ImAP RSD Ongo-02a Image Acquisition and Processing of Remotely Sensed Data

Team Members Advisor: Dr. Basart Client: Space Systems Control Laboratory (SSCL) – Matt Nelson Chief Engineer EE 491: Matt Clausman, Jesse Griggs, Christina McCourt, Andy Schulte, Shobhit Vaish EE 492: Usman Aurakzai, Chia-Yuan Chang

Presentation Outline Overview of Horizon Detection System System Requirements System Block Diagrams Thermopile System Imaging System Testing Semester Summary Questions

ImAP Overview

Horizon Detection System (HDS) Absolute frame of reference is not available Reference the ImAP payload pitch and roll to the horizon (yaw is not accounted for)

ImAP Video Video taken from High Altitude Balloon Experiments in Technology (HABET) payload at approximately 25,000 feet.

HDS Functional Requirements Horizon angle accurate to ±3° when operated between 20,000 and 30,000 feet Minimum sample rate of 10 Hz Operate during daylight hours Less than 30% cloud cover Horizon angle range of ±30°

HDS Functional Requirements Industrial temperature range of -40°C to +85°C Powered by 11.1 V nominal lithium-ion battery 3 hour run time using 4 Amp-hour battery pack

Market Research Horizon detection using imaging  More advanced statistical image processing algorithms  Supercomputers to process data Conclusion: Too expensive Horizon detection using thermopiles  Lower altitude and using model plane  Different control scheme Conclusion: Too simple

System Block Diagram ImAP Payload

Thermopile Overview

Thermopile System Measure sky, ground, and horizon temperature Nominal thermopile accuracy ±1°C (factory calibrated over -40°C to +85°C) Thermopile resolution 0.02°C Thermopile time constant 30 ms (-3 dB Bandwidth = 33 Hz)

Thermopile System (continued) Uncalibrated worst case angular accuracy of ±4° Used mainly for image processing sanity check by comparing thermopile and imaging systems outputs Simple temperature and angle calculations Inexpensive

Thermopile System Algorithm Average Horizon Temperature: Angle of Sky in View: Horizon Angle:

Thermopile System Process

Thermopile System Hardware

Thermopile Test Board Layout

Thermopile Test Board - Page 1

Thermopile Test Board - Page 2

Thermopile Test Board - Page 3

Thermopile Test Board - Page 4

System Block Diagram ImAP Payload

Imaging System Mount horizon facing camera sideways for 640 vertical lines of resolution 0.175° angular resolution Output horizon line equation and R 2 value for least squares fit line Utilize 3 different algorithms

Imaging System (continued) Accuracy varies significantly with conditions Very computation intense therefore requires hardware processing (FPGA) Expensive

Imaging System Process

Imaging System Blue Algorithm

Imaging System Gray Algorithm

Algorithm Comparison Disadvantage: Numerous clouds in the sky may cause incorrect horizon detection Advantage: Performance unaffected by most clouds in the sky Disadvantage: Incorrectly detects horizon when haze or fog is present near the horizon Blue Algorithm Gray Algorithm Advantage: Performance unaffected by haze or fog near the horizon

Decision Algorithm Count the number of edge pixels above the estimated horizon fit line Calculate the trapezoidal area above the estimated horizon fit line If cloud content is above the threshold value, use Blue Algorithm If cloud content is above the threshold value, use Gray Algorithm

Imaging System Hardware

Bus Arbiter Controls the bus time given to each client Camera Interface is highest priority, VGA Controller is lowest priority Allows 64 cycles of uninterrupted transfer 3 cycles overhead for each new read/write operation

SDRAM Controller Accepts variable length packets Automatically activates and deactivates rows Performs Auto-Refreshes 7 overhead cycles for each new read/write operation

Camera Interface Reads data from CMOS VGA Camera Buffers data until the bus is available for transfer into SDRAM Allows triggered or continuous frame acquisition Each image requires 921 KB of RAM

Imaging System Bus Bandwidth 200 MB/s Bus Speed 64 Byte packets nominal SDRAM Controller 89.1% data throughput Bus Arbiter 95.3% data throughput Overall data throughput 84.9% or 170 MB/s Capable of transferring 184 VGA frames per second Estimated 12 FPS process rate with 15 frame transfers to process

HDS Testing T2T2 Optical Rotary Encoder Electrical resolution: 256 quadrature cycles per revolution Angular resolution: ° Single axis pivoting table with an optical rotary encoder to measure the horizon angle of the imaging and thermopile systems Testing Platform

HDS Testing Test Platform Optical Rotary Encoder MicrocontrollerComputer

HDS Testing Procedure Verify the accuracy of the Imaging System Algorithms  Use the test platform to compare the angle values provided by the optical rotary encoder to the horizon angle calculated by the Imaging System Verify Imaging System hardware and circuit robustness  Temperature, humidity, and mechanical shock

HDS Testing Procedure Test thermopile accuracy, precision, and drift  Use a constant temperature black body and data log the thermopile temperature values Verify Thermopile System  Use the test platform to compare the angle values provided by the optical rotary encoder to the value calculated by the Thermopile System Verify thermopile hardware and circuit robustness  Temperature, humidity, and mechanical shock

Team Hours and Budget

Semester Milestones Oct 11 System Design Research Hardware & Software research Dec 7 System Implementation Horizon Detection Systems Dec 12 Documentation Plan, Design & Final Report Dec 19 System Testing Testing Plan Actual Testing

Current Accomplishments Thermopile algorithm determined Thermopile Test Board layout complete Image processing algorithms determined Image processing camera to SDRAM to VGA Controller complete

Next Semester Tasks Complete testing platform construction Test and verify thermopile algorithm Continue testing and verification of image processing algorithms Implement image processing algorithms in FPGA

Next Semester Tasks Implement thermopile algorithm in microcontroller Design and layout single Thermopile and Imaging Systems circuit board Test and verify Thermopile and Imaging Systems board Deliver service manual to client (SSCL)

Demonstration

Questions?