Method of quantifying a loss of visibility through a transparent object

A measurement arrangement for quantifying a loss of visibility through a transparent object caused by icing on a surface of the transparent object, wherein the surface of the transparent object is exposed to icing conditions such that a layer of ice is formed by ice accretion on the surface of the transparent object, the measurement arrangement comprising:

• a light source;
• an image acquisition device;
• and
• a high contrast providing object, the high contrast providing object being positioned between the light source and the image acquisition device;
• the high contrast providing object and the image acquisition device being positioned such that the transparent object is positioned between the high contrast providing object and the image acquisition device with the surface of the transparent object being oriented toward the image acquisition device, wherein the light source, the image acquisition device, the high contrast providing object, and an opposed surface of the transparent object oriented toward the high contrast providing object are isolated from the icing conditions;
• wherein the light source is configured to emit a light beam through the high contrast providing object toward the transparent object, the light beam being directed through the transparent object and the surface of the transparent object toward the image acquisition device and traversing the layer of ice after having traversed the transparent object;
• the image acquisition device is configured to acquire a series of images over time of the high contrast providing object taken through the transparent object while the light beam is being emitted, acquisition of at least two immediately successive images of the series of images being temporally spaced by a predetermined time interval;
• and
• a loss of visibility over the time through the transparent object is quantifiable based on blur occurring in the series of images over the time.

A measurement system for quantifying a loss of visibility through a windshield caused by icing on a surface of the windshield, wherein the surface of the windshield is exposed to an icing wind flow such that a layer of ice is formed by ice accretion on the surface of the windshield, the measurement system comprising:

• a tube having an air flow channel with an inlet opening that is pointed directly into the icing wind flow, the tube having a kinked section;
• a measurement arrangement positioned at the kinked section of the tube, the measurement arrangement including a transparent object, a light source, a high contrast providing object, and an image acquisition device,
• the transparent object being a sample of the windshield and is of a same material as the windshield, the transparent object being positioned within the air flow channel with a surface of the transparent object being exposed to the icing wind flow that enters the air flow channel via the inlet opening such that a layer of ice is formed by ice accretion on the surface of the transparent object and with an opposed surface of the transparent object being isolated from the icing wind flow;
• the high contrast providing object being positioned between the light source and the transparent object, and the high contrast providing object and the image acquisition device being positioned such that the transparent object is positioned between the high contrast providing object and the image acquisition device with the surface of the transparent object being oriented toward the image acquisition device, and the transparent object, the light source, and the image acquisition device being isolated from the icing wind flow;
• wherein the light source is configured to emit a light beam through the high contrast providing object toward the transparent object, the light beam being directed through the transparent object and the surface of the transparent object toward the image acquisition device and traversing the layer of ice formed on the surface of the transparent object after having traversed the transparent object;
• the image acquisition device is configured to acquire a series of images over time of the high contrast providing object taken through the transparent object while the light beam is being emitted, acquisition of at least two immediately successive images of the series of images being temporally spaced by a predetermined time interval;
• and
• a loss of visibility over the time through the transparent object is quantifiable based on blur occurring in the series of images over the time.