Portable field imaging of plant stomata

A system for plant leaf phenotyping, comprising:

• an optical sensor;
• one or more processors configured to execute a method comprising:
• capturing, via the optical sensor, a first set of two or more images of a plant leaf representing two or more focal distances;
• determining a reference focal distance based on the first set of images;
• capturing, via the optical sensor, a second set of two or more images of the plant leaf, wherein at least one image of the second set of images is captured at a focal distance less than the reference focal distance, and wherein at least one image of the second set of images is captured at a focal distance greater than the reference focal distance;
• generating a composite image based on the second set of images;
• and
• providing the composite image to a trainable feature detector in order to determine a number, density, and/or distribution of stomata in the composite image.

A non-transitory computer-readable medium storing instructions that, when executed by one or more processors, cause the one or more processors to execute a method comprising:

• capturing, via an optical sensor, a first set of two or more images of a plant leaf representing two or more focal distances;
• determining a reference focal distance based on the first set of images;
• capturing, via the optical sensor, a second set of two or more images of the plant leaf, wherein at least one image of the second set of images is captured at a focal distance less than the reference focal distance, and wherein at least one image of the second set of images is captured at a focal distance greater than the reference focal distance;
• generating a composite image based on the second set of images;
• and
• providing the composite image to a trainable feature detector in order to determine a number, density, and/or distribution of stomata in the composite image.