RoboticsLesson 2 of 2 in the course Sensors and perception

Lidar: Measurement Principles, Systems, Mapping, and Applications

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

Lidar is a way to measure distance using laser light. This lesson introduces its basic purpose, its development, and the kinds of work it supports.

Lidar is an acronym commonly expanded as light detection and ranging or laser imaging, detection, and ranging. A lidar system sends laser light toward an object or surface and detects light that returns after reflection or backscattering. The time taken by the light to travel out and back can be used to determine range.

All flashcards

What is lidar?
An active sensing method that uses returned laser light to measure distances and map objects or surfaces.
What does coherent lidar detection measure?
Properties of returned light such as phase and Doppler frequency shifts.
What is flash lidar?
A system that illuminates a broad field and captures returns across a detector array.
What is a lidar point cloud?
A collection of measured three-dimensional points representing objects or surfaces.
What is differential absorption lidar (DIAL) used for?
Estimating gas concentrations by comparing returned signals at selected wavelengths.

Quiz questions

  1. Which properties can coherent lidar detection use to measure motion-related changes in returned light?Answer: Phase and Doppler frequency shifts
  2. How does differential absorption lidar (DIAL) estimate gas concentration along a path?Answer: It compares returns at selected wavelengths.
  3. What does a digital surface model (DSM) represent in lidar mapping?Answer: Surface features such as buildings and vegetation
  4. Which instruments commonly help georeference lidar measurements collected from a moving platform?Answer: A GNSS receiver and an inertial measurement unit
  5. Which laser wavelength is commonly used for airborne bathymetric lidar?Answer: 532 nm green light

Based on the Wikipedia article Lidar, licensed CC BY-SA 4.0. Adapted into a summary, flashcards and quizzes.

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