Method for Using Images from a Color Digital Camera to Estimate Flower Number

In many plants, flowering is conspicuous in the field, but enumerating flowers is labor intensive, especially when flowers need to be counted on a daily basis. Frequent trips into plot areas and the physical contact with the plants can result in mechanical damage to plants, which can affect results. The objectives of this work were to develop methods using color digital images to estimate the numbers of flowers present in a scene captured in a digital image and to do all of the processing in a fully automated mode that would allow the counting of flowers in large numbers of images. Images of lesquerella [Lesquerella fendleri (Gray) Wats.] flowers were made using a color digital camera of field plots during the 1996 to 1997 growing season. An automated system to identify all of the pixels in an image that were flowers and to count the number of flower spots in an image was developed. Processing time for individual images was 3.5 min compared with a minimum of 45 min for manual counts. The automated methods produced results that were highly correlated with the number of flowers in an image as counted by hand. Results of the automated methods accurately tracked the temporal changes in flower number. Multiple counts of the same plants were made by the automated methods without damage to either plants that were counted or the plot. This method has the potential to be used to predict harvest dates from peak flowering, to track the response of flowering to environmental conditions, and to evaluate the effects of cultural practices on flowering.