In response to the market’s need for luxurious automobile interiors, automotive parts makers are developing various types of crash pads to give drivers a sense of emotional luxury. In particular, a low-cost and high-quality crash pad manufacturing technology is being developed for mid- to low-priced vehicles, namely, the IMG-S (In Mold Grain-pre Stitch) technology. High defect rate of stitching is a critical problem during the manufacture of crash pad using the IMG-S technology. In order to solve this problem, this paper proposes a method of real-time machine vision inspection of stitches on the automotive crash pad. This paper presents the real-time machine vision inspection system configuration, proposes stitch and reference line detection methods, and method for calculating the distance between stitches and the reference line. According to the distance between the stitch and the reference line, the status of the stitch was judged as normal, warning, or erroneous, and the final result was displayed on the user interface. The applicability of the proposed real-time machine vision inspection method was verified by stitching the test line.

In this investigation, we describe a metrological technique for surface and thickness profiles of a silicon (Si) wafer by using a 6 degree of freedom (DOF) stitching method. Low coherence scanning interferometry employing near infrared light, partially transparent to a Si wafer, is adopted to simultaneously measure the surface and thickness profiles of the wafer. For the large field of view, a stitching method of the sub-aperture measurement is added to the measurement system; also, 6 DOF parameters, including the lateral positioning errors and the rotational error, are considered. In the experiment, surface profiles of a double-sided polished wafer with a 100 mm diameter were measured with the sub-aperture of an 18 mm diameter at 10x10 locations and the surface profiles of both sides were stitched with the sub-aperture maps. As a result, the nominal thickness of the wafer was 483.2 μm and the calculated PV values of both surfaces were 16.57 μm and 17.12μm, respectively.