Visible spectrum images are used to precisely locate the edge of the (moving) tool in the thermal spectrum images. Knowledge of this location is important for the correct estimation of tool temperatures, a major factor for the analysis of tool wear. Steel workpiece, 600 m/min surface speed. All three movies have the same frame rate and the same field of view of about 1 mm high. The movie on the left is a thermal movie displayed in color. The movie in the center is a visible light movie. The movie on the right is a thermal movie displayed in gray scale. A red line is drawn at the precise location of the edge of the tool, as determined by the visible light movie. For more information, see the NIST publication "Cutting Temperature Measurements of Segmented Chips using Dual-Spectrum High-Speed Microvideography".