Sea surface correction of high spatial resolution ikonos images to improve bottom mapping in near-shore environments

Hochberg, Eric J.; Andréfouët, Serge; Tyler, Max

doi:10.1109/tgrs.2003.815408

Cited by 200 publications

(162 citation statements)

References 12 publications

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“…Although these algorithms have been tested widely [77][78][79][80], additional calibrations with in situ time series measurements during different tides and seasons are needed for improved remotely sensed water and bottom retrievals. Multispectral high-resolution satellite imagery has led to better coral reef maps [81][82][83] and successful estimations of coral reefs' gross primary production [84], which provides an important geospatial tool for biodiversity and productivity assessments. Algorithms and models used for these purposes need to account for bottom depth, either measured or modeled [84][85][86].…”

Section: Discussionmentioning

confidence: 99%

Characterization of Available Light for Seagrass and Patch Reef Productivity in Sugarloaf Key, Lower Florida Keys

et al. 2016

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Light availability is an important factor driving primary productivity in benthic ecosystems, but in situ and remote sensing measurements of light quality are limited for coral reefs and seagrass beds. We evaluated the productivity responses of a patch reef and a seagrass site in the Lower Florida Keys to ambient light availability and spectral quality. In situ optical properties were characterized utilizing moored and water column bio-optical and hydrographic measurements. Net ecosystem productivity (NEP) was also estimated for these study sites using benthic productivity chambers. Our results show higher spectral light attenuation and absorption, and lower irradiance during low tide in the patch reef, tracking the influx of materials from shallower coastal areas. In contrast, the intrusion of clearer surface Atlantic Ocean water caused lower values of spectral attenuation and absorption, and higher irradiance in the patch reef during high tide. Storms during the studied period, with winds >10 m¨s´1, caused higher spectral attenuation values. A spatial gradient of NEP was observed, from high productivity in the shallow seagrass area, to lower productivity in deeper patch reefs. The highest daytime NEP was observed in the seagrass, with values of almost 0.4 g¨O 2¨m´2¨h´1 . Productivity at the patch reef area was lower in May than during October 2012 (mean = 0.137 and 0.177 g¨O 2¨m´2¨h´1 , respectively). Higher photosynthetic active radiation (PAR) levels measured above water and lower light attenuation in the red region of the visible spectrum (~666 to~699 nm) had a positive correlation with NEP. Our results indicate that changes in light availability and quality by suspended or resuspended particles limit benthic productivity in the Florida Keys.

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Section: Discussionmentioning

confidence: 99%

Characterization of Available Light for Seagrass and Patch Reef Productivity in Sugarloaf Key, Lower Florida Keys

et al. 2016

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“…Thus, it is difficult to avoid and may seriously influence the bathymetry results, especially for images with high spatial resolution. Fortunately, a sunglint correction algorithm has already been developed by Hochberg et al [54], and it was improved and used to correct the sunglint of high-spatial-resolution images for the estimation of water depth and diffuse attenuation coefficients by Eugenio et al [38,55]. Thus, to perform the sunglint correction in this study, we simply applied Eugenio's method to the remote sensing reflectance image.…”

Section: Sunglint Correction and Subsurface Remote Sensing Reflectancmentioning

confidence: 99%

Bathymetry of the Coral Reefs of Weizhou Island Based on Multispectral Satellite Images

Huang

Wang

et al. 2017

Remote Sensing

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Shallow water depth measurements using multispectral images are crucial for marine surveying and mapping. At present, relevant studies either depend on the use of other auxiliary data (such as field water depths or water column data) or contain too many unknown variables, thus making these studies suitable only for images that contain enough visible wavebands. To solve this problem, a Quasi-Analytical Algorithm (QAA) approach is proposed in this paper for estimating the water depths around Weizhou Island by developing a QAA to estimate the diffuse attenuation coefficients and simplifying the parameterization of the bathymetric model. The approach contains an initialization sub-approach and a novel global adjustment sub-approach. It is not only independent of other auxiliary data but also greatly reduces the number of unknowns. Experimental results finally demonstrated that the Root Mean Square Errors (RMSEs) were 1.01 m and 0.77 m for the ZY-3 image and the WorldView-3 (WV-3) image, respectively, so the approach is competitive to other QAA bathymetric methods. Besides, the global adjustment sub-approach was also seen to be superior to common smoothing filters: if the Signal-to-Noise Ratio (SNR) is as low as 42, i.e., ZY-3, it can smooth the water depths and improve the accuracies, otherwise can avoid the over-smoothing of water depths.

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“…The acquisition geometry of Image 2 places the sensor close to the specular point in the backscattering direction (Figure 1), thus exacerbating the effect of sunglint within this image ( Figure 2). The atmospherically-corrected Image 2 was, therefore, corrected for glint effects, implementing the method revised by [28] after [29]. This method assumes negligible water reflectance in the near-infrared (NIR) band.…”

Section: Pre-processingmentioning

confidence: 99%

“…For example, substratum separability is enhanced by higher solar zenith angles [20], while the probability of sunglint in the image is enhanced by clear skies, shallow waters, high spatial resolution, and wide sensor field of view (FOV) [28,29]. This may lead to the signal from the target being saturated.…”

mentioning

confidence: 99%

Effects of Per-Pixel Variability on Uncertainties in Bathymetric Retrievals from High-Resolution Satellite Images

2016

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Increased sophistication of high spatial resolution multispectral satellite sensors provides enhanced bathymetric mapping capability. However, the enhancements are counter-acted by per-pixel variability in sunglint, atmospheric path length and directional effects. This case-study highlights retrieval errors from images acquired at non-optimal geometrical combinations. The effects of variations in the environmental noise on water surface reflectance and the accuracy of environmental variable retrievals were quantified. Two WorldView-2 satellite images were acquired, within one minute of each other, with Image 1 placed in a near-optimal sun-sensor geometric configuration and Image 2 placed close to the specular point of the Bidirectional Reflectance Distribution Function (BRDF). Image 2 had higher total environmental noise due to increased surface glint and higher atmospheric path-scattering. Generally, depths were under-estimated from Image 2, compared to Image 1. A partial improvement in retrieval error after glint correction of Image 2 resulted in an increase of the maximum depth to which accurate depth estimations were returned. This case-study indicates that critical analysis of individual images, accounting for the entire sun elevation and azimuth and satellite sensor pointing and geometry as well as anticipated wave height and direction, is required to ensure an image is fit for purpose for aquatic data analysis.

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Sea surface correction of high spatial resolution ikonos images to improve bottom mapping in near-shore environments

Cited by 200 publications

References 12 publications

Characterization of Available Light for Seagrass and Patch Reef Productivity in Sugarloaf Key, Lower Florida Keys

Characterization of Available Light for Seagrass and Patch Reef Productivity in Sugarloaf Key, Lower Florida Keys

Bathymetry of the Coral Reefs of Weizhou Island Based on Multispectral Satellite Images

Effects of Per-Pixel Variability on Uncertainties in Bathymetric Retrievals from High-Resolution Satellite Images

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