Mr. Moritz von Wrangel Profile

Moritz von Wrangel

at Leibniz Univ Hannover

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 | 31 May 2022 Presentation + Paper

Robust counting of engine blades in aircraft engine video endoscopy

Moritz v. Wrangel, Markus Kästner, Eduard Reithmeier

Proceedings Volume 12098, 120980C (2022) https://doi.org/10.1117/12.2618504

KEYWORDS: Inspection, Video, Cameras, Optical flow, Detection and tracking algorithms, Correlation function, Endoscopy, Endoscopes, Specular reflections, Defect inspection

Read Abstract +

To ensure the safe operation of aircraft, regular endoscopy of the engines is mandatory. Since the blade stages are particularly susceptible to defects, they must be inspected especially frequently. In the process, a worker must inspect each blade individually. All findings must be carefully documented and assigned to the respective blade. Since there are no individual markings to identify the blades, the operator must count all blades as they pass through the endoscope image. Although electric rotary devices with automatic blade counting are available for some engines, manual counting is often necessary. Simultaneously inspecting and counting blades is tedious and error-prone. We present a novel algorithm for automatic blade counting during jet engine inspection in this paper. The algorithm’s central part is a Pearson correlation of individual video frames as the blades pass before the endoscopes during turning. Adaptive thresholding of the correlation function is used to count the blades. Rotation direction and speed are determined using the Farneback method of optical flow. By using correlation instead of classical image features, the algorithm is highly robust to metallic reflections and smooth blade surfaces without significant image features. In addition, the algorithm is robust to different rotation speeds and directions. Compared to existing approaches, the algorithm is robust and universally applicable for counting engine blades on almost any engine without the need for customization.

Proceedings Article | 20 June 2021 Presentation + Paper

On the development of a flexible borescope fringe projection system

Moritz v. Wrangel, Markus Kästner, Eduard Reithmeier

Proceedings Volume 11782, 1178215 (2021) https://doi.org/10.1117/12.2593019

KEYWORDS: Projection systems, 3D metrology, Inspection, Sensors, RGB color model, Image sensors, Cameras, Time metrology, Robotics, Reconstruction algorithms

Read Abstract +

The 3D measurement of the interior of hollow technical bodies is still a challenge for state-of-the-art measurement systems. This is especially true for complex industrial free-form objects inside confined spaces. Fringe projection enables accurate and fast 3D measurements of object surfaces. To fulfill the task of geometric inspection of confined spaces, we have developed an endoscopic and flexible fringe projection system. The fringe patterns are generated with a RGB LED projector. Fibre-coupling of the structured light is achieved by using a microscope lens and bundle of coherent image fibres. A compact sensor head can be achieved by using a micro-objective for projecting the fringes and a Chip-on-Tip camera to capture the images. A micro lens with a diameter of 1.7 mm was used as the projector lens and a 2 megapixel 1/6” chip was used as the image sensor. By synchronizing the projector with the camera, the system is capable of capturing up to 10 grayscale patterns per second. The measurement volumes result to approximately 20 x 13 x 4 mm³. Typically, the measurement time is in the range of 1 - 3 s, depending on the number of projected images. Measurements on a 50 µm step standard confirmed that a measurement uncertainty of less than 29.4 ± 3.2 µm is achieved with this system. Mounted on a carrier system, the presented fringe projection system offers the possibility to enter confined areas and perform high-precision 3D measurements.

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