ONGO – 02a

http://seniord.ece.iastate.edu/ongo02a

TEAM MEMBERSUsman Aurakzai (EE) Christina McCourt (EE)Chia-Yuan Chang (CPRE) Andy Schulte (EE)Matt Clausman (EE) Shobhit Vaish (EE)Jesse Griggs (EE)

FACULTY ADVISORDr. John Basart

ACKNOWLEDGEMENTHigh Altitude Balloon Experiments in Technology (HABET) Team

CLIENT

IntroductionImAP RSD was created to determine crop health using remotely sensed data and image processing from a high altitude weather balloon. The balloon has an attached payload to capture aerial images at specific GPS locations. The goal for this semester is to design a Horizon Detection System that will capture data from each side of the payload to determine the spatial orientation of the payload.

Thermopile System Imaging System

Testing The test platform, which is shown to the left, is a dual-axis mount that provides a range of motion to simulate different pitch and roll orientations for the HDS. To determine the angle of the platform, we will be using incremental optical rotary encoder. The camera would be placed on one edge of the top board and will be tested by moving the board. The encoder values when compared to the values calculated by the HDS will provide with the degree of accuracy of the system (HDS).

The Horizon Detection System utilizes two subsystems: the Thermopile System and the Imaging System. Each system will detect the horizon and send the information to a single board computer to determine the payload’s pitch and roll.

The Horizon Detection System is mounted on the ImAP RSD Payload Figure, as shown on the far left.

Estimated Resources

Budget

Test Fixture $ 50VGA Camera board $ 57Thermopile board $ 80Student Labor $10/hr $ 7640-----------------------------------------Total $ 7827

Original image

Blue Threshold/ Monochrome

Grayscale

Edge Detection after Grayscale

Edge Detection after Blue Threshold/ Monochrome

Final Image after Blue threshold/monochrome

Final Image after Grayscale

Imaging System Diagram

The imaging system will detect the horizon based on the images captured from each side of the payload. The image will be processed using blue and grayscale based algorithms. The figures to the right illustrate this process. The blue based algorithm is best when cloud cover is present. The grayscale algorithm works best in the presence of haze.

The system block diagram of the image system is shown above. A VGA CCD camera will be connected to an FPGA. All of the processing will be done onboard the FPGA. The FPGA will be interfaced with SDRAM for storage of the images. A VGA port is available for debugging.

The thermopile system detects the horizon based on the average temperature seen by the horizon facing thermopile and comparing it with the sky and ground temperatures. The average horizon temperature is given by the following equation:

The roll of the payload (θroll) can then be determined by the following equation by combining the thermopile system temperatures in the single board computer.

Thermopile Theory of Operation

Thermopile System Diagram Thermopile Function Diagram

sky sky gnd gndavg

fov

T TT

1

2avg gnd

roll fovsky gnd

T T

T T

Horizon Detection System Diagram ImAP RSD Payload

Personal Efforts

Horizon Detection System