Help all mankind

[Haha, seeing the internal structure of the small box made by Lidoff you sent me, I always feel a little familiar.

The structure of this thing is similar to the old-fashioned automatic tracking missile principle. I know what Ridolf thinks.

Closer to home, the human eye's ability to distinguish brightness is very weak.

Professor Frank was worried that Liang Shicheng did not understand his ideas and continued to explain

[As other animals with color blindness, when they cannot distinguish objects by color, it is black and white vision.

But their eyes are better than ours sometimes. Animals rely on differences in brightness to distinguish objects.

This is especially reflected at night, when people's night vision ability is very weak.

In fact, it is not that there is no light at night, and some luminous light will still be leaked, although it is completely dark.

But many animals can see very dark black, extremely black, slightly black, relatively white black and so on.

The degree of darkness in different places is not exactly the same, they can be clearly distinguished, and they have the so-called night vision ability.

However, the degree of black that the human eye can see is limited, so a little black and very black are confused.

Brightness or darkness is actually how many photons pass through a unit area, and theoretically it can be subdivided infinitely from white to black.

Although Liang Shicheng doesn't know much about biology, because of his exposure to photography, he still has some understanding of the defect of human eyes to distinguish brightness, and he followed a sentence.

[Well, so those cameras with high dynamic range, that is, cameras that can subdivide the brightness level, do not need to increase the exposure. After shooting against the dark night, adjust the gamma curve to see a clear picture.

Professor Frank did not understand what Liang Shicheng was saying, so he shook his head and smiled. For a professor like him who makes a living by sweeping the toilet, many concepts are understood, but he forgot the professional terms. about there.

Then Professor Frank continued to add that as the party who took the initiative to answer the question, he obviously paid more attention to the matter of easy understanding.

[Because of our insensitivity to brightness, our night vision ability is extremely poor. In fact, the impact also exists during the day.

It's just that the rich colors during the day make up for this shortcoming.

Answer me a question, in a clear day.

What is the brightness relationship between the sun, sky, clouds, and objects on the ground exposed to sunlight, such as trucks?

Liang Shicheng answered immediately, which seemed to be a simple question.

[They all look the same with their eyes, they are all bright.I understand what you mean, it's actually not like that, right.

Professor Frank explained in detail,

[Yes, you have to remember that from a physics point of view, the light source must be much brighter than other objects.

For example, let me give an example.

It should be night on your side. Look at the glass. Is the picture of the room reflected by the window glass very dark, but the light in the glass is very bright, almost like the real light in the room?

Liang Shicheng did as instructed, but in fact he has noticed this, especially when he is playing with his mobile phone in the car.

[It is true.

Professor Frank quickly picked up the previous topic,

[Actually you see the reflected room in the window, which is more real under certain circumstances.

The reflectivity of the transparent glass window is very low, which can be weakened by a few dozen times, which is equivalent to a mirror that reduces the brightness. Therefore, most objects in the room are darker when seen in the window.

But the light is different. The real brightness of the light is very high, which has been weakened several times, and it is still very bright in our eyes.

So the question is, you pay careful attention to the lights in the lower glass and the lights in the room. Is there a big gap between them?It seems that there is no more than ten times the gap.

That’s because the image that the human eye sees is after PS, it will darken the overly bright areas and brighten the dark areas slightly.

Let us not feel the real brightness gap.

The lights and objects in the room you directly see are almost bright, but this is relatively fake.

The real situation is closer to what is seen in glass, the light source is very bright, and the illuminated object is darker.

As for the answer to the previous question, the sun is brighter than the sky, the sky is much brighter than the clouds, and the sky is much brighter than a truck.

Then you have to keep in mind that the brightness of the light source is always much brighter than the passively irradiated objects that do not emit light.

[One thing I remembered was about the rattlesnake, the face recognition and unlocking of mobile phones.

The general situation is like this. Many mobile phones have begun to open a function that uses face unlocking instead of passwords, which originally requires high security.

But hackers quickly found a way to crack it, that is, to get a picture of the owner of the mobile phone to get through it. For mobile phones with only a front camera, this trick is difficult to solve.

However, if it is not resolved, it means a hidden security hazard. I paid attention to Lidoff's account and found that he had provided mobile phone manufacturers with an easy and perfect solution.

That is to add a lens that mimics the eyes of a rattlesnake. Although the rattlesnake has poor eyesight, it can clearly see the light emitted from the creature.

Any animal emits light of a specific frequency, but it is invisible to the human eye.

The cost of this trick is not high. If someone puts a photo in front of the camera, because the photo is not a creature, it will not emit a specific light on the person, so it will quickly be able to tell that it is not a real person.

When you said that Ridoff was tossing a mouse again, I remembered that although the mouse’s eyes cannot see a clear picture, they can recognize the brightness more accurately than humans.

In the eyes of a mouse, the sky is very bright, and people are dark. For it, face recognition is not needed. When you see a large pile of black blocking the light, you can naturally perceive the danger.

I think the idea of ​​the small box is like this. The small hole is a camera that mimics the eyes of a mouse. Although it cannot perform image recognition, it can accurately recognize the brightness.

The sky is the light source is very bright, the big truck is seriously black in the mouse, no matter it is painted with imitating sky camouflage, it can only deceive people, and it can also deceive ordinary cameras with parameters close to human eyes.

But I can't fool the mouse's eyes.

Liang Shicheng was stunned when he heard this, although he had roughly figured out the principle, he also guessed the method.

But it was only after such an explanation. I have been engaged in image recognition work for so many years, and I know the difficulty of this.

It is very difficult to teach the computer which is the sky, which is the ground, and which is human in a colorful world.

In particular, I am afraid that when a person wears clothes painted in the sky, the AI ​​will confuse the clothes with the sky.

This is why many companies insist on using lidar, but lidar is too expensive.

But I never thought of making changes to the hardware. Just put on another pair of glasses. The sky is bright, people are dark, and the truck is also dark. It is obvious and easy to recognize.

The idea is terrifyingly simple. You only need to change an "eye" and only calculate the brightness, ignoring information such as color, and you don't even need a high resolution to do it.

Liang Shicheng, who was inspired, finally solved all the problems after adding a special lens to identify brightness.

At the same time, Liang Shicheng sighed that Mr. Ridov, who claimed to be not proficient in software technology, was really a rare generalist.