Targets management issue

We are making an iOS app for one of our clients that needs to have image recognition function integrated in it. The client had around 100 products and every one of them has an icon (some examples: https://drive.google.com/folderview?id=0B8Xyp0yvB7ZGYkNhWlRpNGdlSjA&usp=sharing). Those icons are going to be printed on posters and using the app the user would be able to make a photo or video of the icons on the poster and the app should recognize the products related to the icon.  When we use the User defined target feature and take picture of any of our client's icons, the library recognizes it easily. But when we try to load the icons in your Target manager, we got 3 and 4 start for only 2 of the 10 icons we are using for testing. The rest of the icons got 0 stars rating. We've read Vuforia instructions and added noise in the icons (see examples with noise here: https://drive.google.com/folderview?id=0B8Xyp0yvB7ZGV3E5Vml6Nk9MdTA&usp=sharing) to make their histogram wider but this approach worked fine only for 2 of the icons (as I already mention this above): https://drive.google.com/file/d/0B8Xyp0yvB7ZGd0czSnFzNThhY1k/view?usp=sharing and https://drive.google.com/file/d/0B8Xyp0yvB7ZGOERSR1M0ZFVDS1k/view?usp=sharing. Again the rest of the test icons are working fine with the User defined targets feature, but not with the Target manager.  Do you have any ideas why is this happening?Is there a problem with our icons and is there a way to improve them (without changing their design) and make the image recognition feature in our app work using Vuforia library? Thanks in advance! Any help or guidelines would be appreciated.