1、先在UIUC Image Database for Car Detection下载训练数据集。
下载地址：http://cogcomp.org/Data/Car/
下载解压之后文件目录如图所示，这里我们所需的是TrainImages这个文件夹和TestImages文件夹。
2、输入是一幅40*100*1的灰度图片，采用的是CNN网络，经过多次卷积和池化之后得到1*1*1的结果，各层参数如下所示。
我的文件目录组织结构： -CarDetect --CarDetect.py --datas ---CarData --models
input : [None, 40, 100, 1] conv-pool1 : f : 5*5 strides : 1 nc : 6 padding : VALID maxpool : 2 conv-pool2: f : 5*5 strides : 1 nc : 16 padding : VALID maxpool : 2 conv3: f : 5*5 strides : 1 nc : 32 padding : VALID conv4: f : 3*18 strides : 1 nc : 64 padding : VALID conv5: f : 1*1 strides : 1 nc : 1 padding : VALID output : [None, 1, 1, 1]
import tensorflow as tf import numpy as np import matplotlib.pyplot as plt #定义加载数据的函数，注意训练数据的存储位置 def load_carDats(): import cv2 import os file_path = './datas/CarData/TrainImages/' files = os.listdir(file_path) samples = [] for file_name in files: data = cv2.imread(file_path + file_name, 0).reshape(-1) / 255 label = 0 if file_name.split('-')[0] == 'neg' else 1 samples.append((data, label)) return samples #加载数据 datas = load_carDats() #随机打乱数据 np.random.shuffle(datas) #划分数据，xs、ys 用来训练网络，x_test、y_test 用来测试网络训练效果 xs = [i[0] for i in datas[:1000]] ys = np.reshape([i[1] for i in datas[:1000]], newshape=(-1,1)) x_test = [i[0] for i in datas[1000:]] y_test = np.reshape([i[1] for i in datas[1000:]], newshape=(-1,1)) #----------------定义网络中频繁使用的函数，将其重构-----------------# #权重变量 def weight_variables(shape): weights = tf.truncated_normal(shape, stddev=0.1, dtype=tf.float32) return tf.Variable(weights) #偏置变量 def biase_variables(shape): biases = tf.constant(value=1.0, shape=shape) return tf.Variable(biases) #卷积 def conv2d(x, W): '''计算卷积，x为输入层（shape=[-1,width,height,channel]）, W为f*f的共享权重矩阵shape=[f,f,in_layers_num, out_layers_num]， 水平和垂直方向上的步长都为1''' return tf.nn.conv2d(x, W, strides=[1,1,1,1], padding="VALID") #最大值池化 def max_pooling(x): '''计算最大值混合，x为输入层(一般是卷积结果)shape=[-1,width,height,channels] ksize为混合pooling的核大小2*2，水平和垂直方向上的步长都为2''' return tf.nn.max_pool(x, ksize=[1,2,2,1], strides=[1,2,2,1], padding="VALID") #---------------------网络前向传播部分------------------# def deepnn(x, keep_prop): '''定义深层卷积网络，包含了两个卷积-混合层和三个卷积层''' #step1:将原始一维得得数据转换成2维, 第一个表示样本数，第二三个是行列，最后一个是通道数 # x = tf.reshape(x, shape=[-1, 40, 100, 1]) #step2:定义第一的卷积-混合层 with tf.name_scope("conv-pooling1"): W_conv1 = weight_variables([5,5,1,6]) b_conv1 = biase_variables([6]) ret_conv1 = tf.nn.relu(conv2d(x,W_conv1) + b_conv1) #计算卷积，并使用修正单元对卷积结果进一步处理 ret_pooling1 = max_pooling(ret_conv1) #执行混合操作 #step3:定义第二个卷积-混合层 with tf.name_scope("conv-pooling2"): W_conv2 = weight_variables([5,5,6,16]) b_conv2 = biase_variables([16]) ret_conv2 = tf.nn.relu(conv2d(ret_pooling1, W_conv2) + b_conv2) ret_pooling2 = max_pooling(ret_conv2) #step4:定义第三个卷积层 with tf.name_scope("conv-pooling3"): W_conv3 = weight_variables([5,5,16,32]) b_conv3 = biase_variables([32]) ret_conv3 = tf.nn.relu(conv2d(ret_pooling2, W_conv3) + b_conv3) #step5:定义第四个卷积层 with tf.name_scope("conv4"): W_conv4 = weight_variables([3,18,32,64]) b_conv4 = biase_variables([64]) ret_conv4 = tf.nn.relu(conv2d(ret_conv3, W_conv4) + b_conv4) #step6:定义第五个卷积层 with tf.name_scope("conv5"): W_conv5 = weight_variables([1,1,64,1]) b_conv5 = biase_variables([1]) ret_conv5 = conv2d(ret_conv4, W_conv5) + b_conv5 return ret_conv5 #---------------------训练网络前的准备-----------------------# #申明输入数据和标签的占位符 x = tf.placeholder(dtype=tf.float32, shape=[None,None, None, 1], name="x-input") labels = tf.placeholder(dtype=tf.float32, shape=[None, 1], name="y-output") #申明弃权的占位符 keep_prop = tf.placeholder(dtype=tf.float32, name="kprob") #创建分类模型 ret = deepnn(x, keep_prop) #此时的返回值是 -1*1*1*1的， 为了得到方便运算的结果，这里将reshape y = tf.reshape(ret, shape=[-1,1]) #定义损失函数 with tf.name_scope("loss_function"): loss = tf.nn.sigmoid_cross_entropy_with_logits(logits=y, labels=labels) cost = tf.reduce_mean(loss) #定义训练模型（优化模型） with tf.name_scope("optimizor"): train = tf.train.AdamOptimizer(0.0005).minimize(cost) #定义验证模型精度的方法 with tf.name_scope("accuracy"): y_hat = tf.nn.sigmoid(y) accuracy_rate = tf.abs(y_hat - labels) < 0.5 accuracy_rate = tf.cast(accuracy_rate, dtype=tf.float32) accuracy = tf.reduce_mean(accuracy_rate) #--------------开始训练网络，并将训练结果保存到文件中---------------# saver = tf.train.Saver() sess = tf.Session() sess.run(tf.global_variables_initializer()) #初始化变量 for i in range(10): skip = 10 for k in range(0,1000,skip): x_train = np.reshape(xs[k:k+skip], newshape=(-1, 40, 100, 1)) sess.run(train, feed_dict={x:x_train, labels:ys[k:k+skip], keep_prop:0.5}) # 训练模型 # if (i+1) % 10 == 0: train_accuracy = sess.run(accuracy, feed_dict = {x: np.reshape(xs, (-1,40,100,1)), labels: ys, keep_prop:1.0}) print('step %d, train accuracy %g' % (i, train_accuracy)) saver.save(sess, "./models/carDetect_model.ckpt", global_step=i) 这是我的训练结果： step 0, train accuracy 0.859 step 1, train accuracy 0.934 step 2, train accuracy 0.965 step 3, train accuracy 0.971 step 4, train accuracy 0.985 step 5, train accuracy 0.991 step 6, train accuracy 0.995 step 7, train accuracy 0.994 step 8, train accuracy 0.995 step 9, train accuracy 0.997 #--------------------------开始在新图片中检测-------------------# import cv2 #导入图片 pic = cv2.imread("../../datas/CarData/TestImages/test-100.pgm", 0) size = pic.shape img = np.reshape(pic, (-1,size[0], size[1], 1)) #利用上面训练好的网络，开始在新的图片中检测 result = sess.run(ret, feed_dict={x:img}) #将检测结果显示 pt1 = np.array([result.argmax()//result.shape[2], result.argmax()%result.shape[2]]) * 4 pt2 = pt1 + np.array([40, 100]) pic_2 = cv2.rectangle(pic, (pt1[1], pt1[0]), (pt2[1], pt2[0]), 0, 2) plt.imshow(pic_2, "gray") plt.show()
3、结果
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