1.参考博客：

python-----删除同一文件夹下相似的图片
Python-列表删除重复元素/图像相似度判断及删除相似图像
python 图像相似 phash和compare_ssim比较
利用Python轻松实现图片相似度对比（一）
利用Python轻松实现图片相似度对比（二）
因为输入是视频，切完帧之后都是连续图片，所以主要参考第一篇博客的第一种方法。我的目录结构如下：

其中frame_output是视频切帧后的保存路径，1和2文件夹分别对应两个是视频切帧后的图片。

2.切帧的代码如下：

#encoding:utf-8
import os
import sys
import cv2

video_path = '/home/pythonfile/video/'  # 绝对路径，video下有两段视频
out_frame_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'frame_output')  #frame_output是视频切帧后的保存路径
if not os.path.exists(out_frame_path):
    os.makedirs(out_frame_path)
print('out_frame_path', out_frame_path)
files = []
list1 = os.listdir(video_path)
print('list', list1)
for i in range(len(list1)):
    item = os.path.join(video_path, list1[i])
    files.append(item)
print('files',files)
for k,file in enumerate(files):
    frame_dir = os.path.join(out_frame_path, '%d'%(k+1))
    if not os.path.exists(frame_dir):
        os.makedirs(frame_dir)
    cap = cv2.VideoCapture(file)
    j = 0
    print('start prossing NO.%d video' % (k + 1))
    while True:
        ret, frame = cap.read()
        j += 1
        if ret:
        #每三帧保存一张
            if j % 3 == 0:
                cv2.imwrite(os.path.join(frame_dir, '%d.jpg'%j), frame)
        else:
            cap.release()
            break
    print('prossed NO.%d video'%(k+1))

3.删除相似度高的图片

根据我的文件结构参考第一篇博客的第一种方法修改后的代码如下：

# coding: utf-8
import os
import cv2
# from skimage.measure import compare_ssim
# from skimage.metrics import _structural_similarity
from skimage.metrics import structural_similarity as ssim

def delete(filename1):
    os.remove(filename1)


def list_all_files(root):
    files = []
    list = os.listdir(root)
    # os.listdir()方法：返回指定文件夹包含的文件或子文件夹名字的列表。该列表顺序以字母排序
    for i in range(len(list)):
        element = os.path.join(root, list[i])
        # 需要先使用python路径拼接os.path.join()函数，将os.listdir()返回的名称拼接成文件或目录的绝对路径再传入os.path.isdir()和os.path.isfile().
        if os.path.isdir(element):  # os.path.isdir()用于判断某一对象(需提供绝对路径)是否为目录
            # temp_dir = os.path.split(element)[-1]
            # os.path.split分割文件名与路径,分割为data_dir和此路径下的文件名，[-1]表示只取data_dir下的文件名
            files.append(list_all_files(element))

        elif os.path.isfile(element):
            files.append(element)
    # print('2',files)
    return files


def ssim_compare(img_files):
    count = 0
    for currIndex, filename in enumerate(img_files):
        if not os.path.exists(img_files[currIndex]):
            print('not exist', img_files[currIndex])
            break
        img = cv2.imread(img_files[currIndex])
        img1 = cv2.imread(img_files[currIndex + 1])
        #进行结构性相似度判断
        # ssim_value = _structural_similarity.structural_similarity(img,img1,multichannel=True)
        ssim_value = ssim(img,img1,multichannel=True)
        if ssim_value > 0.9:
            #基数
            count += 1
            imgs_n.append(img_files[currIndex + 1])
            print('big_ssim:',img_files[currIndex], img_files[currIndex + 1], ssim_value)
        # 避免数组越界
        if currIndex+1 >= len(img_files)-1:
            break
    return count


if __name__ == '__main__':
    path = '/home/dj/pythonfile/frame_output/'

    img_path = path
    imgs_n = []
   
    all_files = list_all_files(path) #返回包含完整路径的所有图片名的列表
    print('1',len(all_files))
   
    for files in all_files:
        # 根据文件名排序，x.rfind('/')是从右边寻找第一个‘/’出现的位置，也就是最后出现的位置
        # 注意sort和sorted的区别，sort作用于原列表，sorted生成新的列表，且sorted可以作用于所有可迭代对象
        files.sort(key = lambda x: int(x[x.rfind('/')+1:-4]))#路径中包含“/”
        # print(files)
        img_files = []
        for img in files:
            if img.endswith('.jpg'):
                # 将所有图片名都放入列表中
                img_files.append(img)
        count = ssim_compare(img_files)
        print(img[:img.rfind('/')],"路径下删除的图片数量为：",count)
    for image in imgs_n:
        delete(image)

4.关于导入skimage.measure import compare_ssim出错的解决方法：

from skimage.measure import compare_ssim as sk_cpt_ssim error，从skimage导入compare_ssim出错。
将

from skimage.measure import compare_ssim

改为

from skimage.metrics import _structural_similarity

参考官网：https://scikit-image.org/docs/stable/auto_examples/transform/plot_ssim.html#sphx-glr-auto-examples-transform-plot-ssim-py

SSIM（structural similarity）算法原理

5.查看python安装路径及依赖包路径

ubuntu查看python及安装包的位置

6.最后贴上_structural_similarity.py的源码，以后学习

from warnings import warn
import numpy as np
from scipy.ndimage import uniform_filter, gaussian_filter

from ..util.dtype import dtype_range
from ..util.arraycrop import crop
from .._shared.utils import warn, check_shape_equality

__all__ = ['structural_similarity']


def structural_similarity(im1, im2,
                          *,
                          win_size=None, gradient=False, data_range=None,
                          multichannel=False, gaussian_weights=False,
                          full=False, **kwargs):
    """
    Compute the mean structural similarity index between two images.

    Parameters
    ----------
    im1, im2 : ndarray
        Images. Any dimensionality with same shape.
    win_size : int or None, optional
        The side-length of the sliding window used in comparison. Must be an
        odd value. If `gaussian_weights` is True, this is ignored and the
        window size will depend on `sigma`.
    gradient : bool, optional
        If True, also return the gradient with respect to im2.
    data_range : float, optional
        The data range of the input image (distance between minimum and
        maximum possible values). By default, this is estimated from the image
        data-type.
    multichannel : bool, optional
        If True, treat the last dimension of the array as channels. Similarity
        calculations are done independently for each channel then averaged.
    gaussian_weights : bool, optional
        If True, each patch has its mean and variance spatially weighted by a
        normalized Gaussian kernel of width sigma=1.5.
    full : bool, optional
        If True, also return the full structural similarity image.

    Other Parameters
    ----------------
    use_sample_covariance : bool
        If True, normalize covariances by N-1 rather than, N where N is the
        number of pixels within the sliding window.
    K1 : float
        Algorithm parameter, K1 (small constant, see [1]_).
    K2 : float
        Algorithm parameter, K2 (small constant, see [1]_).
    sigma : float
        Standard deviation for the Gaussian when `gaussian_weights` is True.

    Returns
    -------
    mssim : float
        The mean structural similarity index over the image.
    grad : ndarray
        The gradient of the structural similarity between im1 and im2 [2]_.
        This is only returned if `gradient` is set to True.
    S : ndarray
        The full SSIM image.  This is only returned if `full` is set to True.

    Notes
    -----
    To match the implementation of Wang et. al. [1]_, set `gaussian_weights`
    to True, `sigma` to 1.5, and `use_sample_covariance` to False.

    .. versionchanged:: 0.16
        This function was renamed from ``skimage.measure.compare_ssim`` to
        ``skimage.metrics.structural_similarity``.

    References
    ----------
    .. [1] Wang, Z., Bovik, A. C., Sheikh, H. R., & Simoncelli, E. P.
       (2004). Image quality assessment: From error visibility to
       structural similarity. IEEE Transactions on Image Processing,
       13, 600-612.
       https://ece.uwaterloo.ca/~z70wang/publications/ssim.pdf,
       :DOI:`10.1109/TIP.2003.819861`

    .. [2] Avanaki, A. N. (2009). Exact global histogram specification
       optimized for structural similarity. Optical Review, 16, 613-621.
       :arxiv:`0901.0065`
       :DOI:`10.1007/s10043-009-0119-z`

    """
    check_shape_equality(im1, im2)

    if multichannel:
        # loop over channels
        args = dict(win_size=win_size,
                    gradient=gradient,
                    data_range=data_range,
                    multichannel=False,
                    gaussian_weights=gaussian_weights,
                    full=full)
        args.update(kwargs)
        nch = im1.shape[-1]
        mssim = np.empty(nch)
        if gradient:
            G = np.empty(im1.shape)
        if full:
            S = np.empty(im1.shape)
        for ch in range(nch):
            ch_result = structural_similarity(im1[..., ch],
                                              im2[..., ch], **args)
            if gradient and full:
                mssim[..., ch], G[..., ch], S[..., ch] = ch_result
            elif gradient:
                mssim[..., ch], G[..., ch] = ch_result
            elif full:
                mssim[..., ch], S[..., ch] = ch_result
            else:
                mssim[..., ch] = ch_result
        mssim = mssim.mean()
        if gradient and full:
            return mssim, G, S
        elif gradient:
            return mssim, G
        elif full:
            return mssim, S
        else:
            return mssim

    K1 = kwargs.pop('K1', 0.01)
    K2 = kwargs.pop('K2', 0.03)
    sigma = kwargs.pop('sigma', 1.5)
    if K1 < 0:
        raise ValueError("K1 must be positive")
    if K2 < 0:
        raise ValueError("K2 must be positive")
    if sigma < 0:
        raise ValueError("sigma must be positive")
    use_sample_covariance = kwargs.pop('use_sample_covariance', True)

    if gaussian_weights:
        # Set to give an 11-tap filter with the default sigma of 1.5 to match
        # Wang et. al. 2004.
        truncate = 3.5

    if win_size is None:
        if gaussian_weights:
            # set win_size used by crop to match the filter size
            r = int(truncate * sigma + 0.5)  # radius as in ndimage
            win_size = 2 * r + 1
        else:
            win_size = 7   # backwards compatibility

    if np.any((np.asarray(im1.shape) - win_size) < 0):
        raise ValueError(
            "win_size exceeds image extent.  If the input is a multichannel "
            "(color) image, set multichannel=True.")

    if not (win_size % 2 == 1):
        raise ValueError('Window size must be odd.')

    if data_range is None:
        if im1.dtype != im2.dtype:
            warn("Inputs have mismatched dtype.  Setting data_range based on "
                 "im1.dtype.", stacklevel=2)
        dmin, dmax = dtype_range[im1.dtype.type]
        data_range = dmax - dmin

    ndim = im1.ndim

    if gaussian_weights:
        filter_func = gaussian_filter
        filter_args = {
    'sigma': sigma, 'truncate': truncate}
    else:
        filter_func = uniform_filter
        filter_args = {
    'size': win_size}

    # ndimage filters need floating point data
    im1 = im1.astype(np.float64)
    im2 = im2.astype(np.float64)

    NP = win_size ** ndim

    # filter has already normalized by NP
    if use_sample_covariance:
        cov_norm = NP / (NP - 1)  # sample covariance
    else:
        cov_norm = 1.0  # population covariance to match Wang et. al. 2004

    # compute (weighted) means
    ux = filter_func(im1, **filter_args)
    uy = filter_func(im2, **filter_args)

    # compute (weighted) variances and covariances
    uxx = filter_func(im1 * im1, **filter_args)
    uyy = filter_func(im2 * im2, **filter_args)
    uxy = filter_func(im1 * im2, **filter_args)
    vx = cov_norm * (uxx - ux * ux)
    vy = cov_norm * (uyy - uy * uy)
    vxy = cov_norm * (uxy - ux * uy)

    R = data_range
    C1 = (K1 * R) ** 2
    C2 = (K2 * R) ** 2

    A1, A2, B1, B2 = ((2 * ux * uy + C1,
                       2 * vxy + C2,
                       ux ** 2 + uy ** 2 + C1,
                       vx + vy + C2))
    D = B1 * B2
    S = (A1 * A2) / D

    # to avoid edge effects will ignore filter radius strip around edges
    pad = (win_size - 1) // 2

    # compute (weighted) mean of ssim
    mssim = crop(S, pad).mean()

    if gradient:
        # The following is Eqs. 7-8 of Avanaki 2009.
        grad = filter_func(A1 / D, **filter_args) * im1
        grad += filter_func(-S / B2, **filter_args) * im2
        grad += filter_func((ux * (A2 - A1) - uy * (B2 - B1) * S) / D,
                            **filter_args)
        grad *= (2 / im1.size)

        if full:
            return mssim, grad, S
        else:
            return mssim, grad
    else:
        if full:
            return mssim, S
        else:
            return mssim