Object detection has recently experienced substantial progress. Yet, the widely adopted horizontal bounding box representation is not appropriate for ubiquitous oriented objects such as objects in aerial images and scene texts. In this paper, we propose a simple yet effective framework to detect multi-oriented objects. Instead of directly regressing the four vertices, we glide the vertex of the horizontal bounding box on each corresponding side to accurately describe a multi-oriented object. Specifically, We regress four length ratios characterizing the relative gliding offset on each corresponding side. This may facilitate the offset learning and avoid the confusion issue of sequential label points for oriented objects. To further remedy the confusion issue for nearly horizontal objects, we also introduce an obliquity factor based on area ratio between the object and its horizontal bounding box, guiding the selection of horizontal or oriented detection for each object. We add these five extra target variables to the regression head of fast R-CNN, which requires ignorable extra computation time. Extensive experimental results demonstrate that without bells and whistles, the proposed method achieves superior performances on multiple multi-oriented object detection benchmarks including object detection in aerial images, scene text detection, pedestrian detection in fisheye images.

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The purpose of the study is to evaluate right ventricular (RV) regional and global systolic function in patients with pulmonary arterial hypertension (PAH) by 2-dimensional ultrasound speckle tracking echocardiography (STE) and explore the impact of pulmonary artery systolic pressure (PASP) and pulmonary vascular resistance (PVR) on RV systolic function. 42 patients with PAH and 31 healthy controls were included in this study. RV longitudinal peak systolic strain (LS) and strain rate (LSRs) were measured at the basal, mid and apical segments of the RV free wall and septum by STE. RV global longitudinal peak systolic strain (GLS) and strain rate (GLSRs) were also measured by STE. RV ejection fraction (EF) was determinated by cardiac magnetic resonance (CMR) imaging. LS and LSRs of RV 6 segments were significantly reduced in patients with PAH compared with controls. RV GLS and GLSRs were lower in patients with varying degrees of PAH than controls. Furthermore, RV GLS were most altered in patients with severe PAH compared with mild PAH. PVR was correlated with RV GLS and GLSRs (r₁ = -0.549; r₂ = -0.466, respectively, P < 0.05). Similarly, there was correlation between PASP and RV GLS and GLSRs (r₁ = -0.551; r₂ = -0.425, respectively, P < 0.05). GLS and GLSRs were correlated with CMR-derived RVEF. (r₁ = 0.693; r₂ = 0.560, respectively, P < 0.05). STE can identify impaired RV regional and global systolic function in patients with PAH. STE-derived strain and strain rate can be used as novel indices for RV function assessment from 2-dimensional echocardiographic images.