• Title/Summary/Keyword: Quantitative evaluation of image

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대용량 필기체 문자 인식을 위한 비선형 형태 정규화 방법의 정량적 평가 (Quantitative Evaluation of Nonlinear Shape Normalization Methods for the Recognition of Large-Set Handwrittern Characters)

  • 이성환;박정선
    • 전자공학회논문지B
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    • 제30B권9호
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    • pp.84-93
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    • 1993
  • Recently, several nonlinear shape normalization methods have been proposed in order to compensate for the shape distortions in handwritten characters. In this paper, we review these nonlinear shape normalization methods from the two points of view : feature projection and feature density equalization. The former makes feature projection histogram by projecting a certain feature at each point of input image into horizontal-or vertical-axis and the latter equalizes the feature densities of input image by re-sampling the feature projection histogram. A systematic comparison of these methods has been made based on the following criteria: recognition rate, processing speed, computational complexity and measure of variation. Then, we present the result of quantitative evaluation of each method based on these criteria for a large variety of handwritten Hangul syllables.

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Image Quality and Lesion Detectability of Lower-Dose Abdominopelvic CT Obtained Using Deep Learning Image Reconstruction

  • June Park;Jaeseung Shin;In Kyung Min;Heejin Bae;Yeo-Eun Kim;Yong Eun Chung
    • Korean Journal of Radiology
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    • 제23권4호
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    • pp.402-412
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    • 2022
  • Objective: To evaluate the image quality and lesion detectability of lower-dose CT (LDCT) of the abdomen and pelvis obtained using a deep learning image reconstruction (DLIR) algorithm compared with those of standard-dose CT (SDCT) images. Materials and Methods: This retrospective study included 123 patients (mean age ± standard deviation, 63 ± 11 years; male:female, 70:53) who underwent contrast-enhanced abdominopelvic LDCT between May and August 2020 and had prior SDCT obtained using the same CT scanner within a year. LDCT images were reconstructed with hybrid iterative reconstruction (h-IR) and DLIR at medium and high strengths (DLIR-M and DLIR-H), while SDCT images were reconstructed with h-IR. For quantitative image quality analysis, image noise, signal-to-noise ratio, and contrast-to-noise ratio were measured in the liver, muscle, and aorta. Among the three different LDCT reconstruction algorithms, the one showing the smallest difference in quantitative parameters from those of SDCT images was selected for qualitative image quality analysis and lesion detectability evaluation. For qualitative analysis, overall image quality, image noise, image sharpness, image texture, and lesion conspicuity were graded using a 5-point scale by two radiologists. Observer performance in focal liver lesion detection was evaluated by comparing the jackknife free-response receiver operating characteristic figures-of-merit (FOM). Results: LDCT (35.1% dose reduction compared with SDCT) images obtained using DLIR-M showed similar quantitative measures to those of SDCT with h-IR images. All qualitative parameters of LDCT with DLIR-M images but image texture were similar to or significantly better than those of SDCT with h-IR images. The lesion detectability on LDCT with DLIR-M images was not significantly different from that of SDCT with h-IR images (reader-averaged FOM, 0.887 vs. 0.874, respectively; p = 0.581). Conclusion: Overall image quality and detectability of focal liver lesions is preserved in contrast-enhanced abdominopelvic LDCT obtained with DLIR-M relative to those in SDCT with h-IR.

초음파 의료영상에서 ATS 535H 팬텀을 이용한 해상력 특성 평가 (Evaluation of the Resolution Characteristics by Using ATS 535H Phantom for Ultrasound Medical Imaging)

  • 민정환;정회원;강혜경
    • 대한방사선기술학회지:방사선기술과학
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    • 제46권1호
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    • pp.15-21
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    • 2023
  • This study was purpose to assessment of the resolution characteristics by using ATS 535H Basic quality assurance (QA) phantom for ultrasound. The ultrasound equipment was used Logiq P6 (Ultrasound, GE Healthcare System, Chicago, IL, USA). And the ultrasound transducer were used Convex 4C (4~5.5 MHz), Linear 11L (10~13 MHz), Sector 3SP (3~5.5 MHz) probe. As for the noise power spectrum (NPS) comparison results by using ATS 535H Basic QA ultrasound phantom and Convex 4C, Linear 11L, Sector 3SP probe. The NPS value of the Convex 4C probe image was 0.0049, Linear 11L probe image was 0.0049, Sector 3SP probe image was 0.1422 when the frequency is 1.0 mm-1. The modulation transfer function (MTF) comparison results by using ATS 535H Basic QA ultrasound phantom and Linear 11L probe the MTF value of the 3 cm focus image was 0.7511 and 4 cm focus image was 0.9001 when the frequency is 1.0 mm-1. This study was presented characteristics of spatial resolution a quantitative evaluation methods by using ultrasound medical images for QA of ultrasound medical QA phantom. The quality control (QC) for equipment maintenance can be efficiently used in the clinic due to the quantitative evaluation of the NPS and MTF as the standard methods. It is meaningful in that it is applied mutatis mutandis and presented the results of physical resolution characteristics of the ultrasound medical image.

다발성 경화증 질환의 자기공명 T2 강조영상에서 단면 두께 변화에 따른 잡음 평가 (Noise Level Evaluation According to Slice Thickness Change in Magnetic Resonance T2 Weighted Image of Multiple Sclerosis Disease)

  • 홍인기;박민지;강성현;이영진
    • 대한방사선기술학회지:방사선기술과학
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    • 제44권4호
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    • pp.327-333
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    • 2021
  • Magnetic resonance imaging(MRI) uses strong magnetic field to image the cross-section of human body and has excellent image quality with no risk of radiation exposure. Because of above-mentioned advantages, MRI has been widely used in clinical fields. However, the noise generated in MRI degrades the quality of medical images and has a negative effect on quick and accurate diagnosis. In particular, examining a object with a detailed structure such as brain, image quality degradation becomes a problem for diagnosis. Therefore, in this study, we acquired T2 weighted 3D data of multiple sclerosis disease using BrainWeb simulation program, and used quantitative evaluation factors to find appropriate slice thickness among 1, 3, 5, and 7 mm. Coefficient of variation and contrast to noise ratio were calculated to evaluate the noise level, and root mean square error and peak signal to noise ratio were used to evaluate the similarity with the reference image. As a result, the noise level decreased as the slice thickness increased, while the similarity decreased after 5 mm. In conclusion, as the slice thickness increases, the noise is reduced and the image quality is improved. However, since the edge signal is lost due to overlapped signal, it is considered that selecting appropriate slice thickness is necessary.

구강 내 촬영용 센서의 정량적 평가 (Quantitative Analysis for Digital Intraoral Sensor)

  • 정재호;정재은;강희두;나극환
    • 대한디지털의료영상학회논문지
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    • 제11권2호
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    • pp.109-114
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    • 2009
  • Carried out an experiment for quantitative evaluation about intraoral sensor among oral dental imaging equipments in PACS environment. For evaluation, testing environment & evaluation criteria are established that refer to the 'IEC 62220-1-2' and experimented with set up the standard radiation penetration that correspond with RQA-3(IEC 61267). Results of experiments using the image J, derived the ESF(edge spread function), LSF (line spread function) and calculated the MTF(modulation transfer function) finally. As a result, the MTF that 0.1, 0.2sec are 10% about 10 lp/mm and 0.32 sec is the 10% about 9 lp/mm in level represents the value of the MTF. Change of scan condition in dental environmental, according to the MTF value taken note that no changes can be seen enough. However, the dimensions of each other size $1(1200{\times}1600)$, size $2(1440{\times}1920)$ intraoral sensors for 3 lp/mm, respectively 40%, 90% of the note might have been the difference between the value of MTF, in accordance with standard sensors might note differences could be observed.

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Quantitative Evaluation Method for Etch Sidewall Profile of Through-Silicon Vias (TSVs)

  • Son, Seung-Nam;Hong, Sang Jeen
    • ETRI Journal
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    • 제36권4호
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    • pp.617-624
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    • 2014
  • Through-silicon via (TSV) technology provides much of the benefits seen in advanced packaging, such as three-dimensional integrated circuits and 3D packaging, with shorter interconnection paths for homo- and heterogeneous device integration. In TSV, a destructive cross-sectional analysis of an image from a scanning electron microscope is the most frequently used method for quality control purposes. We propose a quantitative evaluation method for TSV etch profiles whereby we consider sidewall angle, curvature profile, undercut, and scallop. A weighted sum of the four evaluated parameters, nominally total score (TS), is suggested for the numerical evaluation of an individual TSV profile. Uniformity, defined by the ratio of the standard deviation and average of the parameters that comprise TS, is suggested for the evaluation of wafer-to-wafer variation in volume manufacturing.

Evaluation of TlBr semiconductor detector in gamma camera imaging: Monte Carlo simulation study

  • Youngjin Lee;Chanrok Park
    • Nuclear Engineering and Technology
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    • 제54권12호
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    • pp.4652-4659
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    • 2022
  • Among the detector materials available at room temperature, thallium bromide (TlBr), which has a relatively high atomic number and density, is widely used for gamma camera imaging. This study aimed to verify the usefulness of TlBr through quantitative evaluation by modeling detectors of various compound types using Monte Carlo simulations. The Geant4 application for tomographic emission was used for simulation, and detectors based on cadmium zinc telluride and cadmium telluride materials were selected as a comparison group. A pixel-matched parallel-hole collimator with proven excellent performance was modeled, and phantoms used for quality control in nuclear medicine were used. The signal-to-noise ratio (SNR), contrast to noise ratio (CNR), sensitivity, and full width at half maximum (FWHM) were used for quantitative analysis to evaluate the image quality. The SNR, CNR, sensitivity, and FWHM for the TlBr detector material were approximately 1.05, 1.04, 1.41, and 1.02 times, respectively, higher than those of the other detector materials. The SNR, CNR and sensitivity increased with increasing detector thickness, but the spatial resolution in terms of FWHM decreased. Thus, we demonstrated the feasibility and possibility of using the TlBr detector material in comparison with commercial detector materials.

3.0T 자기공명영상을 이용한 해상력 특성에 대한 연구 (Study on the Resolution Characteristics by Using Magnetic Resonance Imaging 3.0T)

  • 민정환;정회원;한지현;이시내;한송이;김기원;김현수;손진현
    • 대한방사선기술학회지:방사선기술과학
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    • 제43권4호
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    • pp.251-257
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    • 2020
  • This study was purpose to quantitative evaluation of edge method of modulation transfer function(MTF) and physical image characteristics of by obtain the optimal edge image by using magnetic resonance imaging(MRI). The MRI equipment was used (MAGNETOM Vida 3.0T MRI, Siemense healthcare system, Germany) and the head/neck matrix shim MR coil were 20 channels(elements) receive coil. The MTF results of showed the best value of 0.294 based on the T2 Nyquist frequency of 1.0 mm-1. The MTF results of showed that the T1 image is 0.160, the T1 CE image is 0.250, T1 Conca2 image is 0.043, and the T1 CE (Concatenation) Conca2 image is 0.190. The T2 image highest quantitatively value for MTF. The physical image characteristics of this study were to that can be used efficiently of the MRI and to present the quantitative evaluation method and physical image characteristics of 3.0T MRI.

비 다공성 표면에서 천연분말로 현출된 잠재지문의 농도계 이미지분석을 이용한 예비적인 반 정량적 평가 (Preliminary semi-quantitative evaluation of developed latent fingerprints on non-porous surface with natural powders using a densitometric image analysis)

  • 김은미;허보름;옥윤석;김진경;정인남;최성운
    • 분석과학
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    • 제29권6호
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    • pp.283-292
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    • 2016
  • 범죄현장조사에 사용되는 인체에 유해할 수 있는 일반분말에 대한 대체수단으로 천연분말(오징어 먹물분말, 청대분말, 쌀분말)을 이용하여 비 다공성표면(유리, 플라스틱, 타일)상의 잠재지문을 현출(가시화)하였다. 현출된 잠재지문을 Automatic Fingerprint Identification System (AFIS)으로 분석한 특징점의 수를 흑색분말을 사용한 결과 특징점 수와 비교하였으며 또한 객관적이고 계량적인 평가방법의 개발을 위하여 각 분말로 가시화된 지문의 이미지를 농도계 이미지분석(densitometric image analysis)을 이용한 결과 값인 융선 피크의 면적값을 비교하였다. 천연분말들의 현출효과는 표면에 따라 다양하게 나타났다. 일반적으로 오징어 먹물분말은 대부분의 표면에서 좋은 현출을 보였으며 청대분말은 타일표면에서 그리고 쌀분말은 유리표면에서 최고의 현출을 보였다. 그러나 플라스틱 표면은 천연분말에 의한 지문현출이 가장 어려운 표면이었다. Field Emission Scanning Electron Microscope (SEM)를 이용한 이미지 분석에서 융선에 적절한 흡착력을 가지는 조건으로 천연분말 입자의 크기와 형태가 중요한 인자임을 확인할 수 있었다. 비록 기술적인 어려움으로 특징점의 수와 융선 피크의 면적값과의 상관관계를 볼 수는 없었으나 공평하고 객관적인 지문의 평가방법으로 기준 이미지의 사용을 통한 이미지 보정을 통하여 가능하리라고 사료된다. 저가의 저독성 천연분말은 추가적인 실험을 통하여 적절한 잠재지문 현출제로서의 가능성을 보일 것으로 사료된다.

Study on Highly Accuracy Quality Evaluation of Spot Weld by use of Image Processing Technique

    • 한국생산제조학회지
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    • 제5권4호
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    • pp.38-46
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    • 1996
  • This paper discusses the feasibility of Ultrasonic Nondestructive Evaluation (UNDE) technique for sport weld quality. Ultrasonic c-scan image assisted by image processing technique was used for Nondestructive Evaluation(NDE) of spot weld quality. Ultrasonic testing results obtained were confirmed and compared by Optical Microscope and SAM(Scanning Acoustic Mircroscope) observation of the spot-weld cross section, The results show that the nugget dinameter can be successfully measured with the accuracy of 0.5mm. It was ascertained that ultrasonic c-scan technique is very effective method for the sake of the approach to the quantitative measurement of nugget diameter and the discrimination of the corona bond from nugget. Additional support for the above conclusions is provided by the results for galvanized steel. The ultrasonic results for galvanized welds generally correspond to the results for uncoated steel. Finally, it was found that the above-mentioned technique can be sufficiently applied to NDE method for securing the Quality Assurance(QA) of spot welded products in production line.

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