Development of Line-of-Sight Digital Surface Model for Co-Registering Off-Nadir VHR Satellite Imagery With Elevation Data

Abstract

Co-registration of very-high-resolution (VHR) images with elevation data is extremely important for many remote sensing applications due to the complementary properties of these two data types. However, this type of multidata source registration has many associated challenges. For instance, although VHR satellite images are usually acquired off-nadir, the integration of off-nadir images with digital surface models (DSMs) for the purpose of urban mapping has been rarely seen in research publications. This is due to the relief displacement of the elevated objects, which causes a problematic misregistration between the perspective off-nadir images and the corresponding orthographic DSMs. Therefore, the co-registration of such datasets is almost impossible unless a true orthorectification process is executed. However, true orthoimages are expensive, time consuming, and difficult to achieve. Thus, this paper proposes a registration method based on developing a line-of-sight DSM solution to effectively register elevation data with off-nadir VHR images. The method utilizes the relevant sensor model in two phases: deriving DSM from stereo images and reprojecting the DSM back to one of the stereo images to generate a line-of-sight DSM for accurate co-registration. To demonstrate the applicability of the proposed method and evaluate the effect of the misregistration, a building detection procedure is implemented. The proposed method is found to be feasible, inexpensive, and of subpixel accuracy. Additionally, it improves the overall accuracy of detecting buildings by almost 12% relative to that when the conventional two-dimensional (2-D) registration technique is used solely due to the elimination of the misregistration effect.

Extracting Accurate Building Information from Off-Nadir VHR Images

“…These measures are described and used in Suliman and Zhang (2015). Based on these measures, the overall quality measure was found to be more than 90% relative to manually generated reference data.…”

“…The co-registering methods of image and elevation data are extensively reviewed in our previous work (Suliman and Zhang 2015). In that work, we introduced the line-of-sight DSM (LoS-DSM) solution to overcome most of the limitations in the reviewed methods and provide pixel-by-pixel co-registration.…”

A New Stereo Pair Disparity Index (SPDI) for Detecting Built-Up Areas from High-Resolution Stereo Imagery

“…Then, terrain slopes and building heights extracted from a DSM are used to improve built-up area results obtained by using planar features extracted from a DOM [12,39]. The built-up area identification results cannot be superimposed on the raw stereo imagery for display during evaluation [40][41][42]. These methods do not take full advantage of images with different viewing angles of stereo imagery, since these images are only used to produce DSMs and DOMs.…”

Optical-Elevation Data Co-Registration and Classification-Based Height Normalization for Building Detection in Stereo VHR Images

“…Object-based approaches are usually used to facilitate the integration and reduce the negative effect of the misregistration by changing the processing unit from individual pixels to a group of pixels (i.e., image segments/objects) [7]. Even so, this misregistration problem is still serious for tall buildings appearing in off-nadir VHR images [8].…”

“…As found in the literature, this co-registration can be achieved by four different ways: image-to-image registration, orthorectification, true-orthorectification, and the line-of-sight DSM (LoS-DSM) solution. All of these methods are defined, explained and reviewed extensively in [8]. Except for the LoS-DSM co-registration solution, it has been concluded that all of these methods have some limitations when off-nadir images acquired over dense urban environments are employed.…”