Fast, programmable, sheet-of-light range finder using MAPP2200

Abstract

Range image acquisition can be made in many different ways. In this paper we use an active triangulation method where a sheet-of-light illuminates the scene. The sensor-level signal processing task addressed here is to extract the light impact position in each sensor row. We use a thresholding algorithm implemented on the smart sensor MAPP2200 to extract the range data from the sensor data. The range images can be output with very high frame rates (up to and above video rate). The programmabiity of the sensor makes it possible to generate range images with arbitrary range resolution or image size. Reducing the image size or resolution gives us higher range image frequency. We also present an error correction scheme not found in any other smart sensor implementation.Keywords: Fast sheet-of-light range finder, smart sensor, programmable resolution. SHEET-OF-LIGHT RANGE IMAGINGRange imaging is very important in many machine vision applications. Typical applications are dimension inspection5, sorting18, flatness measurements" and navigation13. Sheet-of-light (or striped light) range imaging is an active triangulation range imaging method which is especially well suited for applications where the scene or the apparatus is moving, for instance conveyor belts5'11, road surveys4 and railway inspections. A typical sheet-of-light range imaging setup is shown in Figure 1.In a sheet-of-light system range data are acquired with triangulation, see Figure 2A. The offset position of the reflected light on the sensor depends on the distance from the light source to the object. To make a sheet-of-light the laser spot light is passing a cylindrical lens, see Figure 2A-B. For each position of the sheet-of-light a one dimensional range profile (range row) of the scene contour is acquired, see Figure 2C. O-8194-1597-9/94/$6.OO SPIE Vol. 2273 / 25 FIGURE 1. Light source •::•::: 2D : Sensor X-axis Scanning__ A typical sheet-of-light range imaging setup using a conveyor belt. Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/26/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx

An underwater laser stripe seabed profiler to measure the physical impact of towed gear components on the seabed

“…As a result they can capture instantaneously the image of the laser stripe and can measure the surface height of the corresponding transect. Similar approaches have been developed for quality control of industrial processes (Johannesson, 1994). Darboux and Huang (2003) modify their analysis further by using a calibration procedure which obviates the need to measure the relative position of the laser and camera.…”