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High Dynamic Range Image Construction and Noise Reduction Using Differently Exposed Images

Öhrn, Anton LU (2014) In Master's Theses in Mathematical Sciences FMA820 20141
Mathematics (Faculty of Engineering)
Abstract
This thesis discuss how to use mutual information in differently exposed images to improve noise reduction. It also investigates how one can create an high dynamic range (HDR) image from multiple differently exposed images taken with a handheld camera while simultaneously cope with the problems this approach introduces.

The proposed method and workflow in this thesis is based on the non-local means algorithm that uses both image registration and a intensity transformation to takes advantage of the mutual information in the different images. It uses alpha expansion to select contiguous areas for the HDR construction and image blending to create seamless transitions between the images.

The noise reduction algorithm shows better results... (More)
This thesis discuss how to use mutual information in differently exposed images to improve noise reduction. It also investigates how one can create an high dynamic range (HDR) image from multiple differently exposed images taken with a handheld camera while simultaneously cope with the problems this approach introduces.

The proposed method and workflow in this thesis is based on the non-local means algorithm that uses both image registration and a intensity transformation to takes advantage of the mutual information in the different images. It uses alpha expansion to select contiguous areas for the HDR construction and image blending to create seamless transitions between the images.

The noise reduction algorithm shows better results with an intensity based noise level compared to a constant one. The methods used to take advantage of the mutual information are proven to be inadequate as the result for using noise reduction in a single image is shown to be just as good. The HDR image construction using both alpha expansion and image blending works well. For smaller movements the approach shows good result and even works as an anti-ghosting algorithm but for larger movements ghosting artifacts are introduced. (Less)
Popular Abstract (Swedish)
High­dynamic­range imaging (HDR) är en mängd tekniker som används för att producera bilder med mer detaljer i både mörka och ljusa områden jämfört med ett traditionellt foto. Ett sätt att göra HDR på är att sätta ihop bilder med olika mängd ljus i sig. Problem uppstår dock om kameran rör på sig mellan bilderna eller föremål i bilderna flyttar på sig.
Please use this url to cite or link to this publication:
author
Öhrn, Anton LU
supervisor
organization
course
FMA820 20141
year
type
H2 - Master's Degree (Two Years)
subject
keywords
HDR, HDR construction, Noise reduction, portable device imaging, image analysis
publication/series
Master's Theses in Mathematical Sciences
report number
LUTFMA-3266-2014
ISSN
1404-6342
other publication id
2014:E50
language
English
id
4697808
date added to LUP
2014-12-15 13:26:58
date last changed
2014-12-15 13:26:58
@misc{4697808,
  abstract     = {{This thesis discuss how to use mutual information in differently exposed images to improve noise reduction. It also investigates how one can create an high dynamic range (HDR) image from multiple differently exposed images taken with a handheld camera while simultaneously cope with the problems this approach introduces.

The proposed method and workflow in this thesis is based on the non-local means algorithm that uses both image registration and a intensity transformation to takes advantage of the mutual information in the different images. It uses alpha expansion to select contiguous areas for the HDR construction and image blending to create seamless transitions between the images.

The noise reduction algorithm shows better results with an intensity based noise level compared to a constant one. The methods used to take advantage of the mutual information are proven to be inadequate as the result for using noise reduction in a single image is shown to be just as good. The HDR image construction using both alpha expansion and image blending works well. For smaller movements the approach shows good result and even works as an anti-ghosting algorithm but for larger movements ghosting artifacts are introduced.}},
  author       = {{Öhrn, Anton}},
  issn         = {{1404-6342}},
  language     = {{eng}},
  note         = {{Student Paper}},
  series       = {{Master's Theses in Mathematical Sciences}},
  title        = {{High Dynamic Range Image Construction and Noise Reduction Using Differently Exposed Images}},
  year         = {{2014}},
}