Magic sensing, electromagnetic, sonic waves, infrared thermal imaging, telescopes, animal vision.

Kaichi wrote down all the methods he thought of as a means of detection on paper, and although his memory was good enough, it was not as intuitive as on paper, and it was more conducive to summarizing.

The first thing he ruled out was animal vision, because animal vision is very limited, if it is blocked, it is useless, and it will be greatly limited in the dense forest. And there are many types of animal vision, including the dynamic vision of frogs and the ultra-long-distance vision of eagles, but these are related to the photoreceptor cells in the eyes.

This leads to the need to operate this kind of spell with his own eyes, and after thinking about it for a long time, he feels that he does not have the intention and strength to go deep into genetic engineering, and he does not think that this spell can be developed before he blinds himself.

Among the existing magic systems is the Eagle Eye Technique, which can be learned as long as he is stronger, and it is not worth wasting time developing this spell.

Instead of developing a spell based on animal vision, it is better to make a telescope. However, this method also has the disadvantage that the line of sight will be blocked, and Kaichi can only use it as an alternative. Even if it's not for scouting, it's good to just play it. And it has a good view on the water, which is somewhat useful.

It's just that Jia Yi doesn't know that there are already things like telescopes in this world, and even microscopes, but because the technical threshold is relatively low, everyone subconsciously keeps it secret, so it is only circulated in a closed small area.

Of course, even if he knows about it, it won't affect him to make one himself, because he can't buy it for the time being. And Jia Yi doesn't have the kind of brain-dead thought that I am crossing my cow B, and all inventions must be made by me personally.

In this world, because of magic, the development of technology and the earth where Kaichi used to be are not the same. To put it bluntly, the author thinks it's as good as he wants.

Removed the first two, and the next thing that was excluded by Kaichi was electromagnetism. The prototype of the application of electromagnetic wave detection is actually radar, but unfortunately although Jiayi has learned a lot of Faraday electric fields and Maxwell's equations, he has no clue how to accept electromagnetic waves. Moreover, the speed of the electromagnetic wave is too fast, and if the distance is too far, it is impossible to tell where the reflected electromagnetic wave is reflected from. The distance of 100 meters is reflected back by electromagnetic waves, and the time difference is less than 1 microsecond, and the difference of one millionth of a second cannot be distinguished by any means.

This technical requirement is too high.

Next, magic sensing and thermal imaging were all ruled out by Jiayi. Magic induction is actually a good direction, but Kaichi doesn't dare to say that he is more intelligent than Ace's ancestors, and designing a magic from scratch is not a simple matter. Although this magic can be used even by Ace's apprentice, it is not easy to sense the subtle difference in magic power in detail.

Otherwise, this magic would not be affected by the environment, and the concentration of magic elements would drop greatly as soon as the distance was high.

Jia Yi didn't think that he could solve this problem, so he could only use this direction as an alternative and leave it for later opportunities to study it.

Infrared thermal sensing is actually good, but the detection distance is a little too close, and thermal imaging cannot penetrate obstacles, not even glass.

Infrared imaging is achieved by detecting the infrared rays that are not visible to the naked eye that are radiated or reflected by the object, because any object cannot be absolutely 0 degrees, so all objects have infrared radiation characteristics, but infrared light is the same as visible light, except that the wavelength is greater than that of visible light, and the spectrum is located outside of red light, so visible light cannot pass through opaque obstacles, and infrared rays naturally cannot pass through. And because the wavelength of infrared rays is too long, they will be reflected by the glass, and only a very small part of it can pass through the glass. By the way, ultraviolet rays are absorbed by the glass, and they cannot penetrate the glass.

Only high-energy particles such as X-rays can have traversal properties.

As for the infrared thermal imaging in film and television works, it can penetrate the wall, art comes from life but is higher than life?

After choosing for a long time, Jiayi still thinks that acoustic detection is the most practical and has the lowest technical requirements. And if it is to detect objects in the water, there is no more suitable than sound waves, and the rest of the means are very seriously attenuated. Of course, this is based on the category of science, and if it is based on magic, there may be a better solution, but Kaichi is not not magic enough, science will make it up.

Sound waves are divided into ultrasonic waves and infrasound waves, based on detection, ultrasonic waves are more concentrated, directivity is better, detection is more accurate, and infrasound attenuation is reduced, which can bypass obstacles. And infrasound can also be used as a covert means of lethality.

For ultrasound and infrasound, Jiayi said a lot in the physics books of his previous life, and he felt that he knew a lot about sound waves.

But the first question now is how to hear ultrasound and infrasound.

Fortunately, Jiayi has magic, and one of the spells is called Hearing, which can make people's hearing more acute, and at the same time, they can hear more sounds. This spell Jiayi didn't know it for the time being, but it wasn't a complicated spell, and he just didn't think it was useful at the time, so he didn't learn it.

And this spell is really of limited use, if you can't filter out the superfluous sounds, it will be torture for your ears to become sharp.

He first parsed out the part of this spell about sound reception, this spell is not complicated, most of it is about sound reception. After parsing it out, the part about hearing acuity was removed, and he didn't need to hear what the human ear could hear.

The rest of this circle is the part where you can hear ultrasound and infrasound, and it just so happens that both ultrasound and infrasound can be heard. Of course, this should be mainly thanks to the author's golden finger.

In fact, the difference in the rune structure of the three bands is not too big, but the structure of the rune circle is slightly different, and it only needs to be slightly adjusted to accept the sound of the whole band.

With the receptive part, it's simple to reconstruct the output part of the sound.

After the sound is output, the sound waves are received back through the receiving part, and through calculation, it is possible to know where the obstacle is. However, this has a disadvantage, you can roughly judge the size of the obstacle, but you can't get a specific outline, and if two objects are close together, they can't be distinguished, and they will be treated as the same object.

The most important thing is that if the other person is still or not, it is impossible to find out whether the other person is a living creature or not. Moreover, it can only judge the body shape, and whether it is a monster or not cannot be detected.

However, being able to get this information is enough for the time being, and Jia Yi doesn't dare to ask for more, after all, it's just a low-level magic. And the application of infrasonic has not yet been able to start researching, such as how to break the internal organs through infrasonic waves, as well as infrasonic resonance collapse buildings, etc., Jiayi has no time to study, because the new ship has arrived, and Jiayi is about to set off.

In fact, before he set off, even half of Jiayi's spells were not successfully constructed, because the transmission, reception and calculation of spells were not well integrated together, resulting in him not being able to accurately receive the returned signal, or the signal was received, but he couldn't be sure that it was launched in a wave.

He decided to learn from the animals in nature, in nature, bats, dolphins, and whales can all emit ultrasound, but now in the river, except for bats, Jia Yi can't get any, let alone use it for experiments.