Multimodal Semantics Extraction from User-Generated Videos

Algorithm 4

Detection of in-view cameras.

(1) Determine the slopes 𝑚^FOV₁and 𝑚^FOV₂of the two lines 𝑙^FOV₁ and 𝑙^FOV₂ which delimit the  field of view of the recording camera, by using the camera pointing angle (horizontal orientation) and the angle of view.

(2) Determine the slope 𝑚_𝑖 of each line 𝑙_𝑖 connecting the position 𝑃_𝑐 of the recording camera to the position 𝑃_𝑖 of each other device i present at the event.

(3) Determine whether each device lies within the determined field of view, by evaluating the slope 𝑚_𝑖 of each line 𝑙_𝑖 with respect to the slopes of the two lines 𝑙^FOV₁ and 𝑙^FOV₂. If 𝑚_𝑖 is within the range [𝑚^FOV₁,𝑚^FOV₂], then the device 𝑖 is considered to be within the field of view of the recording camera.