visiannot.tools.video_loader¶

Summary¶

Module with functions for loading image and video files

Functions¶

`visiannot.tools.video_loader.get_data_video`(path)	Loads video data with openCV
`visiannot.tools.video_loader.get_duration_video`(path)	Gets duration of a video file
`visiannot.tools.video_loader.read_image`(path)	Reads an image with openCV
`visiannot.tools.video_loader.transform_image`(im)	Changes the order of an image channels in order to get RGB color, may reverse the first and second axis (in order to transform shape $(width, height, 3)$ to $(height, width, 3)$ ).

API¶

Functions¶

visiannot.tools.video_loader.get_data_video(path)[source]¶

Loads video data with openCV

Parameters

path (str) – path to the video file

Returns

data_video (cv2.VideoCapture) (None if video file does not exist)
nframes (int) – number of frames in the video (0 if video file does not exist)
fps (int or float) - frame rate of the video (-1 if video file does not exist)

visiannot.tools.video_loader.get_duration_video(path)[source]¶

Gets duration of a video file

Parameters: path (str) – path to the video file
Returns: video file duration in seconds
Return type: float

visiannot.tools.video_loader.read_image(path)[source]¶

Reads an image with openCV

Parameters: path (str) – path to the image file
Returns: RGB image array of shape $(width, height, 3)$
Return type: numpy array

visiannot.tools.video_loader.transform_image(im, RGB_combination='BGR', flag_transpose=True)[source]¶

Changes the order of an image channels in order to get RGB color, may reverse the first and second axis (in order to transform shape $(width, height, 3)$ to $(height, width, 3)$ ).

Particularly useful to display images retrieved with openCV. Indeed, openCV returns images of shape $(width, height, 3)$ with BGR color.

Parameters

im (numpy array) – image array of shape $(width, height, 3)$ , where third axis is a 3-channel color
RGB_combination (str) – order of the color channel (as with openCV)
flag_transpose (bool) – specify if first axis and second axis must be reversed

Returns

image array of shape $(height, width, 3)$ where third axis is RGB color

Return type

numpy array

If im is not a numpy array or is not a 3D array, then the output is im.