def image_draw_mask(input_image,
input_image_mask,
transparency=0.3,
warning=True,
debug=True):
'''
draw a mask on top of an image with certain transparency
parameters:
input_image: a pil or numpy image
input_image_mask: a pil or numpy image
transparency: transparency factor
outputs:
masked_image: uint8 numpy image
'''
np_image, _ = safe_image(input_image, warning=warning, debug=debug)
np_image_mask, _ = safe_image(input_image_mask,
warning=warning,
debug=debug)
if debug:
assert isscalar(transparency), 'the transparency should be a scalar'
assert np_image.shape == np_image_mask.shape, 'the shape of mask should be equal to the shape of input image'
if isfloatimage(np_image): np_image = (np_image * 255.).astype('uint8')
if isfloatimage(np_image_mask):
np_image_mask = (np_image_mask * 255.).astype('uint8')
pil_image, pil_image_mask = Image.fromarray(np_image), Image.fromarray(
np_image_mask)
masked_image = np.array(
Image.blend(pil_image, pil_image_mask, alpha=transparency))
return masked_image
def gray2rgb(input_image,
with_color=True,
cmap='jet',
warning=True,
debug=True):
'''
convert a grayscale image (1-channel) to a rgb image
parameters:
input_image: an pil or numpy image
with_color: add false colormap
output:
rgb_image: an uint8 rgb numpy image
'''
np_image, _ = safe_image(input_image, warning=warning, debug=debug)
if isfloatimage(np_image): np_image = (np_image * 255.).astype('uint8')
if debug:
assert isgrayimage_dimension(
np_image), 'the input numpy image is not correct: {}'.format(
np_image.shape)
assert isuintimage(
np_image
), 'the input numpy image should be uint8 image in order to use opencv'
if with_color:
if cmap == 'jet':
rgb_image = cv2.applyColorMap(np_image, cv2.COLORMAP_JET)
else:
assert False, 'cmap %s is not supported' % cmap
else:
rgb_image = cv2.cvtColor(np_image, cv2.COLOR_GRAY2RGB)
return rgb_image
def image_hist_equalization_hsv(input_image, warning=True, debug=True):
'''
do histogram equalization for an image: could be a color image or gray image
the color space used for histogram equalization is HSV
parameters:
input_image: a pil or numpy image
outputs:
equalized_image: an uint8 numpy image (rgb or gray)
'''
np_image, _ = safe_image(input_image, warning=warning, debug=debug)
if isuintimage(np_image): np_image = np_image.astype('float32') / 255.
if debug:
assert isfloatimage(
np_image), 'the input image should be a float image'
if iscolorimage_dimension(np_image):
hsv_image = rgb2hsv(np_image, warning=warning, debug=debug)
input_data = hsv_image[:, :, 2] # extract the value channel
equalized_hsv_image = (
hist_equalization(input_data, num_bins=256, debug=debug) *
255.).astype('uint8')
hsv_image[:, :, 2] = equalized_hsv_image
equalized_image = hsv2rgb(hsv_image, warning=warning, debug=debug)
elif isgrayimage_dimension(np_image):
equalized_image = (
hist_equalization(np_image, num_bins=256, debug=debug) *
255.).astype('uint8')
else:
assert False, 'the input image is neither a color image or a grayscale image'
return equalized_image
def image_clahe(input_image,
clip_limit=2.0,
grid_size=8,
warning=True,
debug=True):
'''
do contrast limited adative histogram equalization for an image: could be a color image or gray image
the color space used for histogram equalization is LAB
parameters:
input_image: a pil or numpy image
outputs:
clahe_image: an uint8 numpy image (rgb or gray)
'''
np_image, _ = safe_image(input_image, warning=warning, debug=debug)
if isfloatimage(np_image):
np_image = (np_image.astype('float32') * 255.).astype('uint8')
if debug:
assert isuintimage(np_image), 'the input image should be a uint8 image'
clahe = cv2.createCLAHE(clipLimit=clip_limit,
tileGridSize=(grid_size, grid_size))
if iscolorimage_dimension(np_image):
lab_image = rgb2lab(np_image, warning=warning, debug=debug)
input_data = lab_image[:, :, 0] # extract the value channel
clahe_lab_image = clahe.apply(input_data)
lab_image[:, :, 0] = clahe_lab_image
clahe_image = lab2rgb(lab_image, warning=warning, debug=debug)
elif isgrayimage_dimension(np_image):
clahe_image = clahe.apply(np_image)
else:
assert False, 'the input image is neither a color image or a grayscale image'
return clahe_image
def image_pad_around(input_image, pad_rect, pad_value=0, warning=True, debug=True):
'''
this function is to pad given value to an image in provided region, all images in this function are floating images
parameters:
input_image: an pil or numpy image
pad_rect: a list of 4 non-negative integers, describing how many pixels to pad. The order is [left, top, right, bottom]
pad_value: an intger between [0, 255]
outputs:
img_padded: an uint8 numpy image with padding
'''
np_image, _ = safe_image(input_image, warning=warning, debug=debug)
if isfloatimage(np_image): np_image = (np_image * 255.).astype('uint8')
if len(np_image.shape) == 2: np_image = np.expand_dims(np_image, axis=2) # extend the third channel if the image is grayscale
if debug:
assert isuintimage(np_image), 'the input image is not an uint8 image'
assert isinteger(pad_value) and pad_value >= 0 and pad_value <= 255, 'the pad value should be an integer within [0, 255]'
assert islistofnonnegativeinteger(pad_rect) and len(pad_rect) == 4, 'the input pad rect is not a list of 4 non-negative integers'
im_height, im_width, im_channel = np_image.shape[0], np_image.shape[1], np_image.shape[2]
# calculate the padded size of image
pad_left, pad_top, pad_right, pad_bottom = pad_rect[0], pad_rect[1], pad_rect[2], pad_rect[3]
new_height = im_height + pad_top + pad_bottom
new_width = im_width + pad_left + pad_right
# padding
img_padded = np.zeros([new_height, new_width, im_channel]).astype('uint8')
img_padded.fill(pad_value)
img_padded[pad_top : new_height - pad_bottom, pad_left : new_width - pad_right, :] = np_image
if img_padded.shape[2] == 1: img_padded = img_padded[:, :, 0]
return img_padded
def convolve(self, input_image):
'''
convolve the kernel with the input image, whatever the input image format is. If the input image
is a color image, the filter is expanded to a 3D shape
parameters:
input_image: an pil or numpy, gray or color image
outputs:
filtered_image: a float32 numpy image, shape is same as before
'''
np_image, _ = safe_image(input_image,
warning=self.warning,
debug=self.debug)
if isuintimage(np_image): np_image = np_image.astype('float32') / 255.
if self.debug:
assert isfloatimage(
np_image), 'the input image should be a float image'
self.weights is not None, 'the kernel is not defined yet'
if iscolorimage_dimension(np_image):
self.weights = self.expand_3d(
) # expand the filter to 3D for color image
elif isgrayimage_dimension(np_image):
np_image = np_image.reshape(
np_image.shape[0],
np_image.shape[1]) # squeeze the image dimension to 2
filtered_image = ndimage.filters.convolve(np_image, self.weights)
return filtered_image
def image_find_peaks(input_image, percent_threshold=0.5, warning=True, debug=True):
'''
this function find all strict local peaks and a strict global peak from a grayscale image
the strict local maximum means that the pixel value must be larger than all nearby pixel values
parameters:
input_image: a pil or numpy grayscale image
percent_threshold: determine to what pixel value to be smoothed out.
e.g., when 0.4, all pixel values less than 0.4 * np.max(input_image) are smoothed out to be 0
outputs:
peak_array: a numpy float32 array, 3 x num_peaks, (x, y, score)
peak_global: a numpy float32 array, 3 x 1: (x, y, score)
'''
np_image, _ = safe_image_like(input_image, warning=warning, debug=debug)
if isuintimage(np_image): np_image = np_image.astype('float32') / 255.
if debug:
assert isgrayimage(np_image) and isfloatimage(np_image), 'the input image is not a grayscale and float image'
assert isscalar(percent_threshold) and percent_threshold >= 0 and percent_threshold <= 1, 'the percent_threshold is not correct'
max_value = np.max(np_image)
np_image[np_image < percent_threshold * max_value] = 0.0
height, width = np_image.shape[0], np_image.shape[1]
npimage_center, npimage_top, npimage_bottom, npimage_left, npimage_right = np.zeros([height + 2, width + 2]), np.zeros([height + 2, width + 2]), np.zeros([height + 2, width + 2]), np.zeros([height + 2, width + 2]), np.zeros([height + 2, width + 2])
# shift in different directions to find local peak, only works for convex blob
npimage_center[1:-1, 1:-1] = np_image
npimage_left[1:-1, 0:-2] = np_image
npimage_right[1:-1, 2:] = np_image
npimage_top[0:-2, 1:-1] = np_image
npimage_bottom[2:, 1:-1] = np_image
# compute pixels larger than its shifted version of heatmap
right_bool = npimage_center > npimage_right
left_bool = npimage_center > npimage_left
bottom_bool = npimage_center > npimage_bottom
top_bool = npimage_center > npimage_top
# the strict local maximum must be bigger than all nearby pixel values
peakMap = np.logical_and(np.logical_and(np.logical_and(right_bool, left_bool), top_bool), bottom_bool)
peakMap = peakMap[1:-1, 1:-1]
peak_location_tuple = np.nonzero(peakMap) # find true
num_peaks = len(peak_location_tuple[0])
if num_peaks == 0:
if warning: print('No single local peak found')
return np.zeros((3, 0), dtype='float32'), np.zeros((3, 0), dtype='float32')
# convert to a numpy array format
peak_array = np.zeros((3, num_peaks), dtype='float32')
peak_array[0, :], peak_array[1, :] = peak_location_tuple[1], peak_location_tuple[0]
for peak_index in range(num_peaks):
peak_array[2, peak_index] = np_image[int(peak_array[1, peak_index]), int(peak_array[0, peak_index])]
# find the global peak from all local peaks
global_peak_index = np.argmax(peak_array[2, :])
peak_global = peak_array[:, global_peak_index].reshape((3, 1))
return peak_array, peak_global
def hsv2rgb(input_image, warning=True, debug=True):
'''
convert a hsv image to a rgb image using opencv package
parameters:
input_image: an pil or numpy image
output:
rgb_img: an uint8 rgb numpy image
'''
np_image, _ = safe_image(input_image, warning=warning, debug=debug)
if isfloatimage(np_image): np_image = (np_image * 255.).astype('uint8')
if debug:
assert iscolorimage(np_image), 'the input image should be a rgb image'
assert isuintimage(np_image), 'the input numpy image should be uint8 image in order to use opencv'
rgb_img = cv2.cvtColor(np_image, cv2.COLOR_HSV2RGB)
return rgb_img
def image_resize(input_image, resize_factor=None, target_size=None, interp='bicubic', warning=True, debug=True):
'''
resize the image given a resize factor (e.g., 0.25), or given a target size (height, width)
e.g., the input image has 600 x 800:
1. given a resize factor of 0.25 -> results in an image with 150 x 200
2. given a target size of (300, 400) -> results in an image with 300 x 400
note that:
resize_factor and target_size cannot exist at the same time
parameters:
input_image: an pil or numpy image
resize_factor: a scalar
target_size: a list of tuple or numpy array with 2 elements, representing height and width
interp: interpolation methods: bicubic or bilinear
outputs:
resized_image: a numpy uint8 image
'''
np_image, _ = safe_image(input_image, warning=warning, debug=debug)
if isfloatimage(np_image): np_image = (np_image * 255.).astype('uint8')
if debug:
assert interp in ['bicubic', 'bilinear'], 'the interpolation method is not correct'
assert (resize_factor is not None and target_size is None) or (resize_factor is None and target_size is not None), 'resize_factor and target_size cannot co-exist'
if target_size is not None:
if debug: assert isimsize(target_size), 'the input target size is not correct'
target_width, target_height = int(round(target_size[1])), int(round(target_size[0]))
elif resize_factor is not None:
if debug: assert isscalar(resize_factor), 'the resize factor is not a scalar'
height, width = np_image.shape[:2]
target_width, target_height = int(round(resize_factor * width)), int(round(resize_factor * height))
else: assert False, 'the target_size and resize_factor do not exist'
if interp == 'bicubic':
resized_image = cv2.resize(np_image, (target_width, target_height), interpolation = cv2.INTER_CUBIC)
elif interp == 'bilinear':
resized_image = cv2.resize(np_image, (target_width, target_height), interpolation = cv2.INTER_LINEAR)
else: assert False, 'interpolation is wrong'
return resized_image
def image_rotate(input_image, input_angle, warning=True, debug=True):
'''
rotate the image given an angle in degree (e.g., 90). The rotation is counter-clockwise
parameters:
input_image: an pil or numpy image
input_angle: a scalar
outputs:
rotated_image: a numpy uint8 image
'''
if debug: assert isscalar(input_angle), 'the input angle is not a scalar'
rotation_angle = safe_angle(input_angle, warning=warning, debug=True) # ensure to be in [-180, 180]
np_image, _ = safe_image(input_image, warning=warning, debug=debug)
if isfloatimage(np_image): np_image = (np_image * 255.).astype('uint8')
pil_image = Image.fromarray(np_image)
pil_image = pil_image.rotate(rotation_angle, expand=True)
rotated_image = np.array(pil_image).astype('uint8')
return rotated_image
def rgb2hsv_v2(input_image, warning=True, debug=True):
'''
convert a rgb image to a hsv image, using PIL package, not compatible with opencv package
parameters:
input_image: an pil or numpy image
output:
hsv_image: an uint8 hsv numpy image
'''
np_image, _ = safe_image(input_image, warning=warning, debug=debug)
if isfloatimage(np_image): np_image = (np_image * 255.).astype('uint8')
if debug:
assert iscolorimage(np_image), 'the input image should be a rgb image'
assert isuintimage(np_image), 'the input numpy image should be uint8 image in order to use PIL'
pil_rgb_img = Image.fromarray(np_image)
pil_hsv_img = pil_rgb_img.convert('HSV')
hsv_img = np.array(pil_hsv_img)
return hsv_img
def image_crop_center(input_image, center_rect, pad_value=0, warning=True, debug=True):
'''
crop the image around a specific center with padded value around the empty area
when the crop width/height are even, the cropped image has 1 additional pixel towards left/up
parameters:
center_rect: a list contains [center_x, center_y, (crop_width, crop_height)]
pad_value: scalar within [0, 255]
outputs:
img_cropped: an uint8 numpy image
crop_bbox: numpy array with shape of (1, 4), user-attempted cropping bbox, might out of boundary
crop_bbox_clipped: numpy array with shape of (1, 4), clipped bbox within the boundary
'''
np_image, _ = safe_image(input_image, warning=warning, debug=debug)
if isfloatimage(np_image): np_image = (np_image * 255.).astype('uint8')
if len(np_image.shape) == 2: np_image = np.expand_dims(np_image, axis=2) # extend the third channel if the image is grayscale
# center_rect and pad_value are checked in get_crop_bbox and pad_around functions
if debug: assert isuintimage(np_image), 'the input image is not an uint8 image'
im_height, im_width = np_image.shape[0], np_image.shape[1]
# calculate crop rectangles
crop_bbox = get_center_crop_bbox(center_rect, im_width, im_height, debug=debug)
crop_bbox_clipped = clip_bboxes_TLWH(crop_bbox, im_width, im_height, debug=debug)
x1, y1, x2, y2 = crop_bbox_clipped[0, 0], crop_bbox_clipped[0, 1], crop_bbox_clipped[0, 0] + crop_bbox_clipped[0, 2], crop_bbox_clipped[0, 1] + crop_bbox_clipped[0, 3]
img_cropped = np_image[y1 : y2, x1 : x2, :]
# if original image is not enough to cover the crop area, we pad value around outside after cropping
xmin, ymin, xmax, ymax = crop_bbox[0, 0], crop_bbox[0, 1], crop_bbox[0, 0] + crop_bbox[0, 2], crop_bbox[0, 1] + crop_bbox[0, 3]
if (xmin < 0 or ymin < 0 or xmax > im_width or ymax > im_height):
pad_left = max(0 - xmin, 0)
pad_top = max(0 - ymin, 0)
pad_right = max(xmax - im_width, 0)
pad_bottom = max(ymax - im_height, 0)
pad_rect = [pad_left, pad_top, pad_right, pad_bottom]
img_cropped = image_pad_around(img_cropped, pad_rect=pad_rect, pad_value=pad_value, debug=debug)
if len(img_cropped.shape) == 3 and img_cropped.shape[2] == 1: img_cropped = img_cropped[:, :, 0]
return img_cropped, crop_bbox, crop_bbox_clipped
def rgb2hsv(input_image, warning=True, debug=True):
'''
convert a rgb image to a hsv image using opencv package
parameters:
input_image: an pil or numpy image
output:
hsv_image: an uint8 hsv numpy image
'''
np_image, _ = safe_image(input_image, warning=warning, debug=debug)
if isfloatimage(np_image): np_image = (np_image * 255.).astype('uint8')
if debug:
assert iscolorimage_dimension(
np_image), 'the input image should be a rgb image'
assert isuintimage(
np_image
), 'the input numpy image should be uint8 image in order to use opencv'
hsv_img = cv2.cvtColor(np_image, cv2.COLOR_RGB2HSV)
return hsv_img
def rgb2gray(input_image, warning=True, debug=True):
'''
convert a color image to a grayscale image (1-channel)
parameters:
input_image: an pil or numpy image
output:
gray_image: an uint8 HW gray numpy image
'''
np_image, _ = safe_image(input_image, warning=warning, debug=debug)
if isfloatimage(np_image): np_image = (np_image * 255.).astype('uint8')
if debug:
assert iscolorimage_dimension(
np_image), 'the input numpy image is not correct: {}'.format(
np_image.shape)
assert isuintimage(
np_image
), 'the input numpy image should be uint8 image in order to use opencv'
gray_image = cv2.cvtColor(np_image, cv2.COLOR_RGB2GRAY)
return gray_image
