def test_doesnt_get_smaller_than_focal_point(self):
"Test that the cropbox doesn't get any smaller than the focal point"
self.assertEqual(
crop_to_point((640, 480), (10, 10),
FocalPoint(x=320, y=240, width=100, height=100)),
CropBox(270, 190, 370, 290),
)
def detect_faces(self):
if opencv_available:
cascade_filename = os.path.join(
os.path.dirname(__file__), 'face_detection',
'haarcascade_frontalface_alt2.xml')
cascade = cv.Load(cascade_filename)
image = self.opencv_grey_image()
cv.EqualizeHist(image, image)
min_size = (40, 40)
haar_scale = 1.1
min_neighbors = 3
haar_flags = 0
faces = cv.HaarDetectObjects(image, cascade,
cv.CreateMemStorage(0), haar_scale,
min_neighbors, haar_flags, min_size)
if faces:
return [
FocalPoint.from_square(face[0][0], face[0][1], face[0][2],
face[0][3]) for face in faces
]
return []
def test_keeps_composition(self):
"Test that the cropbox tries to keep the composition of the original image as much as it can"
self.assertEqual(
crop_to_point((300, 300), (150, 150), FocalPoint(x=100, y=200)),
CropBox(
50, 100, 200,
250), # Focal point is 1/3 across and 2/3 down in the crop box
)
def test_keeps_focal_point_in_view_bottom_left(self):
"""
Even though it tries to keep the composition of the image,
it shouldn't let that get in the way of keeping the entire subject in view
"""
self.assertEqual(
crop_to_point((300, 300), (150, 150), FocalPoint(x=100, y=200, width=150, height=150)),
CropBox(25, 125, 175, 275),
)
def focal_point(self):
if self.focal_point_x is not None and \
self.focal_point_y is not None and \
self.focal_point_width is not None and \
self.focal_point_height is not None:
return FocalPoint(
self.focal_point_x,
self.focal_point_y,
width=self.focal_point_width,
height=self.focal_point_height,
)
def detect_features(self):
if opencv_available:
image = self.opencv_grey_image()
rows = self.image_size[0]
cols = self.image_size[1]
eig_image = cv.CreateMat(rows, cols, cv.CV_32FC1)
temp_image = cv.CreateMat(rows, cols, cv.CV_32FC1)
points = cv.GoodFeaturesToTrack(image, eig_image, temp_image, 20, 0.04, 1.0, useHarris=False)
if points:
return [FocalPoint(x, y, 1) for x, y in points]
return []
def detect_faces(self):
if opencv_available:
cascade_filename = os.path.join(os.path.dirname(__file__), 'face_detection', 'haarcascade_frontalface_alt2.xml')
cascade = cv.Load(cascade_filename)
image = self.opencv_grey_image()
cv.EqualizeHist(image, image)
min_size = (40, 40)
haar_scale = 1.1
min_neighbors = 3
haar_flags = 0
faces = cv.HaarDetectObjects(
image, cascade, cv.CreateMemStorage(0),
haar_scale, min_neighbors, haar_flags, min_size
)
if faces:
return [FocalPoint.from_square(face[0][0], face[0][1], face[0][2], face[0][3]) for face in faces]
return []
def test_doesnt_exit_bottom_right(self):
"Test that the cropbox doesn't exit the image at the bottom right"
self.assertEqual(
crop_to_point((640, 480), (100, 100), FocalPoint(x=640, y=480)),
CropBox(540, 380, 640, 480),
)
def test_doesnt_exit_top_left(self):
"Test that the cropbox doesn't exit the image at the top left"
self.assertEqual(
crop_to_point((640, 480), (100, 100), FocalPoint(x=0, y=0)),
CropBox(0, 0, 100, 100),
)
def test_basic(self):
"Test basic cropping in the centre of the image"
self.assertEqual(
crop_to_point((640, 480), (100, 100), FocalPoint(x=320, y=240)),
CropBox(270, 190, 370, 290),
)
def crop_to_point(image_size, crop_size, focal_point):
(original_width, original_height) = image_size
(crop_width, crop_height) = crop_size
if not focal_point:
focal_point = FocalPoint(original_width / 2, original_height / 2)
# Make sure that the crop size is no smaller than the focal point
crop_width = max(crop_width, focal_point.width)
crop_height = max(crop_height, focal_point.height)
# Make sure final dimensions do not exceed original dimensions
final_width = min(original_width, crop_width)
final_height = min(original_height, crop_height)
# Get UV for focal point
focal_point_u = focal_point.x / original_width
focal_point_v = focal_point.y / original_height
# Get crop box
left = focal_point.x - focal_point_u * final_width
top = focal_point.y - focal_point_v * final_height
right = focal_point.x - focal_point_u * final_width + final_width
bottom = focal_point.y - focal_point_v * final_height + final_height
# Make sure the entire focal point is in the crop box
focal_point_left = focal_point.x - focal_point.width / 2
focal_point_top = focal_point.y - focal_point.height / 2
focal_point_right = focal_point.x + focal_point.width / 2
focal_point_bottom = focal_point.y + focal_point.height / 2
if left > focal_point_left:
right -= left - focal_point_left
left = focal_point_left
if top > focal_point_top:
bottom -= top - focal_point_top
top = focal_point_top
if right < focal_point_right:
left += focal_point_right - right
right = focal_point_right
if bottom < focal_point_bottom:
top += focal_point_bottom - bottom
bottom = focal_point_bottom
# Don't allow the crop box to go over the image boundary
if left < 0:
right -= left
left = 0
if top < 0:
bottom -= top
top = 0
if right > original_width:
left -= right - original_width
right = original_width
if bottom > original_height:
top -= bottom - original_height
bottom = original_height
return CropBox(left, top, right, bottom)