Complex sentence: Only with a considerably high threshold setting will the blue be detected; this however may greatly distort black lines and add a lot of noise and black speckles, making the image almost indistinguishable.
Split into simpler sentences: Only with a considerably high threshold setting will the blue be detected. However, a setting this high may greatly distort the black lines and add a lot of noise and black speckles to the image, making it almost indistinguishable.