that is made of what looks to be ABS manufactured plastic. Solution Using a Jam Cam lens instead of the lens that came with the camera. We will need a new lens mount built to fit the jam cam lens. Field of view and resolution will need to be recalculated. Different focal length may cause problem with images Acceptable amount? Determining Camera angles Depends on optical power of camera An acceptable amount of error Determining when is a good time to take pictures Determining whether it is a good picture We are going to need to talk with software to see how this is going to work. Time we have to take pictures vs. time we need to take pictures Find USB commands

DINO Science The science subsystem takes stereoscopic images of clouds and processes them to create a topographic map of cloud heights. Colorado Space Grant Consortium

Introduction The science subsystem takes stereoscopic images of clouds and processes them to create a topographic map of cloud heights. The two cameras will be mounted to look forward and aft at +/-7.5deg from Nadir on the satellite. The two images will be timed to photograph the same object. The two images will be sent to the flight computer where an algorithm will create a topographic map. The algorithm and test plan are also covered. Colorado Space Grant Consortium

Science Hardware Block Diagram Camera #1 Camera #2 Digital IO Microcontroller RS-232 C&DH USB USB Colorado Space Grant Consortium

Science Algorithm Flow Chart Find Cloud Take Forward Picture Take Aft Picture Linearize Pictures Find Matching Pixels Generate Topo Map Colorado Space Grant Consortium

Changes Since PDR Camera: Canon Digital Rebel Field of View: 28 degrees Use Microcontroller for Digital IO Weight Budget Increased to 1.75kg Colorado Space Grant Consortium

Functional Requirements Structure Software Stereo Imaging Estimate Cloud Height Capture Image of Cloud Comm. With Camera/Computer Camera Testing Algorithm Colorado Space Grant Consortium

Requirements The Science subsystem shall be designed to meet all of DINO’s science objectives. It will implement a stereoscopic imaging technique in order to measure cloud heights. Clouds imaged in the visible spectrum Field of view of 28 degrees is needed for cameras. Cameras will have a resolution of better than 640x480. Shutter speed of 1/64th of a second or faster Ample amount of time shall be allotted for the software system to finish processing an image before another image is required Each of the multiple images used to produce a topographic map of the cloud must contain the same features Colorado Space Grant Consortium

Requirements Mass- 1.75 kg on the main satellite Power- less than 11 Watts on the main satellite The Science subsystem will operate on 5V and/or 12V lines All Science subsystem components shall comply with NASA’s safety requirements There shall be no pressurized vessels in the science subsystem, including the lens of each camera All components will comply with NASA’s outgassing specifications Any glass components shall comply with NASA’s regulations All components shall either be contained or meet NASA’s requirements to be a low-released mass part Colorado Space Grant Consortium

Camera Mounting System Colorado Space Grant Consortium

Science System Schematic Colorado Space Grant Consortium

The Camera Cannon Digital Rebel Dimensions (W x H x D): 142 x 99 x 72.9 mm Weight: 750 g Power Requirements: 7.4 volts Cost: $1300 Including Lens Thermal Requirements: 0 - 40°C Colorado Space Grant Consortium

Algorithm Needs Two Images Camera Camera Cloud Cloud Ground Reference Point Ground Reference Point First Satellite Position Second Satellite Position Cloud Cloud Ground Reference Point Ground Reference Point First Cloud Image Second Cloud Image Colorado Space Grant Consortium

Algorithm Combines Two Images Cloud #1 Cloud #2 Cloud #1 Cloud #2 Ground Reference Points Ground Reference Points First Images are Overlaid Images are Transformed to Align at Ground Level Cloud #1 Cloud #2 Horizontal Separation Between Matching Point on Images Determines Height Topo Map of Point Separation Allows Integer Math Point Matching Algorithm in Progress Use of Color and Derivative Information Likely Ground Reference Points Images are Shifted Until Features Match Colorado Space Grant Consortium

DINO Moves in Three Axes Yaw  ±10° Pointing Accuracy ±2° Position Knowledge 90 min Oscillation Period Roll Ψ Direction of Flight Pitch Φ Colorado Space Grant Consortium

Pointing Error Moves Two Images Cloud #1 Cloud #2 Ground Reference Points Yaw Rotation is Greatest Error Forward Image has Rotation and Translation with Yaw Error Field of View Must be Large Enough to Accommodate Motion No Error Image Pair Cloud #1 Cloud #2 Ground Reference Points Yaw Rotated Image Pair Colorado Space Grant Consortium

Modeling Motion Errors Forward Camera Correction Yaw Error Model Pitch Error Model Roll Error Model Colorado Space Grant Consortium

Science Algorithm is Under Way Basic Algorithm Determined Floating Point Math Avoided Topo Map in Pixel Distance Saves Bandwidth Point Matching Correlation Finalizing Motion Correction Technique Testing Needed Final Write-up Needed Implementation in Software not started Testing Cloud Detection Algorithm Colorado Space Grant Consortium

Camera Angles Factors influencing camera angle selection Base/height ratio Algorithm matching Illumination Signal to noise ratio Larger camera angles mean smaller ratio Time Movement of clouds Camera Delays Colorado Space Grant Consortium

Influences Base/Height Ratio Error caused by optical system is unchanging Larger ratio decreases relative error Largest camera angle desired Illumination Differences increase with camera angle By change in relative position of cloud, satellite, and sun Cloud position and Illumination change over Time Colorado Space Grant Consortium

Influences Signal/Noise Ratio Decreases with camera angle Large ratio desired for increased accuracy of determining cloud height from stereo pairs Cloud Movement Increases with camera angle Affects algorithm’s ability to successfully match points in stereo pair Smaller camera angle is preferred Colorado Space Grant Consortium

Influences Based on: Altitude - 425 km Velocity – 7.65 km/s Colorado Space Grant Consortium

Simulator Used to simulate topography of the ground produced by stereoscopic sensing Influenced by factors above Atmosphere “magnifies” results Colorado Space Grant Consortium

Results Colorado Space Grant Consortium

Optimization of Stereo Pairs Between 15o (+/-7.5o) Two camera layout Multiple pictures Determining along and cross track wind Large field of view Previous tables and graphs obtained from Boerner, Anko: The Optimisation of the Stereo Angle of CCD-Line-Scanners, ISPRS Vol. XXXI, Part B1, Commission I, pp. 26-30, Vienna 1996 Colorado Space Grant Consortium

Test and Build Facilities Final Test in Clean Room Collaborates all systems for final check Camera Ops Finding Cloud Data Download Algorithm Nadir Forward Colorado Space Grant Consortium

Ground Support Lego Test Bed =Jam Cam Lego Test Bed Yaw  Color of arrow corresponds with movement of table piece. Roll Ψ Purpose: To test accuracy of algorithm using known heights of stacked Lego pieces at different angles to simulate pictures in flight. Direction of Flight Pitch Φ Colorado Space Grant Consortium

Documentation Design Overview Testing Algorithm Disassembly/Assembly Technical manual Testing Outline for first two weeks of camera and entire system Detailed document including testing results Algorithm Outline of how and why it works Disassembly/Assembly Outline of procedures to disassemble/assemble camera Trade Studies Selection of Camera Microcontroller Colorado Space Grant Consortium

Science Subsystem Test Plan Camera Operation a. Set – up: i. Iris (f-stop) ii. Shutter Speed iii. Flash Setting iv. Focus v. Picture type (Mode) b. Acquisition i. Shutter Command ii. Accuracy Colorado Space Grant Consortium

Science Subsystem Test Plan Algorithm a. Individual Pictures i. Find Cloud ii. Find Features b. Picture Sets i. Transform to Same Coordinate ii. Match Reference Features iii. Correlate All Features iv. Generate Contours Colorado Space Grant Consortium

DINO Science Schedule Algorithm Development Camera Preparation Finalize Coordinate Transformations 20 March Linearization (Scaling) Integration 20 March Pixel Correlation Routine 15 April Topo Line Generation Routine 1 May Compression Format 1 May Camera Preparation Disassembly and Procedure 20 March Digital Control 10 April Integrated and Tested 1 May Colorado Space Grant Consortium

Parts List 2 Camera’s - Approx. $1300 each USB Cables PC Board Canon Digital Rebel USB Cables PC Board Microcontroller Components Colorado Space Grant Consortium

Questions? Colorado Space Grant Consortium