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 imagingMore advanced statistical image

processing algorithmsSupercomputers to process data

Conclusion: Too expensive

Horizon detection using thermopilesLower altitude and using model planeDifferent 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 fov 1

2

Tavg Tgnd

Tsky Tgnd

Tavg sky Tsky gnd Tgnd

fov

sky fov Tavg Tgnd

Tsky Tgnd

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 R2 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 AlgorithmAdvantage: 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

Cloud content =

Number of edge pixels above line

Total number of pixels above line

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

T2

Optical Rotary Encoder Electrical resolution: 256 quadrature

cycles per revolution Angular resolution: 0.351 °

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 PlatformOptical Rotary

EncoderMicrocontroller Computer

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?