How Lucis Works
Lucis processing has two steps. The first step is to contrast stretch the image to use the full range of contrasts. So if you process an image with Lucis and do not alter the sliders the image will be contrast stretched. Then contrast differences that are greater than the Smooth Detail slider but less than the Enhance Detail slider are enhanced, and contrast differences outside this range (meaning less than or equal to the Smooth Detail slider and greater than or equal to the Enhance detail slider) are diminished.
Lucis shifts the relative emphasis of contrast variances so the user can more clearly see contrast variances of interest. Lucis does not throw away data.
For this first example 16-bit tiff images were used. The images posted are the results converted to 8-bit jpeg images.
Image 1 is the original 16-bit x-ray image. It only used 25,227 levels of contrast. Lucis was used to contrast stretch the image to use the full range of contrasts (in this case 62,569 intensity levels). This is shown in Image 2.
The test image (Image 3) was created by making a image that was transparent except for a black stripe and using layers in Photoshop to merge the striped image at 90% opacity with Image 2. So now the intensity differences within the black stripe are diminished by 90%.
In Image 3 the Enhance Detail slider was set to 3363. (Image smoothing was not required so the Smooth Detail slider was not used.) This means that contrast differences less than 3363 were enlarged and contrast differences greater or equal to 3363 were diminished. Lucis accurately enhances the smallest differences in contrast throughout the image using just one slider.