Python cv2.COLOR_RGB2LAB Examples

The following are 22 code examples of cv2.COLOR_RGB2LAB(). You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may also want to check out all available functions/classes of the module cv2 , or try the search function

Example #1

Source File: luminosity_threshold_tissue_locator.py From StainTools with MIT License

6 votes

def get_tissue_mask(I, luminosity_threshold=0.8):
        """
        Get a binary mask where true denotes pixels with a luminosity less than the specified threshold.
        Typically we use to identify tissue in the image and exclude the bright white background.

        :param I: RGB uint 8 image.
        :param luminosity_threshold: Luminosity threshold.
        :return: Binary mask.
        """
        assert is_uint8_image(I), "Image should be RGB uint8."
        I_LAB = cv.cvtColor(I, cv.COLOR_RGB2LAB)
        L = I_LAB[:, :, 0] / 255.0  # Convert to range [0,1].
        mask = L < luminosity_threshold

        # Check it's not empty
        if mask.sum() == 0:
            raise TissueMaskException("Empty tissue mask computed")

        return mask

Example #2

Source File: reinhard_color_normalizer.py From StainTools with MIT License

6 votes

def lab_split(I):
        """
        Convert from RGB uint8 to LAB and split into channels.

        :param I: Image RGB uint8.
        :return:
        """
        assert is_uint8_image(I), "Should be a RGB uint8 image"
        I = cv.cvtColor(I, cv.COLOR_RGB2LAB)
        I_float = I.astype(np.float32)
        I1, I2, I3 = cv.split(I_float)
        I1 /= 2.55  # should now be in range [0,100]
        I2 -= 128.0  # should now be in range [-127,127]
        I3 -= 128.0  # should now be in range [-127,127]
        return I1, I2, I3

Example #3

Source File: luminosity_standardizer.py From StainTools with MIT License

6 votes

def standardize(I, percentile=95):
        """
        Transform image I to standard brightness.
        Modifies the luminosity channel such that a fixed percentile is saturated.

        :param I: Image uint8 RGB.
        :param percentile: Percentile for luminosity saturation. At least (100 - percentile)% of pixels should be fully luminous (white).
        :return: Image uint8 RGB with standardized brightness.
        """
        assert is_uint8_image(I), "Image should be RGB uint8."
        I_LAB = cv.cvtColor(I, cv.COLOR_RGB2LAB)
        L_float = I_LAB[:, :, 0].astype(float)
        p = np.percentile(L_float, percentile)
        I_LAB[:, :, 0] = np.clip(255 * L_float / p, 0, 255).astype(np.uint8)
        I = cv.cvtColor(I_LAB, cv.COLOR_LAB2RGB)
        return I

Example #4

Source File: omnirobot_simulator_server.py From robotics-rl-srl with MIT License

6 votes

def renderEnvLuminosityNoise(self, origin_image, noise_var=0.1, in_RGB=False, out_RGB=False):
        """
        render the different environment luminosity
        """
        # variate luminosity and color
        origin_image_LAB = cv2.cvtColor(
            origin_image, cv2.COLOR_RGB2LAB if in_RGB else cv2.COLOR_BGR2LAB, cv2.CV_32F)
        origin_image_LAB[:, :, 0] = origin_image_LAB[:,
                                                     :, 0] * (np.random.randn() * noise_var + 1.0)
        origin_image_LAB[:, :, 1] = origin_image_LAB[:,
                                                     :, 1] * (np.random.randn() * noise_var + 1.0)
        origin_image_LAB[:, :, 2] = origin_image_LAB[:,
                                                     :, 2] * (np.random.randn() * noise_var + 1.0)
        out_image = cv2.cvtColor(
            origin_image_LAB, cv2.COLOR_LAB2RGB if out_RGB else cv2.COLOR_LAB2BGR, cv2.CV_8UC3)
        return out_image

Example #5

Source File: train101_9ch_fold.py From SpaceNet_Off_Nadir_Solutions with Apache License 2.0

5 votes

def clahe(img, clipLimit=2.0, tileGridSize=(5,5)):
    img_yuv = cv2.cvtColor(img, cv2.COLOR_RGB2LAB)
    clahe = cv2.createCLAHE(clipLimit=clipLimit, tileGridSize=tileGridSize)
    img_yuv[:, :, 0] = clahe.apply(img_yuv[:, :, 0])
    img_output = cv2.cvtColor(img_yuv, cv2.COLOR_LAB2RGB)
    return img_output

Example #6

Source File: functional.py From albumentations with MIT License

5 votes

def clahe(img, clip_limit=2.0, tile_grid_size=(8, 8)):
    if img.dtype != np.uint8:
        raise TypeError("clahe supports only uint8 inputs")

    clahe_mat = cv2.createCLAHE(clipLimit=clip_limit, tileGridSize=tile_grid_size)

    if len(img.shape) == 2 or img.shape[2] == 1:
        img = clahe_mat.apply(img)
    else:
        img = cv2.cvtColor(img, cv2.COLOR_RGB2LAB)
        img[:, :, 0] = clahe_mat.apply(img[:, :, 0])
        img = cv2.cvtColor(img, cv2.COLOR_LAB2RGB)

    return img

Example #7