What is a ship guidance method utilizing moire pattern?

Bytheilr

There are strange patterns like race curtains overlapping, such as regular patterns and multiple striped patternsMoireI call it. However, there are few people who think that they can be applied technically because they actually only look like geometric figures even if they see the pattern of moire. Moiré has a characteristic that its shape varies depending on the angle of view, and by using this mechanism it is possible to apply technical applications such as guiding a ship being navigated to the correct position.

Using Moiré Patterns To Guide Ships | Hackaday
https://hackaday.com/2018/04/07/using-moire-patterns-to-guide-ships/

As a way to create a moiré pattern that can indicate the direction depending on the viewing angle, there is an easy one that uses two combs. Align the tips of the two combs as shown in the image below and open the main body side.


Once the front comb is parallel to the display, look at the computer display from the tip of the comb. Then when you see it from the front, a vertical line is drawn.


Shifting the combs a little, looking from the right side, the line changes to diagonally downward from the upper right to the lower left.


Then shift the comb to the opposite direction and from the left side, the line changes to diagonally downward from the upper left to the lower right.


I applied this mechanismU.S. Pat. No. 4,629,325 AIt is a moiré screen for navigating ships. In this moiré screen, the front screen is perpendicular to the ground, but the two screens at the back are inclined at the center as the vertex.


In fact, I will look at the real thing of this moire screen. The following image is a picture of Moire screen viewed from left, front, right. "Right Arrow" when viewed from the left, "Vertical Line" when viewed from the front, "Left Arrow" when viewed from the right. For example, even in a situation with poor visibility at night, if this screen is placed in the middle part of the bridge, the ship cuts the ruffle while watching the screen and moves to the position of "vertical line" It is safe to pass under the bridge.