• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.12 no.6
• /
• pp.14-21
• /
• 2003

With the increased use of lasers in industrial welding applications, techniques for monitoring and controlling these processes become increasingly important. It is very important that we understand the dynamic behaviors of the laser induced Plume in welding, because the laser induced plume has considerable effects on welding efficiency and the quality of materials. As the plume fluctuation was associated with keyhole instability, unstable vapor plume indicated the process was unstable and would result in poor welds. An Infrared Thermal-vision Camera can be utilized compensate for incurracies encountered in real-time monitoring during laser welding. We have results that instabilities of plume are closely related with hot cracking and defect of laser welding.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.41 no.10
• /
• pp.949-957
• /
• 2017

A laser-vision-based height measurement system is developed and implemented for the inspection of two-step variable valve lift module assemblies. The proposed laser-vision sensor module is designed based on the principle of laser triangulation. This paper summarizes the work on 3D point cloud data collection and height difference measurements. The configuration of the measurement system and the proposed height measurement algorithm are described and analyzed in detail. Additional measurement experiments on the height differences of valves and lash adjusters of a two-step variable valve lift module were implemented repeatedly to evaluate the accuracy and repeatability of the proposed measurement system. Experimental results show that the proposed laser-vision-based height measurement system achieves high accuracy, repeatability, and stabilization for the inspection of two-step variable valve lift module assemblies.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.16 no.4
• /
• pp.22-28
• /
• 2007

The welded defects are usually called user's unsatisfaction for appearance and functional usage. For checking these defects effectively without time loss, setup of weldability estimation system is an important for detecting whole specimen quality. In this study, after catching a rawdata on welded specimen profiles and treating vision processing with these data, the qualitative defects are estimated from getting these information by laser vision camera at first. At the same time, the weldability estimation for whole specimen is produced. For user friendly, the weldability estimation results are shown each profiles, final reports and visual graphics method. So, user can easily determined weldability. By applying these system to welding fabrication, these technologies are contribution to on-line setup of weldability estimation system.

• Journal of Institute of Convergence Technology
• /
• v.3 no.2
• /
• pp.31-37
• /
• 2013

This paper proposes a vision-based inspection algorithm for a punch which is used when forming the head of the small screws. To maintain good quality of punch, the precise inspection of its dimension and the depth of the punch head is important. A CCD camera and an illumination dome light are used to measure its dimensions. And a structured line laser is also used to measure the depth of the punch head. Resolution and visible area depend on setup between laser and camera which is determined using CAD-based simulation. The proposed method is successfully evaluated using experiment on #2 punch.

• International Journal of Aeronautical and Space Sciences
• /
• v.12 no.1
• /
• pp.43-56
• /
• 2011

An integrated system composed of guidance, navigation and control (GNC) system for autonomous proximity operations and the docking of two spacecraft was developed. The position maneuvers were determined through the integration of the state-dependent Riccati equation formulated from nonlinear relative motion dynamics and relative navigation using rendezvous laser vision (Lidar) and a vision sensor system. In the vision sensor system, a switch between sensors was made along the approach phase in order to provide continuously effective navigation. As an extension of the rendezvous laser vision system, an automated terminal guidance scheme based on the Clohessy-Wiltshire state transition matrix was used to formulate a "V-bar hopping approach" reference trajectory. A proximity operations strategy was then adapted from the approach strategy used with the automated transfer vehicle. The attitude maneuvers, determined from a linear quadratic Gaussian-type control including quaternion based attitude estimation using star trackers or a vision sensor system, provided precise attitude control and robustness under uncertainties in the moments of inertia and external disturbances. These functions were then integrated into an autonomous GNC system that can perform proximity operations and meet all conditions for successful docking. A six-degree of freedom simulation was used to demonstrate the effectiveness of the integrated system.

• Journal of Ocean Engineering and Technology
• /
• v.32 no.6
• /
• pp.511-517
• /
• 2018

This paper proposes a vision-based underwater laser scanner with separate structures for an underwater camera and a line laser projector. Because the two devices can be adaptively placed regardless of the features of the unmanned underwater vehicle (UUV), the scanner has significant advantages in relation to its availability and flexibility. Position calibration between the underwater camera and laser projector guarantees a 3D measuring performance with high accuracy. To verify the proposed underwater laser scanner, a test-bed system was manufactured, which consisted of the laser projector, camera, Pan&Tilt, and Attitude and Heading Reference System (AHRS). A camera-laser calibration test and simple 3D reconstruction test were performed in a water tank and the experimental results are reported.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.729-734
• /
• 2005

One of the important research issues in mobile robot is how to detect the 3D environment fast and accurately, and recognize it. Sensing methods of utilizing laser structured light and/or stereo vision are representatively used among a number of methodologies developed to date. However, the methods are still in need of achieving high accuracy and reliability to be used for real world environments. In this paper to implement a new robotic environmental sensing algorithm is presented by combining the information between intensity image and that of laser structured light image. To see how effectively the algorithm applied to real environments, we developed a sensor system that can be mounted on a mobile robot and tested performance for a series of environments.

• Journal of the Semiconductor & Display Technology
• /
• v.12 no.1
• /
• pp.15-21
• /
• 2013

In this paper, sensor system and inspection algorithm in order to inspect steel balance weight for automobile is described. Steel balance weight is composed of clip and weight, which is joined by press process. The defective one has a gap between clip and weight. To detect whether there is a gap, sensor system is simply configured with laser line projector and USB camera, which make it possible to measure the height difference of clip and weight area. Laser line pattern which is made on the surface of a balance weight is captured by USB camera. In case that USB camera is used in machine vision, barrel distortion caused by wide angle lens makes the captured image distorted. Image warping function is applied to correct the distortion. Simple image processing algorithm is applied to extract the laser line information and whether it is good or not is judged through the extracted information.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.41 no.5
• /
• pp.422-428
• /
• 2013

Recently, many unmanned aerial vehicle (UAV) studies have focused on small UAVs, because they are cost effective and suitable in dangerous indoor environments where human entry is limited. Map building through distance measurement is a key technology for the autonomous flight of small UAVs. In many researches for unmanned systems, distance could be measured by using laser range finders or stereo vision sensors. Even though a laser range finder provides accurate distance measurements, it has a disadvantage of high cost. Calculating the distance using a stereo vision sensor is straightforward. However, the sensor is large and heavy, which is not suitable for small UAVs with limited payload. This paper suggests a low-cost distance measurement system using a laser pointer and a monocular vision sensor. A method to measure distance using the suggested system is explained and some experiments on map building are conducted with these distance measurements. The experimental results are compared to the actual data and the reliability of the suggested system is verified.

• Journal of Sensor Science and Technology
• /
• v.32 no.5
• /
• pp.320-327
• /
• 2023

In this study, an FPGA-based sealer inspection system was developed to inspect the sealer applied to install vehicle glass on a car body. The sealer is a liquid or paste-like material that promotes adhesion such as sealing and waterproofing for mounting and assembling vehicle parts to a car body. The system installed in the existing vehicle design parts line does not detect the sealer in the glass rotation section and takes a long time to process. This study developed a line laser camera sensor and an FPGA vision signal processing module to solve this problem. The line laser camera sensor was developed such that the resolution and speed of the camera for data acquisition could be modified according to the irradiation angle of the laser. Furthermore, it was developed considering the mountability of the entire system to prevent interference with the sealer ejection machine. In addition, a vision signal processing module was developed using the Zynq-7020 FPGA chip to improve the processing speed of the algorithm that converted the profile to the sealer shape image acquired from a 2D camera and calculated the width and height of the sealer using the converted profile. The performance of the developed sealer application inspection system was verified by establishing an experimental environment identical to that of an actual automobile production line. The experimental results confirmed the performance of the sealer application inspection at a level that satisfied the requirements of automotive field standards.