例如我们用的色系是jet：

import numpy as np
import matplotlib.pylab as plt

def custom_min_max_scaling(data):
    # 计算每列的最小值和最大值
    min_vals = np.min(data)
    max_vals = np.max(data)

    # 最大最小归一化计算公式
    normalized_data = (data - min_vals) / (max_vals - min_vals)
    return normalized_data

if __name__ == '__main__':
    data = np.random.random((100, 100, 3))
    data = custom_min_max_scaling(data)

    a = plt.imshow(data, cmap="jet")

    ax = plt.gca()
    ax.set_xticks([])
    ax.set_yticks([])

    plt.colorbar()
    plt.show()

我们只需要在jet后面加上_r即可实现反转：

import numpy as np
import matplotlib.pylab as plt

def custom_min_max_scaling(data):
    # 计算每列的最小值和最大值
    min_vals = np.min(data)
    max_vals = np.max(data)

    # 最大最小归一化计算公式
    normalized_data = (data - min_vals) / (max_vals - min_vals)
    return normalized_data

if __name__ == '__main__':
    data = np.random.random((100, 100, 3))
    data = custom_min_max_scaling(data)

    a = plt.imshow(data, cmap="jet_r")

    ax = plt.gca()
    ax.set_xticks([])
    ax.set_yticks([])

    plt.colorbar()
    plt.show()