What is the fisheye effect and what does the fisheye effect mean?

Eight years ago, a friend of mine, Comanche, was working on 3D graphics technology, so he bought a book called Amazing 3-D Games Adventure Set (I forgot the Chinese translation). I've borrowed it a few times, but I don't remember the exact technology, except for one of the first few chapters where there was a problem. The basic principle of simulating 3D images with flat graphics is "near big and far small".

However, there is a problem with this: when the player is facing a wall, because the opposite part of the wall is close to each other, and the two sides are relatively far away, there will be a strange situation where the middle is high and the sides are low in the face of a flat wall.

The author cites a term when talking about this: the fisheye effect. As for why this effect is called this name, he can't say why, so he has to jokingly say:

As to whether this is true for what the fish's eyes see is true or not, only God knows (it seems that the fish also knows :p).

This question also puzzled me for a long time, and I didn't know what was going on until I learned about it for a while last year after learning to dive in Shadow Mowgli. See this article about fisheye lenses for details. The fisheye effect mentioned above is similar to the barrel distortion effect of a fisheye lens.

Fisheye Effect - The cut of the diamond pavilion is too shallow, the light leaks out from the surroundings, and the diamond has no fire from the countertop, like a dead fish's eye, which is called the fisheye effect.

The fisheye effect is an unsightly optical phenomenon in which the shape of the girdle is reflected in the diamond table when viewed vertically. It looks dull, much like a dead fish's eye, and is named after the "fisheye effect".

If the girdle is thick and unpolished, it will look like a large round inclusion, and the result is that the diamond will be as bad as i3.

When a diamond is cut too shallowly, light can escape from its pavilion, impairing the diamond's brilliance and losing its luster and dimming it. It is common to see a white circle inside the diamond, which is called the fisheye effect.

This is generalized.

<> fisheye effect means that the fisheye effect is an unsightly optical phenomenon formed by the reflection of the shape of the girdle in the diamond table when viewed vertically. It looks dull, much like a dead fish's eye, and is named after the "fisheye effect".

Detailed interpretation: The fisheye effect is mainly used to describe the worst of diamonds.

1. What is the fisheye effect? A friend asked me if I knew what the fisheye effect was. Suddenly asked, I don't know how to explain.

Hurry up and check the information, and find that the fisheye effect belongs to the category of cut, and it is inextricably related to diamonds. There must be many friends who also have doubts about this, so I hereby translate it to share with you: if the girdle is very thick and not polished, then it will look like a large round inclusion, and the result is that the grade of this diamond is as bad as i3.

2. If you need to tilt a little angle to observe the fisheye effect, such a diamond is acceptable. Because they have a good range of widths. If the fisheye effect can only be observed by an angle of 5 degrees or more, then we call it an ideal diamond.