【问题标题】:How to modify scikit-learn's eigenface face recognition example如何修改scikit-learn的eigenface人脸识别示例
【发布时间】:2016-08-28 19:11:57
【问题描述】:

我正在尝试调整 scikit-learn's eigenface face recognition script 以用于我自己的图像数据集(请注意,此脚本在我的 Python 3 sklearn 0.17 上完美运行)。

下面对fetch_lfw_people() 的调用可能需要修改,我一直在努力让脚本跳过它以指向我自己的图像文件夹。

我想要脚本——而不是从它下载的文件夹中提取数据——从我自己位于 '/User/pepe/images/' 的数据集中获取图像。

# Download the data, if not already on disk and load it as numpy arrays

lfw_people = fetch_lfw_people(min_faces_per_person=70, resize=0.4)

# introspect the images arrays to find the shapes (for plotting)
n_samples, h, w = lfw_people.images.shape

# for machine learning we use the 2 data directly (as relative pixel
# positions info is ignored by this model)
X = lfw_people.data
n_features = X.shape[1]

# the label to predict is the id of the person
y = lfw_people.target
target_names = lfw_people.target_names
n_classes = target_names.shape[0]

etc...

您对如何解决这个问题有什么建议吗?

从 GitHub 代码可以看出,中心部分其实不是fetch_lfw_people() 本身,而是有附加功能的lfw.py 文件。

【问题讨论】:

  • 您是否使用自己的数据集进行了这项工作?

标签: python scipy scikit-learn face-recognition scikit-image


【解决方案1】:

您无需“修改”任何内容,该函数为此提供了一种简单的方法。

见:

https://github.com/scikit-learn/scikit-learn/blob/14031f6/sklearn/datasets/lfw.py#L229

参数data_home(在此处给出您的路径!)和download_if_missing(取消设置,即为其提供False 值)正是为此目的!

【讨论】:

    【解决方案2】:

    我可以将其修改为以下代码,但我无法计算分数。我可以阅读图像,并将其与示例图像进行比较。我不知道如何使用记分器功能。

    from time import time
    import numpy, os
    from sklearn.metrics import classification_report
    from sklearn.metrics import confusion_matrix
    from sklearn.cross_validation import train_test_split
    from sklearn.grid_search import GridSearchCV
    from sklearn.decomposition import RandomizedPCA
    from sklearn.svm import SVC
    from PIL import Image
    
    #Path to the root image directory containing sub-directories of images
    path="<Path to Folder of Training Images>"
    testImage = "<Path to test image>"
    
    #Flat image Feature Vector
    X=[]
    #Int array of Label Vector
    Y=[]
    
    n_sample = 0 #Total number of Images
    h = 750 #Height of image in float
    w = 250 #Width of image in float 
    n_features = 187500 #Length of feature vector
    target_names = [] #Array to store the names of the persons
    label_count = 0
    n_classes = 0
    
    for directory in os.listdir(path):
        for file in os.listdir(path+directory):
            print(path+directory+"/"+file)
            img=Image.open(path+directory+"/"+file)
            featurevector=numpy.array(img).flatten()
            print len(featurevector)
            X.append(featurevector)
            Y.append(label_count)
            n_sample = n_sample + 1
        target_names.append(directory)
        label_count=label_count+1
    
    print Y
    print target_names
    n_classes = len(target_names)
    
    ###############################################################################
    # Split into a training set and a test set using a stratified k fold
    
    # split into a training and teststing set
    X_train, X_test, y_train, y_test = train_test_split(
        X, Y, test_size=0.25, random_state=42)
    
    ###############################################################################
    # Compute a PCA (eigenfaces) on the face dataset (treated as unlabeled
    # dataset): unsupervised feature extraction / dimensionality reduction
    n_components = 10
    
    print("Extracting the top %d eigenfaces from %d faces"
          % (n_components, len(X_test)))
    t0 = time()
    pca = RandomizedPCA(n_components=n_components, whiten=True).fit(X_train)
    print("done in %0.3fs" % (time() - t0))
    
    eigenfaces = pca.components_.reshape((n_components, h, w))
    
    print("Projecting the input data on the eigenfaces orthonormal basis")
    t0 = time()
    X_train_pca = pca.transform(X_train)
    X_test_pca = pca.transform(X_test)
    print("done in %0.3fs" % (time() - t0))
    
    ###############################################################################
    # Train a SVM classification model
    print("Fitting the classifier to the training set")
    t0 = time()
    param_grid = {'C': [1e3, 5e3, 1e4, 5e4, 1e5],
                  'gamma': [0.0001, 0.0005, 0.001, 0.005, 0.01, 0.1], }
    clf = GridSearchCV(SVC(kernel='rbf', class_weight='balanced'), param_grid)
    clf = clf.fit(X_train_pca, y_train)
    print("done in %0.3fs" % (time() - t0))
    print("Best estimator found by grid search:")
    print(clf.best_estimator_)
    
    ###############################################################################
    # Quantitative evaluation of the model quality on the test set
    
    print("Predicting people's names on the test set")
    t0 = time()
    y_pred = clf.predict(X_test_pca)
    print clf.score(X_test_pca,y_test)
    print("done in %0.3fs" % (time() - t0))
    print(classification_report(y_test, y_pred, target_names=target_names))
    print(confusion_matrix(y_test, y_pred, labels=range(n_classes)))
    
    ###############################################################################
    # Prediction of user based on the model
    test = []
    testImage=Image.open(testImage)
    testImageFeatureVector=numpy.array(testImage).flatten()
    test.append(testImageFeatureVector)
    testImagePCA = pca.transform(test)
    testImagePredict=clf.predict(testImagePCA)
    #print clf.score(testImagePCA)
    #print clf.score(X_train_pca,testImagePCA)
    #print clf.best_params_
    #print clf.best_score_
    #print testImagePredict
    print target_names[testImagePredict[0]]
    

    【讨论】:

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