scholarly journals The Sea-Surface Reflectance Factor: Replicability of Computed Values

2021 ◽  
Author(s):  
Davide D Alimonte ◽  
Tamito kajiyama ◽  
Giuseppe Zibordi ◽  
Barbara Bulgarelli
Keyword(s):  
Sea Surface ◽  
Surface Reflectance ◽  
Reflectance Factor

scholarly journals Spectral sea surface reflectance of skylight

2017 ◽  
Vol 25 (4) ◽  
pp. A1 ◽  
Author(s):  
Xiaodong Zhang ◽  
Shuangyan He ◽  
Afshin Shabani ◽  
Peng-Wang Zhai ◽  
Keping Du
Keyword(s):  
Sea Surface ◽  
Surface Reflectance

scholarly journals Refining the sea surface identification approach for determining freeboards in the ICESat-2 sea ice products

2021 ◽  
Vol 15 (2) ◽  
pp. 821-833
Author(s):  
Ron Kwok ◽  
Alek A. Petty ◽  
Marco Bagnardi ◽  
Nathan T. Kurtz ◽  
Glenn F. Cunningham ◽  
...  
Keyword(s):  
Sea Ice ◽  
Sea Surface Height ◽  
Sea Surface ◽  
The Arctic ◽  
Surface Reflectance ◽  
Data Product ◽  
Sea Surface Heights ◽  
Identification Approach ◽  
Southern Oceans

Abstract. In Release 001 and 002 of the ICESat-2 sea ice products, candidate height segments used to estimate the reference sea surface height for freeboard calculations included two surface types: specular and smooth dark leads. We found that the uncorrected photon rates, used as proxies of surface reflectance, are attenuated due to clouds resulting in the potential misclassification of sea ice as dark leads, biasing the reference sea surface height relative to those derived from the more reliable specular returns. This results in higher reference sea surface heights and lower estimated ice freeboards. The resolution of available cloud flags from the ICESat-2 atmosphere data product is too coarse to provide useful filtering at the lead segment scale. In Release 003, we have modified the surface-reference-finding algorithm so that only specular leads are used. The consequence of this change can be seen in the composites of mean freeboard of the Arctic and Southern oceans. Broadly, coverages have decreased by ∼10–20 % because there are fewer leads (by excluding the dark leads), and the composite means have increased by 0–4 cm because of the use of more consistent specular leads.

scholarly journals Polyp Shape Recovery from Single Endoscope Image using Medical Suture

2019 ◽  
Vol 12 (1) ◽  
pp. 1-17
Author(s):  
Hiroyasu Usami ◽  
Yuji Iwahori ◽  
Aili Wang ◽  
M. K. Bhuyan ◽  
Naotaka Ogasawara ◽  
...  
Keyword(s):  
Support System ◽  
Shape Recovery ◽  
Shape From Shading ◽  
Surface Reflectance ◽  
Absolute Size ◽  
Recovery Method ◽  
Constraint Equations ◽  
Medical Structure ◽  
Reflectance Factor ◽  
Lambertian Reflectance

Background:Polyp shapes play an important role in colorectal diagnosis. However, endoscopy images are usually composed of nonrigid objects such as a polyp. Hence, it is challenging for polyp shape recovery. It is demanded to establish a support system of the colorectal diagnosis system based on polyp shape.Introduction:Shape from Shading (SFS) is one valuable approach based on photoclinometry for polyp shape recovery. SFS and endoscope image are compatible on the first sight, but there are constraints for applying SFS to endoscope image. Those approaches need some parameters like a depth from the endoscope lens to the surface, and surface reflectance factor . Furthermore, those approaches assume the whole surface which has the same value of for the Lambertian surface.Methods:This paper contributes to mitigating constraint for applying SFS to the endoscope image based on a cue from the medical structure. An extracted medical suture is used to estimate parameters, and a method of polyp shape recovery method is proposed using both geometric and photometric constraint equations. Notably, the proposed method realizes polyp shape recovery from a single endoscope image.Results:From experiments it was confirmed that the approximate polyp model shape was recovered and the proposed method recovered absolute size and shape of polyp using medical suture information and obtained parameters from a single endoscope image.Conclusion:This paper proposed a polyp shape recovery method which mitigated the constraint for applying SFS to the endoscope image using the medical suture. Notably, the proposed method realized polyp shape recovery from a single endoscope image without generating uniform Lambertian reflectance.

Surface reflectance factor retrieval from thematic mapper data

1989 ◽  
Vol 27 (1) ◽  
pp. 47-57 ◽  
Author(s):  
Ronald G. Holm ◽  
Ray D. Jackson ◽  
Benfan Yuan ◽  
M. Susan Moran ◽  
Philip N. Slater ◽  
...  
Keyword(s):  
Thematic Mapper ◽  
Surface Reflectance ◽  
Thematic Mapper Data ◽  
Reflectance Factor
Sign in / Sign up

Export Citation Format

Share Document