基于深度学习的目标检测 代码

以下是一个基于深度学习的目标检测代码示例，使用的是 TensorFlow 和 Keras 框架。这个代码示例使用的是 Faster R-CNN 模型，可以在 COCO 数据集上进行训练和测试，同时还包括了数据增强和模型评估等功能。

import tensorflow as tf
from tensorflow import keras
from tensorflow.keras import layers
from tensorflow.keras import models
from tensorflow.keras import optimizers
from tensorflow.keras import backend as K
from tensorflow.keras.layers import Input
from tensorflow.keras.applications import ResNet50
from tensorflow.keras.layers import Conv2D
from tensorflow.keras.layers import MaxPooling2D
from tensorflow.keras.layers import Flatten
from tensorflow.keras.layers import Dense
from tensorflow.keras.layers import Dropout
from tensorflow.keras.layers import GlobalAveragePooling2D
from tensorflow.keras.layers import GlobalMaxPooling2D
from tensorflow.keras.layers import TimeDistributed
from tensorflow.keras.layers import AveragePooling2D
from tensorflow.keras.layers import BatchNormalization
from tensorflow.keras.layers import Activation
from tensorflow.keras.layers import Add
from tensorflow.keras.layers import ZeroPadding2D
from tensorflow.keras.layers import Cropping2D
from tensorflow.keras.layers import Lambda
from tensorflow.keras.layers import Reshape
from tensorflow.keras.layers import Concatenate
from tensorflow.keras.layers import Softmax
from tensorflow.keras.models import Model
from tensorflow.keras.callbacks import TensorBoard, ModelCheckpoint, ReduceLROnPlateau, EarlyStopping
from tensorflow.keras.utils import plot_model
import numpy as np
import os
import cv2
import time
import argparse
from tqdm import tqdm
from pycocotools.coco import COCO
from pycocotools import mask as maskUtils

os.environ['TF_CPP_MIN_LOG_LEVEL'] = '3'
np.random.seed(42)
tf.random.set_seed(42)

class Config:
    NAME = "faster_rcnn"
    BACKBONE = "resnet50"
    IMAGE_MIN_DIM = 800
    IMAGE_MAX_DIM = 1333
    RPN_ANCHOR_SCALES = (32, 64, 128, 256, 512)
    RPN_ANCHOR_RATIOS = [0.5, 1, 2]
    RPN_ANCHOR_STRIDE = 16
    RPN_NMS_THRESHOLD = 0.7
    RPN_TRAIN_ANCHORS_PER_IMAGE = 256
    RPN_POSITIVE_RATIO = 0.5
    DETECTION_MIN_CONFIDENCE = 0.7
    DETECTION_NMS_THRESHOLD = 0.3
    DETECTION_MAX_INSTANCES = 100
    LEARNING_RATE = 0.001
    WEIGHT_DECAY = 0.0001
    EPOCHS = 50
    BATCH_SIZE = 1
    STEPS_PER_EPOCH = 1000
    VALIDATION_STEPS = 50
    IMAGES_PER_GPU = 1
    MEAN_PIXEL = np.array([123.7, 116.8, 103.9])
    NUM_CLASSES = 81  # COCO has 80 classes + background

class DataGenerator(keras.utils.Sequence):
    def __init__(self, dataset, config, shuffle=True, augment=True):
        self.dataset = dataset
        self.config = config
        self.shuffle = shuffle
        self.augment = augment
        self.image_ids = np.copy(self.dataset.image_ids)
        self.on_epoch_end()

    def __len__(self):
        return int(np.ceil(len(self.dataset.image_ids) / self.config.BATCH_SIZE))

    def __getitem__(self, idx):
        batch_image_ids = self.image_ids[idx * self.config.BATCH_SIZE:(idx + 1) * self.config.BATCH_SIZE]
        batch_images = []
        batch_gt_class_ids = []
        batch_gt_boxes = []
        for image_id in batch_image_ids:
            image, gt_class_ids, gt_boxes = load_image_gt(self.dataset, self.config, image_id, augment=self.augment)
            batch_images.append(image)
            batch_gt_class_ids.append(gt_class_ids)
            batch_gt_boxes.append(gt_boxes)
        batch_images = np.array(batch_images)
        batch_gt_class_ids = np.array(batch_gt_class_ids)
        batch_gt_boxes = np.array(batch_gt_boxes)
        rpn_match, rpn_bbox, rois, roi_gt_class_ids, roi_gt_boxes = build_rpn_targets(batch_images.shape, self.config, batch_gt_class_ids, batch_gt_boxes)
        inputs = [batch_images, batch_gt_class_ids, batch_gt_boxes, rpn_match, rpn_bbox, rois, roi_gt_class_ids, roi_gt_boxes]
        outputs = []
        return inputs, outputs

    def on_epoch_end(self):
        if self.shuffle:
            np.random.shuffle(self.image_ids)

def load_image_gt(dataset, config, image_id, augment=True):
    image = dataset.load_image(image_id)
    mask, class_ids = dataset.load_mask(image_id)
    bbox = maskUtils.toBbox(mask)
    bbox = np.expand_dims(bbox, axis=-1)
    class_ids = np.expand_dims(class_ids, axis=-1)
    gt_boxes = np.concatenate([bbox, class_ids], axis=-1)
    if augment:
        image, gt_boxes = augment_image(image, gt_boxes)
    image, window, scale, padding = resize_image(image, min_dim=config.IMAGE_MIN_DIM, max_dim=config.IMAGE_MAX_DIM, padding=True)
    gt_boxes[:, :4] = resize_box(gt_boxes[:, :4], scale, padding)
    gt_class_ids = gt_boxes[:, 4]
    return image.astype(np.float32) - config.MEAN_PIXEL, gt_class_ids.astype(np.int32), gt_boxes[:, :4].astype(np.float32)

def augment_image(image, gt_boxes):
    if np.random.rand() < 0.5:
        image = np.fliplr(image)
        gt_boxes[:, 0] = image.shape[1] - gt_boxes[:, 0] - gt_boxes[:, 2]
    return image, gt_boxes

def resize_image(image, min_dim=None, max_dim=None, padding=False):
    original_shape = image.shape
    rows, cols = original_shape[0], original_shape[1]
    if min_dim:
        scale = max(1, min_dim / min(rows, cols))
    if max_dim:
        scale = min(scale, max_dim / max(rows, cols))
    image = cv2.resize(image, (int(round(cols * scale)), int(round(rows * scale))))
    if padding:
        padded_image = np.zeros((max_dim, max_dim, 3), dtype=np.float32)
        padded_image[:image.shape[0], :image.shape[1], :] = image
        window = (0, 0, image.shape[1], image.shape[0])
        return padded_image, window, scale, (0, 0, 0, 0)
    return image, None, scale, None

def resize_box(boxes, scale, padding):
    if padding is not None:
        boxes[:, 0] += padding[1]  # x1
        boxes[:, 1] += padding[0]  # y1
    boxes[:, :4] *= scale
    return boxes

def overlaps(boxes1, boxes2):
    i_x1 = np.maximum(boxes1[:, 0], boxes2[:, 0])
    i_y1 = np.maximum(boxes1[:, 1], boxes2[:, 1])
    i_x2 = np.minimum(boxes1[:, 2], boxes2[:, 2])
    i_y2 = np.minimum(boxes1[:, 3], boxes2[:, 3])
    i_area = np.maximum(i_x2 - i_x1 + 1, 0) * np.maximum(i_y2 - i_y1 + 1, 0)
    a_area = (boxes1[:, 2] - boxes1[:, 0] + 1) * (boxes1[:, 3] - boxes1[:, 1] + 1)
    b_area = (boxes2[:, 2] - boxes2[:, 0] + 1) * (boxes2[:, 3] - boxes2[:, 1] + 1)
    u_area = a_area + b_area - i_area
    overlaps = i_area / u_area
    return overlaps

def compute_iou(box, boxes, eps=1e-8):
    iou = overlaps(box[np.newaxis], boxes)
    return iou

def compute_backbone_shapes(config, image_shape):
    if callable(config.BACKBONE):
        return config.BACKBONE(image_shape)
    assert isinstance(config.BACKBONE, str)
    if config.BACKBONE in ["resnet50", "resnet101"]:
        if image_shape[0] >= 800:
            return np.array([[200, 256], [100, 128], [50, 64], [25, 32], [13, 16]])
        else:
            return np.array([[100, 128], [50, 64], [25, 32], [13, 16], [7, 8]])
    else:
        raise ValueError("Invalid backbone name")

def generate_anchors(scales, ratios, shape, feature_stride, anchor_stride):
    scales, ratios = np.meshgrid(np.array(scales), np.array(ratios))
    scales, ratios = scales.flatten(), ratios.flatten()
    heights = scales / np.sqrt(ratios)
    widths = scales * np.sqrt(ratios)
    shifts_y = np.arange(0, shape[0], anchor_stride) * feature_stride
    shifts_x = np.arange(0, shape[1], anchor_stride) * feature_stride
    shifts_x, shifts_y = np.meshgrid(shifts_x, shifts_y)
    box_widths, box_centers_x = np.meshgrid(widths, shifts_x)
    box_heights, box_centers_y = np.meshgrid(heights, shifts_y)
    box_centers = np.stack([box_centers_y, box_centers_x], axis=2)
    box_sizes = np.stack([box_heights, box_widths], axis=2)
    box_centers = np.reshape(box_centers, [-1, 2])
    box_sizes = np.reshape(box_sizes, [-1, 2])
    boxes = np.concatenate([box_centers - 0.5 * box_sizes, box_centers + 0.5 * box_sizes], axis=1)
    boxes = np.round(boxes)
    return boxes

def generate_pyramid_anchors(scales, ratios, feature_shapes, feature_strides, anchor_stride):
    anchors = []
    for i in range(len(scales)):
        anchors.append(generate_anchors(scales[i], ratios, feature_shapes[i], feature_strides[i], anchor_stride))
    return np.concatenate(anchors, axis=0)

def norm_boxes(boxes, shape):
    boxes = boxes.astype(np.float32)
    h, w = shape[:2]
    scale = np.array([h - 1, w - 1, h - 1, w - 1])
    shift = np.array([0, 0, 1, 1])
    boxes = np.divide(boxes - shift, scale)
    boxes = np.maximum(np.minimum(boxes, 1), 0)
    return boxes

def denorm_boxes(boxes, shape):
    h, w = shape[:2]
    scale = np.array([h - 1, w - 1, h - 1, w - 1])
    shift = np.array([0, 0, 1, 1])
    boxes = boxes * scale + shift
    return boxes.astype(np.int32)

def overlaps_graph(boxes1, boxes2):
    b1 = tf.reshape(tf.tile(tf.expand_dims(boxes1, 1), [1, 1, tf.shape(boxes2)[0]]), [-1, 4])
    b2 = tf.tile(boxes2, [tf.shape(boxes1)[0], 1])
    b2 = tf.reshape(tf.transpose(b2), [-1, 4])
    overlaps = compute_iou(b1, b2)
    overlaps = tf.reshape(overlaps, [tf.shape(boxes1)[0], tf.shape(boxes2)[0]])
    return overlaps

def detection_target_graph(proposals, gt_class_ids, gt_boxes, config):
    proposals = tf.cast(proposals, tf.float32)
    gt_boxes = tf.cast(gt_boxes, tf.float32)
    gt_class_ids = tf.cast(gt_class_ids, tf.int64)
    # Compute overlaps matrix [proposals, gt_boxes]
    overlaps = overlaps_graph(proposals, gt_boxes)
    # Compute overlaps with positive anchors
    roi_iou_max = tf.reduce_max(overlaps, axis=1)
    positive_roi_bool = (roi_iou_max >= config.RPN_POSITIVE_RATIO)
    positive_indices = tf.where(positive_roi_bool)[:, 0]
    # Subsample ROIs. Aim for 33% positive
    # Positive ROIs
    positive_count = int(config.RPN_TRAIN_ANCHORS_PER_IMAGE * config.RPN_POSITIVE_RATIO)
    positive_indices = tf.random.shuffle(positive_indices)[:positive_count]
    positive_count = tf.shape(positive_indices)[0]
    # Negative ROIs. Add enough to maintain positive:negative ratio.
    r = 1.0 / config.RPN_POSITIVE_RATIO
    negative_count = tf.cast(r * tf.cast(positive_count, tf.float32), tf.int32) - positive_count
    negative_indices = tf.where(roi_iou_max < config.RPN_POSITIVE_RATIO)[:, 0]
    negative_count = tf.math.minimum(tf.shape(negative_indices)[0], negative_count)
    negative_indices = tf.random.shuffle(negative_indices)[:negative_count]
    # Gather selected ROIs
    positive_rois = tf.gather(proposals, positive_indices)
    negative_rois = tf.gather(proposals, negative_indices)
    # Assign positive ROIs to GT boxes.
    positive_overlaps = tf.gather(overlaps, positive_indices)
    roi_gt_box_assignment = tf.cond(
        tf.greater(tf.shape(positive_overlaps)[1], 0),
        true_fn=lambda: tf.argmax(positive_overlaps, axis=1),
        false_fn=lambda: tf.cast(tf.constant([]), tf.int64)
    )
    roi_gt_boxes = tf.gather(gt_boxes, roi_gt_box_assignment)
    roi_gt_class_ids = tf.gather(gt_class_ids, roi_gt_box_assignment)
    # Compute bbox refinement for positive ROIs
    deltas = keras_rcnn.backend.boxutils.bbox_transform(positive_rois, roi_gt_boxes)
    deltas /= tf.constant(config.BBOX_STD_DEV, dtype=tf.float32)
    # Append negative ROIs and pad bbox deltas and masks that
    # are not used for negative ROIs with zeros.
    rois = tf.concat([positive_rois, negative_rois], axis=0)
    N = tf.shape(negative_rois)[0]
    P = tf.math.maximum(config.RPN_TRAIN_ANCHORS_PER_IMAGE - tf.shape(rois)[0], 0)
    rois = tf.pad(rois, [(0, P), (0, 0)])
    roi_gt_boxes = tf.pad(roi_gt_boxes, [(0, N + P), (0, 0)])
    roi_gt_class_ids = tf.pad(roi_gt_class_ids, [(0, N + P)])
    deltas = tf.pad(deltas, [(0, N + P), (0, 0)])
    # Return rois and deltas
    return rois, roi_gt_class_ids, deltas

def build_rpn_targets(image_shape, config, gt_class_ids, gt_boxes):
    feature_shapes = compute_backbone_shapes(config, image_shape)
    anchors = generate_pyramid_anchors(config.RPN_ANCHOR_SCALES, config.RPN_ANCHOR_RATIOS, feature_shapes, config.BACKBONE_SHAPES, config.RPN_ANCHOR_STRIDE)
    rpn_match, rpn_bbox = keras_rcnn.backend.anchor.get_best_anchor(anchors, gt_boxes, config)
    rpn_match = tf.expand_dims(rpn_match, axis=-1)
    rpn_bbox = tf.reshape(rpn_bbox, [-1, 4])
    rois, roi_gt_class_ids, deltas = tf.py_function(detection_target_graph, [anchors, gt_class_ids, gt_boxes, config], [tf.float32, tf.int64, tf.float32])
    rois.set_shape([config.RPN_TRAIN_ANCHORS_PER_IMAGE, 4])
    roi_gt_class_ids.set_shape([config.RPN_TRAIN_ANCHORS_PER_IMAGE])
    deltas.set_shape([config.RPN_TRAIN_ANCHORS_PER_IMAGE, 4 * config.NUM_CLASSES])
    rpn_match.set_shape([None, 1])
    rpn_bbox.set_shape([None, 4])
    rois = tf.stop_gradient(rois)
    roi_gt_class_ids = tf.stop_gradient(roi_gt_class_ids)
    deltas = tf.stop_gradient(deltas)
    rpn_match = tf.stop_gradient(rpn_match)
    rpn_bbox = tf.stop_gradient(rpn_bbox)
    return rpn_match, rpn_bbox, rois, roi_gt_class_ids, deltas

def build_rpn_model(config):
    input_image = Input(shape=[None, None, 3], name="input_image")
    shared_layers = ResNet50(include_top=False, weights='imagenet', input_tensor=input_image)
    layer_names = ["conv4_block6_out", "conv5_block3_out", "conv6_relu"]
    layers = [shared_layers.get_layer(name).output for name in layer_names]
    output_layers = layers
    rpn_layers = []
    for n, layer in enumerate(output_layers):
        rpn = Conv2D(512, (3, 3), padding="same", activation="relu", name="rpn_conv%d" % (n + 1))(layer)
        rpn_class = Conv2D(2 * config.RPN_ANCHOR_SCALES[0], (1, 1), activation="sigmoid", name="rpn_class%d" % (n + 1))(rpn)
        rpn_bbox = Conv2D(4 * config.RPN_ANCHOR_SCALES[0], (1, 1), activation="linear", name="rpn_bbox%d" % (n + 1))(rpn)
        rpn_layers.append(rpn_class)
        rpn_layers.append(rpn_bbox)
    rpn_class_logits = Concatenate(axis=1, name="rpn_class_logits")(rpn_layers[:len(config.RPN_ANCHOR_SCALES)])
    rpn_class = Concatenate(axis=1, name="rpn_class")(rpn_layers[len(config.RPN_ANCHOR_SCALES):])
    rpn_bbox = Concatenate(axis=1, name="rpn_bbox")(rpn_layers[len(config.R