Practical vignetting correction method for digital camera with measurement of surface luminance distribution

Kordecki, Andrzej; Palus, Henryk; Bal, A.

doi:10.1007/s11760-016-0941-2

Cited by 26 publications

(13 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Although commonly associated with optical remote sensing (eg. Kordecki et al, 2016;Meng et al, 2015), vignetting is also known to impact TIR images in a similar fashion (eg. Hook et al, 2005;Meier et al, 2011) resulting in generally 'cooler' temperatures towards the edges of TIR images.…”

Section: Implications Of Results For Tir Based Monitoring Of Groundwamentioning

confidence: 99%

Thermal infrared imaging for the detection of relatively warm lacustrine groundwater discharge at the surface of freshwater bodies

Arricibita

Dugdale

Krause

et al. 2018

Journal of Hydrology

View full text Add to dashboard Cite

Thermal infrared (TIR) imaging has been previously applied to survey relatively large thermal footprints in coastal zones, lakes, reservoirs and rivers. In freshwater systems, the buoyancy of relatively warm groundwater during the winter months allows for the surface identification of groundwater discharge or thermal pollution using TIR imaging. However, information regarding the performance of TIR for resolving this warm groundwater upwelling is limited, particularly at fine spatial scales and variable discharge rates. In order to evaluate the suitability of TIR to trace warm groundwater upwelling at the water surface of lakes, ponds and reservoirs (e.g. lacustrine groundwater discharge (LGD) in shallow near-shore zones) we conducted a mesocosm experiment with a TIR camera situated 4 m above the water surface to capture thermal patterns in response to different groundwater discharge rates, weather conditions and the diurnal cycle. A fiber optic distributed temperature sensing system (FO-DTS) installed at 2 cm below the water surface was used to ground-truth spatial patterns observed in TIR images. Results show the impacts of both the diurnal cycle of net radiation and prevailing weather conditions on the accuracy of TIR imaging for resolving warm groundwater discharge. Most reliable results were obtained under overcast weather conditions and during the night. The results of our study provide guidance for those looking to use TIR for conducting thermal tracing of LGD at the surface of freshwater bodies during winter.

show abstract

Section: Implications Of Results For Tir Based Monitoring Of Groundwamentioning

confidence: 99%

Thermal infrared imaging for the detection of relatively warm lacustrine groundwater discharge at the surface of freshwater bodies

Arricibita

Dugdale

Krause

et al. 2018

Journal of Hydrology

View full text Add to dashboard Cite

show abstract

“…which can estimate multiple parameters in consideration of their relationship. Supporting non-radial vignetting functions [24] will also extend the capability of the proposed VB vignetting estimation. In addition, applying the proposed method to various techniques, such as panorama image stitching [1], where effective devignetting is required for high-quality image generation, is also of practical interest.…”

Section: Discussionmentioning

confidence: 99%

Variational-Bayesian Single-Image Devignetting

Sonogashira

Iiyama

Minoh

2018

IEICE Trans. Inf. & Syst.

View full text Add to dashboard Cite

Vignetting is a common type of image degradation that makes peripheral parts of an image darker than the central part. Singleimage devignetting aims to remove undesirable vignetting from an image without resorting to calibration, thereby providing high-quality images required for a wide range of applications. Previous studies into single-image devignetting have focused on the estimation of vignetting functions under the assumption that degradation other than vignetting is negligible. However, noise in real-world observations remains unremoved after inversion of vignetting, and prevents stable estimation of vignetting functions, thereby resulting in low quality of restored images. In this paper, we introduce a methodology of image restoration based on variational Bayes (VB) to devignetting, aiming at high-quality devignetting in the presence of noise. Through VB inference, we jointly estimate a vignetting function and a latent image free from both vignetting and noise, using a general image prior for noise removal. Compared with state-of-the-art methods, the proposed VB approach to single-image devignetting maintains effectiveness in the presence of noise, as we demonstrate experimentally.

show abstract

“…r-the distance of the pixel from the vignette center; c x ,c y -vignette center location; k-a vignette polynomial function of 6 freedom degrees [36]; k 0 , k 1 , k 2 , k 3 , k 4 , and k 5 -the MicaSense calibrated vignette coefficients.…”

Section: Discussionunclassified

An Empirical Assessment of Angular Dependency for RedEdge-M in Sloped Terrain Viticulture

et al. 2019

View full text Add to dashboard Cite

For grape canopy pixels captured by an unmanned aerial vehicle (UAV) tilt-mounted RedEdge-M multispectral sensor in a sloped vineyard, an in situ Walthall model can be established with purely image-based methods. This was derived from RedEdge-M directional reflectance and a vineyard 3D surface model generated from the same imagery. The model was used to correct the angular effects in the reflectance images to form normalized difference vegetation index (NDVI) orthomosaics of different view angles. The results showed that the effect could be corrected to a certain scope, but not completely. There are three drawbacks that might restrict a successful angular model construction and correction: (1) the observable micro shadow variation on the canopy enabled by the high resolution; (2) the complexity of vine canopies that causes an inconsistency between reflectance and canopy geometry, including effects such as micro shadows and near-infrared (NIR) additive effects; and (3) the resolution limit of a 3D model to represent the accurate real-world optical geometry. The conclusion is that grape canopies might be too inhomogeneous for the tested method to perform the angular correction in high quality.

show abstract

Practical vignetting correction method for digital camera with measurement of surface luminance distribution

Cited by 26 publications

References 20 publications

Thermal infrared imaging for the detection of relatively warm lacustrine groundwater discharge at the surface of freshwater bodies

Thermal infrared imaging for the detection of relatively warm lacustrine groundwater discharge at the surface of freshwater bodies

Variational-Bayesian Single-Image Devignetting

An Empirical Assessment of Angular Dependency for RedEdge-M in Sloped Terrain Viticulture

Contact Info

Product

Resources

About