METHOD FOR DETECTING THE PRESENCE OF ICE CRYSTALS IN AN ENVIRONMENT

• US 20190161197A1
• Filed: 11/20/2018
• Published: 05/30/2019
• Est. Priority Date: 11/28/2017
• Status: Active Grant

• Current Assignee: Safran Aerotechnics SAS (Safran SA)
• Original Assignee: Zodiac Aerotechnics
• Inventors: Baudouin, Philippe, Bonneau, Ludovic
• Granted Patent: US 10,640,218 B2
• Time in Patent Office: Days
• CPC Class Codes: B64D 15/20 Means for detecting icing or initiating de-icing
• CPC Class Codes: G01N 15/0211 Investigating a scatter or diffraction pattern
• CPC Class Codes: G01N 2015/0046 in gas, e.g. smoke
• CPC Class Codes: G01N 2015/0222 from dynamic light scattering, e.g. photon correlation spectroscopy
• CPC Class Codes: G01N 2021/1748 Comparative step being essential in the method
• CPC Class Codes: G01N 21/35 using infrared light G01N21/39 takes precedence
• CPC Class Codes: G01N 21/47 Scattering, i.e. diffuse reflection G01N21/25, G01N21/41 take precedence G01N21/55 takes precedence
• CPC Class Codes: G01N 21/4738 Diffuse reflection precedence is given to G01N21/55 - G01N21/57 if specular component is taken into consideration, e.g. also for testing fluids, fibrous materials

Abstract

The invention relates to a method for detecting the presence of ice crystals in an environment, implemented by a detection device in relative motion with respect to said environment, said method comprising at least:

• • an emission step, in which at least one optical radiation is emitted by the detection device into the environment;
  • a reception step, in which at least a portion of the emitted optical radiation is received,
  • a step of calculating a comparison signal, and
  • a step of calculating the noise of the comparison signal,
  • a thresholding step, in which the noise is compared to a defined threshold,
  • a communication step, in which a signal indicating detection of the presence of ice crystals in the environment is transmitted when the noise is greater than the defined threshold.

Claims

1. Method for detecting the presence of ice crystals in an environment, implemented by a detection device in relative motion with respect to said environment, said method comprising at least:

an emission step, in which at least one optical radiation is emitted by the detection device into the environment;

a reception step, in which at least a portion of the emitted optical radiation is received by the detection device, said at least a portion of the received radiation including rays within a first wavelength band (λ

₁) and rays within a second wavelength band (λ

₂);

characterized in that the detection method further comprises at least;

a calculation step, in which the detection device calculates a comparison signal (Comp(t)) representative of the contrast, said contrast being obtained from the following formula;

2. Detection method according to claim 1, wherein the detection method further comprises at least:

a sampling step, in which a time window (FTi) is defined.

3. Detection method according to claim 1, wherein the detection method further comprises at least:

a continuation step, in which a next time window (FTi+1) shifted in time by a duration (D) with respect to time window (FTi) is considered, and/or

a loop step, in which the noise calculation step and the thresholding step are repeated.

4. Detection method according to claim 3, wherein the shift duration (D) is less than the duration of the time window.

5. Detection method according to claim 3, wherein the detection method further comprises at least:

an incrementing step, in which a value (Cj) of a counter is incremented when the noise (B) is greater than the defined threshold (S), and/or

a confirmation step, in which the value (Cj) of the counter is compared to a triggering threshold (Sa).

6. Detection method according to claim 5, wherein the communication step, is transmitted when the value (Cj) of the counter is greater than the triggering threshold (Sa).

7. Detection method according to claim 6, wherein the detection method further comprises at least:

a reset step, in which the counter value (Cj) is initialized to zero.

8. Detection method according to claim 1, wherein the noise calculation step comprises a step of calculating a standard deviation of the comparison signal (Comp(t)) in the time window considered.

9. Detection method according to claim 1, wherein the noise calculation step comprises a step of calculating the Fourier transform of the comparison signal in the time window considered.