Lumens is a very important unit of luminance. The lumens are measured based on human vision. The lumens per unit area is often searched for. Lumens define the light intensity in a specific area in a particular direction. The lumens measurement is very important for designing the lighting spectrum to a great deal.
The light direction is very important and identical for different users. The light requirement for different circumstances is quite different. That is why it is important to know the lumens requirement in particular areas. The table for different Lumens is as follows.
|Description||Lumens per square feet|
|Kitchen (task areas)||20-35|
Calculation of Measuring Lumens
Two light bulbs are measured 1200 lumens and the space length and width are 10 and 10 feet. The lumens per square foot = 60 lumens per square foot.
Lumens Measurement in Outdoor Settings
Measuring lumens in outdoor settings quite different than the indoor settings. In measuring lumens in outdoor setting spectral efficiency is a crucial aspect for quality improvement.
For a particular reason, spectral efficiency measurement is not a straight forward calculation. The new term “Lumen Effectiveness Multiplier” is introduced in modern lumens calculation
Until recently, the light intensity is measured irrespective of the color tone of light. But this is not a recommended practice. All the regulatory and standard organization are putting effort to introduce spectral measurement in the calculation of lumens.
However, this critical lighting measurement technique is used for various purposes. Nowadays the lighting results are measured with effective lumens. The following equation gave the relation of effective lumens.
Effective lumens = photopic lumens × Lumens effective Multiplier ……………………………………………………. (1)
Two important issues related to Lumens Effective Multiplier (LEM) are
- It does not have a fixed value. Based on a different perspective, the value fluctuates.
- The value is relative value can be measured using the following equations
LEM = (visual effects of light source/visual effectiveness of a standard light source) …………………………………..……… (2)
LEM is often measured with on basis of a high-pressure sodium (HPS). The LEM for HPS is often measured with the following equation
LEM = (visual effectiveness of light source/visual effectiveness of a standard HPS source) …………………………..(3)
Methods of Computing LEM
- First, you need to collect brightness data and mesopic functions. With the help of this data, you can measure the LEM for different kinds of lights sources. The value ranges from 2 to 30. Most of the quality lighting will ensure proper lighting arrangement for better purposes. The lighting intensity is also a very important aspect of different environment settings.
- Mesopic functions are in use for a pretty long time. This excellent lighting will enhance the performance to a certain level. The quality of the lighting is very important because the mesopic function determines the factor.
- The mesopic function will have some issues in peripheric conditions. Most of the quality writing is very much essential for high-quality data collection and processing. Different mathematical functions can be evaluated to measure the performance of a distinctive light source in different location settings.
- Direct evaluation of spectral analysis is very important. Some of the key resources are important for the performance to a certain degree. The quality of the lights and their intensity is quite extraordinary for better purposes.
How to Perform Spectral Analysis
Spectral analysis has two broad categories. Among them, one is for deterministic signals and random signals. The quality of the light spectrum is not well defined. Hence you will consider the signal as a random signal. We can evaluate this light signal with the help of different mathematical models to a certain aspect.
These quality signals are quite important to determine the base case intervention. There is some quality mathematical model such as Blackman Turkey methods. There are also some very well-practiced methods to analyze the certain spectral analysis of lighting.
If we want to understand any signals such as light, then we have to move on the frequency domain rather than in the time domain. The quality of lighting can be improved to a great degree based on frequency domain analysis.
FFT (Fast Fourier transform) is a very important aspect for determining the quality of frequency domain analysis to a certain degree to improve the performance. Based on the performance of the light source there are some periodic and nonperiodic signals.
Based on the variables, there are also two different signals such as single variate signal and multivariate signals. There are some quality lighting spectrums which can be used in various conditions with several aspects for better quality management.
Most of the quality signals have some definitive analysis which can greatly be improved by the definition of signals. In the recent past, some of the quality lights spectrum analyzer is built to provide maximum lighting.
FFT analyzer is one of the popular analyzers to measure spectral efficiency and light intensity. The FFT analyzer works in the following formats.
Figure: The FFT Analyzer process
One of the core problems with FFT analyzer with the pulsed signals. There are some common aspects with FFT that it cannot accommodate pulse signals. There are some other popular methods which can accommodate pulse signals.
Construction of light meter is quite fair and simple. Recent developments of Arduino make it a very simple configuration. With Photodiode and supporting resistance, you can build a professional circuit to measure light intensity.
There are some quality lighting arrangements which can be used to build a professional circuit. The lighting technology has improved to a great degree in recent times. With a very simple circuit design, you can build your circuits. There is a sample of different light meters to measure lumens are available in the market.
Microcontroller based charge controllers have better feature and control compared to the electronic light meter. The recent development of microcomputer also enriches the performance of measuring lumens to a certain degree. Many of the quality lights have improved greatly with superior performance.
Measuring Lumens is quite simple if you do not consider a spectral response. But it is wise to consider the spectral response for quality and effecting lighting systems.