Method For Determining The Scope Of Detectability And Readability Of Light Signals

• US 20080120033A1
• Filed: 11/17/2005
• Published: 05/22/2008
• Est. Priority Date: 11/17/2004
• Status: Abandoned Application

• Current Assignee: Deutsche BAHN AG (Government of Germany)
• Original Assignee: Deutsche BAHN AG (Government of Germany)
• Inventors: Wilhelm, Eckehard, Moller, Thorsten
• Application Number:
  US11/666,387
• Publication Number:
  US 20080120033A1
• Time in Patent Office: Days
• US Class Current: 702/1
• CPC Class Codes: B61L 5/1881 Wiring diagrams for power supply, control or testing
• CPC Class Codes: G01J 1/42 using electric radiation detectors optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10
• CPC Class Codes: G01J 2001/4247 for testing lamps or other light sources

Abstract

The invention relates to methods for determining the scope of detectability and readability of light signals with several light spots at a given surrounding radiant density per unit area. According to the invention, calculation of the scope of detectability is carried out with the rod of the assumption that the total radiant density per unit area or the total light intensity of the light signal is obtained by multiplying the radiant density per unit area or light intensity of a single light spot by the number of light spots.

Claims

1. A method for determining the detection distance prevailing in a given direction of a light signal comprising several light spots with an established surrounding radiant density per unit area with the following steps:

measurement of the radiant density per unit area or light intensity prevailing in the given direction of each individual light spot and

calculation of the detectability and readability distance based on the measured radiant densities or light intensities,

wherein

the calculation of the detection distance is performed with the help of the threshold value for the total radiant density per unit area or the total light intensity of the light signal which is obtained through multiplication of the measured radiant density per unit area or light intensity of an individual light spot with a power of the number of light spots and with a correction factor.

2. The method according to claim 1, wherein the correction factor depends on the number of light spots, on the light intensity, the diameter and the position of each of the light spots and on the prevailing distances to one another between the light spots.

3. The method according to claim 2, wherein the correction factor is determined numerically.

4. The method according to claim 3, wherein a virtual additional indicator with user-definable light spot arrangement is specified and the correction factor is calculated by means of an eye model and light beam calculation with given distance between eye and additional indicator.

5. The method according to claim 4, wherein the virtual additional indicator is formed in that a virtual grid with freely selectable positions is occupied with light spots.

6. The method according to claim 1 with the further steps:

Measurement of a first radiant density per unit area for each individual light spot in the switched-off state of the light signal and

Measurement of a second radiant density per unit area for each individual light spot in the switched-off state of the light signal.

7. The method according to claim 6 with the further step:

calculation of the radiant density per unit area differential of each light spot along the optical axis of the light signal by means of the measured first and second radiant densities.

8. The method according to claim 7 with the further step:

Calculation of the standardized radiant density per unit area of each light spot through addition of the radiant density per unit area differential calculated in each case to the established surrounding radiant density per unit area.

9. The method according to claim 1, wherein upon measurement of the radiant density per unit area or the light intensity a mean radiant density per unit area or a mean light intensity is measured.

10. The method according to claim 1, wherein during the measurement of the radiant density per unit area or the light intensity a radiant density per unit area distribution or a light intensity distribution is measured.

11-15. -15. (canceled)