• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.4
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• pp.181-190
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• 2014

The underwater acoustic lens system is one of the systems getting high-resolution images on the seafloor by the beam forming method using acoustic lens. The beam forming using acoustic lenses reduces complexity and driving power. When receiving an incoming beam with the acoustic lens array, beam pattern analysis and arrangement problem of the array sensor must be addressed. Introducing SIR (Signal to Interference Ratio), the relationship among sensor interval, beam pattern and image quality would be analyzed. Generally if the sensor interval getting wider, the less effect of the side lobes makes SIR high. If the amplitude of a side lobe is high, SIR is generally getting low. The type of the apodization function changes the width, shape and amplitude of both main lobe and side lobes. Thus an appropriate apodization function can improve SIR. In this paper, SIR is stable at the sensor interval of 13mm with 0-10dB, which is not high relatively. By applying the Chebyshev function, the SIR becomes 80dB over the sensor interval of 37 mm or higher. The Hann and triangular functions demonstrate better SIR when the sensor interval becomes narrower.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.3
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• pp.226-235
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• 2023

This study aimed to supplement the shortcomings of the Multiple-sensor-based Frost Observation System (MFOS). The developed frost observation system is an improvement of the existing system. Based on the leaf wetness sensor (LWS), it not only detects frost but also functions to predict surface temperature, which is a major factor in frost occurrence. With the existing observation system, 1) it is difficult to observe ice (frost) formation on the surface when capturing an image of the LWS with an RGB camera because the surface of the sensor reflects most visible light, 2) images captured using the RGB camera before and after sunrise are dark, and 3) the thermal infrared camera only shows the relative high and low temperature. To identify the ice (frost) generated on the surface of the LWS, a LWS that was painted black and three sheets of glass at the same height to be used as an auxiliary tool to check the occurrence of ice (frost) were installed. For RGB camera shooting before and after sunrise, synchronous LED lighting was installed so the power turns on/off according to the camera shooting time. The existing thermal infrared camera, which could only assess the relative temperature (high or low), was improved to extract the temperature value per pixel, and a comparison with the surface temperature sensor installed by the National Institute of Meteorological Sciences (NIMS) was performed to verify its accuracy. As a result of installing and operating the MFOS v2, which reflects these improvements, the accuracy and efficiency of automatic frost observation were demonstrated to be improved, and the usefulness of the data as input data for the frost prediction model was enhanced.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.6
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• pp.1493-1498
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• 2015

The autofocus system is automatically to drive the focus. It is very important to computer vision system. In the case of a compact camera, the actuator technology is used for auto-focus in mass production. the position sensor is required, the circuit configuration and easy method is widely used in VCM, compared to the stability of the drive size and the noise is a big stepping motor type, size has a piezo system having a humidity problem and the small leaded vulnerability. In addition, there is a liquid lens system, the advantages of low power in a compact structure but also a structure with proven quality and reliability and features required pressure. In this paper, we implement two control systems that can control the actuator as a liquid range of VCM using a sharpness of the image acquired by the image sensor automatically initiates 5Mpixel class was the implementation verification of focusing.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.6
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• pp.48-56
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• 1989

Contact-type linear image sensors for facsimile have been fabricated by means of rf glow discharge decomposition method of silane. The dependence of their electrical and optical properties on rf power, $SiH_4$ flow rate, ambient gas pressure, $H_2SiH_4$ ratio and substrate temperature are described. The a-Si:H monolayer demonstriated photosensitivity of 0.85 and $I_{ph}/I_d$ ratio of 100 unger 100 lux illumination. However, this monolayer has relatively high dark current due to carrier injection from both electrodes, resulting in low $I_{ph}/I_{dd}$ ratio. To suppress the dark current we have fabricated $SiO_2/i-a-Si:H/p-a-Si:H:B$ multilayer film with blocking structure. The photocurrent of this multilayer sensor with 6 V bias became saturated ar about 20nA under 10 lux illumination, while the dark current was less than 0.2 nA. Moreover, the spectral sensitivity of the multilayer film was enhanced for short wavelength visible region, compared with that of the a-Si:H monolayer. These results show that the fabricated photocon-ductive film can be used as the linear image sensor of the facsimile.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.2
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• pp.99-103
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• 2003

This paper presents lens optimization of the resolution and the distortion for a four-element lens design. In order to have compact optical system, we used the tele-photo type lens composed of a positive and a negative power elements instead of retro-focus lens. The specifications of optical lens design are the focal length of 7.2 mm, the F/number of 2.8 and the field angle of $54.7^{\circ}C$. The MTF values are higher than 0.5 in the spatial frequency range up to 110 lp/mm for all of the designed object heights. Also, it is expected to fulfill all the requirements of a digital still camera lens and especially suited for building low-cost, compact digital cameras because of the low-profile property of the lens design.

• Journal of Platform Technology
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• v.12 no.2
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• pp.34-44
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• 2024

This paper proposes a dynamic clock supply control algorithm and a system load power stabilization algorithm that minimizes the power consumption of the sensing system, which accounts for the largest percentage of power consumption in mobile devices, to extend the usage time of the rechargeable battery mounted on the mobile device. The dynamic clock supply control algorithm can reduce the power consumed by the sensing system by configuring a circuit to cut off the power of the sensing system and by recognizing the state of low sensor change and adjusting the measurement cycle. The system load power stabilization algorithm is an algorithm that controls the power of the surrounding module according to the power consumption state, and when it requires a lot of power, it controls the clock supply to stabilize the operation. The experimental results confirmed that applying only the dynamic clock supply control algorithm reduces the power consumed by the sensing system by 17%, and applying only the system load power stabilization algorithm reduces power consumption by 9.3%, enabling it to operate stably in situations that require a lot of power such as image processing. When both algorithms were applied, the power consumption of the battery was reduced by 67% compared to before applying the algorithm. Through this, the reliability of the proposed method was confirmed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.4
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• pp.753-758
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• 2009

Recently the high-end CMOS image sensors are developed, conforming to the SMIA CCP2 specification, which is a high-speed low-power serial interface based on LVDS technology. But this kind of technology trend makes the existing equipments are no longer useful, although their capability is still good enough to handle the recent image sensors if there was no interfacing problem. In this paper, we propose and realize a data protocol conversion system that translates the SMIA CCP2 serial signals into the existing 10-bit parallel signals. The proposed system is composed of a de-serializer and a FPCA chip, and thus can be constructed on a small PCB which enables easy integration between the existing equipments and the new high-end image sensors. Besides, the maximum transfer rate by the SMIA specification is also achieved on the implemented system. So it is expected that the implemented system can be used as a general-purpose protocol converter in a variety of sensor-related application fields.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.7
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• pp.3207-3213
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• 2011

Most methods of color constancy, which is the ability to determine the object color regardless of the scene illuminant, have failed to meet our expectation of their performance especially about low-illuminated scenes. Some methods with high performance need to be developed, but we must, above all else, obtain experimental images for analyzing the required circumstances or evaluating the methods. Therefore, the paper produces new sets of images so that they can be used in the development of color constancy methods suitable for low-illuminated scenes. These sets are composed of two parts: one part of images which are synthesized with spectral power distribution(SPD) of illuminants, spectral reflectance curve of reflectances, and sensor response functions of camera; the other part of images where the intensity of each image is adjusted at the uniform rate. In an experiment, the use of the sets takes an advantage that its result images are analyzed and evaluated quantitatively as their ground truth data are known in advance.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.11 s.353
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• pp.48-57
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• 2006

This work describes a 12b 200KHz 0.52mA $0.47mm^2$ algorithmic ADC for sensor applications such as motor controls, 3-phase power controls, and CMOS image sensors simultaneously requiring ultra-low power and small size. The proposed ADC is based on the conventional algorithmic architecture with recycling techniques to optimize sampling rate, resolution, chip area, and power consumption. The input SHA with eight input channels for high integration employs a folded-cascode architecture to achieve a required DC gain and a sufficient phase margin. A signal insensitive 3-D fully symmetrical layout with critical signal lines shielded reduces the capacitor and device mismatch of the MDAC. The improved switched bias power-reduction techniques reduce the power consumption of analog amplifiers. Current and voltage references are integrated on the chip with optional off-chip voltage references for low glitch noise. The employed down-sampling clock signal selects the sampling rate of 200KS/s or 10KS/s with a reduced power depending on applications. The prototype ADC in a 0.18um n-well 1P6M CMOS technology demonstrates the measured DNL and INL within 0.76LSB and 2.47LSB. The ADC shows a maximum SNDR and SFDR of 55dB and 70dB at all sampling frequencies up to 200KS/s, respectively. The active die area is $0.47mm^2$ and the chip consumes 0.94mW at 200KS/s and 0.63mW at 10KS/s at a 1.8V supply.

• Journal of Drive and Control
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• v.17 no.3
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• pp.1-8
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• 2020

Recently, a special purpose machine with two manipulators and quadruped crawler system has been developed for rapid life-saving and initial restoration work at disaster sites. This special purpose machine provides the driver with various environmental recognition functions for accurate and rapid task determination. In particular, the human detection technology assists the driver in poor working conditions such as low-light, dust, water vapor, fog, rain, etc. to prevent secondary human accidents when moving and working. In this study, a human detection module is developed to be mounted on a special purpose machine. A thermal sensor and CCD camera were used to detect victims and nearby workers in response to the difficult environmental conditions present at disaster sites. The performance of various AI-based life detection algorithm were verified and then applied to the task of detecting various objects with different postures and exposure conditions. In addition, image visibility improvement technology was applied to further improve the accuracy of human detection.