kth.sePublikationer
Ändra sökning
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Real-time Autofocus Algorithm in Laser Speckle Contrast Imaging
KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
2023 (Engelska)Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)Alternativ titel
Autofokus i Realtid inom Laser Speckle Contrast Avbildning (Svenska)
Abstract [en]

Microcirculation is defined as the blood flow in the smallest blood vessels. Laser speckle contrast imaging (LSCI) is a full field imaging technique that provides instantaneous 2-D perfusion maps of illuminated tissues based on speckle contrast. Perimed’s Perfusion Speckle Imager (PSI) is a medical device developed at Perimed AB that exploits LSCI to measure tissue blood perfusion. In this thesis work, a robust Autofocus (AF) algorithm for PSI was implemented. AF is a procedure to drive PSI camera to reach the depth of focus and acquire sharp images, that relies only on signal processing. Therefore, several Blind image sharpness assessment (BISA) methods, to judge the degree of image sharpness, were compared to choose which BISA method to incorporate in the algorithm. An optimized focus scanning technique was implemented to more efficiently find the depth of focus. When working with LSCI, speckle is a source of noise that destroys image content. Experiments were performed to study laser speckle filtration: digital filters were employed to attenuate the speckle noise that corrupted details in the acquired images. Finally, two methods to perform AF were provided. These procedures were proven practically with LED images. However, with laser source image information is corrupted by speckle despite the application of digital filters and AF remains a real challenge. Moreover, important hardware limitations require to be overcome to make the technique real-time. Focus motor speed should be higher to acquire images at different focus positions faster which could benefit the speed of the AF procedure and speckle filtration. 

Ort, förlag, år, upplaga, sidor
2023. , s. 92
Serie
TRITA-CBH-GRU ; 2023:010
Nyckelord [en]
Laser speckle contrast imaging, Autofocus, Blind image sharpness assessment, Speckle noise, Perimed’s Perfusion Speckle Imager
Nationell ämneskategori
Medicinteknik
Identifikatorer
URN: urn:nbn:se:kth:diva-323329OAI: oai:DiVA.org:kth-323329DiVA, id: diva2:1731044
Externt samarbete
Perimed AB
Ämne / kurs
Medicinsk teknik
Utbildningsprogram
Teknologie masterexamen - Medicinsk teknik
Handledare
Examinatorer
Tillgänglig från: 2023-01-26 Skapad: 2023-01-25 Senast uppdaterad: 2023-01-26Bibliografiskt granskad

Open Access i DiVA

fulltext(38396 kB)891 nedladdningar
Filinformation
Filnamn FULLTEXT01.pdfFilstorlek 38396 kBChecksumma SHA-512
6b913bb90fb795334d4e5ff7949bf73cee3a745f20cc5f605c428cae168672aae36e604d18c9497a9cc7ff9a7f2c4b415e828556f1298e554c18939a2fe91046
Typ fulltextMimetyp application/pdf

Av organisationen
Skolan för kemi, bioteknologi och hälsa (CBH)
Medicinteknik

Sök vidare utanför DiVA

GoogleGoogle Scholar
Totalt: 893 nedladdningar
Antalet nedladdningar är summan av nedladdningar för alla fulltexter. Det kan inkludera t.ex tidigare versioner som nu inte längre är tillgängliga.

urn-nbn

Altmetricpoäng

urn-nbn
Totalt: 519 träffar
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf