WinRhizo also contains tools for color analysis. We have used WinRhizo to measure leaf area of individual plants or percent ground cover of stands of plants. In this case, images are acquired using a camera, and an object of known dimension should be included in each image for proper calibration of that image. The user creates color classes which can be assigned to groups, for example the group "leaves" may contain several shades of green, the group "soil" may contain shades of brown and black, and the group "litter" may contain shades of brown and yellow. WinRhizo documentation is helpful for learning this process.
Similar color analyses can be carried out in Photoshop or GIMP (Gnu Image Manipulation Program). Photoshop is the most standard photo manipulation program, but GIMP has the advantage of being freeware.
