• JSTS:Journal of Semiconductor Technology and Science
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• 제16권3호
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• pp.375-379
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• 2016

A current subtraction technique with parallel operation system is proposed to remove excessive current in touch screen application. The proposed current subtraction remove the current which go into the input node of charge amplifier. The value of subtraction current is same with current when touch screen is not touched. As a result, charge amplifier output is only proportional to variation of mutual capacitor, which make dynamic rage is increased. Also, Transmitter (Tx) driving signal and subtraction driving signal are out of phase each other. Thus, noise generated in Tx is cancelled. The proposed IC is implemented in a mixed-mode 0.18-um CMOS process. Overall system is designed for touch screen panel (TSP) with 16 driving lines and 8 sensing lines. 5-V supply voltages are used in the proposed circuits. For multiple Tx driving signal, Walsh codes are used and signal frequency is 300 khz. By using proposed technique, dynamic rage is improved 36 dB.

• Journal of Educational Research in Mathematics
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• 제19권2호
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• pp.307-319
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• 2009

Current school mathematics introduces addition/subtraction between natural numbers, fractions, decimal fractions, and square roots, step-by-step in order. It seems that, however, school mathematics focuses too much on learning the calculation method of addition/subtraction between each stages of numbers, to lead most of students to understand the coherent principle, lying in addition/subtraction algorithm between real numbers in all. This paper raises questions on this problematic approach of current school mathematics, in learning addition/subtraction. This paper intends to clarify the fact that, if we recognize addition/subtraction between numbers from the viewpoint of 'measuring' and 'common measure', as Dewey did when he argued that the psychological origin of the concept of number was measuring, then we could find some common principles of addition/subtraction operation, beyond the superficial differences among algorithms of addition/subtraction between each stages of numbers. At the end, this paper suggests the necessity of improving the methods of learning addition/subtraction in current school mathematics.

• Korean Journal of Optics and Photonics
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• 제14권4호
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• pp.423-428
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• 2003

In a direct modulated semiconductor laser diode. the structural dependence of current blocking layers was studied in view of the leakage current reduction and the bandwidth expansion. To analyze the leakage current and the parasitic effects, the current-voltage derivation characteristics and the subtraction method were used, respectively. It was shown that the‘inin’type current blocking structure might be the best choice for the purpose of the static and dynamic characteristics.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권4호
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• pp.782-804
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• 2011

In video-based recognition systems, stationary cameras are used to monitor an area of interest. These systems focus on a segmentation of the foreground in the video stream and the recognition of the events occurring in that area. The usual approach to discriminating the foreground from the video sequence is background subtraction. This paper presents a novel background subtraction method based on a probabilistic approach. We represent the posterior probability of the foreground based on the current image and all past images and derive an updated method. Furthermore, we present an efficient fusion method for the color and edge information in order to overcome the difficulties of existing background subtraction methods that use only color information. The suggested method is applied to synthetic data and real video streams, and its robust performance is demonstrated through experimentation.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• 제27권2호
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• pp.83-90
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• 1997

This study was performed to demonstrate the effect of linear or nonlinear contrast enhancement on subtraction images. Three different textures were radiograped on dental film. The first radiograph was taken without the presence of an object. the second, which showed trabucular bone, was taken of the molar area of a human. the third radiograph was taken of the coronal part of molars. Each film was digitized into a 1312 x 1024 pixel x 8 bit depth matrix by means of a Nikon 35 mm film scanner(LS-3510AF, Japan) with fixed gain and internal dark current correction to maintain constant illumination. The scanner was interfaced to a Macintosh Le ill computer(Apple Computer, Charlotte, N.C) This resulted in three pairs of images, including different textures-plain, bone and enamel. Digital regular, linearly and nonlinearly enhanced subtraction was performed. Computer software was ,used to simulate lesions in the shape of a 2D-Gaussian curve on each of a pair of images. The each subtraction images were presented in a random sequence to two groups of 10 observers(students and dentists). ROC analysis was used to compare observer performance. The following results were obtained ; 1. All of LCE subtraction, equalized subtraction and regular subtraction images of plain texture were diagnosed the best by far. 2. The data revealed a siginificant LCE effect in both the student group and the expert group. 3. Clinical expertise was a helphul factor for the observers in this study.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2009년도 학술대회
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• pp.631-636
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• 2009

Foreground segmentation methods have steadily been researched in the field of computer vision. Especially, background subtraction which extracts a foreground image from the difference between the current frame and a reference image, called as "background image" have been widely used for a variety of real-time applications because of low computation and high-quality. However, if the background scene was dynamically changed, the background subtraction causes lots of errors. In this paper, we propose an efficient background subtraction method in dynamic environment with both static and dynamic scene. The proposed method is a hybrid method that uses the conventional background subtraction for static scene and depth information for dynamic scene. Its validity and efficiency are verified by demonstration in dynamic environment, where a video projector projects various images in the background.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권6호
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• pp.1946-1963
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• 2014

Most background subtraction methods focus on dynamic and complex scenes without considering robustness against noise. This paper proposes a background subtraction algorithm based on dictionary learning and sparse coding for handling low light conditions. The proposed method formulates background modeling as the linear and sparse combination of atoms in the dictionary. The background subtraction is considered as the difference between sparse representations of the current frame and the background model. Assuming that the projection of the noise over the dictionary is irregular and random guarantees the adaptability of the approach in large noisy scenes. Experimental results divided in simulated large noise and realistic low light conditions show the promising robustness of the proposed approach compared with other competing methods.

• Proceedings of the Korean Society of Medical Physics Conference
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• 한국의학물리학회 2002년도 Proceedings
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• pp.454-456
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• 2002

The evaluation of interval changes between temporally sequential chest radiographs is necessary for the detection of new abnormalities or interval changes, such as pulmonary nodules and interstitial disease. For interstitial lung disease, the interval changes are very important for diagnosis and treatment. Especially, interstitial lung disease may show rapid changes in the radiographs, show changes in the entire lung field in minute detail, or show changes in multiple parts depending on the type. It is therefore difficult to have an accurate grasp of the condition of the disease only with conventional radiographs. The temporal subtraction technique which was developed at the University of Chicago, provides a subtraction image of the current warped image and the previous image. A temporal subtraction image, shows only differences and changes between the two images, can be very useful for a diagnosis of interstitial lung disease. However, the evaluation of the temporal subtraction technique for interstitial lung disease using receiver operating characteristic(ROC) studies has not been reported yet. Therefore, we have evaluated the clinical usefulness of a temporal subtraction technique for detection of interval changes of interstitial lung disease by ROC analysis.

• Journal of Institute of Control, Robotics and Systems
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• 제21권8호
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• pp.766-772
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• 2015

This paper proposes an object detection method based on motion estimation using background subtraction in the fisheye images obtained through omni-directional camera mounted on the vehicle. Recently, most of the vehicles installed with rear camera as a standard option, as well as various camera systems for safety. However, differently from the conventional object detection using the image obtained from the camera, the embedded system installed in the vehicle is difficult to apply a complicated algorithm because of its inherent low processing performance. In general, the embedded system needs system-dependent algorithm because it has lower processing performance than the computer. In this paper, the location of object is estimated from the information of object's motion obtained by applying a background subtraction method which compares the previous frames with the current ones. The real-time detection performance of the proposed method for object detection is verified experimentally on embedded board by comparing the proposed algorithm with the object detection based on LKOF (Lucas-Kanade optical flow).

• Journal of the Korean Institute of Telematics and Electronics B
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• 제32B권5호
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• pp.730-736
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• 1995

This paper presents the design of a CMOS programmable slew rate operational amplifier based upon a newly proposed concept, that is a switched parallel current subtraction circuit with adaptive biasing technique. By utilizing the newly designed circuit, it was proven that slew rate was linearly controlled and power dissipation was optimized. If the programmable slew rate amplifier is employed into mixed signal system, it can furnish the convenience of timing control and optimized power dissipation. Simulated data showed the slew rate ranging from 5. 83V/$\mu$s to 41.4V/$\mu$s, power dissipation ranging from 1.13mW to 4.1mW, and the other circuit performance parameters were proven to be comparable with those of a conventional operational amplifier.