• Proceedings of the Optical Society of Korea Conference
• /
• 2004.02a
• /
• pp.196-197
• /
• 2004

• Proceedings of the Optical Society of Korea Conference
• /
• 2003.07a
• /
• pp.26-27
• /
• 2003

A wide variety of devices and systems exist whose main function is to generate an image. These devices and systems are used for many different purposes and find applications in many different walks of life. We are all very familiar with some of these systems such as the photographic camera (that can produce a permanent record of a scene on sensitized sheet material) and the television set (that can receive a suitably coded electromagnetic signal broadcast through space and convert it into an image). (omitted)

• Proceedings of the Korean Society for Emotion and Sensibility Conference
• /
• 2000.04a
• /
• pp.407-411
• /
• 2000

Color reproduction n CRT monitors needs colorimetric characterization concluding two stages with 3x3 matrix and three TRCs (Tone-Reproduction Characteristics). The 3x3 matrix is based on the additivity of RGB emissions, and the TRC represents the non-linearity between the input digital counts and the output luminance. The objective of this project is to evaluate the accuracy of color reproduction on LCD monitors using conventional CRT model(GOG model). For two different manufacturers, colorimetric characterizations of desktop LCDs have been performed. Because the transfer function for LCD is very differ from TRC of CRT, some researchers had reported that GOG model is inadequate for the colorimetric characterization of LCDs. However in our experiment, the degree of accuracy was dependent on the shape of electro-optical transfer functions of LCD. It has been founded that the GOG model could be applied for LCD monitors having monotonically increased Electro-optical transfer function.

• Korean Journal of Optics and Photonics
• /
• v.31 no.3
• /
• pp.134-141
• /
• 2020

Optical three-dimensional (3D) measurement systems based on digital fringe projection are used in many contactless measurement applications. The system which can measure a dozen micrometers uses a liquid-crystal display (LCD) as the projection unit for generating a digital fringe pattern, because a flexible fringe pattern can be easily made by computer software. According to the gamma nonlinearity of the LCD projection unit, the digital fringe projection error on the object affects the accuracy of 3D object measurement. An improved method of LCD gamma-nonlinearity error reduction is proposed, by using the inverse function of the intensity transfer function to improve the accuracy. The improvement due to the proposed method is shown by measuring the difference in precision between a computer-generated sine wave and a camera-obtained sine wave for a standard semiconductor specimen.

• Korean Journal of Optics and Photonics
• /
• v.18 no.1
• /
• pp.31-36
• /
• 2007

In order to evaluate the performance of phone camera lenses, we have developed equipment for measuring the modulation transfer function(MTF) for small size lenses. The equipment is composed of an an image analyzer, object generator, and a lens mount. The object generator is rotated for on and off-axis measurement. The lens mount is of horizontal type and tiltable for precise alignment to the optical axis. After the initial alignment process, the measurement is done within 10 seconds automatically

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.1 s.94
• /
• pp.191-199
• /
• 1999

In designing the tracking system of an optical disc drive, it is first necessary to eliminate the undesired influence of any visible mechanical vibrations. In this paper a geometrical method to analyze the frequency response of an elastically supported planar rigid body has been presented. Using the theory of screw, a geometrical expression of a compliant transfer function which describes the effects of the locations of an applied force and observation on the response has been derived. Applying the substructure synthesis method, a technique to stabilize the tracking mechanical system has been presented with a numerical example.

• ETRI Journal
• /
• v.9 no.2
• /
• pp.24-35
• /
• 1987

A Design and Fabrication of 565 Mbit/s Optical Fiber Transmission Link We calculated the transfer functions of optical channel components and formulated the optimum transfer function of optical receiver for optical transmission to show a design rule of fiber optical link for digital transmission. And we evaluated various causes of sensitivity degradation to determine the receiver specification. Also we fabricated and demonstrated a 565Mbit/s single mode fiber optic link, 27km, to show the practicality of designed fiber optic link. The output power of the transmitter was above -3dBm, and the sensitivity of the optical receiver was -37.8dBm which is the same value we expected. Also the dynamic range was more than 25dB.

• Korean Journal of Optics and Photonics
• /
• v.16 no.1
• /
• pp.63-70
• /
• 2005

We propose a method for evaluating the image quality of color liquid crystal display(LCD) monitors by using the polychromatic modulation transfer function(PMTF), which is calculated from the modulation transfer function(MTF) weighted by the overall color response of the system including the test LCD monitor. We confirm that experimental results using the PMTF agree well with simulated results of the PMTF of a color LCD monitor by using three bar targets with different amplitudes and three elementary colors such as red(R), green(G), and blue(B). As a results, we should choose the PMTF instead of the white color MTF or monochromatic MTF in order to evaluate correctly the image quality of color LCD monitors.

• Journal of the Optical Society of Korea
• /
• v.18 no.5
• /
• pp.472-476
• /
• 2014

The Joint Transform Correlator (JTC) has been the most suitable technique for real time optical pattern recognition and target tracking applications. This paper proposes a new application of the JTC system for an analysis of the blurring effect of the optical images caused by a defocused lens. We present the relation between the correlation peak, optical transfer function (OTF), and the amount of blurring caused by focusing error. Moreover, we show a possibility of calibrating the blurred image by simply measuring the correlation peak.

• Smart Structures and Systems
• /
• v.4 no.4
• /
• pp.439-448
• /
• 2008

Optical fiber sensors are by now broadly accepted as an innovative and reliable device for structural health monitoring, to be used either embedded into or bonded on structures. The accuracy of the strain measurement achievable by optical fiber sensors is critically dependent on the characteristics of the bonding of the various interface layers involved in the sensor bonding/embedding (structure material and gluing agent, fiber coating and gluing agent, fiber coating and fiber core). In fact, the signal of the bonded/embedded optical fiber sensor must correspond to the strain experienced by the monitored structure, but the quality of each involved interface can affect the strain transfer. This paper faces the characterization, carried on by both mechanical tests and morphological analysis, of the strain transfer function resulting with epoxidic and vinylester gluing agent on polyimide and acrylate coated optical fibers.