GGE3353 Lab 2
Lab 2 -- Bottom Detection
Due date October 18th --- E-mail pdf to email@example.com (In MSword use save as--pdf). Individual submissions.
Questions can be e-mailed to firstname.lastname@example.org or visit Majed in E16.
- Download data and matlab routine from blackboard.
- Code up bottom detection, should be at least configurable for threshold, range gate, echo duration
- Load data in matlab, create images, and plot a few echo traces to estimate threshold, range gate, and echo duration.
- Run bottom detection for 33 kHz and 200 kHz channels
- Load in the ascii file and associate the seconds since 1970 with each ping. From lab 1 the Knudsen attitude file has a seconds since 1970 as well as the Newfoundland summer time. This will allow you to use the seconds since 1970 to put a heave and UTC value with each ping (you will do this in lab 3).
- Images of echo traces in linear and logarithmic intensities (choose best for subsequent images)
- Images of echo traces (equivalent of paper trace), w/ bottom detection plotted (sample number)
- Plot the difference between the 33 kHz and 200 kHz bottom detections.
- A plot of one time series (one column of the 8bit matrix) and mark on it the location of your range gate and threshold.
(In general: comments in the code is appreciated)
some tips ...
- Compare/contrast bottom tracking between different frequencies
- Explain what the range gate, threshold and echo duration are, and their role in the bottom detection.
- In the echo trace, what is the first spike?
- Why would this vessel have the two different frequencies?
- In the gray scale image, high backscatter (e.g. the seabed) should appear darker, so flip the 8bit values before
writing the array to an image-file.
- For delivrable 1 & 2: Ping # on the x-axis, Sample # on the y-axis. Also you may find the imagesec function in Matlab useful.
- For delivrable 3: Time (seconds since 1970) on the x-axis. For example in seconds since the start of line.
Sample # on the y-axis.
Created by Steve Brucker 2006, last modified October 2nd 2010, Travis Hamilton