Question

我有一个项目，应该使用fft和过滤器（lpf或hpf）实现视频稳定器

这是我要修改的部分代码：

import cv2
import numpy as np

# Create a VideoCapture object and read from input file
cap = cv2.VideoCapture('Vibrated2.avi')

# load data
data = np.loadtxt('Vibrated2.txt', delimiter=',')

# Define the codec and create VideoWriter object
frame_width = int(cap.get(3))
frame_height = int(cap.get(4))
out = cv2.VideoWriter('Stabilized.avi',cv2.VideoWriter_fourcc('M','J','P','G'), 25, (frame_width,frame_height))

# Check if camera opened successfully
if (cap.isOpened()== False): 
  print("Error opening video stream or file")

def transform(frame, param):
  ti = cv2.getRotationMatrix2D((0,0), 0, 1)
  ti[0,2] += param[0]
  ti[1,2] += param[1]
  frame = cv2.warpAffine(frame, ti, frame.shape[1:-4:-1])
  return frame

num = 0 
# Read until video is completed
while(cap.isOpened()):
  # Capture frame-by-frame
  ret, frame = cap.read()
  if ret == True:
    # apply transformation
    frame = transform(frame, data[num])
    print (frame, "dn")
    num+=1

    # Display the resulting frame
    cv2.imshow('Frame',frame)

    # Write the frame into the file 'output.avi'
    out.write(frame)

    # Press Q on keyboard to  exit
    if cv2.waitKey(25) & 0xFF == ord('q'):
      break

  # Break the loop
  else: 
    break

# When everything done, release the video capture object
cap.release()

# Closes all the frames
cv2.destroyAllWindows()

有一个名为Vibrated1.avi的视频还有一个包含框架差异的文本文件，名为Virated1.txt，看起来像这样：

0.341486，-0.258215

0.121945，1.27605

-0.0811261，0.78985

，...

我不知道如何以及在此代码中添加一些过滤器以消除视频振动

有人可以帮助我吗？

Answer 1

我可以用C ++部分编写简短的伪代码：

cv::Mat homoFiltered = cv::Mat::eye(3, 3, CV_32F);
const double alpha = 0.9;
cv::Mat a1 = cv::Mat::eye(3, 3, CV_32F) * alpha;
cv::Mat a2 = cv::Mat::eye(3, 3, CV_32F) * (1. - alpha);


while cap >> frame:
    cv::Mat homo = CalcHomography(frame)
    homoFiltered = a1 * (homoFiltered * homo) + a2 * homo;
    cv::warpPerspective(..., homoFiltered, ...)

alpha -在[0; 1]

a1 和 a2 -用于将alpha和（1-alpha）应用于变换矩阵的矩阵

homoFiltered -过滤后的转换矩阵

homo -帧（t-1）和帧（t）之间的当前矩阵

使用低通滤波器的Python视频稳定器

1 个答案: