In the steel industry, laser triangulation based measurement systems can be utilizedfor evaluating the flatness of the steel products. Shapeline is a company in Linköpingthat manufactures such measurement systems. This thesis work will present a series ofexperiments on a Shapeline measurement system in a relatively untested environment, thehot rolling mill at SSAB in Borlänge.The purpose of this work is to evaluate how the conditions at a hot rolling mill affectsthe measurement performance. It has been anticipated that measuring in high temperatureenvironment would introduce difficulties that do not exist when measuring in cold environments.A number of different experiments were conducted, where equipment such as laserand camera bandpass filter were alternated. Via the experiments, information about noisedue to the environment in the hot rolling mill was gained. The most significant noise wascaused by heat shimmering. Using the presented methods, the magnitude and frequencyspectrum of the heat shimmering noise could be determined. The results also indicates thatheat shimmering cause large errors and is quite troublesome to counter. In addition to this,the quality of the line detections under the hot rolling mill circumstances was examined. Itcould be observed that the line detections did not introduce any significant errors despitethe harmful conditions.