• Korean Journal of Radiology
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• v.22 no.7
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• pp.1163-1171
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• 2021

Objective: To analyze the correlations between intraoperative ultrasound and MRI metrics of the spinal cord in degenerative cervical myelopathy and identify novel potential predictive ultrasonic indicators of neurological recovery for degenerative cervical myelopathy. Materials and Methods: Twenty-two patients who underwent French-door laminoplasty for multilevel degenerative cervical myelopathy were followed up for 12 months. The Japanese Orthopedic Association (JOA) scores were assessed preoperatively and 12 months postoperatively. Maximum spinal cord compression and compression rates were measured and calculated using both intraoperative ultrasound imaging and preoperative T2-weight (T2W) MRI. Signal change rates of the spinal cord on preoperative T2W MRI and gray value ratios of dorsal and ventral spinal cord hyperechogenicity on intraoperative ultrasound imaging were measured and calculated. Correlations between intraoperative ultrasound metrics, MRI metrics, and the recovery rate JOA scores were analyzed using Spearman correlation analysis. Results: The postoperative JOA scores improved significantly, with a mean recovery rate of 65.0 ± 20.3% (p < 0.001). No significant correlations were found between the operative ultrasound metrics and MRI metrics. The gray value ratios of the spinal cord hyperechogenicity was negatively correlated with the recovery rate of JOA scores (ρ = -0.638, p = 0.001), while the ventral and dorsal gray value ratios of spinal cord hyperechogenicity were negatively correlated with the recovery rate of JOA-motor scores (ρ = -0.582, p = 0.004) and JOA-sensory scores (ρ = -0.452, p = 0.035), respectively. The dorsal gray value ratio was significantly higher than the ventral gray value ratio (p < 0.001), while the recovery rate of JOA-motor scores was better than that of JOA-sensory scores at 12 months post-surgery (p = 0.028). Conclusion: For degenerative cervical myelopathy, the correlations between intraoperative ultrasound and preoperative T2W MRI metrics were not significant. Gray value ratios of the spinal cord hyperechogenicity and dorsal and ventral spinal cord hyperechogenicity were significantly correlated with neurological recovery at 12 months postoperatively.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.3 s.116
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• pp.47-60
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• 2006

This study was carried out to investigate the sheet formation properties of Morus Hanjis, made of bast and whole stalk pulps by different pulping methods, such as alkali, alkali-peroxide and sulfomethylated pulping. Two species of Morus, M. alba and M. lhou, were used. Effect of morphological properties of pulp stocks on the sheet formation and its gray levels based on optical property were evaluated using an Image analyzer. In addition, the effect of fiber distribution index(FDI) which was calculated from tile data of Confocal laser scanning microscopy(CLSM) on the sheet formation and optical properties of Morus Hanji were also discussed. On the sheet formation, Hanji from whole stalk pulp was superior than that of bast pulp. The more the sheet formation improved, the more paper opacity decreased. In the aspect of Hanji's surface characteristics analyzed by an Image analyzer, the average gray level and its standard deviation of Hanji from the whole stalk pulp were rather lower than those of bast pulp because of better sheet formation of the former. However, high brightness Hanji showed high value of gray level. The sheet formation and paper opacity were increased with the decrease of standard deviation of gray level. From these results, gray level measurement could be used to predict the paper opacity as well as sheet formation. Sheet formation of whole stalk Hanji and its FDI measured by CLSM were higher than those of bast fibers. In conclusion, the sheet formation and opacity of Hanji could be evaluated by standard deviation value of Hanji's gray level using an Image analyzer and by fiber distribution index using CLSM.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.4
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• pp.17-22
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• 2003

A kind of image analysis system is used to investigate the structural features of the papers made from Indian mallow. The screen mark on the paper was identified and analyzed. The dusts, shives and fiber bundles were manifested and calculated. In the aspect of Indian mallow hanji's surface characteristics analyzed by an Image analyzer, the average of gray level and its standard deviation hanji from the woody core were rather lower than of bast fiber pulp because of better sheet formation of the formers. Hower. high brightness hanji showed high value of gray level. The sheet formation and paper opacity were increased with the decrease of standard deviation of gray level. From these results, gray level measurement could be used to predict the paper opacity as well as sheet formation.

• The KIPS Transactions:PartB
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• v.9B no.6
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• pp.727-734
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• 2002

Currently. people become interested in the development of measuring instrument related to eyesight. In this study, we developed software of electronic part in automatic refracto-keratometer. If an automatic system, which uses images from an optical instrument, can inform the in-spector of an accurate eyesight measured value after the internal process, the frequency of mistakenly observed value will be reduced considerably. This software is using morphological filtering and gray-level signal enhancing techniques. The morphological filtering is the first process, from images of the optical instrument, to transform an original image which is hard to process into manageable one. The second process is a signal enhancing technique to the first processed image using gray -level thresholding technique and is used to reduce an error caused by the variety in distribution of the gray value of image. Therefore, this software system in electronic part will make more effective eyesight measurement by reducing the error effectively when applied to the optical image which is difficult to get accurate measurement value.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.4
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• pp.466-471
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• 2007

Conventional thresholding methods including Otsu's thresholding method are based on the gray levels frequency histogram. But the gray levels frequency histogram is obtained by recomposing only frequency information from an input image, where frequency histogram dose not contain any other informations such as the distribution of gray levels and relation between gray levels. Therefore the methods using the gray levels frequency histogram occasionally present inappropriate threshold values because it cannot reflect informations of the given image sufficiently. In this paper, we define a correlation function of gray levels and propose a novel thresholding method using the gray levels frequency histogram and the spatial correlation information. The effectiveness of the proposed method will be shown through comparison with Otsu's thresholding method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.395-401
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• 1993

The purpose of this paper is to develop an automatic measuring system based on the digital image processing which can be applied to the in-process measurement of the characteristics of the thin thickness. The derivative operators is used for edge detection in gray level image. This concept can be easiliy illustrated with the aid of object shows an image of a simple light object on a dark background, the gray level profile along a horizontal scan line of the image, and the first and second derivatives of the profile. The first derivative of an edge modeled in this manner is () in all regions of constant gray level, and assumes a constant value during a gray level transition. The experimental results indicate that the developed qutomatic inspection system can be applied in real situation.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.12a
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• pp.283-286
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• 2001

Based on a fuzzy system representation of gray scale images, we derive an edge detection algorithm whose convolution kernel is different from the known kernels such as those of Roberts', Prewitt's or Sobel's gradient. Our fuzzy system representation is an exact representation of the bicubic spline function which represents the gray scale image approximately. Hence the fuzzy system is a continuous function and it provides a natural way to define the gradient and the Laplacian operator. We show that the gradient at grid points can be evaluated by taking the convolution of the image with a 3 3 kernel. We also show that our gradient coupled with the approximate value of the continuous function generates an edge detection method which creates edge images clearer than those by other methods. A few examples of applying our methods are included.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.6
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• pp.72-79
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• 1995

The purpose of this paper is to develop an automatic measuring system based on the digital image processing which can be applied to the in-process measurment of the characteristics of the thin thickness. The derivative operators is used for edge detection in gray level image. This concept can be easily illustrated with the aid of object shows an image of a simple light object on a dark background, the gray level profile along a horizontal scan line of the image, and the first and second derivatives of the profile. The first derivative of an edge modeled in this manner is 0 in all regions of constant gray level, and assumes a constant value during a gray level transition. The experimental results indicate that the developed automatic inspection system can be applied in real situation.

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.307-310
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• 2002

Color reproductions in most ink jet printer are quite different from that of standard CRT (cathode ray tube) monitor display because of the nonlinear characteristic in subtractive color reproduction. Gray scale CCT(correlated color temperature) reproductions in a typical printer are vary with the input RGB level. A simple method for making constant gray scale CCT and gamma value in photo paper is proposed in this paper. The compensation of the CCT with white point of the photo paper under the CIE standard illuminant D65 and color correction has been confirmed using the LUT(look-up table) to compensate the CCT and gamma curve characteristic.

• Journal of Biosystems Engineering
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• v.27 no.4
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• pp.341-348
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• 2002

Quality evaluation of red ginsengs is determined by outer shape and inner qualities. Especially, the inner qualities are main grading criteria. Currently, red ginsengs are classified into 3-grades; heaven, earth and good. The best heaven grade must not include inner holes and sponge tissues. This study was conducted to develop a red ginseng sorting system using x-ray image processing technique. Because of lens characteristic, gray values of the central region in the x-ray image are higher and gradually decreased towards the edge regions. This difference of gray values gives trouble in segmentation and detection of inner holes in red ginseng image, so preprocessing technique is necessary. The preprocessing was done by subtracting source image from an empty background image. But, simple subtraction was not quite appropriate because of too small contrast between inner holes and sound part. Scaled subtraction images were obtained by multiplying all gray values by some numbers. However this method could not help to set threshold value because the gray values of root part are generally lower than body part when red ginseng is exposed to the x-ray. To determine threshold value for detecting inner holes, an algorithm was developed by increasing overall gray values of less clear images.