The small lecture hall of Qinghe Bureau is located on the first floor of the office building.

The green plants inside are a bit dry, but no one cares.

Along with other unimportant departments, it has its doors open and welcomes visitors from all directions, including people who don't know the truth, as well as police officers from all over who don't know the truth.

However, the utilization rate of the small lecture hall is still very high.

As a pragmatic bureau, the Qinghe Bureau attaches great importance to the organization and reporting of various activities. Otherwise, its existence would be too meaningless.

Today, there were quite a few people sitting in the small lecture hall, and then there was a tall young man who was lecturing slowly, as if a college student was giving a speech on the stage.

It's just that the atmosphere is quite different.

The young policeman wears gray epaulettes, which means he is a technical policeman. He wears a full police uniform and looks very good. Although he does not look like the popular little celebrity, he can be regarded as a gentle and sunny boy, and he has the bonus of a uniform. He sits and talks.

At the banquet, his expression was serious and he acted freely. Taking a random photo seemed to be enough for publicity.

Jiang Yuan also wore a pair of plain glasses for this training. In fact, he was not nearsighted, but he had a tender face, so the master said it would be better to wear glasses.

The policemen sitting in the viewing area looked at the projection screen with nervous and solemn expressions. The muscles in their cheeks were obviously slightly touched, and their eyes were wide open, with great effort.

The 20 approximate fingerprints matched in the first pass are listed in vertical rows on the right side of the screen.

The three-quarters on the left are the one with the highest approximate fingerprint value, which is fully displayed.

"Well, let's take a look at the fingerprints returned from the first pass."

Jiang Yuan pushed the unfamiliar glasses frame with one hand, grabbed the mouse with the other hand, clicked, and enlarged the fingerprint on the left to the full screen again.

On the projection screen, the fingerprints displayed simultaneously are also relatively clear.

"Well, there is an exclusion point here." Jiang Yuan clicked twice and enlarged the fingerprint again. Then, his mouse drew a small circle on the right side of the fingerprint to show everyone.

For fingerprints that have been matched, what is implemented is not the standard of how many feature points are consistent, but whether there are inconsistent feature points.

This is easy to understand. If two fingerprints are the same, then in theory, all their feature points should be the same.

Therefore, if one feature point of two fingerprints is inconsistent, it can be considered "excluded".

That is to say, the two fingerprints are different and are not the same fingerprint.

Following this idea, Jiang Yuan killed two similar fingerprints in a row.

At this time, Cao Keyang from the Qinghe Municipal Bureau, who was sitting in the front row below, said: "Teacher Jiang, should we take out the two fingerprints and compare them. This way we can directly rule them out, and everyone will not be able to see clearly."

Jiang Yuan reacted quickly and immediately clicked twice, causing the original fingerprint and the matching fingerprint to appear on the left three-quarters of the screen at the same time.

"Sorry, I was thinking that the first few fingerprints could be done faster." Jiang Yuan said sincerely.

Cao Keyang felt an inexplicable sadness in his heart and said hurriedly: "It's okay, this is not your problem, that is, we are giving a lecture. It is better to speak slower and more clearly."

"Yeah, I'll pay attention." Jiang Yuan nodded and said, "Then let's exclude the first two fingerprints again."

Then, Jiang Yuan used the exact same action to draw a circle on the right side.

The difference is that he then also drew a circle on the left side.

As a result, the audience below finally let out a coherent "oh" sound.

Seeing this, Jiang Yuan kept up his efforts, circled the second and third fingerprints, and then persuaded him to leave.

The "oohs" in the audience gradually became less and less.

Technicians whose fingerprint level is lower than LV1 begin to feel sour and bitter in their hearts, which is an indescribable feeling.

They finally understood that Jiang Yuan had written down the original fingerprints in their entirety.

So, what I just did was a process of elimination purely based on memory.

There is no need to compare. You have the original pattern in your mind, and it is naturally very fast to eliminate or compare.

This is actually nothing.

If we start preparing lessons a few days ago, it will take a long time for everyone to remember the fingerprint... part.

The key is who will do this?

No one expects such fine fingerprints to be remembered.

Fingerprints are annoying to me.

On the other hand, when a fingerprint examiner pays attention to a certain difficult fingerprint over many years, he will gradually remember the characteristics of the fingerprint, but...

While some people were thinking wildly, Jiang Yuan ruled out three more similar fingerprints.

Then, I heard Jiang Yuandao: "At this time, it is generally recommended to read all 20 fingerprints. But we won't read it today, because the similarity of the fingerprints is getting lower and lower, which means that the probability of winning in the subsequent comparison has been

Very low..."

Cao Keyang was stunned.

The crowd was stunned.

Why does this feel so familiar?

It's like, when I was still studying, I lowered my head to pick up a pencil. When I raised my head again, I couldn't understand the teacher's words.

Even the language at the last moment is the same: I won’t write the following steps, because they are relatively simple, so we will skip them, but the conclusion that can be drawn from this is...

Jiang Yuan had no intention of stopping.

After the first wave of fingerprint screening, Jiang Yuan pulled out the original fingerprints and said: "Now we mark the feature points for the second time."

dazzled,

Random flowers and charming eyes,

Out of sight out of mind,

No use bothering

After the operation, Jiang Yuan re-completed the marking of the thirteen marking points.

Jiang Yuandao: "The location we just marked is a relatively common marking point. There is no match, which shows that the basic work of the previous trace inspection was completed well. The suspect did not leave very clear full fingerprints for us to match.

.It doesn’t matter, let’s try again.”

Similar to the previous steps, Jiang Yuan threw the marked fingerprints into the fingerprint database for comparison.

After a while, the data returned by the fingerprint database was another 20 fingerprints in a row.

"You still need to compare left and right, right?" Jiang Yuan asked Cao Keyang this time as a courtesy.

Cao Keyang nodded obediently and looked at the projector calmly.

This time, he felt that he should be ready.

Two fingerprints were listed three-quarters of the way to the left side of the projector.

Jiang Yuan moved his mouse slightly, ticking a small circle on the left and a small circle on the right, and said: "Excluded, right? It's almost the same as before."

"The second one is also ruled out."

"Same."

"For the lower ones, we don't have to tick them one by one."

While Jiang Yuan was talking, he quickly took his fingerprints.

He taps the space bar on the keyboard, and a new fingerprint will appear on the screen, replacing the old fingerprint.

Since Jiang Yuan no longer had to check the circle, he just took one look at it and said "no", then tapped the space bar again and replaced it with a new fingerprint.

Cao Keyang stared at it at first, but soon fell into the same state again:

Eye

chaos

Eye

bother

For a moment, Cao Keyang almost thought he was watching short videos.

The screen is full of Internet celebrity ladies, and they all look alike.

Take a look and swipe away.

Look at another picture and swipe away.

In a daze, half an hour passed.

At this time, Jiang Yuan also re-marked the characteristic points of the fourth wave and said: "Actually, the characteristic points we just marked are not very necessary, just to show everyone."

"In the future, if you have the opportunity and you become proficient in practice, you can omit the marking mode just now, because the feature points you just marked are the same as those in the previous two times. If it is just for trial, it will not be efficient."

"A more efficient way is to delineate a small area and then mark as many feature points as possible. In this way, the accuracy of the fingerprints fed back will also be improved. Of course, the difficulty will be higher."

"Still the same method as before..."

As Jiang Yuan spoke, the sound of tapping the space bar could be heard in the lecture hall.

Not only Cao Keyang, but also most of the technicians in the lecture hall were a little numb.
To be continued...