In these images of young plantations, palm trees generally have dome-shaped intensity profiles after some smoothing. Young trees tend to be well delineated at this resolution because of their distances of separation. As the trees grow bigger, the gaps among individual trees decrease and eventually disappear. However, the dome-shaped profiles remain visible. Counting trees in an image is much more manageable as workers can label the trees easily on the image.
Verification is much easier.
To further reduce the tediousness of the task and to speed it up, tree counting can actually be automated and the human worker needs only to verify the counting and make minor corrections when necessary. There are existing image processing techniques, which can be easily adopted and modified to automate tree counting. This technique is based on the concepts of edge and curvature in differential geometry. The boundaries of the dome-shaped intensity profiles show up as edge segments. The curvature primal sketches obtained at various resolutions are summed together to form a cumulative primal sketch.