Sa Gao's research while affiliated with Tongji University and other places

Publications (10)

Article
Full-text available
Fourier-based image correlation is a powerful area-based image registration technique which involves aligning images based on a translation model or similarity model by means of the image information and operation in the frequency domain. In recent years, Fourier-based image correlation has made significant progress and attracted extensive research...
Article
en High‐speed cameras are able to effectively and efficiently obtain the location of moving objects over time in many practical applications. In order to meet the requirement for fast computing and processing in the object‐tracking process, this paper adopts parallel computing to process multiple video‐image sequences by using open multi‐processing...
Article
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en Full‐field deformation measurement of specific materials is an important issue in civil engineering materials testing. This paper presents a flexible videogrammetric scheme to measure full‐field deformation of an artificial rock‐like material under uniaxial compression. In this scheme, two high‐speed cameras were used to measure the spatial morp...
Article
The Fourier-based image correlation technique has been widely concerned due to its accuracy, efficiency, and robustness to image contrast and brightness. Accordingly, a variety of subpixel methods have been proposed. However, the detailed subpixel-level influence of the complicated radiometric variations has yet to be investigated, and few correspo...
Article
Full-text available
Videogrammetry is an extension to close-range photogrammetry which provides a convenient way to capture the three-dimensional (3D) dynamic response of moving objects in a non-contact manner. The performance of tracking in image sequence is crucial to the measurement accuracy. This paper proposes an improved subpixel phase correlation method for tra...
Article
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The monitoring of a progressive collapse test of a structure model has always been a technical issue in civil engineering. This paper proposes a novel videogrammetric approach to monitor a single-layer lattice shell, which consists of three main parts: A videogrammetry system with six high-speed cameras is established to measure the morphological c...
Article
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In the summer and autumn, which is the primary cropland planting preparation and harvest time, cropland burning is very common in China. The Moderate Resolution Imaging Spectroradiometer (MODIS) Terra active fire product (MOD14) and GlobeLand30-2010 data are used here to analyze the fire activity of the predominant land cover types. A total of 44,8...
Article
Full-text available
In this letter, an improved phase correlation (PC) method based on 2-D plane fitting and the maximum kernel density estimator (MKDE) is proposed, which combines the idea of Stone's method and robust estimator MKDE. The proposed PC method first utilizes a vector filter to minimize the noise errors of the phase angle matrix and then unwraps the filte...

Citations

... Correlation measures the degree to which two variables are related and expresses in quantitative terms the strength and direction of the relationship between these variables. Practically, correlation, autocorrelation, and phase-correlation become basic tools in many applications, including computer vision, robotics, sport, biomedicine, acoustic, human movement and rehabilitation research, quantum computation, geophysical applications, and image and signal processing applications, to name only a few [1]- [4]. For example, cross-correlation is a key statistical method for getting the degree of relationship/similarity among two templates/images [1] or analyses in the human movement and rehabilitation sciences [2]. ...
... NCC is frequently used to estimate the similarity between matching entities in two images due to its simplicity and reliability [51]. For a patch r(x, y) in the reference image and a corresponding patch t(x + m, y + n) in the template image, where m and n stand for the offsets within the search range, the NCC between two patches is defined as [52]: ...
... However, the requirements of template size to obtain valid results are diverse for different grid positions, since a small template size is adequate for certain positions. Therefore, an adaptive strategy for adjusting template size based on local structural statistics is highlighted [62,64]. Future work will explore the combination of the presented LUGC method with adaptive template strategies to ensure both the correctness in low textured areas and the locality in areas with strong velocity gradient. ...
... Applying PC approach for 2-D images requires applying it for each direction separately and finally combining the results. Final PC equation at location (x) will be given as [13,[19][20][21][22][23][24][25][28][29][30]. ...
... A wide variety of applications utilize videos that have spatial and temporal overlaps [1,2]. Overlapping videos are commonly used in surveillance and security applications [3,4], industrial monitoring [5,6], 3D modeling [7], and 3D videos production [8]. Some of these are implemented by designing systems consisting of more than one camera in a fixed position relative to each other [2,8]. ...
... Video-photogrammetry is often used to measure rapidly changing objects in a short time. (19,20) Regarding the monitoring of building deformation, video-photogrammetry has often been used to monitor the deformation of bridges. (21)(22)(23)(24) Rodriguez et al. (25) applied a videophotogrammetric system to monitor the condition of a wind turbine. ...
... Smoke and flames produced during combustion can be detected in the visible light bands of remote sensing images, and high temperatures on the surface of fires are easily detected in the mid-infrared, shortwave infrared and thermal infrared bands (Leblon et al., 2012). In moderate or low spatial resolution images, the fire is represented as a fire spot with extremely high temperature, which also called thermal anomalies on a per-pixel basis (Xie et al., 2016). For instance, MOD14 monitors fire actively at a 1 km spatial resolution. ...
... Only observing the PC layer as shown in Fig. 3 (b), the details of part A are more obvious. Considering that only a certain number of projection planes are used in practice and one projection view could be enough to achieve high performance [26], we project the PC on the fitting plane obtained by the least-squares method [36] which is an optimization process. The purpose of establishing the fitting plane is to reduce the points that are projected on the same position repeatedly and to better reflect the geometric structure on the plane for considering all points. ...