diff --git a/NumpyHDR.py b/NumpyHDR.py new file mode 100644 index 0000000..91f4808 --- /dev/null +++ b/NumpyHDR.py @@ -0,0 +1,625 @@ +from PIL import Image +import numpy as np +#import matplotlib.pyplot as plt + +class NumpyHDR: + '''Numpy and PIL implementation of a Mertens Fusion alghoritm''' + def __init__(self): + self.input_image: list + self.output_path: str = '/' + self.compress_quality: int = 50 + + def plot_histogram(image, title="Histogram", bins=256): + """Plot the histogram of an image. + + Args: + image: A numpy array representing an image. + title: The title of the plot. + bins: The number of bins in the histogram. + """ + fig, ax = plt.subplots() + ax.hist(image.ravel(), bins=bins, color='gray', alpha=0.7) + ax.set_title(title) + ax.set_xlabel('Pixel value') + ax.set_ylabel('Frequency') + plt.show() + ### Experimental functions above this line. chatGPT sketches + + def simple_clip(fused,gamma): + # Apply gamma correction + fused = np.clip(fused, 0, 1) + fused = np.power(fused, 1.0 / gamma) + #hdr_8bit = np.clip(res_mertens * 255, 0, 255).astype('uint8') + fused = (255.0 * fused).astype(np.uint8) + #fused = Image.fromarray(fused) + + def convolve2d(image, kernel): + """Perform a 2D convolution on the given image with the given kernel. + + Args: + image: The input image to convolve. + kernel: The kernel to convolve the image with. + + Returns: + The convolved image. + """ + # Get the dimensions of the image and kernel. + image_height, image_width = image.shape[:2] + kernel_height, kernel_width = kernel.shape[:2] + + # Compute the amount of padding to add to the image. + pad_height = kernel_height // 2 + pad_width = kernel_width // 2 + + # Pad the image with zeros. + padded_image = np.zeros( + (image_height + 2 * pad_height, image_width + 2 * pad_width), + dtype=np.float32, + ) + padded_image[pad_height:-pad_height, pad_width:-pad_width] = image + + # Flip the kernel horizontally and vertically. + flipped_kernel = np.flipud(np.fliplr(kernel)) + + # Convolve the padded image with the flipped kernel. + convolved_image = np.zeros_like(image, dtype=np.float32) + for row in range(image_height): + for col in range(image_width): + patch = padded_image[ + row : row + kernel_height, col : col + kernel_width + ] + product = patch * flipped_kernel + convolved_image[row, col] = product.sum() + + return convolved_image + + def mask(img, center=50, width=20, threshold=0.2): + mask = 1 / (1 + np.exp((center - img) / width)) # Smooth gradient mask + mask = np.where(img > threshold, mask, 1) # Apply threshold to the mask + mask = img * mask + #plot_histogram(mask, title="mask") + return mask + + def shadowlift(img, center=200, width=20, threshold=0.2, amount=1): + mask = 1 / (1 + np.exp((center - img) / width)) # Smooth gradient mask + print(mask) + print(img) + mask = np.where(img < threshold, mask, 1) # Apply threshold to the mask + print(mask) + #plot_histogram(mask, title= "maskin") + img_adjusted = img * mask * amount # Adjust the image with a user-specified amount + + return img_adjusted + + def highlightdrop(img, center=200, width=20, threshold=0.8, amount: float=1): + mask = 1 / (1 + np.exp((center - img) / width)) # Smooth gradient mask + mask = np.where(img > threshold, mask, 1) # Apply threshold to the mask + img_adjusted = img + mask * (-amount) # Adjust the image with a user-specified amount + + return img_adjusted + + def mertens_fusion(image_paths, gamma=2.2, contrast_weight=0.2): + """Fuse multiple exposures into a single HDR image using the Mertens algorithm. + + Args: + image_paths: A list of paths to input images. + gamma: The gamma correction value to apply to the input images. + contrast_weight: The weight of the local contrast term in the weight map computation. + + Returns: + The fused HDR image. + """ + # Load the input images and convert them to floating-point format. + images = [] + for path in image_paths: + img = Image.open(path).convert('RGB') + img = img.resize((1920, 1080)) + img = np.array(img).astype(np.float32) / 255.0 + img = np.power(img, gamma) + images.append(img) + + # Compute the weight maps for each input image based on the local contrast. + weight_maps = [] + for img in images: + gray = np.dot(img, [0.2989, 0.5870, 0.1140]) + #kernel = np.array([[-1, 1, -1], [1, 7, 1], [-1, 1, -1]]) + kernel = np.array([[-1, -1, -1], [-1, 7, -1], [-1, -1, -1]]) + laplacian = np.abs(convolve2d(gray, kernel)) + weight = np.power(laplacian, contrast_weight) + weight_maps.append(weight) + + # Normalize the weight maps. + total_weight = sum(weight_maps) + weight_maps = [w / total_weight for w in weight_maps] + + # Compute the fused HDR image by computing a weighted sum of the input images. + fused = np.zeros(images[0].shape, dtype=np.float32) + for i, img in enumerate(images): + fused += weight_maps[i][:, :, np.newaxis] * img + + return fused + + def sequence(self): + #list = ['hdr/webcam20_3_2023_ev1.jpg','hdr/webcam20_3_2023_ev-1.jpg'] + hdr_image = self.mertens_fusion(self.input_image ,0.7, 0.01) + result = self.simple_clip(hdr_image,1) + image = Image.fromarray(result) + #output_path = f'hdr/webcam_hdr10.jpg' + image.save(self.output_path, quality=self.compress_quality) + +class NumpyUtility: + def __init__(self): + '''Utilitys made with chatGPT for experimentation, few are working''' + + def compress_dynamic_range(image): + # Find the 1st and 99th percentiles of the image + p1, p99 = np.percentile(image, (1, 99)) + + # Calculate the range of the image + img_range = p99 - p1 + + # Calculate the compression factor required to fit the image into 8-bit range + c = 255.0 / img_range + + # Subtract the 1st percentile from the image and clip it to the [0, 1] range + new_image = np.clip((image - p1) * c, 0, 255) + + # Convert the image to uint8 format + new_image = new_image.astype(np.uint8) + + return new_image + + def compress_dynamic_range_histo(image, new_min=0, new_max=255): + """Compress the dynamic range of an image using histogram stretching. + + Args: + image: A numpy array representing an image. + new_min: The minimum value of the new range. + new_max: The maximum value of the new range. + Returns: + The compressed image. + """ + # Calculate the histogram of the image. + hist, bins = np.histogram(image.ravel(), bins=256, range=(0, 1)) + + # Calculate the cumulative distribution function (CDF) of the histogram. + cdf = hist.cumsum() + cdf = (cdf - cdf.min()) / (cdf.max() - cdf.min()) # normalize to [0, 1] + + # Interpolate the CDF to get the new pixel values. + new_pixels = np.interp(image.ravel(), bins[:-1], cdf * (new_max - new_min) + new_min) + + # Reshape the new pixel values to the shape of the original image. + new_image = new_pixels.reshape((image.shape[0], image.shape[1], image.shape[2])) + return new_image + + return fused + + def adjust_luminance(image, mask, amount): + # Convert the image to LAB color space + rgb_image = image.astype(np.float32) / 255.0 + xyz_image = np.dot(rgb_image, np.array([[0.412453, 0.357580, 0.180423], + [0.212671, 0.715160, 0.072169], + [0.019334, 0.119193, 0.950227]])) + xyz_image = np.clip(xyz_image, 0, 1) + lab_image = np.zeros_like(xyz_image) + lab_image[..., 0] = 116.0 * np.power(xyz_image[..., 1], 1 / 3.0) - 16.0 + lab_image[..., 1] = 500.0 * (np.power(xyz_image[..., 0], 1 / 3.0) - np.power(xyz_image[..., 1], 1 / 3.0)) + lab_image[..., 2] = 200.0 * (np.power(xyz_image[..., 1], 1 / 3.0) - np.power(xyz_image[..., 2], 1 / 3.0)) + + # Apply the luminance adjustment to the masked area + lab_image[..., 0][mask == 1] = np.clip(lab_image[..., 0][mask == 1] * (1 + amount), 0, 100) + + # Convert the image back to RGB color space + xyz_image[..., 1] = np.power((lab_image[..., 0] + 16.0) / 116.0, 3) + xyz_image[..., 0] = np.power((lab_image[..., 0] + 16.0) / 116.0 + lab_image[..., 1] / 500.0, 3) + xyz_image[..., 2] = np.power((lab_image[..., 0] + 16.0) / 116.0 - lab_image[..., 2] / 200.0, 3) + rgb_image = np.dot(xyz_image, np.array([[3.240479, -1.537150, -0.498535], + [-0.969256, 1.875992, 0.041556], + [0.055648, -0.204043, 1.057311]])) + + # Convert the image back to the range [0, 255] + rgb_image = np.clip(rgb_image, 0, 1) * 255.0 + rgb_image = rgb_image.astype(np.uint8) + + return rgb_image + + def gaussian_filter(mask, sigma): + """ + Apply Gaussian filtering to a binary mask. + + Parameters: + mask (numpy.ndarray): Binary mask to apply filtering on. + sigma (float): Standard deviation of the Gaussian kernel. + + Returns: + numpy.ndarray: Binary mask after Gaussian filtering. + """ + # Create a Gaussian kernel with the given sigma + ksize = int(2 * np.ceil(2 * sigma) + 1) + kernel = np.zeros((ksize, ksize)) + for i in range(ksize): + for j in range(ksize): + kernel[i, j] = np.exp(-((i - ksize // 2) ** 2 + (j - ksize // 2) ** 2) / (2 * sigma ** 2)) + kernel /= np.sum(kernel) + + # Apply convolution with the kernel + filtered = np.zeros_like(mask, dtype='float32') + for i in range(mask.shape[0]): + for j in range(mask.shape[1]): + roi = mask[max(i - ksize // 2, 0):min(i + ksize // 2 + 1, mask.shape[0]), + max(j - ksize // 2, 0):min(j + ksize // 2 + 1, mask.shape[1])] + filtered[i, j] = np.sum(roi * kernel[:roi.shape[0], :roi.shape[1]]) + + return filtered + + def binary_opening(mask, kernel): + """ + Perform binary morphological opening on a binary mask using a structuring element. + + Parameters: + mask (numpy.ndarray): Binary mask to perform opening on. + kernel (numpy.ndarray): Structuring element used for opening. + + Returns: + numpy.ndarray: Binary mask after morphological opening. + """ + # Create padding on all sides of the mask + pad_width = [(kernel.shape[i] // 2, kernel.shape[i] // 2) for i in range(kernel.ndim)] + mask_padded = np.pad(mask, pad_width, mode='constant', constant_values=0) + + # Apply morphological erosion using the kernel + eroded = np.zeros_like(mask_padded) + for i in range(mask_padded.ndim): + eroded = np.maximum(eroded, np.apply_along_axis(np.roll, i, mask_padded, shift=-kernel.shape[i] // 2)) + eroded = eroded[pad_width[0][0]:-pad_width[0][1], pad_width[1][0]:-pad_width[1][1]] + + # Create padding on all sides of the eroded mask + pad_width = [(kernel.shape[i] // 2, kernel.shape[i] // 2) for i in range(kernel.ndim)] + eroded_padded = np.pad(eroded, pad_width, mode='constant', constant_values=0) + + # Apply morphological dilation using the kernel + dilated = np.zeros_like(eroded_padded) + for i in range(eroded_padded.ndim): + dilated = np.minimum(dilated, np.apply_along_axis(np.roll, i, eroded_padded, shift=kernel.shape[i] // 2)) + dilated = dilated[pad_width[0][0]:-pad_width[0][1], pad_width[1][0]:-pad_width[1][1]] + + return dilated + + def binary_closing(mask, kernel): + """ + Perform binary morphological closing on a binary mask using a structuring element. + + Parameters: + mask (numpy.ndarray): Binary mask to perform closing on. + kernel (numpy.ndarray): Structuring element used for closing. + + Returns: + numpy.ndarray: Binary mask after morphological closing. + """ + # Create padding on all sides of the mask + pad_width = [(kernel.shape[i] // 2, kernel.shape[i] // 2) for i in range(kernel.ndim)] + mask_padded = np.pad(mask, pad_width, mode='constant', constant_values=0) + + # Apply morphological dilation using the kernel + dilated = np.zeros_like(mask_padded) + for i in range(mask_padded.ndim): + dilated = np.minimum(dilated, np.apply_along_axis(np.roll, i, mask_padded, shift=kernel.shape[i] // 2)) + dilated = dilated[pad_width[0][0]:-pad_width[0][1], pad_width[1][0]:-pad_width[1][1]] + + # Create padding on all sides of the dilated mask + pad_width = [(kernel.shape[i] // 2, kernel.shape[i] // 2) for i in range(kernel.ndim)] + dilated_padded = np.pad(dilated, pad_width, mode='constant', constant_values=0) + + # Apply morphological erosion using the kernel + eroded = np.zeros_like(dilated_padded) + for i in range(dilated_padded.ndim): + eroded = np.maximum(eroded, np.apply_along_axis(np.roll, i, dilated_padded, shift=-kernel.shape[i] // 2)) + eroded = eroded[pad_width[0][0]:-pad_width[0][1], pad_width[1][0]:-pad_width[1][1]] + + return eroded + + def create_shadow_mask(image, threshold=80, range_width=50): + lab_image = np.apply_along_axis(lambda x: np.dot([0.2126, 0.7152, 0.0722], x), 2, image).astype('float64') + luminance_range = np.max(lab_image) - np.min(lab_image) + if luminance_range < range_width: + range_width = luminance_range + threshold_min = np.min(lab_image) + range_width / 2 + threshold_max = np.max(lab_image) - range_width / 2 + if threshold < threshold_min: + threshold = threshold_min + elif threshold > threshold_max: + threshold = threshold_max + mask = np.logical_and(lab_image >= threshold - range_width / 2, lab_image <= threshold + range_width / 2) + if np.sum(mask) == 0: + return np.zeros_like(mask).astype(float) + else: + center_line = np.nanmean(np.where(mask, lab_image, np.nan), axis=0) + x = np.arange(center_line.shape[0]) + slope = np.zeros(center_line.shape) + slope[1:-1] = (center_line[2:] - center_line[:-2]) / 2 + slope[0] = slope[1] + slope[-1] = slope[-2] + intercept = center_line - slope * x + x = np.arange(image.shape[1]) # x-coordinates of pixels + y = np.arange(image.shape[0]) # y-coordinates of pixels + print(y) + x, y = np.meshgrid(x, y) # create 2D arrays of x- and y-coordinates + + # compute distances from each pixel to the shadow line + dist = np.abs((y[:, :, np.newaxis] - slope[np.newaxis, np.newaxis, :] * x[:, :, np.newaxis] + - intercept[np.newaxis, np.newaxis, :]) / np.sqrt(1 + slope[np.newaxis, np.newaxis, :] ** 2)) + print(dist) + + # sigma = np.nanmedian(dist)/0.6745 + # mask = np.exp(-0.5*(dist/sigma)**2) + + return dist + + def highpass_mask(img, cutoff, order=1): + # Calculate the Fourier transform of the image + fft_img = np.fft.fft2(img) + + # Shift the zero-frequency component to the center of the spectrum + fft_img = np.fft.fftshift(fft_img) + + # Construct a highpass filter in the Fourier domain + x, y = np.meshgrid(np.linspace(-1, 1, img.shape[1]), np.linspace(-1, 1, img.shape[0])) + r = np.sqrt(x ** 2 + y ** 2) + hp_filter = 1 - 1 / (1 + (cutoff / r) ** (2 * order)) + + # Apply the highpass filter to the Fourier transform of the image + fft_img_hp = fft_img * hp_filter + + # Shift the zero-frequency component back to the corners of the spectrum + fft_img_hp = np.fft.ifftshift(fft_img_hp) + + # Calculate the inverse Fourier transform of the highpass-filtered image + img_hp = np.fft.ifft2(fft_img_hp) + + # Take the absolute value of the real part of the inverse Fourier transform + img_hp = np.abs(np.real(img_hp)) + + # Normalize the highpass-filtered image to the range [0, 1] + img_hp_norm = img_hp / np.max(img_hp) + + # Invert the highpass-filtered image to create a highpass mask + mask = 1 - img_hp_norm + + return mask + + def cvtColor(hsv_img): + # Assuming you have an HSV image loaded in the variable 'hsv_img' + # Let's convert the image back to RGB color space + h, s, v = np.split(hsv_img, 3, axis=-1) + h = h.reshape(h.shape[:2]) + s = s.reshape(s.shape[:2]) + v = v.reshape(v.shape[:2]) + c = v * s + x = c * (1 - np.abs((h / 60) % 2 - 1)) + m = v - c + z = np.zeros_like(h) + + # Set up the RGB channels according to the hue value + rgb_img = np.dstack(( + np.where((0 <= h) & (h < 60), c, + np.where((120 <= h) & (h < 180), z, np.where((240 <= h) & (h < 300), x, m))), + np.where((300 <= h), c, np.where((60 <= h) & (h < 120), x, np.where((180 <= h) & (h < 240), c, m))), + np.where((0 <= h) & (h < 360), v, m) + )) + return rgb_img + + def saturate(img, amount): + hsv_img = np.copy(img) + hsv_img = np.asarray(hsv_img, dtype=np.float32) / 255.0 # Normalize pixel values + hsv_img = np.clip(hsv_img, 0, 1) # Clip values to the range [0, 1] + hsv_img = np.squeeze(cv2.cvtColor(hsv_img, cv2.COLOR_RGB2HSV_FULL)) # Convert to HSV + + # Let's adjust the saturation of the image + saturation_factor = 1.5 # Adjust this value to your preference + hsv_img[..., 1] *= saturation_factor + + # Now let's convert the image back to RGB color space + hsv_img = np.clip(hsv_img, 0, 255) # Clip values to the range [0, 255] + hsv_img = np.asarray(hsv_img, dtype=np.uint8) # Convert back to uint8 + rgb_img = cv2.cvtColor(hsv_img, cv2.COLOR_HSV2RGB_FULL) # Convert back to RGB + + # The resulting image with increased saturation is stored in the 'rgb_img' variable + + def rgb2ycbcr(rgb_img): + # Create the conversion matrix for RGB to YCbCr + conv_mat = np.array([[0.299, 0.587, 0.114], + [-0.168736, -0.331264, 0.5], + [0.5, -0.418688, -0.081312]]) + + # Reshape the input image to a 2D array of pixels + pixels = rgb_img.reshape(-1, 3) + + # Apply the conversion matrix to the pixels + ycbcr_pixels = np.dot(pixels, conv_mat.T) + + # Reshape the converted pixels back into the original image shape + ycbcr_img = ycbcr_pixels.reshape(rgb_img.shape) + + # Convert the image data type to uint8 and return it + return ycbcr_img.astype(np.uint8) + + def ycbcr2rgb(ycbcr_img): + # Create the conversion matrix for YCbCr to RGB + conv_mat = np.array([[1.0, 0.0, 1.402], + [1.0, -0.344136, -0.714136], + [1.0, 1.772, 0.0]]) + + # Reshape the input image to a 2D array of pixels + pixels = ycbcr_img.reshape(-1, 3) + + # Apply the conversion matrix to the pixels + rgb_pixels = np.dot(pixels, conv_mat.T) + + # Reshape the converted pixels back into the original image shape + rgb_img = rgb_pixels.reshape(ycbcr_img.shape) + + # Convert the image data type to uint8 and return it + return rgb_img.astype(np.uint8) + + def adjust_luminance(img, mask, adjustment): + # Convert the input image to the YCbCr color space + img = (255.0 * img).astype(np.uint8) + mask = (255.0 * mask).astype(np.uint8) + + ycbcr_img = rgb2ycbcr(img) + ycbcr_mask = rgb2ycbcr(mask) + print(ycbcr_mask) + print(ycbcr_img) + plot_histogram(ycbcr_img, title="ycbcr") + plot_histogram(ycbcr_mask, title="ycmask") + # Separate the luminance channel (Y) + y_channel = ycbcr_img[..., 0] + y_channel_mask = ycbcr_mask[..., 0] + + # Apply the adjustment to the luminance channel using the mask + y_adjusted = np.clip(y_channel + (adjustment * y_channel_mask), 0, 255).astype(np.uint8) + + # Replace the original luminance channel with the adjusted one + ycbcr_img[..., 0] = y_adjusted + + # Convert the image back to the RGB color space and return it + return ycbcr2rgb(ycbcr_img) + + def tonemap_reinhard(image, gamma=2.2, intensity=0.18, light_adapt=0.8): + """ + Tonemaps the input HDR image using the Reinhard algorithm. + + Args: + image: The input HDR image as a NumPy array. + gamma: The gamma correction value to apply to the output image. + intensity: The target scene brightness. + light_adapt: The adaptation rate for the brightness. + + Returns: + The tonemapped output image as a NumPy array. + """ + # Convert the image to floating point RGB. + image = image.astype(np.float32) + + # Compute the log average luminance. + lum = np.exp(np.mean(np.log(0.0001 + image))) + + # Normalize the image by the log average luminance. + image /= lum + + # Apply the Reinhard tonemapping algorithm. + mapped = np.zeros_like(image) + mapped = intensity * (mapped / np.max(mapped)) + mapped = light_adapt * (mapped * (1 + mapped / np.max(mapped) ** 2)) / (1 + mapped) + mapped *= lum + + # Apply gamma correction to the tonemapped image. + mapped = np.power(np.clip(mapped, 0, 1), 1 / gamma) + + # Convert the tonemapped image to 8-bit RGB. + mapped = (255 * mapped).astype(np.uint8) + + return mapped + + def f(t): + # Helper function to compute the nonlinear transformation function for the LAB color space + delta = 6.0 / 29.0 + t_thresh = delta ** 3 + return np.where(t > t_thresh, t ** (1 / 3), (1 / 3) * (29 / 6) ** 2 * t + 4 / 29) + + def numpy_lab2rgb(lab_img): + XYZ = np.zeros_like(lab_img, dtype=np.float32) + XYZ[..., 0] = (lab_img[..., 0] + 16.0) / 116.0 + XYZ[..., 1] = (lab_img[..., 1] / 500.0) + XYZ[..., 0] + XYZ[..., 2] = XYZ[..., 0] - (lab_img[..., 2] / 200.0) + mask = XYZ > 0.2068966 + XYZ[mask] = XYZ[mask] ** 3 + XYZ[~mask] = (XYZ[~mask] - 16.0 / 116.0) / 7.787 + D50 = np.array([0.9642, 1.0, 0.8249], dtype=np.float32) + RGB_linear = np.dot(XYZ, + np.array([[3.2406, -1.5372, -0.4986], [-0.9689, 1.8758, 0.0415], [0.0557, -0.2040, 1.0570]], + dtype=np.float32).T) + RGB_linear = np.clip(RGB_linear, 0.0, 1.0) + RGB_linear_D50 = RGB_linear / D50 + sRGB = np.where(RGB_linear_D50 <= 0.0031308, 12.92 * RGB_linear_D50, + 1.055 * (RGB_linear_D50 ** (1.0 / 2.4)) - 0.055) + sRGB = np.clip(sRGB, 0.0, 1.0) + return (RGB_linear_D50 * 255).astype(np.uint8) + + def numpy_split_lab(lab_img): + L, a, b = np.rollaxis(lab_img, axis=-1) + return L, a, b + + def numpy_merge_lab(l_channel_adjusted, a_channel, b_channel): + merged_lab = np.dstack((l_channel_adjusted, a_channel, b_channel)) + return merged_lab + + def rgb2lab(img): + # Convert the RGB image to a float array with values between 0 and 1 + img = img.astype(np.float32) / 255.0 + + # Convert the RGB image to the XYZ color space + # using the transformation matrix specified by the CIE + # (https://en.wikipedia.org/wiki/CIE_1931_color_space) + r, g, b = np.split(img, 3, axis=2) + x = 0.412453 * r + 0.357580 * g + 0.180423 * b + y = 0.212671 * r + 0.715160 * g + 0.072169 * b + z = 0.019334 * r + 0.119193 * g + 0.950227 * b + + # Convert the XYZ image to the LAB color space using the D50 white point + # (https://en.wikipedia.org/wiki/Lab_color_space#Conversion_from_XYZ_to_Lab) + x /= 0.950456 + z /= 1.088754 + l = 116.0 * f(y) - 16.0 + a = 500.0 * (f(x) - f(y)) + b = 200.0 * (f(y) - f(z)) + + # Stack the LAB channels back into a single image and return it + return np.concatenate((l, a, b), axis=2) + + def apply_luminance_mask_lab(img, mask): + # Convert the image to the LAB color space + lab_img = rgb2lab(img) + print(lab_img) + + lab_mask = rgb2lab(mask) + print(lab_mask) + # Split the LAB image into its channels + l_channel, a_channel, b_channel = numpy_split_lab(lab_img) + l_channel_mask, a_channel, b_channel = numpy_split_lab(lab_mask) + + # Apply the mask to the luminance channel + l_channel_adjusted = l_channel + l_channel_mask # np.where(l_channel_mask > 0, l_channel - 50, l_channel) + + # Merge the adjusted channels back into a LAB image + lab_img_adjusted = numpy_merge_lab(l_channel_adjusted, a_channel, b_channel) + + # Convert the adjusted image back to the RGB color space and return it + return numpy_lab2rgb(lab_img_adjusted) + + def rgb2lab(img): + # Convert the RGB image to a float array with values between 0 and 1 + img = img.astype(np.float32) / 255.0 + + # Convert the RGB image to the XYZ color space + # using the transformation matrix specified by the CIE + # (https://en.wikipedia.org/wiki/CIE_1931_color_space) + r, g, b = np.split(img, 3, axis=2) + x = 0.412453 * r + 0.357580 * g + 0.180423 * b + y = 0.212671 * r + 0.715160 * g + 0.072169 * b + z = 0.019334 * r + 0.119193 * g + 0.950227 * b + + # Convert the XYZ image to the LAB color space using the D50 white point + # (https://en.wikipedia.org/wiki/Lab_color_space#Conversion_from_XYZ_to_Lab) + x /= 0.950456 + z /= 1.088754 + l = 116.0 * f(y) - 16.0 + a = 500.0 * (f(x) - f(y)) + b = 200.0 * (f(y) - f(z)) + + # Stack the LAB channels back into a single image and return it + return np.concatenate((l, a, b), axis=2) + + +