Evaluation of Slit Light System for Objects with Metallic Reflection and Application to Iron Wheels

This paper divides slit light steps into slit light operation, image pickup, and cross-section profile restoration, and present calculations for each operation to evaluate measurement design using slit light for objects with metallic reflection. First, it present calculation for solid objects using simplified representation, particularly for objects with axially uniform sections such as rails and for the bodies of revolution with circumferentially uniform sections such as iron wheels. It presents an approximation model and specific parameters for obtaining the amount of reflected light based on tests using actual rails and iron wheels to evaluate the amount of reflected light, which has great significance in slit light evaluation for objects with metallic reflection. Last, it applies the above evaluation to concave abrasion inspection design for iron wheels using slit light to satisfy practical railway maintenance needs, and verifies the method's usefulness. A prototype of practical iron wheel inspection was realized and its practicality verified through field tests.