Flat Versus Hemispherical Dome Ports in Underwater
Photogrammetry

Menna, Fabio; Nocerino, Erica; Remondino, Fabio

doi:10.5194/isprs-archives-xlii-2-w3-481-2017

Cited by 29 publications

(23 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A similar systematic pattern is observed for N750 and PL41, with higher residuals arranged in a circular shape around the image center and towards the corners. The residual systematic effect for the N750 was already reported in [36] and is also confirmed by the visual analysis of the images (Figure 11). The behavior is assumed to be related to optical effects introduced by the dome port.…”

Section: Residual Systematic Patternssupporting

confidence: 82%

“…The image residuals are quite high in magnitude for the GoPro. This is not surprising due to poorer image quality caused by a combination of the cheaper sensor and lens and the presence of a flat port [36]. Comparing the reprojection errors, the GoPros produced values that were greater than the higher quality systems by a factor of 2.…”

Section: Residual Systematic Patternsmentioning

confidence: 99%

See 1 more Smart Citation

Coral Reef Monitoring by Scuba Divers Using Underwater Photogrammetry and Geodetic Surveying

et al. 2020

View full text Add to dashboard Cite

Underwater photogrammetry is increasingly being used by marine ecologists because of its ability to produce accurate, spatially detailed, non-destructive measurements of benthic communities, coupled with affordability and ease of use. However, independent quality control, rigorous imaging system set-up, optimal geometry design and a strict modeling of the imaging process are essential to achieving a high degree of measurable accuracy and resolution. If a proper photogrammetric approach that enables the formal description of the propagation of measurement error and modeling uncertainties is not undertaken, statements regarding the statistical significance of the results are limited. In this paper, we tackle these critical topics, based on the experience gained in the Moorea Island Digital Ecosystem Avatar (IDEA) project, where we have developed a rigorous underwater photogrammetric pipeline for coral reef monitoring and change detection. Here, we discuss the need for a permanent, underwater geodetic network, which serves to define a temporally stable reference datum and a check for the time series of photogrammetrically derived three-dimensional (3D) models of the reef structure. We present a methodology to evaluate the suitability of several underwater camera systems for photogrammetric and multi-temporal monitoring purposes and stress the importance of camera network geometry to minimize the deformations of photogrammetrically derived 3D reef models. Finally, we incorporate the measurement and modeling uncertainties of the full photogrammetric process into a simple and flexible framework for detecting statistically significant changes among a time series of models.

show abstract

Section: Residual Systematic Patternssupporting

confidence: 82%

Section: Residual Systematic Patternsmentioning

confidence: 99%

Coral Reef Monitoring by Scuba Divers Using Underwater Photogrammetry and Geodetic Surveying

et al. 2020

View full text Add to dashboard Cite

show abstract

“…However, self-calibration is challenging in our dataset as camera network geometry is particularly weak when dealing with elongated strips with only nadir images and no side overlap and/or oblique imagery [57]. Systematic errors produced in such datasets can cause bending and non-linear deformations in the photogrammetric models as confirmed by our tests [57,58]. Here we apply a simple preliminary solution to the camera calibration problem using a constrained self-calibration approach by taking advantage of the flat under-ice surface, the known transect lengths and a series of identifiable reference points that were also measured from above the surface.…”

Section: Rgb Imagery and Sfm Digital Photogrammetrymentioning

confidence: 74%

An Under-Ice Hyperspectral and RGB Imaging System to Capture Fine-Scale Biophysical Properties of Sea Ice

et al. 2019

View full text Add to dashboard Cite

Sea-ice biophysical properties are characterized by high spatio-temporal variability ranging from the meso-to the millimeter scale. Ice coring is a common yet coarse point sampling technique that struggles to capture such variability in a non-invasive manner. This hinders quantification and understanding of ice algae biomass patchiness and its complex interaction with some of its sea ice physical drivers. In response to these limitations, a novel under-ice sled system was designed to capture proxies of biomass together with 3D models of bottom topography of land-fast sea-ice. This system couples a pushbroom hyperspectral imaging (HI) sensor with a standard digital RGB camera and was trialed at Cape Evans, Antarctica. HI aims to quantify per-pixel chlorophyll-a content and other ice algae biological properties at the ice-water interface based on light transmitted through the ice. RGB imagery processed with digital photogrammetry aims to capture under-ice structure and topography. Results from a 20 m transect capturing a 0.61 m wide swath at sub-mm spatial resolution are presented. We outline the technical and logistical approach taken and provide recommendations for future deployments and developments of similar systems. A preliminary transect subsample was processed using both established and novel under-ice bio-optical indices (e.g., normalized difference indexes and the area normalized by the maximal band depth) and explorative analyses (e.g., principal component analyses) to establish proxies of algal biomass. This first deployment of HI and digital photogrammetry under-ice provides a proof-of-concept of a novel methodology capable of delivering non-invasive and highly resolved estimates of ice algal biomass in-situ, together with some of its environmental drivers. Nonetheless, various challenges and limitations remain before our method can be adopted across a range of sea-ice conditions. Our work concludes with suggested solutions to these challenges and proposes further method and system developments for future research.

show abstract

“…Both Van den Heuvel et al (2006) and Pöntinen (2008) report chromatic aberration in fisheye lens systems. In addition, Menna et al (2017) and Helmholz and Lichti (2019) both report the presence of chromatic aberration effects in underwater imagery captured with a camera system coupled with a planar housing port. The common thread among these examples is the presence of chromatic aberration effects in imagery produced by a colour filter array sensor and broadband illumination.…”

Section: Introductionmentioning

confidence: 99%

Investigation Into the Behaviour and Modelling of Chromatic Aberrations in Non-Metric Digital Cameras

Lichti

Jarron

Shahbazi

et al. 2019

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

View full text Add to dashboard Cite

Abstract. Chromatic aberration in colour digital camera imagery can affect the accuracy of photogrammetric reconstruction. Both longitudinal and transverse chromatic aberrations can be effectively modelled by making separate measurements in each of the blue, green and red colour bands and performing a specialized self-calibrating bundle adjustment. This paper presents the results of an investigation with two aims. The first aim is to quantify the presence of chromatic aberration in two sets of cameras: the six individual cameras comprising a Ladybug5 system, calibrated simultaneously in air; and four GoPro Hero 5 cameras calibrated independently under water. The second aim is to investigate the impacts of imposing different constraints in the self-calibration adjustment. To this end, four different adjustment cases were performed for all ten cameras: independent adjustment of the observations from each colour band; combined adjustment of all colour bands’ observations with common object points; combined adjustment of all colour bands with common object points and common exterior orientation parameters for each colour band triplet; and combined adjustment with common object points and certain common interior orientation parameters. The results show that the Ladybug5 cameras exhibit a small (1-2 pixel) amount of transverse chromatic aberration but no longitudinal chromatic aberration. The GoPro Hero 5 cameras exhibit significant (25 pixel) transverse chromatic aberration as well as longitudinal chromatic aberration. The principal distance was essentially independent of the adjustment case for the Ladybug5, but it was not for the GoPro Hero 5. The principal point position and precision were both affected considerably by adjustment case. Radial lens distortion was invariant to the adjustment case. The impact of adjustment case on decentring distortion was minimal in both cases.

show abstract

Flat Versus Hemispherical Dome Ports in Underwater Photogrammetry

Cited by 29 publications

References 11 publications

Coral Reef Monitoring by Scuba Divers Using Underwater Photogrammetry and Geodetic Surveying

Coral Reef Monitoring by Scuba Divers Using Underwater Photogrammetry and Geodetic Surveying

An Under-Ice Hyperspectral and RGB Imaging System to Capture Fine-Scale Biophysical Properties of Sea Ice

Investigation Into the Behaviour and Modelling of Chromatic Aberrations in Non-Metric Digital Cameras

Contact Info

Product

Resources

About