Foulum spring 2004

The purpose of these experiments was to compare the use of laser range equipment with the use of a digital colour camera for gap fraction measurements. A laser of the type AccuRange 4000 was used. On the camera side, a consumer-grade RGB camera of the type Nikon Coolpix 4500 was used.

Measurements were made in spring wheat plots established in a climate-controlled greenhouse. A greenhouse was selected for the experiment because of the out-of-season time of the experimenta, and for the sheltered no wind conditions offered here. Several times throughout the experiments, reference measurements of leaf area were obtained though harvesting. Two experiments were conducted:

1. In the first experiment, a single wheat plot was used for measurements, and in the end, part of it was harvested for reference measurement of leaf area index.
2. In the second experiment, one wheat plot was used for measurements, and another one for reference harvesting at regular intervals. In this experiment, laser measurements were made several times a day in order to follow the growth pattern over time.

	Anton Thomsen operating the laser equipment at the first experiment.
	Camera equipment at the first experiment. The high dynamic range camera shown to the left was not used in the subsequent sessions due to problems with glass interreflections of sunlight when using colour filters.
	Laser equipment at the first experiment.
	The second experiment. The plant box in the foreground was used for laser and camera measurements, and the box behind the laser was used for destructive reference measurements (harvesting). In the back to the left, the plants in the first experiment are just visible.
	Example of a canopy image from the second experiment. This image shows a challenging lighting situation.
	Example of a canopy image from the second experiment. Note the problem with green moss in the soil.
	Example of a canopy image from the second experiment.
	Example of a canopy image from the second experiment.
	Profile of the canopy late in the second experiment.

Last modified: 12 August 2004 (Kristian Kirk)