• Laser Solutions
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• v.14 no.4
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• pp.21-27
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• 2011

In this work, we have studied on time-resolved transient reflective image of single crystalline Si surface after single-shot fs-laser irradiation with varying the laser fluence under two different laser spot sizes. The temporal profiles of transient reflectivity changes as well as its maximum values at the early delay time were found to be strongly dependent on both the laser beam spot size and laser fluence. We have interpreted the dependence of transient reflectivity changes on the laser spot size in terms of a relaxation of the generated free carriers to the bulk silicon, which should be interacted with the plasma.

• Proceedings of the KIEE Conference
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• 2004.07e
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• pp.62-67
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• 2004

In this paper, we present the new method for joint aspect inspecting system. We use the image processing and laser maker for light source. We can find the matrial joint status through processing the line pattern which is made by laser maker. To get the line pattern, in first, we had done the preprocss of threshold. If the shape of line had over two segments, then the joint status is abnormal. We show our system efficency by experiment on tire facility.

• 전자공학회논문지 IE
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• v.45 no.2
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• pp.20-27
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• 2008

In this paper, we propose a new image processing technique that reliably detects the various defects of TFT-LCD polarizing films. The image of polarizing film is acquisited from reflected laser beam First, we apply the morphological image processing technique to remove the background noise. Next, we use the 2-dimensional LMS adaptive filtering and statistical characteristics to detect the white and black defects. Performance of the proposed method is evaluated on real TFT-LCD polarizing film samples.

• Journal of Korea Society of Industrial Information Systems
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• v.16 no.1
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• pp.21-30
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• 2011

In this paper, an effective method to detect the laser pointer on the screen using the neural network algorithm for implementing the human-computer interaction system. The proposed neural network algorithm is used to train the patches without a laser pointer from the input camera images, the trained neural network then generates output values for an input patch from a camera image. If a small variation is perceived in the input camera image, amplify the small variations and detect the laser pointer spot in the camera image. The proposed system consists of a laser pointer, low-price web-camera and image processing program and has a detection capability of laser spot even if the background of computer monitor has a similar color with the laser pointer spot. Therefore, the proposed technique will be contributed to improve the performance of human-computer interaction system.

• Laser Solutions
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• v.10 no.4
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• pp.18-22
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• 2007

In this paper, we suggested the femtosecond laser processing using the mask which makes Gaussian spatial beam distribution to a normalized distribution by Fresenel diffraction. Holography pattern of the size of $320{\times}320{\mu}m^2$ on the Cr thin film on glass substrate with a pixel size of $5{\times}5{\mu}m^2$ was fabricated according to the pattern generated by the iterative Fourier transform algorithm(IFTA) algorithm. We analysed the damage threshold with an assumption the power distribution as Gaussian profile as 45 $mJ/cm^2$. The regenerated image of letters through the diffractive pattern was well recognized at the screen.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.123.1-123
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• 2001

For Autonomous navigation of the mobile robots, the robots' capability to recognize 3D environment is necessary. In this paper, an on-line 3D map building method for autonomous mobile robots is proposed. To get range data on the environment, we use an sensor system which is composed of a structured light and a CCD camera based on optimal triangulation. The structured laser is projected as a horizontal strip on the scene. The sensor system can rotate $\pm$ $30{\Circ}$ with a goniometer. Scanning the system, we get the laser strip image for the environments and update planes composing the environment by some image processing steps. From the laser strip on the captured image, we find a center point of each column, and make line segments through blobbing these center poings. Then, the planes of the environments are updated. These steps are done on-line in scanning phase. With the proposed method, we can efficiently get a 3D map about the structured environment.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.123.5-123
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• 2001

For autonomous navigation of the mobile robots, the robots' capability to recognize 3D environment is necessary. In this paper, an on-line 3D map building method for autonomous mobile robots is proposed. To get range data on the environment, we use a sensor system which is composed of a structured light and a CCD camera based on optimal triangulation. The structured laser is projected as a horizontal strip on the scene. The sensor system can rotate$\pm$30$^{\circ}$ with a goniometer. Scanning the system, we get the laser strip image for the environments and update planes composing the environment by some image processing steps. From the laser strip on the captured image, we find a center point of each column, and make line segments through blobbing these center points. Then, the planes of the environments are updated. These steps are done on-line in scanning phase. With the proposed method, we can efficiently get a 3D map about the structured environment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.12
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• pp.122-130
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• 2010

This paper presents an active ranging system based on laser structured-light image. The structured-light image processing is computationally efficient in comparison with the conventional stereo image processing, since the burdensome correspondence problem is avoidable. In order to achieve robustness against environmental illumination noise, an efficient image processing algorithm, i.e., integration of difference images with structured-light modulation is proposed. Distance equation from the measured structured light pixel distance and system parameter calibration are addressed in this paper. Experiments and analysis are carried out to verify performance of the proposed ranging system.

• Journal of the Korean Society for Nondestructive Testing
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• v.10 no.1
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• pp.47-55
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• 1990

This paper presents experimental results which explore the capability of a CW laser speckle photography for tile measurement of in-plane displacement at high temperature. The serious restrictions on the application of the method seem to be the ambient air turbulence and the change of surface texture caused by the oxidation, as they tend to decorrelate the double exposured speckle patterns. In order to assess only the effect of air turbulence, a ceramics-coated stainless steel plate is heated in air and Ar-laser specklegrams are made with combination of temperature and lateral translation displacement. The slight reduction in visibility of Young's fringes is observed at $1000^{\circ}C$. The analyses of Young's fringes are carried out by a image processing system using a TV-camera and computers, and the result agrees well with the micrometer reading. Futhermore, uncoated stainless steel and Hastelloy X plates are tested and the effect of oxidation is also evaluated. The experimental results demonstrate that a CW laser speckle photography is applicable at temperatures up to $1000^{\circ}C$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.3
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• pp.594-601
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• 2009

Shooting simulation systems not only reduce a great amount of expense and time for military exercises but also prevent accidents. In particular, the shooting simulation systems using laser beam have an advantage which is very similar to the shooting exercise that uses real bullets. However, real time technique for laser beam recognition in a target image is necessary. The method proposed in this paper takes a difference image from two adjacent image frames. Then a thresholding is applied on this difference image to discriminate laser beam from background. To decide the threshold value the intensity distribution of background points is modeled assuming normal distribution. Then a noise reduction and a region segmentation are applied on the binary image to find the position of a laser beam. The time complexity of this process depends on the size of an image multiplied by the size of a mask used in the noise reduction process. The experimental result showed that the accuracy of the system was 93.3%. Even in the inaccurate cases the beam was always found in the resultant region.