如何使用 Python 和 OpenCV 将漩涡等效果应用于网络摄像头 stream？

Question

我正在做一个学校项目，我想通过实时对网络摄像头 stream 应用各种效果来模拟 LSD 旅行。 我正在使用Python和OpenCV来捕获和显示网络摄像头stream。我想应用的效果是：鬼影效果（类似于这个https://www.learnpythonwithrune.org/opencv-python-webcam-create-a-ghost -effect/ ), colors 中更多的活力/饱和度, 轻微的模糊, 扭曲的外部边缘和一种漩涡效果 (类似于这个https://www.alamy.com/stock-photo-checkered-pattern-with-spiral-旋转漩涡失真效果 104721121.html )

我已经能够使用 OpenCV 的 cv2.VideoCapture 和 cv2.imshow 函数捕获和显示网络摄像头 stream。 但是，我无法弄清楚如何将漩涡等效果应用到 stream。

我曾尝试使用 OpenCV 的 cv2.getRotationMatrix2D 和 cv2.warpAffine 函数来应用漩涡效果，但 output 不是我所期望的。

有什么解决办法吗？ 或者我应该 go 换个方式。

这是我到目前为止所得到的：

`

import cv2
import numpy as np

# Open the webcam
cap = cv2.VideoCapture(0)

# Initialize the previous frame to None
frame_prev = None

while True:
    # Capture a frame from the webcam
    ret, frame = cap.read()
    
    # If this is the first frame, store it as the previous frame
    if frame_prev is None:
        frame_prev = frame.copy()
    
    # Apply the ghost effect by blending the current frame with a slightly transparent previous frame
    alpha = 0.5
    frame = cv2.addWeighted(frame, 1-alpha, frame_prev, alpha, 0)
    
    # Update the previous frame
    frame_prev = frame.copy()
    
    # Apply slight blur
    frame = cv2.GaussianBlur(frame, (5, 5), 0)
    
    # Increase saturation
    frame = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)
    frame[:,:,1] = np.clip(frame[:,:,1] * 1.5, 0, 255)
    frame = cv2.cvtColor(frame, cv2.COLOR_HSV2BGR)
    
    # Distort outer edges
    height, width = frame.shape[:2]
    center = (width//2, height//2)
    radius = min(width, height) // 2
    mask = np.zeros((height, width), np.uint8)
    cv2.circle(mask, center, radius, (255, 255, 255), thickness=-1)
    mask = cv2.dilate(mask, kernel=np.ones((radius//10, radius//10), np.uint8))
    frame = cv2.GaussianBlur(frame, (3, 3), 0)
    frame = cv2.seamlessClone(frame, frame_prev, mask, center, cv2.NORMAL_CLONE)
    
    # Display the result
    cv2.imshow('Webcam', frame)
    
    # Check for user input
    key = cv2.waitKey(1)
    if key == 27:  # Esc key to exit
        break

# Release the webcam and close all windows
cap.release()
cv2.destroyAllWindows()

`

感谢您的帮助，非常感谢，因为我对编码非常陌生。

Answer 1

以下是如何使用 Python/OpenCV/Skimage 制作漩涡 animation。

• 读取输入
• 设置 arguments
• 循环输入图像并增加漩涡量（强度）并使用 skimage 漩涡应用变换以 PIL 格式保存结果
• 循环输入图像并减少漩涡量（强度）并使用 skimage 漩涡应用变换以 PIL 格式保存结果
• 当所有帧都生成并保存在帧列表中时，使用 PIL 将 animation 写入磁盘文件

输入：

import numpy as np
import cv2
from skimage.transform import swirl
from PIL import Image


img = cv2.imread("mandril.jpg")

# get dimensions
h, w = img.shape[:2]

# get center
cx = w//2
cy = h//2

# set amount, number of frames and delay
max_amount = 20
dist = min(h,w)/2
angle = 0
num_frames = 50
delay = 50
border_color = (128,128,128)


frames = []
# loop and increase swirl
for i in range(0,num_frames):

    # compute phase to increment over 360 degree for number of frames specified so makes full cycle
    amount = i*max_amount/num_frames

    # do swirl
    result = swirl(img, center=(cx,cy), rotation=angle, strength=amount, radius=dist, preserve_range=True).astype(np.uint8)
        
    # show result
    cv2.imshow('result', result)
    cv2.waitKey(delay)

    # convert to PIL format and save frames
    result = cv2.cvtColor(result, cv2.COLOR_BGR2RGB)
    pil_result = Image.fromarray(result)
    frames.append(pil_result)

# loop and decrease swirl
for i in range(0,num_frames):

    # compute phase to increment over 360 degree for number of frames specified so makes full cycle
    amount = (num_frames-i)*max_amount/num_frames

    # do swirl
    result = swirl(img, center=(cx,cy), rotation=angle, strength=amount, radius=dist, preserve_range=True).astype(np.uint8)
        
    # show result
    cv2.imshow('result', result)
    cv2.waitKey(delay)

    # convert to PIL format and save frames
    result = cv2.cvtColor(result, cv2.COLOR_BGR2RGB)
    pil_result = Image.fromarray(result)
    frames.append(pil_result)

# write animated gif from frames using PIL
frames[0].save('mandril_swirl_animation.gif',save_all=True, append_images=frames[1:], optimize=False, duration=delay, loop=0)

全尺寸 Animation

缩小尺寸 Animation：