Mr. Simon Frey Profile

Simon Frey

at Fraunhofer Institute for Physical Measurement Techniques IPM

SPIE Involvement:

Author

Publications (2)

This will count as one of your downloads.

You will have access to both the presentation and article (if available).

DOWNLOAD NOW

This content is available for download via your institution's subscription. To access this item, please sign in to your personal account.

Email or Username Forgot your username?

Password Forgot your password?

Show

Keep me signed in

No SPIE account? Create an account

Proceedings Article | 15 August 2023 Presentation + Paper

A lightweight laser scanner for UAV-based applications

Jannis Gangelhoff, Philipp von Olshausen, Simon Frey, Alexander Reiterer

Proceedings Volume 12618, 126181B (2023) https://doi.org/10.1117/12.2673689

KEYWORDS: Laser scanners, Unmanned aerial vehicles, Point clouds, Inspection, LIDAR, Data processing, Scanners, Fiber lasers, Optical inspection

Read Abstract +

Laser scanners are widely used for the 3D-measurement of large-scale infrastructure objects. For objects like bridges or special tunnels unmanned aerial vehicles (UAVs) are well suited mobile platforms for inspection. Laser scanners used in these scenarios must be lightweight and low in power consumption to maximize flight time. A laser scanner optimized for UAV-based applications was developed by the Fraunhofer Institute for Physical Measurement Techniques IPM. The system is based on the pulsed time-of-flight measurement technique. A 1550 nm pulse laser featuring a repetition rate of 1 MHz for high point density is used as a light source. The short pulse length of less than 1 ns allows for a precise detection of the reflected signal in the time domain. Beam deflection is done with a rotating 45° mirror as in typical profile scanners. To optimize for detection aperture and weight, a custom mirror was designed. A lightweight scanning motor with a maximum rotation frequency of 120 Hz was chosen. An optical deflection path was developed that allows for a full 360° scan without any shading. The housing is made from aluminium and carbon fibre to reduce weight. The prototype of the laser scanner has a total weight of 2.1 kg and a power consumption of less than 100 W. The laser scanner is eye-safe (laser class 1) which is especially important for UAV-based applications. Test measurements in an indoor facility show a measurement uncertainty (one standard deviation) of approximately 3 mm on a surface at 10 m distance. The system was also mounted on a drone for flights in a tunnel which resulted in dense point clouds with high precision confirming the laboratory tests. Regarding the measurement uncertainty there is still a large potential for improvement by optimizing the full waveform analysis. First tests indicate that a reduction of the uncertainty by one order of magnitude may be possible.

Proceedings Article | 11 August 2023 Presentation + Paper

Automated visual vegetation detection for weed management on transportation infrastructure

Christoph Werner, Simon Frey, Alexander Reiterer

Proceedings Volume 12623, 126230G (2023) https://doi.org/10.1117/12.2673849

KEYWORDS: Cameras, Vegetation, Near infrared, Light emitting diodes, RGB color model, Optical filters, Sensors, Transportation, Multispectral sensing

Read Abstract +

Vegetation on traffic routes is not only an aesthetic problem. On railways and roads, it poses a safety risk by reducing the elasticity of track beds or damaging road surfaces. Therefore, complex weed management is indispensable. This is currently achieved mainly through the extensive use of herbicides or manual removal, which pollutes the environment and incurs high costs. These negative impacts can be mitigated by an automated vegetation detection which allows efficient, targeted treatment and preventive long-term monitoring. A reliable method to achieve this is to exploit the characteristic spectral fingerprint of vegetation: Chlorophyll shows a high reflectivity in the green and infrared spectral region while strongly absorbing red and blue light. We present such a visual monitoring system comprising multiple cameras and an active illumination which is employed on railroads. The individual cameras address different spectral regions and are superimposed through a position-synchronized triggering to obtain a multi-spectral image. Multi-pixel binning greatly extends the dynamic range of the cameras and, in combination with active illumination and high-speed dark frame recording, allows operation during day and night without degradation from ambient light conditions. The system achieves about 5 mm effective resolution and can operate up to a speed of 100 km/h. This is possible through embedded real-time pre-processing and data reduction already in the camera units. A processing delay of less than 100 ms is the consequence which allows targeted actuation of weed-treatment methods (e.g., spray nozzles) during movement. In combination with GNSS-sensors geo-referenced documentation of the coverage rate is possible.

My Library

You currently do not have any folders to save your paper to! Create a new folder below.

Folder Name

Folder Description

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks. You are receiving this notice because your organization may not have SPIE eBooks access.*

*Shibboleth/Open Athens users─please sign in to access your institution's subscriptions.

To obtain this item, you may purchase the complete book in print or electronic format on SPIE.org.

ORGANIZATIONAL
Sign in with credentials provided by your organization.

Organizational Username

Organizational Password

Show/Hide Password

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members:

Non-members: ADD TO CART

Keywords/Phrases

Search In:

Publication Years