打开 fp = io.BytesIO(fp.read()) AttributeError: 'str' 对象在 PIL/image.py 中没有属性 'read'

Question

I'm a little new to Python especially Imaging library that I'm currently working with. I'm working with a facial recognition code and running it in my Raspberry Pi 2 B+ running Jessie. I'm using Opencv 2.4.9 and Python 2.7. The code that I'm currently working with worked till a few minutes ago but now I keep getting an error. I didn't alter the code or update anything.

What I have tried: I uninstalled pillow and installed different versions, but it is still not working.

I just don't understand what has changed. I tried by changing the variable names still no effect.

import cv
import cv2
import sys
import os
import datetime
import time
from PIL import Image
import numpy as np


def EuclideanDistance(p, q):
    p = np.asarray(p).flatten()
    q = np.asarray(q).flatten()
    return np.sqrt(np.sum(np.power((p-q),2)))


class EigenfacesModel():

    def __init__(self, X=None, y=None, num_components=0):
        self.num_components = 0
        self.projections = []
        self.W = []
        self.mu = []
        if (X is not None) and (y is not None):
            self.compute(X,y)

    def compute(self, X, y):
        [D, self.W, self.mu] = pca(asRowMatrix(X),y, self.num_components)
        # store labels
        self.y = y
        # store projections
        for xi in X:
            self.projections.append(project(self.W, xi.reshape(1,-1), self.mu))

    def predict(self, X):
        minDist = np.finfo('float').max
        minClass = -1
        Q = project(self.W, X.reshape(1,-1), self.mu)
        for i in xrange(len(self.projections)):
            dist = EuclideanDistance(self.projections[i], Q)
            #print i,dist
            if dist < minDist:
                minDist = dist
                minClass = self.y[i]
        print "\nMinimum distance ", minDist        
        return minClass,minDist


def asRowMatrix(X):
    if len(X) == 0:
        return np.array([])
    mat = np.empty((0, X[0].size), dtype=X[0].dtype)
    for row in X:
        mat = np.vstack((mat, np.asarray(row).reshape(1,-1)))
    return mat

def read_images(filename, sz=None):
    c = 0
    X,y = [], []
    with open(filename) as f:
        for line in f:
            line = line.rstrip()
            im = Image.open(line)
            im = im.convert("L")
            # resize to given size (if given)
            if (sz is None):
                im = im.resize((92,112), Image.ANTIALIAS)
            X.append(np.asarray(im, dtype=np.uint8))
            y.append(c)
            c = c+1

    print c
    return [X,y]

def pca(X, y, num_components=0):
    [n,d] = X.shape
    print n
    if (num_components <= 0) or (num_components>n):
        num_components = n
    mu = X.mean(axis=0)
    X = X - mu
    if n>d:
        C = np.dot(X.T,X)
        [eigenvalues,eigenvectors] = np.linalg.eigh(C)
    else:
        C = np.dot(X,X.T)
        [eigenvalues,eigenvectors] = np.linalg.eigh(C)
        eigenvectors = np.dot(X.T,eigenvectors)
        for i in xrange(n):
            eigenvectors[:,i] = eigenvectors[:,i]/np.linalg.norm(eigenvectors[:,i])
    # or simply perform an economy size decomposition
    # eigenvectors, eigenvalues, variance = np.linalg.svd(X.T, full_matrices=False)
    # sort eigenvectors descending by their eigenvalue
    idx = np.argsort(-eigenvalues)
    eigenvalues = eigenvalues[idx]
    eigenvectors = eigenvectors[:,idx]
    # select only num_components
    num_components = 25
    eigenvalues = eigenvalues[0:num_components].copy()
    eigenvectors = eigenvectors[:,0:num_components].copy()
    return [eigenvalues, eigenvectors, mu]

def project(W, X, mu=None):
    if mu is None:
        return np.dot(X,W)
    return np.dot(X - mu, W)




def reconstruct(W, Y, mu=None):
    if mu is None:
        return np.dot(W.T,Y)
    return np.dot(W.T,Y) + mu

#if __name__ == "__main__":

def FaceRecognitionWrapper(Database_Address,TestImages_Address):

    out_dir = "Output_Directory"

    [X,y] = read_images(Database_Address)
    y = np.asarray(y, dtype=np.int32)
    #print len(X)

    model = EigenfacesModel(X[0:], y[0:])
    # get a prediction for the first observation
    [X1,y1] = read_images(TestImages_Address) 
    y1 = np.asarray(y1, dtype=np.int32)
    OutputFile = open("Output.txt",'a')
    for i in xrange(len(X1)):
        predicted,difference = model.predict(X1[i])
        predicted1 = int(predicted/10) + 1
        if difference <= 1000:
            print i+1 , "th image was recognized as individual" , predicted+1
            OutputFile.write(str(predicted1))
            OutputFile.write("\n")
        else:
            os.chdir(out_dir)
            print i+1,"th image could not be recognized. Storing in error folder."

            errorImage = Image.fromarray(X1[i])
            current_time = datetime.datetime.now().time()
            error_img_name=current_time.isoformat()+'.png'
            errorImage.save(error_img_name)
            os.chdir('..')
    OutputFile.close()





#Create Model Here

cascPath = '/home/pi/opencv-2.4.9/data/haarcascades/haarcascade_frontalface_default.xml'
faceCascade = cv2.CascadeClassifier(cascPath)
Test_Files = []

video_capture = cv2.VideoCapture(0)

i = 0

while True:
    # Capture frame-by-frame
    ret, frame = video_capture.read()

    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

    faces = faceCascade.detectMultiScale(
        gray,
        scaleFactor=1.1,
        minNeighbors=5,
        minSize=(30, 30),
        flags=cv2.cv.CV_HAAR_SCALE_IMAGE
    )

    # Draw a rectangle around the faces
    for (x, y, w, h) in faces:
        dummy_image = frame
        cv2.rectangle(dummy_image, (x, y), (x+w, y+h), (0, 255, 0), 2)
        dummy_image=dummy_image[y:y+h, x:x+w]
        dirname = 'detection_output'
        os.chdir(dirname)
        current_time = datetime.datetime.now().time()   
        final_img_name=current_time.isoformat()+'.png' 
        Test_Files.append(final_img_name)  
        dummy_image = cv2.cvtColor(dummy_image, cv2.COLOR_BGR2GRAY) 
        cv2.imwrite(final_img_name,dummy_image)
        os.chdir('..')


    # Display the resulting frame
    cv2.imshow('Video', frame)

    if cv2.waitKey(1) & 0xFF == ord('q'):
        break
    i = i + 1

    if i % 20 == 0:
        dirname = 'detection_output'
        os.chdir(dirname)
        TestFile = open('CameraFeedFaces.txt',"w")
        for Files in Test_Files:
            TestFile.write(os.getcwd()+"/"+Files+"\n")
        TestFile.close()
        os.chdir("..")
        #Call testing.py
        FaceRecognitionWrapper("/home/pi/train_faces/temp.txt",os.getcwd()+"/detection_output/CameraFeedFaces.txt")
        #Open Output File and Copy in a separate folder where distance greater than threshold
        #Then delete all the files in the folder
        break


# When everything is done, release the capture
video_capture.release()
cv2.destroyAllWindows()

And here's the Traceback:

Traceback (most recent call last):
  File "hel.py", line 213, in <module>
    FaceRecognitionWrapper("/home/pi/train_faces/temp.txt",os.getcwd()+"/detection_output/CameraFeedFaces.txt")
  File "hel.py", line 127, in FaceRecognitionWrapper
    [X,y] = read_images(Database_Address)
  File "hel.py", line 68, in read_images
    im = Image.open(line)
  File "/usr/local/lib/python2.7/dist-packages/PIL/Image.py", line 2277, in open
    fp = io.BytesIO(fp.read())
AttributeError: 'str' object has no attribute 'read'

Output when code was working

I read it somewhere and if I try and edit im = Image.open(open(line,'rb')) I'm getting this error instead of the previous one

Traceback (most recent call last):
  File "hel.py", line 208, in <module>
    FaceRecognitionWrapper("/home/pi/train_faces/temp.txt",os.getcwd()+"/detection_output/CameraFeedFaces.txt")
  File "hel.py", line 122, in FaceRecognitionWrapper
    [X,y] = read_images(Database_Address)
  File "hel.py", line 63, in read_images
    im = Image.open(open(line,'rb'))
IOError: [Errno 2] No such file or directory: ''

Answer 1

Your subject line is confusing. You fixed that problem and then exposed a different bug.

IOError: [Errno 2] No such file or directory: ''

The message shows that you are trying to open a file with no name and that means that the input file you are reading has at least one blank line. If its okay for that file to have blank lines, just skip those like:

def read_images(filename, sz=None):
    c = 0
    X,y = [], []
    with open(filename) as f:
        for line in f:
            line = line.rstrip()
            if line:
                im = Image.open(open(line,'rb')) 
                im = im.convert("L"
                # resize to given size (if given)
                if (sz is None):
                    im = im.resize((92,112), Image.ANTIALIAS)
                X.append(np.asarray(im, dtype=np.uint8))
                y.append(c)
                c = c+1

Otherwise, you have a legitimate error and you should catch and handle the exception.