如何在Keras中使用训练好的模型预测输入图像?

xnifntxz  于 2022-12-23  发布在  其他
关注(0)|答案(5)|浏览(185)

我训练了一个模型来对2类图像进行分类,并使用model.save()保存了它。

from keras.preprocessing.image import ImageDataGenerator
from keras.models import Sequential
from keras.layers import Conv2D, MaxPooling2D
from keras.layers import Activation, Dropout, Flatten, Dense
from keras import backend as K

# dimensions of our images.
img_width, img_height = 320, 240

train_data_dir = 'data/train'
validation_data_dir = 'data/validation'
nb_train_samples = 200  #total
nb_validation_samples = 10  # total
epochs = 6
batch_size = 10

if K.image_data_format() == 'channels_first':
    input_shape = (3, img_width, img_height)
else:
    input_shape = (img_width, img_height, 3)

model = Sequential()
model.add(Conv2D(32, (3, 3), input_shape=input_shape))
model.add(Activation('relu'))
model.add(MaxPooling2D(pool_size=(2, 2)))

model.add(Conv2D(32, (3, 3)))
model.add(Activation('relu'))
model.add(MaxPooling2D(pool_size=(2, 2)))

model.add(Conv2D(64, (3, 3)))
model.add(Activation('relu'))
model.add(MaxPooling2D(pool_size=(2, 2)))

model.add(Flatten())
model.add(Dense(64))
model.add(Activation('relu'))
model.add(Dropout(0.5))
model.add(Dense(1))
model.add(Activation('sigmoid'))

model.compile(loss='binary_crossentropy',
              optimizer='rmsprop',
              metrics=['accuracy'])

# this is the augmentation configuration we will use for training
train_datagen = ImageDataGenerator(
    rescale=1. / 255,
    shear_range=0.2,
    zoom_range=0.2,
    horizontal_flip=True)

# this is the augmentation configuration we will use for testing:
# only rescaling
test_datagen = ImageDataGenerator(rescale=1. / 255)

train_generator = train_datagen.flow_from_directory(
    train_data_dir,
    target_size=(img_width, img_height),
    batch_size=batch_size,
    class_mode='binary')

validation_generator = test_datagen.flow_from_directory(
    validation_data_dir,
    target_size=(img_width, img_height),
    batch_size=batch_size,
    class_mode='binary')

model.fit_generator(
    train_generator,
    steps_per_epoch=nb_train_samples // batch_size,
    epochs=epochs,
    validation_data=validation_generator,
    validation_steps=5)

model.save('model.h5')

它成功地训练了0.98的精度,这是相当不错的。为了在新的图像上加载和测试这个模型,我使用了下面的代码:

from keras.models import load_model
import cv2
import numpy as np

model = load_model('model.h5')

model.compile(loss='binary_crossentropy',
              optimizer='rmsprop',
              metrics=['accuracy'])

img = cv2.imread('test.jpg')
img = cv2.resize(img,(320,240))
img = np.reshape(img,[1,320,240,3])

classes = model.predict_classes(img)

print classes

它输出:
0
为什么它不给出类的实际名称,为什么是[[0]]

zyfwsgd6

zyfwsgd61#

如果有人仍然难以对图像进行预测,下面是加载保存的模型并进行预测的优化代码:

# Modify 'test1.jpg' and 'test2.jpg' to the images you want to predict on

from keras.models import load_model
from keras.preprocessing import image
import numpy as np

# dimensions of our images
img_width, img_height = 320, 240

# load the model we saved
model = load_model('model.h5')
model.compile(loss='binary_crossentropy',
              optimizer='rmsprop',
              metrics=['accuracy'])

# predicting images
img = image.load_img('test1.jpg', target_size=(img_width, img_height))
x = image.img_to_array(img)
x = np.expand_dims(x, axis=0)

images = np.vstack([x])
classes = model.predict_classes(images, batch_size=10)
print classes

# predicting multiple images at once
img = image.load_img('test2.jpg', target_size=(img_width, img_height))
y = image.img_to_array(img)
y = np.expand_dims(y, axis=0)

# pass the list of multiple images np.vstack()
images = np.vstack([x, y])
classes = model.predict_classes(images, batch_size=10)

# print the classes, the images belong to
print classes
print classes[0]
print classes[0][0]
nwnhqdif

nwnhqdif2#

您可以使用model.predict()来预测单个图像的类别,如下所示doc(https://keras.io/models/sequential/):

# load_model_sample.py
from keras.models import load_model
from keras.preprocessing import image
import matplotlib.pyplot as plt
import numpy as np
import os

def load_image(img_path, show=False):

    img = image.load_img(img_path, target_size=(150, 150))
    img_tensor = image.img_to_array(img)                    # (height, width, channels)
    img_tensor = np.expand_dims(img_tensor, axis=0)         # (1, height, width, channels), add a dimension because the model expects this shape: (batch_size, height, width, channels)
    img_tensor /= 255.                                      # imshow expects values in the range [0, 1]

    if show:
        plt.imshow(img_tensor[0])                           
        plt.axis('off')
        plt.show()

    return img_tensor

if __name__ == "__main__":

    # load model
    model = load_model("model_aug.h5")

    # image path
    img_path = '/media/data/dogscats/test1/3867.jpg'    # dog
    #img_path = '/media/data/dogscats/test1/19.jpg'      # cat

    # load a single image
    new_image = load_image(img_path)

    # check prediction
    pred = model.predict(new_image)

在这个例子中,图像被加载为numpy数组,形状为(1, height, width, channels),然后,我们将其加载到模型中并预测其类别,返回为范围[0,1]中的真实的值(在这个例子中为二进制分类)。

zynd9foi

zynd9foi3#

keras predict_classes(docs)outputs类预测的numpy数组。在您的模型中,它是最后一个(softmax)层的最高激活的神经元的索引。[[0]]意味着您的模型预测您的测试数据是类0。(通常您将传递多个图像,结果看起来像[[0], [1], [1], [0]]
您必须将实际标签(例如'cancer', 'not cancer')转换为二进制编码(0表示“cancer”,1表示“not cancer”)以进行二进制分类。然后,您将把[[0]]的序列输出解释为具有类标签'cancer'

jfgube3f

jfgube3f4#

这是因为你得到的是与类相关联的数值。例如,如果你有两个类cats和dogs,Keras会将它们关联为数值0和1。要得到你的类和它们相关联的数值之间的Map,你可以使用

>>> classes = train_generator.class_indices    
>>> print(classes)
    {'cats': 0, 'dogs': 1}

现在你知道了类和索引之间的Map,你现在可以做的是
第一个月

dldeef67

dldeef675#

通过@ritiek转发这个例子,我也是一个ML初学者,也许这种格式将有助于看到名称,而不仅仅是班级编号。

images = np.vstack([x, y])

prediction = model.predict(images)

print(prediction)

i = 1

for things in prediction:  
    if(things == 0):
        print('%d.It is cancer'%(i))
    else:
        print('%d.Not cancer'%(i))
    i = i + 1

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