• Journal of the Optical Society of Korea
• /
• v.9 no.1
• /
• pp.22-25
• /
• 2005

The differential heterodyne interferometer (DHI) is suitable for precise measurement of step height and line width, since its differential configuration can significantly reduce disturbances from the environment [1,2]. Like most phase measuring interferometers, however, the DHI is limited, in that it can obtain only the phase from 0 to 2π, because of the sinusoidal nature of the optical interference involved. Thus, the measurable step height is limited to one quarter of the wavelength of the light source. This study describes a confocal differential heterodyne interferometer (CDHI) for measuring step heights of several micrometers, with a high resolution and line width with high repeatability. The CDHI has a simple structure and rapid measurement speed.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.5 no.6
• /
• pp.1163-1168
• /
• 2001

The ranging systems measure range data in three-dimensional coordinate from target surface. These non-contact remote ranging systems is widely used in various automation applications, including military equipment, construction field, navigation, inspection, assembly, and robot vision. The active ranging systems using time of flight technique or light pattern illumination technique are complex and expensive, the passive systems based on stereo or focusing principle are time-consuming. The proposed algorithm, that is based on cross correlation of projection profile of vertical edge, provides advantages of fast and simple operation in the range acquisition. The results of experiment show the effectiveness of the proposed algorithm.

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.6
• /
• pp.210-217
• /
• 2000

Noncontact measuring methodology of 3-dimensional profile using CCD camera are very attractive because of it's high measuring speed and it's high sensitivity. Especially when projecting a grid pattern over the object, the captured image have 3 dimensional information of the object. Projection moire extract 3-D information with another grid pattern in front of CCD camera. However phase measuring profilometry(PMP) obtain similar results without additional grid pattern. In this paper, the projection moire are compared with the PMP mathematically, and it is shown that PMP can generate moire image with simple mathematical computations. Experimental works are also carried out showing the same results. It is shown that using a single gird pattern, moire image can be obtained directly without any mathematical operation when some conditions are satisfied.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1999.05a
• /
• pp.187-192
• /
• 1999

Noncontact measuring methodology of 3-dimensional profile using CCD camera are very attractive because of it's high measuring speed and its's high sensitivity. Especially when projecting a grid pattern over the object, the captured image have 3 dimensional information of the object. Projection moire extract 3-D information with another grid pattern in front of CCD camera. However phase measuring profilometry(PMP) obtain similar results without additional grid pattern. In this paper, the projection moire are compared with the PMP mathematically, and it is shown that PMP can generate moire image with simple mathematical computations. Experimental works are also carried out showing the same results. It is shown that using a single gird pattern, moire image can be obtained directly without any mathematical operation when some conditions are satisfied.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.4
• /
• pp.151-158
• /
• 2005

An important component of a cooling tower is an axial fan, and there happens distortion in its shape which brings significant loss of efficiency. In this paper, a surface profile measuring system for large size axial fan of cooling towers is developed. A laser sensor is used as a measuring device and aluminum profiles and stepping motors are engaged into the system as frame structure and driving devices respectively. The measuring data are compared to the design data to compute the distortion of the axial fans. Two types of errors, axial and twist errors, are used to represent the precision of axial fan distortion. Genetic algorithm is used to solve the optimization problem during computing the precision. Results are displayed three dimensionally in a solid-modeler as well as 2-D drawings to help users find it with ease.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.11 no.3
• /
• pp.192-197
• /
• 2003

The ‘AEIPR’(Accelerometer Established Inertial Profiling Reference) method has been applied to measure the road profile. The dynamic road profiling method using AEIPR has the advantages of cost effectiveness, measuring speed and relatively high reliability. However, it is required to improve the double integration algorithm to get the measurement results with the accuracy of hither level. In the first part of this paper, the effective double integration algorithm is suggested and the ‘Road Profiler’ software is developed on the basis of the algorithm. Road profiling tests are performed using the developed ‘Road Profiler’ system on the specially designed tracks for the durability tests and the various types of pubic roads. Test results are shown and evaluated by the international road evaluation indicies and classification.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.11a
• /
• pp.19-22
• /
• 2000

Noncontact measuring methodology of 3-dimensional profile using CCD camera are very attractive because of it's high measuring speed and its's high sensitivity. Especially, when projecting a grid pattern over the object the captured image have 3 dimensional information of the object. Projection moire extract 3-D information with another grid pattern in front of CCD camera. However phase measuring profilometry(PMP) obtain similar results without additional grid pattern. In this paper, new method for grid pattern generation system by polygonal mirror and Laser Diode. This system is applied the projection moire and the PMP.

• Current Optics and Photonics
• /
• v.7 no.1
• /
• pp.73-82
• /
• 2023

In this study, we demonstrate ultrahigh-resolution spectral-domain optical coherence tomography with a 200-kHz line rate using a superluminescent diode with a -3-dB bandwidth of 100 nm at 849 nm. To increase the line rate, a subset of the total number of camera pixels is used. In addition, a partial-spectrum detection method is used to obtain OCT images within an imaging depth of 2.1 mm while maintaining ultrahigh axial resolution. The partially detected spectrum has a flat-topped intensity profile, and side lobes occur after fast Fourier transformation. Consequently, we propose and apply the super-Gaussian window function as a new window function, to reduce the side lobes and obtain a result that is close to that of the axial-resolution condition with no window function applied. Upon application of the super-Gaussian window function, the result is close to the ultrahigh axial resolution of 4.2 ㎛ in air, corresponding to 3.1 ㎛ in tissue (n = 1.35).

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.35 no.2
• /
• pp.164-170
• /
• 2006

The purpose of this study was to compare the nutrient intakes, blood pressure, and biochemical values and lipid profile in blood according to smoking status. Subjects were recruited from Korean adult men, which included non-smoker (n=47), smoker (n=58), and ex- smoker (n=44) . Anthropometrical measurement, blood pressure measurement, dietary intake assessment using 24-hour recall method, and blood collection and analysis were conducted. The average age, height, weight, and BMI of the subject were 54.7 years, 165.8 cm, 67.3 kg, and $24.5\;kg/m^2 $, respectively. There was no significant difference in general characteristics among three groups. The mean daily intakes of energy and protein were 1740.9 kcal and 69.6 g. The daily folate intake of the smoker was significantly lower than that of the non- smoker or ex-smoker. However, cholesterol intake of the smoker was significantly higher than two groups. The daily total food intake was 1250.0 g for non-smoker, 1180.1 g for smoker, and 1237.5 g for ex-smoker. The mushrooms intake in the smoker was significantly lower than that in the ex - smoker. However, eggs intake of the smoker was significantly higher than two groups. The RBC count and serum GOT/GPT of the subjects were $4598.2\times1000/mm^3$ and 27.3/27.3 U/L. The WBC count, hematocrit and hemoglobin of the smoker were significantly higher than those of the non-smoker and ex-smoker. Blood pressure and serum lipids of the subjects were 128.3/75.5 mmHg for SBP/DBP, 180.2 mg/dL for total cholesterol, 160.8 mg/dL for triglyceride, 41.5 mg/dL for HDL-cholesterol, 106.5 mg/dL for LDL-cholesterol, and 3.5 for atherogenic index. Especially serum triglyceride of smoker was significantly higher than that of non-smoker. The above results revealed that some nutrient intakes, such as folate and cholesterol, and hematological findings, and serum triglyceride of the smoker were different from non-smoker. However, these differences were recovered to non-smoking status by prohibition of smoking. Therefore, in order to stop smoking, the effect of smoking on nutritional and health status should be informed to smoker and more systematic study should be conducted.

• Journal of the Korean Society for Precision Engineering
• /
• v.31 no.3
• /
• pp.199-205
• /
• 2014

We propose a new variant of lateral shearing interferometer with a tunable laser source that enables 3D surface profile measurements of freeform optics with high speed, high vertical resolution, large departure, and large field-of-view. We have verified the proposed technique by comparing our measurement result with that of an existing technique and measuring a representative sample of freeform optics. Moreover, we propose a new algorithm that is able to compensate the rotational inaccuracy.