add example reader

example/image-classification/nets.py

-# coding: utf-8
-# this model is copy from paddle models repo as a demo for fine-tuning
-# for more detail, see https://github.com/PaddlePaddle/models/blob/develop/fluid/PaddleCV/image_classification/
-
 from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function

example/image-classification/reader.py

+import os
+import math
+import random
+import functools
+import numpy as np
+import paddle
+from PIL import Image, ImageEnhance
+
+random.seed(0)
+np.random.seed(0)
+
+DATA_DIM = 224
+
+THREAD = 8
+BUF_SIZE = 102400
+
+DATA_DIR = 'dataset'
+
+img_mean = np.array([0.485, 0.456, 0.406]).reshape((3, 1, 1))
+img_std = np.array([0.229, 0.224, 0.225]).reshape((3, 1, 1))
+
+
+def resize_short(img, target_size):
+    percent = float(target_size) / min(img.size[0], img.size[1])
+    resized_width = int(round(img.size[0] * percent))
+    resized_height = int(round(img.size[1] * percent))
+    img = img.resize((resized_width, resized_height), Image.LANCZOS)
+    return img
+
+
+def crop_image(img, target_size, center):
+    width, height = img.size
+    size = target_size
+    if center == True:
+        w_start = (width - size) / 2
+        h_start = (height - size) / 2
+    else:
+        w_start = np.random.randint(0, width - size + 1)
+        h_start = np.random.randint(0, height - size + 1)
+    w_end = w_start + size
+    h_end = h_start + size
+    img = img.crop((w_start, h_start, w_end, h_end))
+    return img
+
+
+def random_crop(img, size, scale=[0.08, 1.0], ratio=[3. / 4., 4. / 3.]):
+    aspect_ratio = math.sqrt(np.random.uniform(*ratio))
+    w = 1. * aspect_ratio
+    h = 1. / aspect_ratio
+
+    bound = min((float(img.size[0]) / img.size[1]) / (w**2),
+                (float(img.size[1]) / img.size[0]) / (h**2))
+    scale_max = min(scale[1], bound)
+    scale_min = min(scale[0], bound)
+
+    target_area = img.size[0] * img.size[1] * np.random.uniform(
+        scale_min, scale_max)
+    target_size = math.sqrt(target_area)
+    w = int(target_size * w)
+    h = int(target_size * h)
+
+    i = np.random.randint(0, img.size[0] - w + 1)
+    j = np.random.randint(0, img.size[1] - h + 1)
+
+    img = img.crop((i, j, i + w, j + h))
+    img = img.resize((size, size), Image.LANCZOS)
+    return img
+
+
+def rotate_image(img):
+    angle = np.random.randint(-10, 11)
+    img = img.rotate(angle)
+    return img
+
+
+def distort_color(img):
+    def random_brightness(img, lower=0.5, upper=1.5):
+        e = np.random.uniform(lower, upper)
+        return ImageEnhance.Brightness(img).enhance(e)
+
+    def random_contrast(img, lower=0.5, upper=1.5):
+        e = np.random.uniform(lower, upper)
+        return ImageEnhance.Contrast(img).enhance(e)
+
+    def random_color(img, lower=0.5, upper=1.5):
+        e = np.random.uniform(lower, upper)
+        return ImageEnhance.Color(img).enhance(e)
+
+    ops = [random_brightness, random_contrast, random_color]
+    np.random.shuffle(ops)
+
+    img = ops[0](img)
+    img = ops[1](img)
+    img = ops[2](img)
+
+    return img
+
+
+def process_image(sample, mode, color_jitter, rotate):
+    img_path = sample[0]
+
+    img = Image.open(img_path)
+    if mode == 'train':
+        if rotate: img = rotate_image(img)
+        img = random_crop(img, DATA_DIM)
+    else:
+        img = resize_short(img, target_size=256)
+        img = crop_image(img, target_size=DATA_DIM, center=True)
+    if mode == 'train':
+        if color_jitter:
+            img = distort_color(img)
+        if np.random.randint(0, 2) == 1:
+            img = img.transpose(Image.FLIP_LEFT_RIGHT)
+
+    if img.mode != 'RGB':
+        img = img.convert('RGB')
+
+    img = np.array(img).astype('float32').transpose((2, 0, 1)) / 255
+    img -= img_mean
+    img /= img_std
+
+    if mode == 'train' or mode == 'val':
+        return img, sample[1]
+    elif mode == 'test':
+        return [img]
+
+
+def _reader_creator(file_list,
+                    mode,
+                    shuffle=False,
+                    color_jitter=False,
+                    rotate=False,
+                    data_dir=DATA_DIR):
+    def reader():
+        with open(file_list) as flist:
+            full_lines = [line.strip() for line in flist]
+            if shuffle:
+                np.random.shuffle(full_lines)
+            if mode == 'train' and os.getenv('PADDLE_TRAINING_ROLE'):
+                # distributed mode if the env var `PADDLE_TRAINING_ROLE` exits
+                trainer_id = int(os.getenv("PADDLE_TRAINER_ID", "0"))
+                trainer_count = int(os.getenv("PADDLE_TRAINERS", "1"))
+                per_node_lines = len(full_lines) // trainer_count
+                lines = full_lines[trainer_id * per_node_lines:
+                                   (trainer_id + 1) * per_node_lines]
+                print(
+                    "read images from %d, length: %d, lines length: %d, total: %d"
+                    % (trainer_id * per_node_lines, per_node_lines, len(lines),
+                       len(full_lines)))
+            else:
+                lines = full_lines
+
+            for line in lines:
+                if mode == 'train' or mode == 'val':
+                    img_path, label = line.split()
+                    #                     img_path = img_path.replace("JPEG", "jpeg")
+                    img_path = os.path.join(data_dir, img_path)
+                    yield img_path, int(label)
+                elif mode == 'test':
+                    img_path = os.path.join(data_dir, line)
+                    yield [img_path]
+
+    mapper = functools.partial(
+        process_image, mode=mode, color_jitter=color_jitter, rotate=rotate)
+
+    return paddle.reader.xmap_readers(mapper, reader, THREAD, BUF_SIZE)
+
+
+def train(data_dir=DATA_DIR):
+    file_list = os.path.join(data_dir, 'train_list.txt')
+    return _reader_creator(
+        file_list,
+        'train',
+        shuffle=True,
+        color_jitter=False,
+        rotate=False,
+        data_dir=data_dir + "/train")
+
+
+def val(data_dir=DATA_DIR):
+    file_list = os.path.join(data_dir, 'val_list.txt')
+    return _reader_creator(
+        file_list, 'val', shuffle=False, data_dir=data_dir + "/val")
+
+
+def test(data_dir=DATA_DIR):
+    file_list = os.path.join(data_dir, 'val_list.txt')
+    return _reader_creator(file_list, 'test', shuffle=False, data_dir=data_dir)