Signal Processing for an Optical Sensor � With Applications to Bee LIDAR Project

Fall 2005

ECE students:

This project will develop software in MATLAB that will detect the presence of particular frequencies collected in a set of data. This data is gathered from the scattered light of an Nd: YAG laser that emits 1nm pulses of light every 140us. An optical sensor detects the light scattered back from objects in front of the laser. The modulated light scattered back to the optical receiver will have a time delay that yields range information of the object that reflects the lasers light back to the optical sensor. The optical sensor detects the intensity of the light as voltage vs. time. From this it is possible to determine the frequency components contained within the data. The software will take the data as an input and display a graph of time vs. range. For this particular project the customer is using the Nd: YAG laser and the MATLAB software to detect the presence of bees. Specifications for this project include the following:

1. The user is able to choose which frequencies are to be detected.
2. The user is able to choose how long data is to be taken.
3. The user is able to choose the range (how far away) of the data to be considered.
4. The resolution is determined by the user.
5. The users select if they want to have a spectrogram taken of a certain section of data to have a look at the frequencies present in a particular range.

PROPOSED DESIGN

STANDARDS AND CONSTRAINTS

Crops that use honeybees for pollination

This is how the output of our program should look like.

Figure 3: Plot of detected bees (Time vs. Range)

Experimental setup used for remote detection of honeybees via wing beat modulation of backscattered cw laser light.

Picture of Laboratory equipment.

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