owlv2_helper.py

import os
from matplotlib import pyplot as plt
import skimage
from skimage import io as skimage_io
import numpy as np
import re
import cv2


def rescale_detection_box(boxes, image):
    h_img, w_img, _ = image.shape
    size = max(h_img, w_img)

    pad_h = size - h_img
    pad_w = size - w_img

    recovered_boxes = []
    for box in boxes:
        cx, cy, w, h = box
        cx = cx * size
        cy = cy * size
        w = w * size
        h = h * size

        # if cx < 0 or cx > w_img or cy < 0 or cy > h_img:
        #   continue;

        x1 = cx - w / 2
        y1 = cy - h / 2
        x2 = cx + w / 2
        y2 = cy + h / 2
        recovered_boxes.append((x1, y1, x2, y2))
    return recovered_boxes




def read_images(image_dir):
    images = []
    filenames = [p for p in os.listdir(image_dir) if os.path.splitext(p)[-1].lower() in [".png", ".jpg", ".jpeg",]]
    filenames.sort(key=lambda p: os.path.splitext(p)[0])
    for filename in filenames:
        file_path = os.path.join(image_dir, filename)
        image_uint8 = skimage_io.imread(file_path)
        image = image_uint8.astype(np.float32) / 255.0
        images.append(image)
    return images, filenames




def preprocess_images(images, model_input_size):
    processed_images = []
    for image in images:
        # Pad image to square
        h, w, d = image.shape
        size = max(h, w)
        image_padded = np.pad(image, ((0, size - h), (0, size - w), (0, 0)), constant_values=0.5)
        # Resize image to fit model's input size
        image_resized = skimage.transform.resize(
            image_padded,
            (model_input_size, model_input_size),
            anti_aliasing=True,
        )
        processed_images.append(image_resized)
    # Shape: (b, h, w, d)
    return np.array(processed_images, dtype=np.float32)




def too_small(bbox, threshold=400):
    x1, y1, x2, y2 = bbox
    width = max(0, x2 - x1)
    height = max(0, y2 - y1)
    area = width * height
    # Return True if area is too small
    return area < threshold  


def too_large(bbox, image, threshold=0.9):
    x1, y1, x2, y2 = bbox

    bbox_width = x2 - x1
    bbox_height = y2 - y1
    bbox_area = bbox_width * bbox_height

    image_height, image_width = image.shape[:2]
    image_area = image_width * image_height

    area_ratio = bbox_area / image_area
    return area_ratio >= threshold




def plot_bboxes_on_orig_image(image, boxes, output_path):
    plt.clf()
    plt.imshow(image)
    plt.axis('off')

    for box in boxes:
        x1, y1, x2, y2 = box
        plt.plot(
            [x1, x2, x2, x1, x1], 
            [y1, y1, y2, y2, y1], 
            linewidth=0.8, alpha=0.6
        )

    plt.savefig(output_path, bbox_inches='tight', pad_inches=0.1, dpi=300)
    plt.close()
    print(f"    Done! Visualization saved to {output_path}")




def compute_iou(box1, box2):
    x1_inter = max(box1[0], box2[0])
    y1_inter = max(box1[1], box2[1])
    x2_inter = min(box1[2], box2[2])
    y2_inter = min(box1[3], box2[3])
    inter_width = max(0, x2_inter - x1_inter)
    inter_height = max(0, y2_inter - y1_inter)
    inter_area = inter_width * inter_height
    box1_area = (box1[2] - box1[0]) * (box1[3] - box1[1])
    box2_area = (box2[2] - box2[0]) * (box2[3] - box2[1])
    union_area = box1_area + box2_area - inter_area
    return inter_area / union_area if union_area > 0 else 0




def remove_overlapping_bboxes(bboxes, iou_threshold=0.7):
    if not bboxes:
        return []
    bboxes = sorted(bboxes, key=lambda x: (x[2] - x[0]) * (x[3] - x[1]), reverse=True)
    keep = []
    for bbox in bboxes:
        should_keep = True
        for kept_bbox in keep:
            if compute_iou(bbox, kept_bbox) > iou_threshold:
                should_keep = False
                break
        if should_keep:
            keep.append(bbox)
    return keep




def get_centroid(bbox):
    x1, y1, x2, y2 = bbox
    cx = (x1 + x2) / 2
    cy = (y1 + y2) / 2
    return (int(cx), int(cy))