从csv读取numpy数组时出错

Question

I am working on a program to take an image and flatten it so it can be written into a CSV file. That part works. I am having an issue when I try to read back the line from the CSV file. I try to reconstruct the image and I get an error of "ValueError: cannot reshape array of size 0 into shape (476,640,3)". I added sample output from the CSV file.

sample output

            import csv
            import cv2
            import numpy as np
            from skimage import io
            from matplotlib import pyplot as plt

            image = cv2.imread('Li.jpg')

            def process_images (img):
                img = np.array(img)
                img = img.flatten()
                return img

            def save_data(img):
                dataset = open('dataset.csv', 'w+')
                with dataset:
                    writer = csv.writer(dataset)
                    writer.writerow(img)

            def load_data():
                with open('dataset.csv', 'r') as processed_data:  
                    reader = csv.reader(processed_data)
                    for row in reader:
                        img = np.array(row , dtype='uint8')
                        img = img.reshape(476,6, 3)
                return img

            def print_image_stats (img):
                print (img)
                print (img.shape)
                print (img.dtype)

            def rebuilt_image(img):
                img = img.reshape(476,640,3)
                plt.imshow(img)
                plt.show()
                return img      

            p_images = process_images(image)

            print_image_stats(p_images)

            r_image = rebuilt_image(p_images)

            print_image_stats(r_image)

            save_data(p_images)

            loaded_data = load_data()

            #r_image = rebuilt_image(load_data)

            #print_image_stats(r_image)

Answer 1

The empty lines at the end of the file you posted are significant. They are considered rows by the CSV reader object, and will be iterated over in your for loop. Thus there are passes through the loop in which an empty row is converted to an array of size zero, as the row has no elements. Resizing that obviously fails.

Either remove the rows from the CSV file, or directly use the np.loadtxt function, specifying the delimiter=',' option.