Here are some examples of different ways to scan reflective CD's.
Some scanner do better than others when it comes to suppressing the reflective qualities of a CD.
This is a scan using a Epson V600. The reflections are kept in a gray scale. This is ideal as it's predictable to cancel out.
This is using a Optiarc A320E. The reflections have a rainbow look. The rainbow effect is not ideal.
One way to make the disc brightness more even is to scan the disc twice at 90* angles. This makes the bright and dark sections appear opposite each other, but when the 2 images are rotated and aligned, the bright and dark areas cancel each other out. Using a different blend mode for the layers, and adjusting opacity and levels can achieve a pretty good image. It does take additional time though.
Use 3 layers. 2 layers are disc scanned at 90* angles from each other. Scan it once. Then rotate it 90* and scan again. This will make the bright areas opposite each other. The 3rd layer is just an isolated section of the hub. That way when the 2 other layers interact with each other, the center hub will not get it's brightness blown out of proportion.
- 3 layer additive layers.jpg (85.32 KiB) Viewed 6440 times
Here is the result
Another way to eliminate is to use a lightbox with a well lit white surface above the CD. And a small hole right in the middle for a camera sensor. The reflective part of the CD will reflect the whiteness, and the center hub will hide the reflection of the hole with the camera looking through it.
