Chosen problems of the light techniques in the transport

SUMARY Radiation spectrum Luminous flux Luminous intensity Illuminance Luminance Photometeric Screen ISO Measurements1. Measurement of lighting distribution of low beam lights in a car;2. Measuring distribution of lighting and angle from the car signal lights3. Measuring of luminance and contrast from different number plates of a car,4. Integrating spheres for luminous flux measurements RADIATION SPECTRUMLight usually refers to visible light, which is electromagnetic radiation that is visible to the human eye and is responsible for the sense of sight. Visible light is usually defined as having a wavelength in the range of 400 nanometres (nm), or 400109 m, to 700 nanometres between the infrared, with longer wavelengths and the ultraviolet, with shorter wavelengths.

Generally, EM radiation, or EMR (the designation 'radiation' excludes static electric and magnetic and near fields) is classified by wavelength into radio, microwave, infrared, the visible region that we perceive as light, ultraviolet, X-rays and gamma rays. LUMINOUS FLUXLuminous flux is the amount of electromagnetic energy emitted by a light source per time unit. It forms the basis for photometric system.

The luminous flux can be also defined as the average of the radiant flux in the visible spectrum (of the electromagnetic wavelength from ).

The luminous flux value is proportional to the luminous flux multiplied by spectral relative luminous efficacy V() where Km is the photometric equivalent to radiation (Km = 638 lm/W).

LUMINOUS INTENSITYLuminous intensity is an expression of the amount of light power emanating from a point source within a solid angle of one steradian . For reference, a frequency of 540 terahertz (540 THz or 5.40 x 10 14 Hz ) is specified. The quantities used to express luminous intensity are arcane to most non-scientists. A frequency of 540 THz corresponds to a wavelength of about 555 nanometers (nm), which is in the middle of the visible-light spectrum , and is generally accepted as the frequency and wavelength at which the average human eye is most sensitive. A steradian is the standard unit solid angle; a sphere encloses 4 p (approximately 12.57) steradians. ILLUMINANCEIn photometry, illuminance is the total luminous flux incident on a surface, per unit area. It is a measure of how much the incident light illuminates the surface, wavelength-weighted by the luminosity function to correlate with human brightness perception. Similarly, luminous emittance is the luminous flux per unit area emitted from a surface. Luminous emittance is also known as luminous exitance.Illuminance was formerly often called brightness, but this leads to confusion with other uses of the word, such as to mean luminance. "Brightness" should never be used for quantitative description, but only for nonquantitative references to physiological sensations and perceptions of light.

The human eye is capable of seeing somewhat more than a 2 trillion-fold range: The presence of white objects is somewhat discernible under starlight, at 5105 lux, while at the bright end, it is possible to read large text at 108 lux, or about 1000 times that of direct sunlight, although this can be very uncomfortable and cause long-lasting afterimages LUMINANCELuminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through or is emitted from a particular area, and falls within a given solid angle. The SI unit for luminance is candela per square metre (cd/m2). A non-SI term for the same unit is the "nit". The CGS unit of luminance is the stilb, which is equal to one candela per square centimetre or 10 kcd/m2.

Luminance is often used to characterize emission or reflection from flat, diffuse surfaces. The luminance indicates how much luminous power will be detected by an eye looking at the surface from a particular angle of view. Luminance is thus an indicator of how bright the surface will appear. In this case, the solid angle of interest is the solid angle subtended by the eye's pupil. Luminance is used in the video industry to characterize the brightness of displays. A typical computer display emits between 50 and 300 cd/m2. The sun has luminance of about 1.6109 cd/m2 at noon.

Photometeric Screen ISO

ECE-Regulation No.48Distance 10m

Measurement of lighting distribution of low beam lights in a carLamp:

Light source: TUNGSRAM

Voltage: 13.56 [V] Curent: 4.12 [A]

Point and area on the screenIlluminance E [lx] for the reflector with bulb

H7 (25m)H7 (10m)Measurement

B50LE0.3E1.873

75LE12E7515.3

75RE12E75190.1

50LE