Lehrstuhl für Informatik VIII
Luft- und Raumfahrt Dynamik I
Universität Würzburg
Summer School 2016
26.07.2016
Prof. Dr. Hakan Kayal
Exercise
For a Transient Lunar Phenomenon (TLP) observation mission a lunar horizon sensor in optical
range has to be developed. A CMOS image sensor with a resolution of 1024 x 1024 pixels and a
pixel size of 5.6 µm x 5.6 µm is used as a detector. The full moon is observed from a 600 km high
Low Earth Orbit (distance earth-moon = 384,440 km; RE= 6,378 km; RM= 1,737 km).
a.)
Calculate the required characteristics of the optical system:
focal length (f), field of view (σ).
b.)
Write the required software in C++ to calculate the center of the moon.
The software should be able to perform the following tasks:
1.
Binarization using a threshold filter
a=1 if pixel value >threshold
a=0 if pixel value ≤ threshold
2.
Reducing the image by erosion operator.
Definition: Erosion is a process in which a 3x3 structured element with a control pixel (CP) in the
center is moved line by line through the image. For all CP the following function will be performed:
a'=1 if z ≥ m
a'=0 if z < m
where z = number of pixels in the structuring element having the value 1
and m = erosion limit (free to choose in the area >1 and <8 )
3.
Creating the contour of the moon by subtracting the eroded image from the original image:
(x,y) = a – a'
4.
Calculating the center of the circle.
Y (rows)
yc = (y2-y1)/2+ y1= (y2+y1)/2
xc = (x2-x1)/2+ x1 = (x2+x1)/2
3. x1
4. x2
2. y2
yc
+
1. y1
xc
X (columns)