The Wall Flatness Detector Of Laser Line Scaning Based On Embedded ARM9

With the rise of the real estate industry and the popularity of decorated family personal, wall flatness has received more and more attention which as an important content of building inspection. Based on the ARM9, this paper designs and realizes laser scanning wall flatness detector, which in view of the limitation of the traditional detection methods, such as Guiding rule, Dial indicator dot, Thickness interferometer, Electronic Total Station, etc, in operation of convenient, detection efficiency and cost-effective. This detector completely satisfying the requirements of wall flatness detection, it has high practical value and economic value because of the convenient, accurate and real-time detection of wall roughness. Specific research contents outlined below:(1) Put forward the overall design scheme of the laser line scan wall flatness detector.Paper first puts forward the overall scheme of the detector after analysis the principle and performance requirements of laser scanning wall flatness detector. Then analysis of selection of the key technologies based on the overall scheme,which with freescale MCIMX283 for embedded processor, Linux for operating system, least squares method for fitting method of scanning laser line. Finally outlined the goals of detector, and expounds the overall design the hardware and software development.(2) Build the hardware platform of wall flatness detector based on embedded ARM9.Using the modular design, this paper discusses the detector’s architecture of hardware with freescale MCIMX283 for embedded processor. The hardware design is divided into three parts: the microprocessor and memory module, including microprocessor that is core processing module of the detector, DDR2 for running the program and operating system and NAND Flash for storing operation system and detecting program code; On chip auxiliary module, including power supply of detector, clock, reset, and launch configuration module; Peripheral interface circuit module, including UART that supply auxiliary for commissioning of detector, the USB interface for download the kernel, procedure of detection, mount USB camera, ect, the LCD interface for display the result of detection, pin circuit of PSWITCH. Finally paper introducts detailly the problems that should be paid attention to in the design of each functional module.(3) Build the software development platform of wall flatness detector based on Linux.First installed the operating system and build cross development environment, and then complete the transplantation of embedded Linux operating system, which including the transplantation of BootLoader, the cutting and transplantation of kernel, the production and transplantation of the root file system. Then realize respectively drive transplantation and initialization code of DDR2, detection button for realizing the function of detection, USB camera, and the LCD, etc. which according to the hardware design and application requirements.While detects whether is success of drive transplantation by test code, at the same time paper introduces the settings, installation and unloading process of peripheral drive.(4) Put forward the scanning laser line wall flatness detection algorithm based on the hardware and software platform.The algorithm mainly including to realize the collection of video and image by using of V4L2 library function(make the program has the ability to discovery and operating equipment), to fit laser line using the least squares, to compress image using the downsampling, to realize the display of video and image by using of SDL library function that is a cross-platform multimedia development kit for multimedia display, and so on. Improve the detection algorithm for enhance the robustness in order to answer special applications such as special light, detector jitter. The practical detection results, that in difference of concave and convex, measuring distance and angle measurement, show that algorithm proposed by this paper can fast and accurately detect the wall flatness and can achieve the desired effect. Results of detection also show that the detector can measure the flatness of the ground, doors, desktop, which expand the application range of the detector.