每次通过后 matplotlib 都会变慢

Question

为什么我的代码会随着时间的推移而变慢？当代码最初开始时，循环需要 ~.1 秒到运行。到第 90 次传球时，我达到了 1+ 秒。我正在显示并保存图像。我注意到如果我按预期注释掉 fig.canvas.draw() 和 fig.canvas.flush_events() 代码运行s。问题在于显示和更新交互式 window。是否有我需要清除的变量？

from flirpy.camera.lepton import Lepton
import matplotlib.pyplot as plt
import numpy as np
import cv2
from PIL import Image as im
import os, sys
import time

%matplotlib notebook
savefold = ('Therm')
if not os.path.exists(savefold):
    os.makedirs(savefold)
    
    
camera = Lepton()
plt.ion()
fig = plt.figure()
ax = fig.add_subplot(111)
                         
def getFrame():
    image = camera.grab()
    
    fimage = np.around((image/100 - 273.15) * 9 / 5 + 32, 2)
    cimage = np.around(image/100 - 273.15, 2)
    kimage = np.around(image/100, 2)
    
    cimage = np.where(cimage < 20, 20, cimage)
    cimage = np.where(cimage > 30, 30, cimage)
    
    getFrame.z = cimage
    return getFrame.z

getFrame.z = None
i = 0
while True:
    tic = time.perf_counter()

    npimage=getFrame()
    npimage=npimage
    
    data = im.fromarray(npimage)
    plt.imshow(data)
    fig.canvas.draw()
    fig.canvas.flush_events()
    
    plt.imsave(os.path.join(savefold, f'test_{i:05}.png'), data)
    i += 1
    
    toc = time.perf_counter()
    print(f'Time to execute: {toc - tic:0.4f} seconds')
    

camera.close()

Answer 1

因为您为每次迭代添加一张图像：之前的所有图像仍在 matplotlib 缓冲区中，并且它们被渲染了！

您需要清除缓冲区。尝试在 imshow 命令之前使用这行代码：

plt.gca().images.clear()

每次通过后 matplotlib 都会变慢

matplotlib slows after every pass

python

matplotlib