• Journal of Biosystems Engineering
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• v.20 no.4
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• pp.368-375
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• 1995

A computer vision system was built to generate images of a stationary egg. This system includes a. CCD camera, a frame grabber, and an incandescent back lighting system An image processing algorithm was developed to accurately detect surface holes and surface cracks on eggs. With 20W of incandescent back light, the detection rate was shown to be the highest. The Sobel operator was found to be the best among various enhancing filters examined. The threshold value to distinguish between the crack and the translucent spots was found to be linear with the average gray level of a whole egg image. Those values of both gray level and area were used as criteria to detect holes in egg and those values of both area and roundness were used to detect cracks in egg. For a sample of 300 eggs, this system was able to correctly analyze an egg for the presence of a defect 97.5% of the time. On the average, it took 59.5 seconds to analyze an egg image and determine whether or not it was defected.

• Journal of the Korea Computer Industry Society
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• v.4 no.12
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• pp.923-928
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• 2003

A severe drawback to the calculation of watershed images is over segmentation. Relevant object contours are lost in a sea of irrelevant ones. This is partly caused by random noise, inherent to a data, which gives rise to additional local minima, such that many catchments basins are further subdivided. Proposed watershed image segmentation algorithm is iteratively merging neighboring regions that have similar gray level distributions, to restore image.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11a
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• pp.511-514
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• 2003

본 연구는 입력된 영상으로부터 특정한 형태를 이루고 있는 대상 물체를 추출함에 있어, 처리에 소요되는 시간 비용(Time cost)을 줄이는 것을 목적으로 하고 있다. 이를 위하여 특정 관심 지역(Region of Interest)이나 대상 물체(Tareet object)의 경계 검출(Boundary detection)을 하는 과정에 통계학적 수치자료(SSM : Statistical Shape Model)를 사용한 접근법을 이용하였다. 또한, 향후 연구 방향인 의료 영상해석(Medical image analysis)으로의 확장성을 고려, 의료 영상 해석에 많이 사용되어지는 MRI, CT, X-Ray 이미지가 Gray level 영상이라는 것을 감안하여 Gray level 영상을 연구 대상으로 삼았다.

• Journal of the Optical Society of Korea
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• v.15 no.3
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• pp.244-251
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• 2011

We propose a new 2-step phase-shifting digital holographic optical encryption technique and analyze tolerance error for this cipher system. 2-step phase-shifting digital holograms are acquired by moving the PZT mirror with phase step of 0 or ${\pi}$/2 in the reference beam path of the Mach-Zehnder type interferometer. Digital hologram with the encrypted information is Fourier transform hologram and is recorded on CCD camera with 256 gray-level quantized intensities. The decryption performance of binary bit data and image data is analyzed by considering error factors. One of the most important errors is quantization error in detecting the digital hologram intensity on CCD. The more the number of quantization error pixels and the variation of gray-level increase, the more the number of error bits increases for decryption. Computer experiments show the results to be carried out encryption and decryption with the proposed method and the graph to analyze the tolerance of the quantization error in the system.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1998.10a
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• pp.211-221
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• 1998

A digital image processing technique which is able to get the velocity vector distribution of a surface of the spilled oil in the ocean without contacting the flow itself. This technique is based upon the PIV(Particle Imaging Velocimetry) technique and its system mainly consists of a high sensitive camera, a CCD camera, an image grabber, and a host computer in which an image processing algorithm is adopted for velocity vector acquisition. For the acquisition of the advective velocity vector of floating matters on the ocean, a new multi-frame tracking algorithm is proposed, and for the acquisition of the diffusion velocity vector distribution of the spilt oil onto the water surface, a high sensitive gray-level cross-correlation algorithm is proposed.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1487-1490
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• 2006

One of the factors deteriorating PDP image quality is the nonlinearity and nonuniform of output luminance as a function of input gray level. A novel method using modified ADS driving scheme is proposed to decrease this nonlinearity. It optimizes the reset pulse and adjusts the subfields, makes the relation of output luminance and input gray level almost linear. This method can be applied to general commercial PDPs.

• Transactions of the Korean Society of Mechanical Engineers
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• v.8 no.6
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• pp.576-583
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• 1984

This paper presents an algorithm for recognition of simple curved two dimensional objects. The algorithm is divided into four steps, determining threshold, edge finding, feature extracting and model matching. To evaluate the performance of this algorithm some experiments were conducted for various objects and illuminations. The results shows that the proposed algorithm can be effectively used for part recognition and quality inspection.

• IEIE Transactions on Smart Processing and Computing
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• v.3 no.6
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• pp.358-365
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• 2014

This paper proposes a method that reduces the flickering effect caused by A-GLG (Adaptive Gray-Level Grouping) during video contrast enhancement. Of the GLG series, A-GLG shows the best contrast enhancement performance. The GLG series is based on histogram grouping. Histogram grouping is calculated differently between the continuous frames with a similar histogram and causes a subtle change in the transformation function. This is the reason for flickering effect when the video contrast is enhanced by A-GLG. To reduce the flickering effect caused by A-GLG, the proposed method calculates a modified transformation function. The modified transformation function is calculated using a previous and current transformation function applied with a weight separately. The proposed method was compared with A-GLG for flickering effect reduction and video contrast enhancement. Through the experimental results, the proposed method showed not only a reduced flickering effect, but also video contrast enhancement.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.447-452
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• 2000

The grinding plays a key role which decide the quality of a product finally. But the grinding process is very irregular, so it is very difficult to analyse the process accurately. Therefore it is very important in the aspect of precision and automation to reduce the idle time and to decide the proper dressing time by visualizing. In this study, we choose the direct method of observation by making use of computer vision, and apply pattern classification technique to the method of measuring the wheel surface. Pattern classification technique is proper to analyse complex surface image. We observe the change of the wheel surface by making use of the gray level run lengths which are representative prince in this technique.

• Journal of Korea Multimedia Society
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• v.6 no.6
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• pp.968-976
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• 2003

In this paper, we propose a novel method for lip recognition. Lip model is built based on the concatenated gray level distribution model, and the recognition problem is simplified as the minimization problem of matching object function. The Down Hill Simplex Algorithm is used for the minimization with the proposed novel method for setting initial condition, which can refrain Iteration from converging to local minima. The proposed algorithm shows extracting lip shape from the test image where Active Shape Model fails.