Acquire 2 Images' Contrast and Brightness Difference

[waigit]

Hi,

I am seeking for a image processing tool or LabVIEW module which could possibly tell the difference between 2 images contrast and brightness values. The reason is that all the grey-scale templates captured earlier failed to pass the pattern match whenever the camera location is changed to another lighting environment. I believe it will be helpful to apply the known difference of these values and apply the changes to all templates in batch, in hope that the pattern match will eventually pass.

Kindly provide your advice.

[VuD]

Hi waigit,

If you have an auto-gain option on your camera, I would like to suggest turning this off so that you can manually set the lighting environment of your setup.  The pattern matching functions are designed to be robust enough to account for changes in contrast and lighting; however you may get a lower match score.  If this is the case, you may want to try lowering the match score in order to compensate for these changes.  For other options to improve your pattern match, I would also review Chapter 12 of the Vision Concepts manual which can be found by navigating to Start >> Programs>> National Instruments >> Vision >> Documentation >> Search the NI Vision Bookshelf.  If you need do to change the contrast/brightness manually you can use our histogram functions along with the image operator functions (subtract, add, etc.).  If you are interested in just acquiring the color brightness and contrast of a particular image, you can directly wire a property node to your IMAQ Snap/Grab function to obtain these values to compare.  I hope this helps.  If you would like further clarification or assistance please let us know. 

Best regards,

Vu D