• Journal of the Optical Society of Korea
• /
• v.13 no.4
• /
• pp.464-467
• /
• 2009

The grating projection method with phase-shifting technique is very useful in measuring the 3-dimensional (3D) shape with high accuracy and speed. In this work, we have developed an ultra high-speed digital laser grating projection system using a high-power laser diode and a highsensitivity CMOS camera. With our system, the optical measurement required to find out the profile of a 3D object could be carried out within 2.6 ms, which is a significant ($\sim$10 times) improvement compared with those of the previous studies.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.16 no.6
• /
• pp.223-230
• /
• 2007

It is absolutely that jewelry industry are cut and formed by using Nd-YAG laser for most accuracy shapes. Moreover, Jewelry manufacturing is needed to be more precise working, more saved time and more improved finance. So, This Study will show the ideas which make exactly formed shape and advanced qualities when cutting Ag-alloy. This ideas will give the fact that beginners are able to use easily to change and compound the form of jewelries by using Nd-YAG laser.

• Journal of Sensor Science and Technology
• /
• v.22 no.6
• /
• pp.387-392
• /
• 2013

Camera rigs for shooting 3D video are classified as manual, motorized, or fully automatic. Even in an automatic camera rig, the process of Stereoscopic 3D (S3D) video capture is very complex and time-consuming. One of the key time-consuming operations is capturing the distance parameters, which are near distance, far distance, and convergence distance. Traditionally these distances are measured by tape measure or triangular indirect measurement methods. These two methods consume a long time for every scene in shot. In our study, a compact laser distance sensing system with long range distance sensitivity is developed. The system is small enough to be installed on top of a camera and the measuring accuracy is within 2% even at a range of 50 m. The shooting time of an automatic camera rig equipped with the laser distance sensing system can be reduced significantly to less than a minute.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.967-968
• /
• 2007

This report is the study for laser scanning. Scanning control of $CO_2$ laser, He-Ne laser, used for the treatment of body skin, has relatively low band about hundered Hz. It could be used as a substitiute for expensive galvanometer that is the established scan method, which operates the number of KHz movement by using step motor when it operates low speed. To increase the accuracy of step motor's the angle of rotation, We could materialize 100Hz low band by using open loop, closed loop method with microprocessor. This causes it to be stable even direction by attaching electric capacity sensor. Therefore, We could expect to reduce the cost by manufacturing low band scanner rather than costly feedback galvanometer.

• Proceedings of the KSRS Conference
• /
• 2003.11a
• /
• pp.1137-1139
• /
• 2003

This paper proposed a practical method for building detection and extraction using airborne laser scanning data. The proposed method consists mainly of two processes: low and high level processes. The major distinction from the previous approaches is that we introduce a concept of pseudogrid (or binning) into raw laser scanning data to avoid the loss of information and accuracy due to interpolation as well as to define the adjacency of neighboring laser point data and to speed up the processing time. The approach begins with pseudo-grid generation, noise removal, segmentation, grouping for building detection, linearization and simplification of building boundary , and building extraction in 3D vector format. To achieve the efficient processing, each step changes the domain of input data such as point and pseudo-grid accordingly. The experimental results shows that the proposed method is promising.

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.1
• /
• pp.21-26
• /
• 2000

This paper describes a positioning system for ultra-precision that will be utilized in semiconductor manufacturing field and precision machinery. This system is composed with laser scale unit with 10nm resolution, ball screw with LM guide, brushless DC servo motor, vibration isolator and is equipped in chamber for continuous measuring environment. The dynamic of table, the problem of servo control and the traceability for micro step motion are described. These data will be applied for getting more stable system with 50nm resolution.

• Current Optics and Photonics
• /
• v.7 no.1
• /
• pp.90-96
• /
• 2023

We numerically solve the nonlinear Schrödinger equation for pulse propagation in a passively mode-locked Yb:KGW laser. The soliton-like pulse formation as a result of balanced negative group-delay dispersion (GDD) and nonlinear self-phase modulation is analyzed. The cavity design and optical parameters of a previously reported high-power Yb:KGW laser were adopted to compare the simulation results with experimental results. The pulse duration and energy obtained by varying the small-signal gain or GDD reproduce the overall tendency observed in the experiments, demonstrating the reliability and accuracy of the model simulation and the optical parameters.

• The Journal of Korea Robotics Society
• /
• v.18 no.2
• /
• pp.135-142
• /
• 2023

Light detection and ranging (LiDAR) sensors have been most widely used in terrestrial robotic applications because they can provide dense and precise measurements of the surrounding environments. However, the reliability of LiDAR measurements can considerably vary due to the different reflectivities of laser beams to the reflecting surface materials. This study presents a robust LiDAR-based mapping method for the varying laser reflectivities in indoor environments using the framework of simultaneous localization and mapping (SLAM). The proposed method can minimize the performance degradations in the SLAM accuracy by checking and discarding potentially unreliable LiDAR measurements in the SLAM front-end process. The gaps in point-cloud maps created by the proposed approach are filled by a Gaussian process regression method. Experimental results with a mobile robot platform in an indoor environment are presented to validate the effectiveness of the proposed methodology.

• Journal of the Korean Society for Heat Treatment
• /
• v.37 no.2
• /
• pp.73-78
• /
• 2024

This study presents a real-time method that uses Laser Absorption Spectroscopy (LAS) to measure exhaust gas temperatures in turbulent flow fields. It was possible to measure temperature by passing a laser beam through the exhaust gas in a grid pattern, and obtain a temperature distribution image through time series analysis at 0.1 second intervals. Temperature image resolution has been improved with CT reconstruction algorithms. Estimating maximum temperature values and locations enabled 2D temperature analysis, surpassing single-point methods like thermocouples. The accuracy of LAS measurements was evaluated by comparison with thermocouple measurements. This approach will contribute to automotive technology and environmental protection by providing reliable temperature data for interpreting turbulent temperature distributions.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2004.04a
• /
• pp.291-298
• /
• 2004

Effective 3 dimensional modelling is to be essential work for design of construction, mechanic and industrial part. Especially, it makes possible for reverse design. It need rapidity, accuracy, reality. Data acquisition method for modelling are contact 3dimensional measurement system, LASER scanner, Pattern scanner, and digital photogrammetry. This study introduce to 3 dimensional modelling methods and analysis of these method. We tried to 3D modelling of automobile part using OPTO-Top pattern scanner which system have rapidity and accuracy, and compared effectiveness of each method. The 3D display web environment was made.