Chapter 66 Matching Successful
In fingerprint identification analysis, collecting fingerprints is only the first step.
is the basis for all subsequent work.
It is like building a building. If the foundation is not laid in place, the building will not be high.
It's like going to some KTVs with diversified services to sing. There is a difference between the service of 800 yuan and the singing girl of 1,000 yuan.
It’s not that the more money you have, the less you wear. On the contrary, the more money you have, the more clothes you may wear.
Lu Chuan’s basic work is completed, and the rest is getting down to business.
Intermediate fingerprint collection skills make Lu Chuan competent for most fingerprint collection needs.
Next, it’s time to show off your intermediate fingerprint identification and analysis skills.
Although he was physically exhausted after staying up all night, Lu Chuan was in a relatively excited state mentally.
Although the process of collecting fingerprints is complicated and boring.
But the more difficult the fingerprint collection is, the greater the sense of accomplishment will be after success.
In front of the computer, Lu Chuan stared at the screen with red eyes.
Lu Chuan still uses the image processing software that comes with the fingerprint comparison system.
The first thing he started with was the fingerprints collected from the picture frame that Yang Sen and Lao Bai failed to compare yesterday.
Compared with the two or three hours it took Lao Bai and Lao Bai to process a fingerprint, Lu Chuan's processing speed was much faster.
The enlarged fingerprint is like a line drawing, with curved and twisted lines and irregular distribution on the screen.
The preprocessing Lu Chuan needs to do now is to restore the fingerprints that have been severely deformed due to force and friction to their normal form.
And find feature comparison points based on experience.
At this moment, Liu Guodong, Yang Sen and Lao Bai were all watching quietly behind Lu Chuan.
"Last time, I remember Xiao Lu said that he has research on fingerprint collection, but he is average about fingerprint identification..."
But when Lao Bai saw the speed at which Lu Chuan operated the software to process fingerprint images, it was obviously not ordinary. look.
Liu Guodong also frowned as he watched Lu Chuan preprocess the fingerprints.
Among the three, he has the highest level. Lu Chuan has been studying with him after going to work.
Including the previous few fingerprint identifications, Liu Guodong also taught Lu Chuan some techniques and methods.
Therefore, Liu Guodong knew Lu Chuan's fingerprint identification skills.
I have mastered some skills and have relatively solid theoretical knowledge, but I lack experience and exercise.
But it had only been a few days, and Liu Guodong felt that he couldn't understand Lu Chuan's operations on the computer.
A fingerprint photo is constantly zooming in and out, and each feature point is marked, then canceled and marked again.
Liu Guodong felt quite dazzled when he saw it.
call!
Lu Chuan breathed a sigh of relief and finally got a fingerprint. The intermediate fingerprint identification and analysis skills not only gave him many skills that he had not been exposed to before.
There is also rich experience, and the direct benefit is that the speed of identification and analysis is greatly improved.
"Put it in the system and run aside first."
Lu Chuan said to himself, directly entering the fingerprints he had just processed into the fingerprint comparison system.
After stretching, Lu Chuan stood up and almost fell down due to fright.
"Master, why are you here?"
Facing the three big heads, Lu Chuan looked confused.
Ahem.
Liu Guodong coughed twice: "I just saw you processing fingerprints. Let's come over and take a look."
"Yes, come and take a look."
"We just came here too."
Yang Sen and Lao Bai's postures in cooperation with Liu Guodong were very standard.
"Xiao Lu, what you just dealt with were the fingerprints extracted from yesterday's picture frame, right?"
Lao Bai was very impressed by the few fingerprints yesterday, and stared at two or three of them. When he was young, he recognized at a glance that Lu Chuan was dealing with the same fingerprint he had fought with yesterday.
However, the result is obviously because Lao Bai's skills are not good, and the fingerprints produced are not satisfactory at all.
Lu Chuan nodded and rubbed his eyes: "This fingerprint is quite severely deformed and has some scratches, but fortunately there are not many breakpoints, so it is relatively simple to handle and relatively easy to handle."
Easy?
Easy to do?
Lao Bai swallowed his throat. He didn't think this fingerprint was simple and easy to get yesterday.
The preprocessing of deformed fingerprints has always been a difficult problem. It is a level that tests the strength of the criminal police involved in trace inspection.
Lao Bai and Yang Sen are at the bottom of the criminal police food chain.
Much better than the new college students, rich in experience, and have many unique methods.
Some fingerprints that are not too severely deformed can be compared successfully.
Far better than the technical staff of the county-level criminal police brigade.
In the eyes of the people below, Lao Bai and Yang Sen are already the technical masters that normal criminal police can come into contact with, reaching the ceiling level.
But when I encountered the scratched and severely deformed fingerprints extracted from the picture frame yesterday, there was nothing I could do.
Just like chasing women, the levels that Lao Bai and Yang Sen can handle are limited.
Liu Guodong's strength is even stronger.
When dealing with some complex fingerprint identifications, such as severely deformed fingerprints, the probability of successful comparison is much higher than that of Lao Bai and Yang Sen.
Among more than a dozen criminal investigation detachments across the province, he is at the level of a normal technical leader.
It can meet the needs of on-the-spot investigation and trace inspection of major cases that are generally not too complex.
But compared with the experts from the provincial department, there are many gaps.
Just met the requirements to participate in the fingerprint battle at the provincial and department level, the kind at the bottom.
Now, Lu Chuan was doing fingerprint identification and analysis, which made Liu Guodong feel like he was watching senior experts from the provincial department doing fingerprint identification.
Know what you are doing, but don’t quite know.
It’s like... it’s gone in, but it’s not long enough and it’s not completely gone in.
If I could describe it in one sentence, it would be unclear.
Ding!
Just as I was thinking about it, a distinctive beep came from the computer speaker.
Liu Guodong and the other two people who work with the fingerprint comparison system basically every day are all too familiar with this voice.
"Successful?"
A surprised expression flashed across Lao Bai's face and he threw himself at the screen.
“Comparison successful!”
The fingerprint comparison system used by the Haeju Criminal Investigation Detachment was built from the first generation system.
System upgrades are basically done every year.
So far, the system basically has three modes for fingerprint comparison.
First, the comparison failed.
Commonly known as fool mode.
After the fingerprints are pre-processed, the system will compare the features of all fingerprints in the database based on the previously marked feature points.
This has relatively low requirements for fingerprint identification.
Because only one feature point needs to be determined, as long as this feature point is different from the same feature points of other fingerprints, the failure can be determined.
The comparison is completed.
However, there is a problem with such comparison, that is, when preprocessing fingerprints, the selection of feature points must be standard.
Only by selecting standards can the comparison be successful.
If the selected location is not standard, it will definitely fail.
This is why Lao Bai and Yang Sen failed in their comparison last night.
When they preprocessed the fingerprints, they failed because there was a problem with the selected feature points.
The second mode is similarity comparison.
This is also the most commonly used identification analysis method. The system will fully match the fingerprints in the database based on the characteristic points marked by the fingerprints.
Then a ranking is given based on the similarity of the feature points.
Of course, this does not mean that the one ranked first is definitely the successful target.
It is also necessary to manually confirm the two fingerprints. If obviously different feature points can be found, the comparison will fail.
The advantage of this mode is that the system will give you dozens or even hundreds of similar fingerprints.
It is very likely that there is a target fingerprint here, but it needs to be checked manually.
The last one is the fingerprint comparison method chosen by Lu Chuan.
(End of this chapter)