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Apparatus for the measurement of the vertical bidirectional lighting intensity profile Disclosure Number: IPCOM000021828D
Publication Date: 2004-Feb-10
Document File: 1 page(s) / 25K

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Apparatus for the measurement of the vertical bidirectional lighting intensity profile

The standard way to measure light distributions is to use a luxmeter with a diffuser that measures the total flux at a given location. These meters are hand-held devices that are walked through the greenhouse and produce readings at the places where a measurement is made. These meters give integrated readings on one spot only and the measurements are very time-consuming. The gist of the invention is to provide an optical device that gives a spatially and angularly resolved representation (e.g. an image) of the light distribution and a projection screen to capture the light distribution, combined with a calibrated camera to record the intensity data.

This invention overcomes two problems:

a)      it offers angular resolution of the measurement and

b)      it captures a whole intensity profile (spatial resolution) in one measurement.

The invention makes use of the basic features of the Parousiameter (US-6577397B1): a screen and a camera. To produce the spatial resolution a measuring cell in the form of a Parousiameter or a derivative screen is used, and to produce the spatial resolution an array of these devices is used, with separate cameras or with a common camera, depending of the screen configuration. The array of parousiameters or derivative screens is placed on a vertical row with the measuring apertures facing up (for the down lighting) or facing down (for upward lighting). The array can be placed in a transparent protective tube or sheath to prevent dust or water spray (which is ubiquitous in a greenhouse) to enter the measuring units. The whole array can be mounted on a common automated greenhouse cart or robot that trav...