get_flow_data.py

# Code from OpenCV Optical Flow Demo #
import os
import cv2 as cv
import numpy as np
from pathlib import Path


def processVideo(vid, savePath, filename):
    cap = cv.VideoCapture(cv.samples.findFile(vid))
    ret, frame1 = cap.read()
    scale_percent = 33.3333333333 # percent of original size
    width = int(frame1.shape[1] * scale_percent / 100)
    height = int(frame1.shape[0] * scale_percent / 100)
    dim = (width, height)
    frame1 = cv.resize(frame1, dim)
    prev = cv.cvtColor(frame1,cv.COLOR_BGR2GRAY)
    
    flow_data_1 = np.zeros((30, frame1.shape[0], frame1.shape[1], 2)) 
    frameCount = 0
    while(cap.isOpened() and frameCount < 30):
        ret, frame2 = cap.read()

        if ret == False:
            break
        frame2 = cv.resize(frame2, dim)
        cur = cv.cvtColor(frame2,cv.COLOR_BGR2GRAY)

        # Get dense optical flow
        flow = cv.calcOpticalFlowFarneback(prev, cur, None, 0.5, 3, 15, 3, 5, 1.2, 0)
        flow = flow.astype(np.int8)

        # Convert datatype
        flow_data_1[frameCount, :, :, :] = flow
        frameCount += 1
    
    with open(savePath + filename + '_flow_1.npz', 'wb') as file:
        np.savez_compressed(file, flow_data_1)

    flow_data_2 = np.zeros((30, frame1.shape[0], frame1.shape[1], 2))
    frameCount = 0
    while(cap.isOpened() and frameCount < 30):
        ret, frame2 = cap.read()

        if ret == False:
            break
        frame2 = cv.resize(frame2, dim)
        cur = cv.cvtColor(frame2,cv.COLOR_BGR2GRAY)

        # Get dense optical flow
        flow = cv.calcOpticalFlowFarneback(prev, cur, None, 0.5, 3, 15, 3, 5, 1.2, 0)
        flow = flow.astype(np.int8)

        # Convert datatype
        flow_data_2[frameCount, :, :, :] = flow
        frameCount += 1

    with open(savePath + filename + '_flow_2.npz', 'wb') as file:
        np.savez_compressed(file, flow_data_2)
    
    cap.release()
    cv.destroyAllWindows()

# For each video save clips of 60 frames - w/ 60 frames in between - Save file with nparray of extracted info for each frame
# Save outlined contour - delete bad examples

savePath = "ProcessedDataPresentation/"
findPath = "TrimmedData/"
for filename in os.listdir(findPath):
    print("file", filename)
    if filename.endswith(".mov") or filename.endswith(".avi"):
        processVideo(findPath + filename, savePath, Path(filename).stem)