• Journal of Information Display
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• v.10 no.1
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• pp.1-5
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• 2009

A novel computational integral imaging technique with enhanced depth sensitivity is proposed. For each lateral position at a given depth plane, the dissimilarity between corresponding pixels of the elemental images is measured and used as a suppressing factor for that position. The intensity values are aggregated to determine the correct depth plane of each plane object. The experimental and simulation results show that the reconstructed depth image on the incorrect depth plane is effectively suppressed, and that the depth image on the correct depth plane is reconstructed clearly without any noise. The correct depth plane is also exactly determined.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.773-776
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• 1998

In this paper, we propose an efficient multi-view images coding algorithm which finds the optimal texture from the restricted number of multi-view images. The X-Y plane of the normalized object space is divided into triangular patches. The depth value of the node is determined by applying the block based disparity compensation method and then the texture of the each patch is extracted by applying the affine transformation patch is extracted by applying the affine transformation based disparity compensation method to the multi-view images. We restricted the number of images contributed to determining the texture comapred to traditional methods which use all the multi-view images in the texture extraction. Experimental results show that the SNR of images encoded by the proposed algorithm is better than that of imaes encoded by the traditional method by the amount about 0.2dB for the test sets of multi-view images called dragon, kid, city and santa. The recovered images from the encoded data by the proposed method show the better visual images than the recovered images from the encoded data by the traditional methods.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.4
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• pp.18-29
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• 1994

For the efficient recognition of Korean Alphabets, we proposed the tree structure algorithm which was based on K-tuple NRF-SDF using representative images as training images. Representative images consisted of ECP-SDF images of several consonants or vowels. To reduce the effect of sidelobe in the output correlation plane, we used the representative images as training images and obtained the elements of a vector inner product matrix using the peak value of AMPOF correlation of training images with one another. The proposed algorithm consisted of three main-step containing several substeps. In filter synthesis of each step, representative images were used as training images in the first and the second main-step and each consonant or vowel was used as training images in the third main-step. The performance of this algorithm is demonstrated by computer simulation and optical experiment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.1
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• pp.111-119
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• 1994

In this paper we propose a reversible image coding methods with progressive build-up function by bit-plane of multi-lavel image. Firstly, the differencial conversion is applied to reduce the entropy of source images. Then the bit-plane sequences of converted images are coded by means of the newly designed VFRL(Variable to Fixed Run-Llength) code and the RDHC(Run-length Dynamic Huffman Coding). We aim to the simple construction to reduce the complexity. The computer simulated results show that the proposed methods are very effective to the multi-level digital images. For "GIRL" and "COUPLE" of 1EEE monochromatic standard images, the compressibility are superior to the results obtained by the well-known universal codes.own universal codes.

• Journal of the Optical Society of Korea
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• v.17 no.5
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• pp.410-414
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• 2013

In this paper, we propose a 3D display method combining a pickup process using axially recorded multiple images and an integral imaging display process. First, we extract the color and depth information of 3D objects for displaying 3D images from axially recorded multiple 2D images. Next, using the extracted depth map and color images, elemental images are computationally synthesized based on a ray mapping model between 3D space and an elemental image plane. Finally, we display 3D images optically by an integral imaging system with a lenslet array. To show the usefulness of the proposed system, we carry out optical experiments for 3D objects and present the experimental results.

• Journal of The Korean Astronomical Society
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• v.38 no.2
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• pp.219-222
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• 2005

We present the high-resolution (2"-4") images of the molecular envelopes surrounding the evolved stars, V Hya, VY CMa, and ${\pi}^1$ Gru observed with the Submillimeter Array. The CO J=2-1 and 3-2 images of the carbon star V Hya show that the circumstellar structure of this star consists of three kinematic components; there is a flattened disk-like envelope that is expanding with a velocity of ${\~}16 km\;s^{-1}$, the second component is the medium-velocity wind having a deprojected velocity of 40-120 km $s^{-l}$ moving along the disk plane, and the third one is the bipolar molecular jet having an extreme velocity of 70-185 km $s^{-l}$. The axis of this high velocity jet is perpendicular to the plane of the disk-like envelope. We found that the circumstellar structure of the S-star ${\pi}^1$ Gru traced by the CO J =2-1 resembles that of V Hya quite closely; the star is surrounded by the expanding disk-like envelope and is driving the medium-velocity wind along the disk plane. We also obtained the excellent images of VY CMa with the CO and $^{13}CO$ J=2-1 and $SO\;6_5-5_4$ lines. The maps of three molecular lines show that the envelope has a significant velocity gradient in the east-west direction, suggesting that the envelope surrounding VY CMa is also flattened and expanding along its radial direction. The high-resolution images obtained with the SMA show that some AGB stars are associated with the asymmetric mass loss including the equatorial wind and bipolar jet.

• Geomechanics and Engineering
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• v.30 no.1
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• pp.67-73
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• 2022

In this study, the fiber orientation distribution (FOD) is investigated using both micro-CT (computerized tomography) and image analysis of physically cut specimens prepared from Polyvinyl Alcohol (PVA) fiber reinforced cemented Toyoura sand. The micro-CT images of the fiber reinforced cemented sand specimens were visualized in horizontal and vertical sections. Scans were obtained using a frame rate of two frames and an exposure time of 500 milliseconds. The number of images was set to optimize and typically resulted in approximately 3000 images. Then, the angles of the fibers for horizontal sections and in vertical section were calculated using the VGStudio MAX software. The number of fibers intersecting horizontal and vertical sections are counted using these images. A similar approach was used for physically cut specimens. The variation of results of fiber orientation between micro-CT scans and visual count were approximately 4-8%. The micro-CT scans were able to precisely investigate the fiber orientation distribution of fibers in these samples. The results show that 85-90% of the PVA fibers are oriented between ±30° of horizontal, and approximately 95% of fibers have an orientation that lies within ±45° of the horizontal plane. Finally, a comparison of experimental results with the generalized fiber orientation distribution function 𝜌(θ) is presented for isotropic and anisotropic distribution in fiber reinforced cemented Toyoura sand specimens. Experimentally, it can be seen that the average ratio of the number of fibers intersecting the finite area on a vertical plane to number of fibers intersecting the finite area on a horizontal plane (N^V_tot/N^H_tot) cut through a sample varies from 2.08 to 2.12 (an average ratio of 2.10 is obtained in this study). Based up on the analytical predictions, it can be seen that the average N^V_tot/N^H_tot ratio varies from 2.13 to 2.17 for varying n values (an average ratio of 2.15).

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.40 no.3
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• pp.123-129
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• 2014

Objectives: The aim of this study was to verify the concordance of the measurement values when the same cephalometric analysis method was used for two-dimensional (2D) cephalometric radiography and three-dimensional computed tomography (3D CT), and to identify which 3D Frankfort horizontal (FH) plane was the most concordant with FH plane used for cephalometric radiography. Materials and Methods: Reference horizontal plane was FH plane. Palatal angle and occlusal plane angle was evaluated with FH plane. Gonial angle (GA), palatal angle, upper occlusal plane angle (UOPA), mandibular plane angle (MPA), U1 to occlusal plane angle, U1 to FH plane angle, SNA and SNB were obtained on 2D cephalmetries and reconstructed 3D CT. The values measured eight angles in 2D lateral cephalometry and reconstructed 3D CT were evaluated by intraclass correlation coefficiency (ICC). It also was evaluated to identify 3D FH plane with high degree of concordance to 2D one by studying which one in four FH planes shows the highest degree of concordance with 2D FH plane. Results: ICCs of MPA (0.752), UOPA (0.745), SNA (0.798) and SNB (0.869) were high. On the other hand, ICCs of gonial angle (0.583), palatal angle (0.287), U1 to occlusal plane (0.404), U1 to FH plane (0.617) were low respectively. Additionally GA and MPA acquired from 2D were bigger than those on 3D in all 20 patients included in this study. Concordance between one UOPA from 2D and four UOPAs from 3D CT were evaluated by ICC values. Results showed no significant difference among four FH planes defined on 3D CT. Conclusion: FH plane that can be set on 3D CT does not have difference in concordance from FH plane on lateral cephalometry. However, it is desirable to define FH plane on 3D CT with two orbitales and one porion considering the reproduction of orbitale itself.

• Clinics in Shoulder and Elbow
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• v.21 no.3
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• pp.113-119
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• 2018

Background: This study was undertaken to evaluate the positional relationship between planes of the glenoid component (the scapular plane and the perpendicular plane to the glenoid) and its surrounding structures. Methods: Computed tomography (CT) images of both shoulders of 100 patients were evaluated using the 3-dimensional CT reconstruction program ($Aquarius^{(R)}$; TeraRecon). We determined the most lateral scapular bony structure of the scapular plane and measured the shortest distance between the anterolateral corner of the acromion and the scapular plane. The distance between the scapular plane and the midpoint of the line connecting the posterolateral corner of acromion and the anterior tip of the coracoid process (fulcrum axis) was also evaluated. The perpendicular plane was then adjusted to the glenoid and the same values were re-assessed. Results: The acromion was the most lateral scapular structure of scapular plane and perpendicular plane to the glenoid. The average distance from the anterolateral corner of the acromion to the scapular plane was $10.44{\pm}5.11mm$, and to the plane perpendicular to the glenoid was $9.55{\pm}5.13mm$. The midpoint of fulcrum axis was positioned towards the acromion and was measured at $3.90{\pm}3.21mm$ from the scapular plane and at $3.84{\pm}3.17mm$ from the perpendicular plane to the glenoid. Conclusions: Our data indicates that the relationship between the perpendicular plane to the glenoid plane and its surrounding structures is reliable and can be used as guidelines during glenoid component insertion (level of evidence: Level IV, case series, treatment study).

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2393-2396
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• 2005

We present a method to detect on-road vehicle using geometric invariant of feature points on side planes of the vehicle. The vehicles are assumed into a set of planes and the invariant from motion information of features on the plane segments the plane from the theory that a geometric invariant value defined by five points on a plane is preserved under a projective transform. Harris corners as a salient image point are used to give motion information with the normalized correlation centered at these points. We define a probabilistic criterion to test the similarity of invariant values between sequential frames. Experimental results using images of real road scenes are presented.