Is there specific type of camera can be use?

Hi Pleas I have small problem if any body can help. when i acquire image using webcam there small changing in illumination and color from image to image .But it effects the image analysis. what can I do to bring this changing ( illumination color value ) to the min level? . webcam placed on the top of object and the distance between webcam and objects is about 50 cm. Do you think using camera with flash is good solution ? Is there specific type of camera can be use?

Regards