• Transactions on Electrical and Electronic Materials
• /
• v.13 no.6
• /
• pp.310-316
• /
• 2012

A new method for early caries diagnosis was proposed and tested through a home-made optical examination system that used quantitative light fluorescence (QLF) and digital imaging fiber optic transillumination (FOTI) (DIFOTI), with light sources across a wide spectral range, from 350 nm to 1,000 nm. The front-illuminated infrared light scattering image (FIR) showed similar diagnostic abilities to that of DIFOTI. The FIR method was invented based on the observation that caries lesions lose the high transmittance and low scattering properties of benign enamel tissue. There are various methods for the early diagnosis of caries, such as visual examination, exploration, X-ray radiography, QLF, FOTI, and infrared fluorescence (diagnodent). Among them, methods based on optical properties are regarded as having the most potential. A comparative study was performed between the FOTI, QLF, diagnodent, optical coherence tomography, and FIR scattering image methods, using 20 extracted teeth samples with early caries. A scale of lesion measurement based on optical image contrast was proposed. The statistical analysis showed a significant correlation between the DIFOTI and FIR methods (r = 0.35, p < 0.05). However, the QLF and diagnodent methods showed little association with FIR images, as they have different detection principles as compared with FIR. Tomographic images obtained by OCT, using 1,330 nm super luminescent LED as a gold standard of tooth structure, verified that the FOTI and FIR results correctly represented the lack of homogeneity in dental tissue. The newly proposed FIR method attained similar diagnostic results to those of FOTI, but with an easier approach.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.1C
• /
• pp.8-16
• /
• 2010

This paper presents a new small target detection method using the cross product of the temporal pixels based on the temporal profile in infrared (IR) image sequences. The temporal characteristics of small targets and the various backgrounds are different. A new algorithm classifies target pixels and the background pixels through the hypothesis testing using the cross product of pixels on the temporal profile and predicts the temporal backgrounds based on the results. The small targets are detected by subtracting the predicted temporal background profile from the original temporal profile. For the performance comparison between the proposed algorithm and the conventional algorithms, the receiver operating characteristics (ROC) curves is computed in experiment. Experimental results show that the proposed algorithm has better discrimination and a lower false alarm rate than the conventional methods.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.49 no.1
• /
• pp.63-73
• /
• 2021

This paper presents a algorithm for automatic target recognition robust to the influence of the flame in order to track the target by EOTS(Electro-Optical Targeting System) equipped on UAV(Unmanned Aerial Vehicle) when there is aerial target or marine target with flame at the same time. The proposed method converts infrared images of targets and flames into a gradient vector field, and applies each gradient magnitude to a polynomial curve fitting technique to extract polynomial coefficients, and learns them in a shallow neural network model to automatically recognize targets and flames. The performance of the proposed technique was confirmed by utilizing the various infrared image database of the target and flame. Using this algorithm, it can be applied to areas where collision avoidance, forest fire detection, automatic detection and recognition of targets in the air and sea during automatic flight of unmanned aircraft.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.15 no.12
• /
• pp.4292-4307
• /
• 2021

For the research field of night infrared surveillance video, the target imaging in the video is easily affected by the light due to the characteristics of the active infrared camera and the classical ViBe algorithm has some problems for moving target extraction because of background misjudgment, noise interference, ghost shadow and so on. Therefore, an improved ViBe algorithm (I-ViBe) for moving target extraction in night infrared surveillance video is proposed in this paper. Firstly, the video frames are sampled and judged by the degree of light influence, and the video frame is divided into three situations: no light change, small light change, and severe light change. Secondly, the ViBe algorithm is extracted the moving target when there is no light change. The segmentation factor of the ViBe algorithm is adaptively changed to reduce the impact of the light on the ViBe algorithm when the light change is small. The moving target is extracted using the region growing algorithm improved by the image entropy in the differential image of the current frame and the background model when the illumination changes drastically. Based on the results of the simulation, the I-ViBe algorithm proposed has better robustness to the influence of illumination. When extracting moving targets at night the I-ViBe algorithm can make target extraction more accurate and provide more effective data for further night behavior recognition and target tracking.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.32 no.3
• /
• pp.284-290
• /
• 2012

Infrared thermography uses infrared energy radiated from any objects above absolute zero temperature, and the range of its application has been constantly broadened. As one of the active test techniques detecting radiant energy generated when energy is applied to an object, ultrasound infrared thermography is a method of detecting defects through hot spots occurring at a defect area when 15~100 kHz of ultrasound is excited to an object. This technique is effective in detecting a wide range affected by ultrasound and vibration in real time. Especially, it is really effective when a defect area is minute. Therefore, this study conducted thermography through lock-in signal processing when an actual defect exists inside the austenite STS304 seamless pipe, which simulates thermal fatigue cracks in a nuclear power plant pipe. With ultrasound excited, this study could detect defects on the rear of a pipe by using an aluminium reflector. Besides, by regulating the angle of the aluminium reflector, this study could detect both front and rear defects as a single infrared thermography image.

• Journal of Institute of Control, Robotics and Systems
• /
• v.13 no.2
• /
• pp.128-132
• /
• 2007

Thermal Imaging systems are reported to be crucial for fire fighting and beginning to be used by fire fighters. The performance of thermal imaging system is determined by both the radiation of infrared from the target and the attenuation of infrared signal in the optical path by the absorption, scattering, diffraction and reflection. In the scene of fire, water drops with various sizes such as vaporized water, wafer mist from sprinkler, and wafer to suppress the fire reside with various gas generated by burning. To measure the transmission of infrared radiation in the scene of fire, fire simulating system and thermal imagers with cooled detector which detects $3{\sim}5{\mu}m$ infrared and uncooled detector fabricated by the MEMS technology which detects $8{\sim}12{\mu}m$ infrared. are made. With thermal imagers and Ire simulating system, the change of thermal image with respect to the change of visibility controlled with the burned fas was measured. It was found that the transmission of infrared was not reduced by the burned gas, which could be explained by the long wavelength of infrared ray compared with visible ray. However, the transmission of infrared ray was largely reduced by the combination of burned gas and water mist supplied by sprinkler. This is contrary to the results of calculated transmission through the pure water mist and shows that the transmission of infrared ray is mostly affected by the compounds of water mist and burned gas. In this case, it was found that the uncooled detector which detects $8{\sim}12{\mu}m$ infrared ray is better than cooled detector which detects $3{\sim}5{\mu}m$ infrared ray for fire fighting.

• International Journal of Internet, Broadcasting and Communication
• /
• v.7 no.1
• /
• pp.15-19
• /
• 2015

The depth information of an image is used in a variety of applications including 2D/3D conversion, multi-view extraction, modeling, depth keying, etc. There are various methods to acquire depth information, such as the method to use a stereo camera, the method to use the depth camera of flight time (TOF) method, the method to use 3D modeling software, the method to use 3D scanner and the method to use a structured light just like Microsoft's Kinect. In particular, the depth camera of TOF method measures the distance using infrared light, whereas TOF sensor depends on the sensitivity of optical light of an image sensor (CCD/CMOS). Thus, it is mandatory for the existing image sensors to get an infrared light image by bundling several pixels; these requirements generate a phenomenon to reduce the resolution of an image. This thesis proposed a measure to acquire a high-resolution image through gradual area movement while acquiring a low-resolution image through pixel bundling method. From this measure, one can obtain an effect of acquiring image information in which illumination intensity (lux) and resolution were improved without increasing the performance of an image sensor since the image resolution is not improved as resolving a low-illumination intensity (lux) in accordance with the gradual pixel bundling algorithm.

• The Journal of the Korea Contents Association
• /
• v.11 no.5
• /
• pp.205-215
• /
• 2011

Films are sensitive to ultraviolet rays and in contrast, digital camera sensors are extremely sensitive to infrared rays due to the differences in spectral characteristics. As a result, all digital cameras that use CCD or CMOS are equipped with IR Cut-Off Filter on the overall sensor. Complete block out of infrared rays is ideal, but the actual experiment results showed that infrared rays were not being blocked out completely. Infrared permeability was also different for each camera. Therefore, this study aims to analyze the effect of the minute quantities of infrared rays, which get transmitted due to mechanical properties of IR Cut-Off Filters that are installed on digital cameras, on digital picture images. The results obtained by carrying out a comparative analysis of a UV Filter (infrared transmitting state) and a UV-IR Filter (infrared blocked out state) are as follows. It was confirmed that the minute quantities of infrared rays do affect dynamic range and resolution to some extent, despite the little or no difference in noise and color reproduction.

• Journal of information and communication convergence engineering
• /
• v.9 no.6
• /
• pp.725-728
• /
• 2011

Infrared transmission images from GaAs semi insulating wafers were considered for years as directly related to the quantum absorption by electrons on fundamental states of deep centers, especially EL2. The satisfying correspondence of these images with the dislocations revealed by etching or X ray topography or infrared tomography led to the opinion that a strong concentration of EL2 centers was to be expected in the immediate vicinity of the dislocations. More recent work indicates that contrary to the expected behavior the photoqu$\acute{e}$nching of transmission images at T=80K does not appreciably change the image structure itself but more largely the uniform background level of absorption. Such investigations show that the transmission images of isolated dislocations (Indium doped materials) or cell structures of tangled dislocations (undoped materials) can be partly attributed to scattered light; similar operation at T=10K removes the dark features associated to EL2 but still preserves the skeleton of the pattern which is due to scattering. A result of the measurements is that dislocations must not be considered any longer as inexhaustive EL2 reservoirs. The lifetime of the photoqu$\acute{e}$nching mechanism is shown to vary differently for EL2 centers located close to the dislocations or in the matrix. In this paper we will develop the details of infrared image photoqu$\acute{e}$nching experiments in the vicinity of dislocations; undoped and In doped GaAs materials will be shown. These results will be discussed in the light of surface etching experiments.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.34 no.3
• /
• pp.248-253
• /
• 2014

Camera calibration is an indispensable process for improving measurement accuracy in industry fields such as machine vision. However, existing calibration cannot be applied to the calibration of mid-wave and long-wave infrared cameras. Recently, with the growing use of infrared thermal cameras that can measure defects from thermal properties, development of an applicable calibration target has become necessary. Thus, based on heat conduction analysis using finite element analysis, we developed a calibration target that can be used with both existing visible cameras and infrared thermal cameras, by implementing optimal design conditions, with consideration of factors such as thermal conductivity and emissivity, colors and materials. We performed comparative experiments on calibration target images from infrared thermal cameras and visible cameras. The results demonstrated the effectiveness of the proposed calibration target.