8 research outputs found
Enhanced phase congruency feature-based image registration for multimodal remote sensing imagery
Multimodal image registration is an essential image processing task in remote sensing. Basically, multimodal image registration searches for optimal alignment between images captured by different sensors for the same scene to provide better visualization and more informative images. Manual image registration is a tedious task and requires more effort, hence developing an automated image registration is very crucial to provide a faster and reliable solution. However, image registration faces many challenges from the nature of remote sensing image, the environment, and the technical shortcoming of the current methods that cause three issues, namely intensive processing power, local intensity variation, and rotational distortion. Since not all image details are significant, relying on the salient features will be more efficient in terms of processing power. Thus, the feature-based registration method was adopted as an efficient method to avoid intensive processing. The proposed method resolves rotation distortion issue using Oriented FAST and Rotated BRIEF (ORB) to produce invariant rotation features. However, since it is not intensity invariant, it cannot support multimodal data. To overcome the intensity variations issue, Phase Congruence (PC) was integrated with ORB to introduce ORB-PC feature extraction to generate feature invariance to rotation distortion and local intensity variation. However, the solution is not complete since the ORB-PC matching rate is below the expectation. Enhanced ORB-PC was proposed to solve the matching issue by modifying the feature descriptor. While better feature matches were achieved, a high number of outliers from multimodal data makes the common outlier removal methods unsuccessful. Therefore, the Normalized Barycentric Coordinate System (NBCS) outlier removal was utilized to find precise matches even with a high number of outliers. The experiments were conducted to verify the registration qualitatively and quantitatively. The qualitative experiment shows the proposed method has a broader and better features distribution, while the quantitative evaluation indicates improved performance in terms of registration accuracy by 18% compared to the related works
A Study on Image Registration between High Resolution Optical and SAR Images Using SAR-SIFT and DLSS
ํ์๋
ผ๋ฌธ (์์ฌ)-- ์์ธ๋ํ๊ต ๋ํ์ : ๊ณต๊ณผ๋ํ ๊ฑด์คํ๊ฒฝ๊ณตํ๋ถ, 2018. 8. ๊น์ฉ์ผ.์ต๊ทผ ์์ฑ์ผ์ ๊ธฐ์ ์ ๋ฐ๋ฌ๋ก ๋ค์ํ ์ผ์๋ฅผ ํ์ฌํ ์ง๊ตฌ๊ด์ธก์์ฑ์ด ๋ฐ์ฌ๋๋ฉด์, ๋ค์ค์ผ์ ์์ฑ์์์ ์ตํฉ ๋ถ์ํ๋ ์ฐ๊ตฌ๊ฐ ํ๋ฐํ ์งํ๋๊ณ ์๋ค. ํนํ, ๊ดํ์์๊ณผ SAR์์์ ์ทจ๊ธํ๋ ํ์ฅ๋๊ฐ ๋ฌ๋ผ ๋์์ ํ์ฉํ ๊ฒฝ์ฐ ์งํ๋ฉด์ ๋ํด ๋ณด๋ค ๊ตฌ์ฒด์ ์ธ ์ ๋ณด๋ฅผ ์ทจ๋ํ ์ ์์ผ๋ฉฐ, ๋ ๋์๊ฐ, ๊ฐ์ฒด ์ถ์ถ, ๋ณํํ์ง, ์ฌ๋์ฌํด ๋ชจ๋ํฐ๋ง ๋ฑ ์๊ฒฉํ์ฌ ๋ถ์ผ์ ํญ๋๊ฒ ์ ์ฉ์ด ๊ฐ๋ฅํ๋ค. ์ด๋ฅผ ์ํด์๋ ์ ์ฒ๋ฆฌ ์์
์ผ๋ก ๋ ์์ ๊ฐ ์ ํฉ์ด ํ์์ ์ผ๋ก ์ด๋ฃจ์ด์ ธ์ผ ํ๋ค. ๊ทธ๋ฌ๋, ๊ดํ์์๊ณผ SAR์์์ ์์ ์ทจ๋์ ์์ฑ์ผ์ ์์ธ ๋ฐ ์ทจ๊ธํ๋ ํ์ฅ๋์ ์์ดํจ์ผ๋ก ๊ธฐํ ๋ฐ ๋ถ๊ด ์ ๋ณด ์ฐจ์ด๋ฅผ ์ ๋ฐํ์ฌ ์์ ์ ํฉ์ ์์ด ์ ๋
์ด๋ ค์์ด ์กด์ฌํ๋ค. ์ด๋ฌํ ์ฐจ์ด๋ ๊ฑด๋ฌผ์ด ๋ฐ์ง๋ ๋์ฌ์ง์ญ์์ ๋ถ๊ฐ๋๋ฉฐ, ์คยท์ ํด์๋ ์์๋ณด๋ค ๊ณ ํด์๋ ์์์์ ๋๋๋ฌ์ง๋ค. ๋ฐ๋ผ์, ๋ณธ ์ฐ๊ตฌ์์๋ ๋์ฌ์ง์ญ์ ๋ํ ๊ณ ํด์๋ ๊ดํ์์๊ณผ SAR์์ ๊ฐ ์ ํฉ์ ํจ๊ณผ์ ์ธ ๋ฐฉ๋ฒ๋ก ์ ์ ์ํ์๋ค.
๊ธฐ์กด ๊ดํ์์๊ณผ SAR์์ ๊ฐ ์ ํฉ ๊ด๋ จ ์ฐ๊ตฌ๋ ํฌ๊ฒ ํน์ง๊ธฐ๋ฐ ์ ํฉ๊ธฐ๋ฒ๊ณผ ๊ฐ๋๊ธฐ๋ฐ ์ ํฉ๊ธฐ๋ฒ์ผ๋ก ์งํ๋์๋ค. ๊ฐ๋๊ธฐ๋ฐ ์ ํฉ๊ธฐ๋ฒ์ ๋ถ๊ด ํน์ฑ์ด ๋ค๋ฅธ ์์ ๊ฐ ์ ํฉ์ ํจ๊ณผ์ ์ด๋, ์์ ๊ฐ ์๊ณก์ด ์กด์ฌํ์ง ์๊ฑฐ๋ ๊ธฐํํ์ ์์น ์ฐจ์ด๊ฐ ์ ์ ๋์๋ง ์ ์ฉ ๊ฐ๋ฅํ๋ค. ๊ณ ํด์๋ ๊ดํ์์๊ณผ SAR์์์ ์ง์ญ์ ์๊ณก์ด ์กด์ฌํ๋ฉฐ, ๋ ์์ ๊ฐ ์์ญm ์ด์์ ๊ธฐํํ์ ์์น ์ฐจ์ด๊ฐ ๋ฐ์ํ ์ ์๋ค. ๋ฐ๋ผ์, ๊ณ ํด์๋ ๊ดํ์์๊ณผ SAR์์ ๊ฐ ์ ํฉ ์ฐ๊ตฌ๋ ๊ฐ๋๊ธฐ๋ฐ ์ ํฉ๊ธฐ๋ฒ ๋ณด๋ค ํน์ง๊ธฐ๋ฐ ์ ํฉ๊ธฐ๋ฒ์ด ์ค์ ์ ์ผ๋ก ์งํ๋๊ณ ์๋ค. ๊ทธ๋ฌ๋, ํน์ง๊ธฐ๋ฐ ์ ํฉ๊ธฐ๋ฒ์ ๋ถ๊ด ํน์ฑ์ด ๋ค๋ฅธ ๊ดํ์์๊ณผ SAR์์์์ ์ค์ ํฉ์์ ๋ค์ ์ถ์ถํ์ฌ ์ ํฉ ์ฑ๋ฅ์ด ๋จ์ด์ง๋ค. ์ด๋ฅผ ํด๊ฒฐํ๊ธฐ ์ํด, ๊ฐ๋๊ธฐ๋ฐ ์ ํฉ๊ธฐ๋ฒ๊ณผ ํน์ง๊ธฐ๋ฐ ์ ํฉ๊ธฐ๋ฒ์ ๊ฒฐํฉํ ๊ธฐ๋ฒ๋ค์ด ์ ์๋์์ผ๋, ๋์ฌ์ง์ญ์์ ์ ํ์์ด ์กด์ฌํ๋ ์ง์ญ์ด๋ ๊ฑด๋ฌผ๋ฐ์ง์ง์ญ์ ์ ์ธํ ์ง์ญ ๋ฑ๊ณผ ๊ฐ์ด ์ ํ๋ ์ง์ญ์์๋ง ์ ์ฉ ๊ฐ๋ฅํ๋ค๋ ํ๊ณ์ ์ ๋ณด์๋ค. ์ด๋ฅผ ๊ฐ์ ํ๊ธฐ ์ํด, ๋ณธ ์ฐ๊ตฌ์์๋ ํน์ง๊ธฐ๋ฐ ์ ํฉ๊ธฐ๋ฒ์ธ SAR-SIFT ๊ธฐ๋ฒ๊ณผ ๊ฐ๋๊ธฐ๋ฐ ์ ํฉ๊ธฐ๋ฒ์ธ DLSS ๊ธฐ๋ฒ์ ๊ฒฐํฉํ ์ ํฉ๊ธฐ๋ฒ์ ์ ์ํ์๋ค. ๋ํ, ์ ํฉ์์ ์ถ์ถํ๊ธฐ ์ํด, ์ ์ฒ๋ฆฌ ๋จ๊ณ, ํ๋ณด ์ ํฉ์ ์ถ์ถ ๋จ๊ณ, ์ ๋ฐ ์ ํฉ์ ์ถ์ถ ๋จ๊ณ์ธ ์ด ์ธ ๋จ๊ณ๋ฅผ ์ถ๊ฐํ์๋ค.
๊ณ ํด์๋ ๊ดํ์์๊ณผ SAR์์ ๊ฐ ์ ํฉ์ ์ํด์, SAR-SIFT ๊ธฐ๋ฒ์ ์ด์ฉํ์ฌ ํน์ง์ ์ ์ถ์ถํ๊ณ , ์ถ์ถ๋ ํน์ง์ ์์ DLSS ๊ธฐ๋ฒ์ ์ด์ฉํ์ฌ ์ ํฉ์์ ์ถ์ถํ์๋ค. ๊ทธ๋ฌ๋, ์ถ์ถ๋ ์ ํฉ์์ ๋ค์์ ์ค์ ํฉ์์ด ํฌํจ๋๋ ๋ฌธ์ ์ ์ด ์กด์ฌํ์๋ค. ์ด๋ฅผ ํด๊ฒฐํ๊ธฐ ์ํด, ์ถ์ถ๋ ์ ํฉ์์์ ์๊ณ์น์ ํน์ง์ ๊ฐ ๋ณ์๋์ ์ด์ฉํ ์ ์ฒ๋ฆฌ ๋จ๊ณ์ ํ๋ณด ์ ํฉ์ ์ถ์ถ ๋จ๊ณ๋ฅผ ํตํด ํ๋ณด ์ ํฉ์์ ์ถ์ถํ๊ณ , ํ๋ณด ์ ํฉ์์ RANSAC ๊ธฐ๋ฒ์ ์ ์ฉํ์ฌ ์ ๋ฐ ์ ํฉ์์ ์ถ์ถํ๋ ๋ฐฉ๋ฒ์ ์ ์ํ์๋ค. ์ต์ข
์ ์ผ๋ก ์ถ์ถ๋ ์ ๋ฐ ์ ํฉ์์ ์ด์ฉํ์ฌ ์ดํ ๋ณํ์(affine transformation)์ ๊ตฌ์ฑํ๊ณ , ์ด๋ฅผ ์ ์ฉํ์ฌ ๊ดํ์์์ ์ ํฉ๋ SAR์์์ ์์ฑํ์๋ค.
๋ณธ ์ฐ๊ตฌ์ ์ ํ๋๋ฅผ ๊ฒ์ฆํ๊ธฐ ์ํ์ฌ, ๋ํ์ ์ธ ๊ณ ํด์๋ ๊ดํ์์์ธ KOMPSAT-2์์๊ณผ ๊ณ ํด์๋ SAR์์์ธ TerraSAR-X, Cosmo-SkyMed์์์ ์ฌ์ฉํ์๊ณ , ์๊ฐ์ , ์ ๋์ ํ๊ฐ๋ฅผ ์งํํ์๋ค. ์๊ฐ์ ํ๊ฐ๋ฅผ ์ํด์ ๋ชจ์์ดํฌ ์์์ ์์ฑํ์์ผ๋ฉฐ, ๋ ์์ ๊ฐ ๊ฒฝ๊ณ์์ ๊ฐ์ฒด์ ํ์์ด ์ ์ง๋จ์ ํตํด ์ ํฉ์ด ์ฐ์ํ๊ฒ ์ํ๋จ์ ํ์ธํ์๋ค. ์ ๋์ ํ๊ฐ๋ฅผ ์ํด์ ์๋ ๊ฒ์ฌ์ ์ ํตํ RMSE โ
๊ณผ ๊ต์ฐจ๊ฒ์ฆ์ ํตํ RMSE โ
ก๋ฅผ ์ฌ์ฉํ์์ผ๋ฉฐ, ๋ชจ๋ ์คํ์ง์ญ์ ๋ํด RMSE โ
์ 1.51m์์ 2.04m, RMSE โ
ก๋ 1.34m์์ 1.69m๋ก ์ ํ๋๊ฐ ๋์ถ๋์๋ค. ์ด๋, ์ ํ์ฐ๊ตฌ๊ฒฐ๊ณผ์ ๋น๊ตํ์์ ๋ ์ฐ์ํ ์์ค์ ์ ํ๋๋ก ํ์ธ๋์๋ค. ์ด๋ฅผ ํตํด, ์ ์ ๊ธฐ๋ฒ์ด ๊ณ ํด์๋ ๊ดํ์์๊ณผ SAR์์ ๊ฐ ์ ํฉ์ ํจ๊ณผ์ ์ด๋ฉฐ, ๋ ์์ ๊ฐ ์ตํฉ ๋ถ์์ ์ํด ํจ๊ณผ์ ์ธ ์ ํฉ ๊ธฐ์ ๋ก ํ์ฉ๋ ๊ฒ์ผ๋ก ์ฌ๋ฃ๋๋ค.1. ์ ๋ก 1
1.1 ์ฐ๊ตฌ๋ฐฐ๊ฒฝ 1
1.2 ์ฐ๊ตฌ๋ํฅ 4
1.3 ์ฐ๊ตฌ์ ๋ชฉ์ ๋ฐ ๋ฒ์ 7
2. ํน์ง์ ์ถ์ถ 10
2.1 ์์ ์ ์ฒ๋ฆฌ 10
2.2 SAR-SIFT ๊ธฐ๋ฒ์ ํตํ ํน์ง์ ์ถ์ถ 11
2.2.1. SIFT ๊ธฐ๋ฒ์ ๋ฌธ์ ์ 11
2.2.2. SAR-SIFT ๊ธฐ๋ฒ 15
3. ์ ํฉ์ ์ถ์ถ 18
3.1 DLSS ๊ธฐ๋ฒ์ ํตํ ์ ํฉ์ ์ถ์ถ 18
3.1.1. ํ์ ์์ ์ LSS 19
3.1.2. ํ์ ์์ ์ ๋ฒกํฐ DLSS 21
3.1.3. DLSS ๊ธฐ๋ฒ์ ๋ฌธ์ ์ 22
3.2 ์ ์๋ ์ ํฉ์ ์ถ์ถ ๋ฐฉ๋ฒ 24
3.2.1. ์ ์ฒ๋ฆฌ ๋จ๊ณ 24
3.2.2. ํ๋ณด ์ ํฉ์ ์ถ์ถ ๋จ๊ณ 26
3.2.3. ์ ๋ฐ ์ ํฉ์ ์ถ์ถ ๋จ๊ณ 28
3.3 ์ ํฉ ๋ฐ ์ ํ๋ ํ๊ฐ ๋ฐฉ๋ฒ 29
3.3.1. ์ดํ ๋ณํ์ 29
3.3.2. ์ ํ๋ ํ๊ฐ ๋ฐฉ๋ฒ 31
4. ์คํ์ ์ ์ฉ ๋ฐ ํ๊ฐ 32
4.1 ์คํ์ง์ญ ๋ฐ ์๋ฃ 32
4.2 ํน์ง์ ์ถ์ถ ๊ฒฐ๊ณผ 35
4.2.1. SIFT ๊ธฐ๋ฒ์ ํตํ ํน์ง์ ์ถ์ถ ๊ฒฐ๊ณผ 35
4.2.2. SAR-SIFT ๊ธฐ๋ฒ์ ํตํ ํน์ง์ ์ถ์ถ ๊ฒฐ๊ณผ 37
4.3 ์ ํฉ์ ์ถ์ถ ๊ฒฐ๊ณผ 40
4.3.1. ๊ธฐ์กด ๊ธฐ๋ฒ์ ํตํ ์ ํฉ์ ์ถ์ถ ๊ฒฐ๊ณผ 40
4.3.2. ์ ์ ๊ธฐ๋ฒ์ ํตํ ์ ํฉ์ ์ถ์ถ ๊ฒฐ๊ณผ 44
4.4 ์ ํฉ ๊ฒฐ๊ณผ ๋ฐ ํ๊ฐ 49
5. ๊ฒฐ๋ก 55
Abstract 67Maste
Computer aided detection of defects in FRP bridge decks using infrared thermography
The objective of this research is to develop a turn-key system that is able to interface with the FLIR ThermaCAM S60 infrared camera and automatically capture and analyze defects in infrared images of FRP bridge decks. Infrared thermography is one of the nondestructive evaluation (NDE) techniques that are being used to locate defects (debonds and delaminations) in bridge components. It is a rapid data collection and interpretation technique having high sensitivity and reliability. Analysis of infrared images by human interpretation is dependent on the users knowledge and hence introduces ambiguity in the defect detection process.;This thesis investigates the use of an automated defect detection system to locate defects in infrared images of FRP bridge decks to eliminate/reduce human intervention. Air-filled and water-filled debonds were inserted between the wearing surface and the underlying FRP deck. Also, simulated subsurface delaminations (of various sizes and thickness) were created at the flange-to-flange junction between two FRP deck modules. (Abstract shortened by UMI.)
Reports to the President
A compilation of annual reports for the 1985-1986 academic year, including a report from the President of the Massachusetts Institute of Technology, as well as reports from the academic and administrative units of the Institute. The reports outline the year's goals, accomplishments, honors and awards, and future plans
Reports to the President
A compilation of annual reports for the 1986-1987 academic year, including a report from the President of the Massachusetts Institute of Technology, as well as reports from the academic and administrative units of the Institute. The reports outline the year's goals, accomplishments, honors and awards, and future plans
Housing quality and lost (public) space in Croatia
IN ENGLISH: In the post-socialist period and within the current social transition context, urban and rural Croatia has, just like other transition countries, experienced many changes in the social structure and space. One example is the housing quality which is a replica of the situation in the Croatian society and has also undergone some major changes. Socially oriented housing construction co-financed by the state and the cities is in an unfavourable position compared to private housing construction. In the last twenty years the amount of the social housing construction has been only a minor part of the total contruction work in the country. For instance, out of nine newly planned residential housing developments in Zagreb, the capital city, only three have been completed and the work on the rest of them has stopped and is unlikely to continue. Private construction work prevails especially on the edge of the city and is characterised by high density housing. This type of housing construction doesn't benefit the majority of citizens in search of accommodation (price per square meter is too high, low-quality building). There is also a big problem of the community facilities (primary and secondary infrastructure, schools, kindergartens, playgrounds, green areas, sidewalks, public transport etc.). The existing globalisation-transition circumstances of the Croatian society corroborate the fact which experts of various profiles often point out: ignoring the process of (urban) planning will irreparably damage the space. The city transformation shows the absence of comprehensive urban planning which results in an ever increasing number of random buildings which do not fit in the surroundings. This leads up to yet another important issue โ the shrinking and, in some cases, disappearance of public space which becomes the โlost spaceโ. In recent years there has been a lot of building in the city core and on the edge which does not quite fit in the existing urban structure, image or the skyline of the city. The current situation in the process of planning can be characterized as a conflict and imbalance between the powerful actors (mostly political and economic) and less powerful actors (mostly professional and civil). The actors who have the political power and influence and the ones who possess the capital are forming an โallianceโ between two important layers of the social structure. The lack of civil and professional actors, โlost spatial actorsโ, and therefore of civic aggregation is also present and that is also the cause of public space โdisappearanceโ and undermined process of public participation. --------------- IN CROATIAN: U postsocijalistiฤkom razdoblju i trenutnom tranzicijskom kontekstu urbana i ruralna Hrvatska su, kao i ostale tranzicijske zemlje, doลพivjele mnoge promjene u druลกtvenoj strukturi i samom prostoru. Na primjeru kvalitete stanovanja kao replike stanja u hrvatskom druลกtvu mogu se vidjeti znaฤajne promjene. Druลกtveno usmjerena stambena izgradnja sufinancirana od strane drลพave i gradova je stoga rjeฤa i u nepovoljnijoj je situaciji prema privatnoj stanogradnji. Zadnjih dvadeset godina udjel socijalne stambene gradnje je zanemariv u ukupnoj izgradnji na razini zemlje. Primjerice, od devet planiranih stambenih naselja izgraฤenih po modelu POS-a u Zagrebu samo su tri i zavrลกena. Na ostalima je proces gradnje zastao i ne ฤini se da ฤe se privesti kraju. Privatna je gradnje prisutnija, posebno na rubovima grada, a obiljeลพava je visoka gustoฤa gradnje. Ovakav tip gradnje ne odgovara veฤini stanovnika koji su u procesu potraลพnje stambene nekretnine (visoka cijena kvadratnog metra, a slaba kvaliteta gradnje). Postoji takoฤer i problem nedostatne opremljenosti susjedstva (primarna i sekundarna infrastruktura, ลกkole, vrtiฤi, igraliลกta, zelene povrลกine, pjeลกaฤke staze, javni transport itd.). Navedene globalizacijsko-tranzicijske okolnosti hrvatskog druลกtva potvrฤuju ono ลกto eksperti razliฤitih profila istiฤu, a to je da ฤe ignoriranje procesa (urbanog) planiranja nepovratno uniลกtiti prostor gradova. Ovakve transformacije pokazuju nedostatak sustavnog urbanog planiranja ลกto rezultira sve veฤim brojem zgrada koje se ne uklapaju u neposrednu okolinu. To nadalje dovodi do drugog vaลพnog aspekta โ smanjivanja i u nekim sluฤajevima, nestanka javnog prostora koji postaje โizgubljeni prostorโ. Posljednjih je godina izgraฤen velik broj zgrada, i u srediลกtu i na rubovima grada, koje se ne uklapaju u postojeฤu urbanu strukturu, izgled ili vizuru grada. Ovakvu situaciju obiljeลพavaju sukob i neravnoteลพa izmeฤu moฤnijih druลกtvenih aktera (veฤinom politiฤkih i ekonomskih) i onih manje moฤnih (veฤinom profesionalnih i civilnih). Politiฤki i ekonomski akteri se ฤesto povezuju u โsavezโ dvaju najjaฤih u druลกtvenoj strukturi. S druge strane nedostatak utjecaja civilnih i profesionalnih aktera kao โizgubljenih prostornih akteraโ dovodi do โnestankaโ javnih prostora te smanjenja vaลพnosti procesa participacije (sudjelovanja javnosti)