Publication

In-flight quality assessment and data processing for airborne laser scanning

Philipp Schär
2010
Theses

Abstract

One of the main problems of today's Airborne Laser Scanning (ALS) systems is the lack of reliable data QA/QC (Quality Assurance/ Quality Control) within or shortly after the airborne survey campaign. This thesis presents the development of methods to perform automated processing and QA/QC of ALS data during data acquisition (in-flight). The backbone of these methods is an error propagation algorithm that estimates the expected accuracy of the point-cloud. The error propagation considers the uncertainties induced by the direct georeferencing (DG) and the changing scanning geometry. A novel methodology that derives the scanning geometry directly from the point-cloud and computes a final quality indicator for every laser point is developed. To predict the accuracy of the navigation solution, this research also proposes a methodology to estimate in realtime (RT) the likelihood of fixing the differential carrier-phase ambiguities during post-processing. Furthermore, an innovative procedure to describe the quality of digital terrain models (DTM) derived from ALS data is presented. The successful implementation of these concepts into a fully functional in-flight quality monitoring tool embedded in an ALS system is demonstrated. The proposed tool incorporates RT GPS/INS processing and point-cloud georeferencing. The general performance of the tool, the validity of the quality indicators and the achievable improvement in efficiency for ALS data acquisition are assessed in airborne surveys. It is shown that when using RTK GPS (real-time kinematics) as positioning mode, the tool can provide point-clouds with sub-decimeter accuracy in RT.

Official source

https://infoscience.epfl.ch/entities/publication/8c423fcb-8226-4511-8483-1bf5b360ffde

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Philipp Schär
2010
Theses

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/8c423fcb-8226-4511-8483-1bf5b360ffde

About this result

Related concepts (32)

Quality assurance

Quality assurance (QA) is the term used in both manufacturing and service industries to describe the systematic efforts taken to assure that the product(s) delivered to customer(s) meet with the contractual and other agreed upon performance, design, reliability, and maintainability expectations of that customer. The core purpose of Quality Assurance is to prevent mistakes and defects in the development and production of both manufactured products, such as automobiles and shoes, and delivered services, such as automotive repair and athletic shoe design.

Quality management

Quality management ensures that an organization, product or service consistently functions well. It has four main components: quality planning, quality assurance, quality control and quality improvement. Quality management is focused not only on product and service quality, but also on the means to achieve it. Quality management, therefore, uses quality assurance and control of processes as well as products to achieve more consistent quality. Quality control is also part of quality management.

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Quality control (QC) is a process by which entities review the quality of all factors involved in production. ISO 9000 defines quality control as "a part of quality management focused on fulfilling quality requirements". This approach places emphasis on three aspects (enshrined in standards such as ISO 9001): Elements such as controls, job management, defined and well managed processes, performance and integrity criteria, and identification of records Competence, such as knowledge, skills, experience, and qualifications Soft elements, such as personnel, integrity, confidence, organizational culture, motivation, team spirit, and quality relationships.

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