本次讲述的表情分类是识别的分析流程分为：

• 1、加载pre-model网络与权重；
• 2、利用opencv的函数进行简单的人脸检测；
• 3、抠出人脸的图并灰化；
• 4、表情分类器检测

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一、表情数据集

主要来源于kaggle比赛，下载地址。 
有七种表情类别： (0=Angry, 1=Disgust, 2=Fear, 3=Happy, 4=Sad, 5=Surprise, 6=Neutral). 
数据是48x48 灰度图，格式比较奇葩。 
第一列是情绪分类，第二列是图像的numpy，第三列是train or test。 

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二、opencv的人脸识别

参考《opencv+Recorder︱OpenCV 中使用 Haar 分类器进行面部检测》 
理论略过，直接来看重点： 
（1）加载人脸检测器，haarcascade_frontalface_default.xml； 
（2）图片加载并灰化，cvtColor，可参考： opencv︱图像的色彩空間cvtColor（HSV、HSL、HSB 、BGR） 
（2）人脸探测，detectMultiScale.

# （1）加载人脸检测器
cascPath = '/.../haarcascade_frontalface_default.xml'
faceCascade = cv2.CascadeClassifier(cascPath)

# （2）图片加载并灰化
jpg_file = '/home/ubuntu/keras/image/8c80abb4gw1f3b5hxd3aaj20jg0cx411.jpg'
img_gray = cv2.imread(jpg_file)
img_gray = cv2.cvtColor(img_gray, cv2.COLOR_BGR2GRAY)

# 人脸探测
faces = faceCascade.detectMultiScale(
        img_gray,
        scaleFactor=1.1,
        minNeighbors=1,# minNeighbors=5比较难检测
        minSize=(30, 30),
        flags=cv2.cv.CV_HAAR_SCALE_IMAGE
    )

 
 


  
  
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其中minNeighbors设置小一些，容易检测出来。这个检测器还是有点粗糙。 
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三、表情分类与识别

本节源自github的mememoji。 
网络结构： 

opencv中的人脸检测的pre-model文件（haarcascade_frontalface_default.xml）和表情识别pre-model文件（model.h5）都在作者的github下载。

是利用Keras实现的。直接来看完整的代码：

import cv2
import sys
import json
import time
import numpy as np
from keras.models import model_from_json


emotion_labels = ['angry', 'fear', 'happy', 'sad', 'surprise', 'neutral']

# load json and create model arch
json_file = open('/.../model.json','r')
loaded_model_json = json_file.read()
json_file.close()
model = model_from_json(loaded_model_json)

# load weights into new model
model.load_weights('/.../model.h5')

def predict_emotion(face_image_gray): # a single cropped face
    resized_img = cv2.resize(face_image_gray, (48,48), interpolation = cv2.INTER_AREA)
    # cv2.imwrite(str(index)+'.png', resized_img)
    image = resized_img.reshape(1, 1, 48, 48)
    list_of_list = model.predict(image, batch_size=1, verbose=1)
    angry, fear, happy, sad, surprise, neutral = [prob for lst in list_of_list for prob in lst]
    return [angry, fear, happy, sad, surprise, neutral]


# -------------------直接预测-----------------------
img_gray = cv2.imread('/.../real-time_emotion_analyzer-master/meme_faces/angry-angry.png')
img_gray = cv2.cvtColor(img_gray, cv2.COLOR_BGR2GRAY)
angry, fear, happy, sad, surprise, neutral = predict_emotion(img_gray)


# -------------------人脸预测-----------------------
# 加载检测器
cascPath = '/.../real-time_emotion_analyzer-master/haarcascade_frontalface_default.xml'
faceCascade = cv2.CascadeClassifier(cascPath)

# 图像灰化
jpg_file = '/.../001.jpg'
img_gray = cv2.imread(jpg_file)
img_gray = cv2.cvtColor(img_gray, cv2.COLOR_BGR2GRAY)

# 人脸检测
faces = faceCascade.detectMultiScale(
        img_gray,
        scaleFactor=1.1,
        minNeighbors=1,# minNeighbors=5比较难检测
        minSize=(30, 30),
        flags=cv2.cv.CV_HAAR_SCALE_IMAGE
    )

# 表情画框
for (x, y, w, h) in faces:
    face_image_gray = img_gray[y:y+h, x:x+w]
    cv2.rectangle(frame, (x, y), (x+w, y+h), (0, 255, 0), 2)
    angry, fear, happy, sad, surprise, neutral = predict_emotion(face_image_gray)



from:https://blog.csdn.net/sinat_26917383/article/details/72885715