Batch Analysis of Digital Images to Evaluate Turfgrass Characteristics


Douglas Karcher and Michael Richardson

Department of Horticulture

University of Arkansas
Crop Sci. 45:1536-1539



Download SigmaScan Pro macro for batch analysis of turf images: Turf Analysis.bas.
(right click link and then choose “Save Target As…”)

  PLEASE NOTE:  some PCs may add a “.txt” extension to the macro file when downloading so that it is downloaded as “Turf Analysis.bas.txt”.  In such cases, the “.txt” extension should be deleted so that the downloaded file name is “Turf Analysis.bas”.

Detailed instructions on using this macro have been published in Crop Sci. 45:1536-1539.


Click above thumbnail to view a screen shot of the original Turf Analysis macro running from within SigmaScan Pro.

Turf Analysis 1.2 now available:  allows browsing for images to be analyzed (does not require entering the file path fixed bug that advanced “To Sat” value by one with each macro execution.

Macro-related questions or suggestions for improvement should be directed to Douglas Karcher.


Macro Troubleshooting

A reoccurring problem with the Turf Analysis macro is an error that results from analyzing high resolution images, especially those with relatively low green turf cover.  Analysis of such images may “crash” the macro because there are not enough worksheet rows for making calculations on image objects that have been selected during the color threshold process.  In such cases, the macro stops running and the user will see the macro code with the following statement highlighted:

  ResultCode = Turfimage.MeasureObjects(1)

  This is typically only a problem with images with resolutions larger than 1 megapixel (1,000,000 pixels).  Therefore, the problem can be corrected by “resampling” the images at a lower resolution (800 x 600 pixels rarely causes this error).  A SigmaScan macro named “Edit Images.bas” will automate the resampling process as long as the images are named consecutively.  This macro may be downloaded and executed as the “Turf Analysis.bas macro above”    

Digital Image Analysis Reprints

Reprints of publications related to digital image analysis may be requested from Douglas Karcher.