问为啥读入csv之后 plot显示的图片是乱码？

from scipy.signal import savgol_filter
import matplotlib.pyplot as plt


with open('/min.csv') as mm:
    reader = csv.DictReader(mm)
    fre = [row1['x'] for row1 in reader]
with open(path+'/min.csv') as mn:
    readers = csv.DictReader(mn)
    column = [row['y10'] for row in readers]

columns = savgol_filter(column, 11, 2)
columns.to_csv(path + '/abc.csv', index=False)
plt.plot(fre, column, 'k', lw=1.5, label='Original signal')
plt.plot(fre, columns, 'r', label='Filtered signal')
plt.legend()
plt.show()