import cv2 import requests import os from collections import defaultdict from math import log, sqrt import numpy as np from PIL import Image, ImageDraw GREEN = "#0F0" BLUE = "#00F" RED = "#F00" def crop_image(im, settings): """ Intelligently crop an image to the subject matter """ scale_by = 1 if is_landscape(im.width, im.height): scale_by = settings.crop_height / im.height elif is_portrait(im.width, im.height): scale_by = settings.crop_width / im.width elif is_square(im.width, im.height): if is_square(settings.crop_width, settings.crop_height): scale_by = settings.crop_width / im.width elif is_landscape(settings.crop_width, settings.crop_height): scale_by = settings.crop_width / im.width elif is_portrait(settings.crop_width, settings.crop_height): scale_by = settings.crop_height / im.height im = im.resize((int(im.width * scale_by), int(im.height * scale_by))) im_debug = im.copy() focus = focal_point(im_debug, settings) # take the focal point and turn it into crop coordinates that try to center over the focal # point but then get adjusted back into the frame y_half = int(settings.crop_height / 2) x_half = int(settings.crop_width / 2) x1 = focus.x - x_half if x1 < 0: x1 = 0 elif x1 + settings.crop_width > im.width: x1 = im.width - settings.crop_width y1 = focus.y - y_half if y1 < 0: y1 = 0 elif y1 + settings.crop_height > im.height: y1 = im.height - settings.crop_height x2 = x1 + settings.crop_width y2 = y1 + settings.crop_height crop = [x1, y1, x2, y2] results = [] results.append(im.crop(tuple(crop))) if settings.annotate_image: d = ImageDraw.Draw(im_debug) rect = list(crop) rect[2] -= 1 rect[3] -= 1 d.rectangle(rect, outline=GREEN) results.append(im_debug) if settings.destop_view_image: im_debug.show() return results def focal_point(im, settings): corner_points = image_corner_points(im, settings) if settings.corner_points_weight > 0 else [] entropy_points = image_entropy_points(im, settings) if settings.entropy_points_weight > 0 else [] face_points = image_face_points(im, settings) if settings.face_points_weight > 0 else [] pois = [] weight_pref_total = 0 if len(corner_points) > 0: weight_pref_total += settings.corner_points_weight if len(entropy_points) > 0: weight_pref_total += settings.entropy_points_weight if len(face_points) > 0: weight_pref_total += settings.face_points_weight corner_centroid = None if len(corner_points) > 0: corner_centroid = centroid(corner_points) corner_centroid.weight = settings.corner_points_weight / weight_pref_total pois.append(corner_centroid) entropy_centroid = None if len(entropy_points) > 0: entropy_centroid = centroid(entropy_points) entropy_centroid.weight = settings.entropy_points_weight / weight_pref_total pois.append(entropy_centroid) face_centroid = None if len(face_points) > 0: face_centroid = centroid(face_points) face_centroid.weight = settings.face_points_weight / weight_pref_total pois.append(face_centroid) average_point = poi_average(pois, settings) if settings.annotate_image: d = ImageDraw.Draw(im) max_size = min(im.width, im.height) * 0.07 if corner_centroid is not None: color = BLUE box = corner_centroid.bounding(max_size * corner_centroid.weight) d.text((box[0], box[1]-15), "Edge: %.02f" % corner_centroid.weight, fill=color) d.ellipse(box, outline=color) if len(corner_points) > 1: for f in corner_points: d.rectangle(f.bounding(4), outline=color) if entropy_centroid is not None: color = "#ff0" box = entropy_centroid.bounding(max_size * entropy_centroid.weight) d.text((box[0], box[1]-15), "Entropy: %.02f" % entropy_centroid.weight, fill=color) d.ellipse(box, outline=color) if len(entropy_points) > 1: for f in entropy_points: d.rectangle(f.bounding(4), outline=color) if face_centroid is not None: color = RED box = face_centroid.bounding(max_size * face_centroid.weight) d.text((box[0], box[1]-15), "Face: %.02f" % face_centroid.weight, fill=color) d.ellipse(box, outline=color) if len(face_points) > 1: for f in face_points: d.rectangle(f.bounding(4), outline=color) d.ellipse(average_point.bounding(max_size), outline=GREEN) return average_point def image_face_points(im, settings): if settings.dnn_model_path is not None: detector = cv2.FaceDetectorYN.create( settings.dnn_model_path, "", (im.width, im.height), 0.9, # score threshold 0.3, # nms threshold 5000 # keep top k before nms ) faces = detector.detect(np.array(im)) results = [] if faces[1] is not None: for face in faces[1]: x = face[0] y = face[1] w = face[2] h = face[3] results.append( PointOfInterest( int(x + (w * 0.5)), # face focus left/right is center int(y + (h * 0.33)), # face focus up/down is close to the top of the head size = w, weight = 1/len(faces[1]) ) ) return results else: np_im = np.array(im) gray = cv2.cvtColor(np_im, cv2.COLOR_BGR2GRAY) tries = [ [ f'{cv2.data.haarcascades}haarcascade_eye.xml', 0.01 ], [ f'{cv2.data.haarcascades}haarcascade_frontalface_default.xml', 0.05 ], [ f'{cv2.data.haarcascades}haarcascade_profileface.xml', 0.05 ], [ f'{cv2.data.haarcascades}haarcascade_frontalface_alt.xml', 0.05 ], [ f'{cv2.data.haarcascades}haarcascade_frontalface_alt2.xml', 0.05 ], [ f'{cv2.data.haarcascades}haarcascade_frontalface_alt_tree.xml', 0.05 ], [ f'{cv2.data.haarcascades}haarcascade_eye_tree_eyeglasses.xml', 0.05 ], [ f'{cv2.data.haarcascades}haarcascade_upperbody.xml', 0.05 ] ] for t in tries: classifier = cv2.CascadeClassifier(t[0]) minsize = int(min(im.width, im.height) * t[1]) # at least N percent of the smallest side try: faces = classifier.detectMultiScale(gray, scaleFactor=1.1, minNeighbors=7, minSize=(minsize, minsize), flags=cv2.CASCADE_SCALE_IMAGE) except: continue if len(faces) > 0: rects = [[f[0], f[1], f[0] + f[2], f[1] + f[3]] for f in faces] return [PointOfInterest((r[0] +r[2]) // 2, (r[1] + r[3]) // 2, size=abs(r[0]-r[2]), weight=1/len(rects)) for r in rects] return [] def image_corner_points(im, settings): grayscale = im.convert("L") # naive attempt at preventing focal points from collecting at watermarks near the bottom gd = ImageDraw.Draw(grayscale) gd.rectangle([0, im.height*.9, im.width, im.height], fill="#999") np_im = np.array(grayscale) points = cv2.goodFeaturesToTrack( np_im, maxCorners=100, qualityLevel=0.04, minDistance=min(grayscale.width, grayscale.height)*0.06, useHarrisDetector=False, ) if points is None: return [] focal_points = [] for point in points: x, y = point.ravel() focal_points.append(PointOfInterest(x, y, size=4, weight=1/len(points))) return focal_points def image_entropy_points(im, settings): landscape = im.height < im.width portrait = im.height > im.width if landscape: move_idx = [0, 2] move_max = im.size[0] elif portrait: move_idx = [1, 3] move_max = im.size[1] else: return [] e_max = 0 crop_current = [0, 0, settings.crop_width, settings.crop_height] crop_best = crop_current while crop_current[move_idx[1]] < move_max: crop = im.crop(tuple(crop_current)) e = image_entropy(crop) if (e > e_max): e_max = e crop_best = list(crop_current) crop_current[move_idx[0]] += 4 crop_current[move_idx[1]] += 4 x_mid = int(crop_best[0] + settings.crop_width/2) y_mid = int(crop_best[1] + settings.crop_height/2) return [PointOfInterest(x_mid, y_mid, size=25, weight=1.0)] def image_entropy(im): # greyscale image entropy # band = np.asarray(im.convert("L")) band = np.asarray(im.convert("1"), dtype=np.uint8) hist, _ = np.histogram(band, bins=range(0, 256)) hist = hist[hist > 0] return -np.log2(hist / hist.sum()).sum() def centroid(pois): x = [poi.x for poi in pois] y = [poi.y for poi in pois] return PointOfInterest(sum(x)/len(pois), sum(y)/len(pois)) def poi_average(pois, settings): weight = 0.0 x = 0.0 y = 0.0 for poi in pois: weight += poi.weight x += poi.x * poi.weight y += poi.y * poi.weight avg_x = round(x / weight) avg_y = round(y / weight) return PointOfInterest(avg_x, avg_y) def is_landscape(w, h): return w > h def is_portrait(w, h): return h > w def is_square(w, h): return w == h def download_and_cache_models(dirname): download_url = 'https://github.com/opencv/opencv_zoo/blob/91fb0290f50896f38a0ab1e558b74b16bc009428/models/face_detection_yunet/face_detection_yunet_2022mar.onnx?raw=true' model_file_name = 'face_detection_yunet.onnx' if not os.path.exists(dirname): os.makedirs(dirname) cache_file = os.path.join(dirname, model_file_name) if not os.path.exists(cache_file): print(f"downloading face detection model from '{download_url}' to '{cache_file}'") response = requests.get(download_url) with open(cache_file, "wb") as f: f.write(response.content) if os.path.exists(cache_file): return cache_file return None class PointOfInterest: def __init__(self, x, y, weight=1.0, size=10): self.x = x self.y = y self.weight = weight self.size = size def bounding(self, size): return [ self.x - size//2, self.y - size//2, self.x + size//2, self.y + size//2 ] class Settings: def __init__(self, crop_width=512, crop_height=512, corner_points_weight=0.5, entropy_points_weight=0.5, face_points_weight=0.5, annotate_image=False, dnn_model_path=None): self.crop_width = crop_width self.crop_height = crop_height self.corner_points_weight = corner_points_weight self.entropy_points_weight = entropy_points_weight self.face_points_weight = face_points_weight self.annotate_image = annotate_image self.destop_view_image = False self.dnn_model_path = dnn_model_path