Frequently Asked Questions
What is Leafscan's accuracy?
To test Leafscan's accuracy, we used the Licor LI-3100C leaf area meter as a reference. We found an excellent correlation between the two methods for various plant species (see our project page on ResearchGate). Typical percent errors were between 2% and 5%.
We do recommend, however, that you test Leafscan's accuracy against your own independent measurements for your particular plant species. It is essential that you accurately measure the distance between the dots on the reference sheet, and then enter this value in the app's settings.
What kind of leaves can Leafscan measure?
Leafscan has been used successfully with leaves of alfalfa, cotton, cowpea, maize, okra, peanut, garden bean, giant pumpkin, grain sorghum, rice, and soybean. While Lefascan for Android can be used with many types of leaves, Leafscan for iOS is best suited for leaves with a single blade or with clearly separate blades—it is not suited for leaves that run into each other and form empty spaces (e.g., ferns and other pinnated leaves).
Can Leafscan measure leaves non-destructively?
Yes, as long as the leaf can be placed flat against the white reference sheet. We recommend that you use a solid surface on which to put the reference sheet, such as a cardboard or clipboard. It also helps to use a clear, anti-glare cover to flatten the leaf and prevent it from moving as you take the picture. If there's still some glare, you can take the picture at an angle to avoid the glare. The app is able to take the angle of the image into account (as long as it's not too extreme).
Can Leafscan measure herbivory?
Leafscan was not specifically designed to measure herbivory. However, Leafscan for Android can detect leaf holes, including those due to herbivory, and treat them separately from the total surface area. Leafscan for iOS, on the other hand, considers any herbivory inside the leaf as part of the total surface area. Any herbivory on the periphery of the leaf is not detected by neither Leafscan for Android nor iOS.
Can Leafscan measure a whole plant?
Leafscan was designed to measure individual leaves that can be placed on a white background. A picture of a whole plant, if taken from above, may include the soil and other non-leaf artifacts that could confuse the app. Also, the pattern of leaves of the plant may form empty spaces that the app will include in the measurement.
Can Leafscan exclude the petiole?
Leafscan does not remove the petiole automatically. However, you can cover the petiole with a white piece of paper, or you can remove it digitally by painting it with a white color.
Can Leafscan measure necrosis?
Leafscan cannot measure necrotic or senescent tissue on the leaf.
How should I cite Leafscan on my research paper?
If you used Leafscan for iOS, please cite it as follows (APA style):
Anderson, Carlos J. R. and Rosas-Anderson, Pablo J. (2017). Leafscan (Version 1.3.21). [Mobile application software]. Retrieved from https://itunes.apple.com/app/id1254892230.
If you used Leafscan for Android, please cite it as follows (APA style):
Anderson, Carlos J. R. (2020). Leafscan (Version 2.1.1). [Mobile application software]. Retrieved from https://play.google.com/store/apps/details?id=com.carlosjanderson.leafscan.
Note that you may be using a different version than the citations above."