1995, Starting as a Criminal Investigation Expert

Although the office building of the Nanjiang Municipal Public Security Bureau is over twenty years old, it is quite impressive.

It was once one of the landmark buildings in Nanjiang City.

However, the staff dormitory nearby was unusually old and dilapidated.

The three-story tenement building has a concrete facade.

The electrical wires were laid out in a haphazard, disorganized manner, and once inside the building, they were even worse, resembling a spider web.

The hallway was filled with shoe cabinets, gas cylinders, flower pots, and all sorts of other things.

There was no private bathroom; the water room and toilet were shared. Li Shu ran over and took a peek, and had only one thought: he should hold it in and go to the office building to use the toilet in the morning.

Fortunately, not many of my colleagues live here.

Many colleagues have been allocated housing and moved to family compounds further away.

Therefore, those who stay here are generally those who didn't get assigned housing, as well as young people like Li Shu.

Living here is free; you only need to pay a token amount for utilities.

Renting a place nearby would cost at least a hundred yuan, so the money saved would be yours.

"Come on, stop looking so disgusted. It's great, isn't it? The city park is just a short walk away, so you can go for a stroll after get off work."

After Tan Guoxiong finished making the bed, he started wiping the windows efficiently. Seeing Li Shu sitting still, he assumed that Li Shu was annoyed by the poor environment.

He knew that Li Shu's family was well-off.

Li Shu snapped out of his daze and said speechlessly, "Come on, didn't you have enough fun when you were a kid?"

For the children of Nanjiang, the city park is an unforgettable and important memory.

However, Li Shu wasn't complaining about the accommodation.

I'm not that particular about things. The reason I was spacing out was because I was looking at the system data in a daze, trying to figure out this partition comparison method.

In fingerprint identification, two areas are crucial to a fingerprint.

Core area and triangle area.

The so-called core area is the center of the fingerprint, the location that can distinguish between whorls and loops.

The features here are the most intuitive.

When comparing fingerprints, if it's confirmed to be a whorl, and a quick scan of the file card shows it's not a whorl, then proceed directly.

Then comes the triangle area.

It's located just below the core area, in the triangular region formed by the horizontal creases of the finger joints.

Depending on the pattern, it will generally form one or two triangles.

When comparing fingerprints, first look at the pattern, then check how many triangles are in the pattern. If the number is incorrect, skip the comparison.

Once all of the above match up, then look for the feature points of the core area.

It matches the first one.

If you count eight from the inside out, then there's a good chance you'll match them.

The old adage "seven dead, eight alive" refers to this principle.

In daily comparison work, everyone counts the features one by one. Once they count eight, everyone is happy.

If there aren't enough cards, then move on to the next one.

However, the methods created by this expert within the system are not like that.

He partitioned the fingerprints, cutting them into fixed, standardized areas.

Then, different comparison rules are set for each area.

For example, the direction of the triangular opening and the number of inner lines.

Just like a coordinate system in mathematics, it allows for quantitative analysis of this area.

After confirming the key features, we then compare them with the fingerprint database.

At first glance, they seem to be not much different.

There's only one fingerprint. The traditional method is to look at it, while the systematic method is simply to look at it separately.

Moreover, what they were looking at was always the same: triangles, core areas.

So after looking at it for a while, Li Shu felt there was no difference, it felt like a pointless fart.

But as he read on, Li Shu realized that wasn't the case.

This system's approach differs significantly from the underlying logic of fingerprint comparison.

To give an analogy.

Traditional fingerprint matching is like trying to find someone by looking at a photo in a crowded park.

At first glance, all the women were overlooked.

Then look at the hairstyle and face shape, like a sieve, filtering through them round after round until you find your target.

The system's approach is also to look for people.

But I found a key detail in the photos I had.

For example, if someone has a mole on the corner of their mouth, then look at everyone's mouth and go directly to the person with the mole.

Once you've matched up, you can use other features, such as a large nose, to further distinguish them.

This means that by moving from a broad perspective to a specific point, the efficiency of the comparison has been improved.

However, as Li Shu continued reading, he understood why this criminal investigation expert had created this method.

It turns out that this method is not suitable for fingerprints that are relatively complete and have good matching conditions.

It only applies to incomplete, bloody, deformed, or blurred fingerprints.

According to the old professor who taught fingerprinting at the school, if you encounter this kind of fingerprint, just give up and there's no need to waste time on it.

They also said that only truly experienced experts are qualified to tackle such tough challenges.

Li Shu immediately understood.

In other words, this system's method is designed to extract local features from fingerprints with incomplete features in order to complete the comparison process.

Most importantly, it also relies on the AFIS system to some extent.

The comparison area and feature points are manually set on the system, instructing the system to perform targeted comparisons.

It's important to know that the current AFIS system, just like a person, uses fingerprints for comparison.

If it looks like it, then it is; if it doesn't, then it isn't.

It's just that the speed is faster thanks to the power of technology.

That's troublesome, Nanjiang doesn't have this thing.

It's like I spent all that time looking at it and it was all for nothing.

Fortunately, there are many "makeshift methods" to improve fingerprint comparison within the system.

For example, there are many fingerprint experts using methods such as the "feature point topology localization method" and the "feature point golden combination method".

There are also methods for encoding archives.

These methods seem to be developed by criminal investigation experts based on their experience over a long period of work.

Now everything is gathered in this system.

If I learn all of these techniques, I can definitely become the top fingerprint comparison expert in China.

Just as he was daydreaming, Tan Guoxiong changed into his police uniform and asked Li Shu if he had any more film rolls and if he could take a picture of himself so he could show it to his mother later.

Li Shu snapped out of his daze and quickly stood up: "I had forgotten about it if you hadn't mentioned it."

I just received my police uniform.

The Type 92 still retains the classic olive green color.

Li Shu quickly changed into a light green shirt. Although the weather was still hot, he still put on his spring and autumn casual clothes.

The two zigzags on the collar insignia are a bit eye-catching, but once the peaked cap is fastened, it all comes together perfectly.

"Is he handsome?"

Li Shu stood tall and proud.

Tan Guoxiong across from him gave him a thumbs up, snapped two photos, and then quickly handed the camera to Li Shu, asking Li Shu to take photos for him.

I only took two pictures, and this guy couldn't hide his grin anymore. He came over and asked if the pictures were good.

"Alright, let's go to a photo studio to take pictures after get off work. People are professionals."

After taking off his coat, Li Shu grabbed Tan Guoxiong and hurriedly returned to the team.

The partitioning comparison method may not be applicable to the current situation.

However, there are some methods that Li Shu wants to try to see if they can improve his work efficiency.

For example, there is a very basic method.

It's called the "Feature Point Rapid Location Method".

It can pick out a few key features from the target fingerprint, and use a pin to poke the corresponding points on a hard plastic board to make a simple homemade locator.

Then, during the comparison, we take this locator, place it on the file card, and quickly complete the location, focusing on the position of those key feature points.

Li Shu felt that this method was quite suitable for comparing the fingerprints of a complete target at present.

Most other methods focus on extremely difficult-to-access, blurry, and incomplete fingerprints.

I rushed to the team.

As always, everyone is busy with their own things.

Comparing hundreds of fingerprints a day is like a human machine, painstakingly grinding them out.

Sharpening the axe won't delay the work of chopping wood, so Li Shuxian devised a way to make this kind of positioning device.

It's not difficult.

Li Shu even used his own ingenuity to make some improvements, such as making a photo frame out of cardboard with a transparent plastic film sandwiched in the middle, and then directly placing it on the file card for comparison.

Once he got started, Li Shu quickly discovered the beauty of this method.

During the production process, Li Shu still had one question.

Even if you tap the spot, the fingerprint size will be different, so how do you determine the center point?

After trying it out, I realized that this method places more emphasis on the distance and positional relationship between feature points.

This allows for quick screening without the need to meticulously examine every single detail.

In this way, efficiency is more than doubled.

Because it's not just about finding the most prominent features, but also about determining the spatial relationships.

The feature points may match, but the positional relationship will definitely be correct.

That's why it's called a locator.

After the initial screening was completed, the system unexpectedly added 150 experience points.

It seems like Li Shuxue applied his knowledge to practice and received a one-time reward for mastering a fingerprint comparison method.

If you look at it this way, as long as you study more, master more methods, and practice more, it's not as difficult as you might imagine to master the skills.

Li Shu immediately became motivated and threw himself into his work.

Efficiency has been greatly improved.

Before long, the remaining files from the morning had been completely compared.

Li Shudu got up and went to the archives to get his fingerprint card.

A stack of 50 sheets can complete the screening in just over half an hour.

Zhao Yong noticed this speed.

Li Shuzheng was engrossed in comparing things when he suddenly looked up and almost bumped into Zhao Yong's chin.

He paid no attention, staring intently at Li Shu's homemade locator.

"Li Shu, what...what is this thing?"

Zhao Yong looked suspicious.