Chapter 8 Fingerprint Matching

The old desktop computer was creaking as it was running. Google Search Reading

The whirring hot air blew out of the chassis and dissipated into the air.

After a while, the right side of the LCD screen released 20 fingerprints with the highest matching values.

Jiang Yuan was not in a hurry. He drank a sip of tea and clicked on the first fingerprint to look at it.

In the past two days, the criminal police team, which had been running at full power because of Uncle Seventeen's murder case, suddenly relaxed, and Jiang Yuan also returned to the daily state of forensic medicine - it seemed that there was nothing to do.

At the same time, he gradually became proficient in the use of the "Chongqing-style single-finger fingerprint analysis method - bow pattern identification (lv3)" that he had just received as a system reward.

After practicing with the exercise books from his school days and public information, Jiang Yuan decided to enter the actual combat: first find a bow pattern, and then find out who it belongs to.

As the first step, Jiang Yuan chose the fingerprints collected from a robbery case in Longli County, a neighboring city.

The reason why fingerprints of murder cases are not selected is that under the guidance of "murder cases must be solved", murder cases are highly valued and have a lot of resources. Before becoming a backlog case, fingerprints are repeatedly compared. The fingerprints of murder cases that are still retained in the fingerprint database must be extremely difficult.

If there is an unsolved murder case in Longli County and the fingerprint of the suspected suspect is extracted, then this fingerprint will first be compared many times by the trace inspection personnel of Longli County. If the comparison fails, it will be necessary to go to the scene many times to try to extract it again. If all attempts are unsuccessful, the city-level criminal science and technology squadron will definitely be asked for help, or it is possible to find the provincial department directly.

If the fingerprint still fails to match at the provincial department level and the case is not solved, then every one or two years, the provincial department or even the ministry will organize a special fingerprint battle to compare the fingerprints involved in major backlog cases. The participants are often experts from the criminal technology talent pool or youth talent pool of the provincial department or ministry.

Jiang Yuan had already eaten LV3 egg fried rice, so he didn't expect much from the LV3 bow pattern identification.

Egg fried rice is delicious, but it doesn't glow yet.

It can be inferred that the LV3 bow pattern identification is very powerful, but not superb.

Not to mention, the fingerprint database he can compare is limited now. Jiang Yuan feels too easily frustrated when he challenges a murder case with his first fingerprint.

In contrast, robbery cases are more suitable for the present.

On the one hand, ordinary robbery cases cannot reach the level of major cases in the provincial department. On the other hand, robbery cases are highly valued in the county bureau, which determines that the police officers must have been serious enough when extracting fingerprints. The fingerprints uploaded to the database are highly related to the case.

Having said that, Jiang Yuan was also quite surprised when he first opened the fingerprint image of the case.

I don't know under what circumstances the fingerprints extracted are blurred or incomplete, only about half of the normal fingerprints. Fortunately, more of the fingertips are retained, which provides a basis for comparison.

In addition, it goes without saying that the fingerprints are deformed.

This situation is completely different from the fingerprints left by ordinary people when they clock in for work. Without any professional skills, it is difficult to mark the feature points, and it is difficult to determine which finger it is.

The 20 fingerprints automatically matched by the system were not matched as expected.

Jiang Yuan was not discouraged. This kind of fingerprint was uploaded to the system because it was difficult for the local trace inspection to match. As for the failure to match locally, it may be a technical problem, or it may be that the corresponding fingerprint was not collected in the fingerprint database.

If it is the latter, Jiang Yuan has no choice but to hope that the fingerprint database of this bureau is larger... and he is now fighting for the former.

For the trace inspection police who do fingerprint matching, hard work is a must. Only by working hard can they have a chance to try their luck.

Jiang Yuan closed the fingerprint matching page and reopened the suspect's fingerprint image, this time using Photoshop.

He carefully observed the state of the incomplete fingerprint, and then began to adjust the contrast and brightness.

Jiang Yuan made extremely detailed adjustments, so that it took half an hour to slightly improve the clarity of the fingerprint image.

However, sharpening the knife does not delay the chopping of wood. After Jiang Yuan waited for everything to be ready, he carefully examined the fingerprint image and saw the direction of the lines more clearly.

Then, Jiang Yuan slightly adjusted the center point of the fingerprint.

Because the fingerprint was severely incomplete, the center point itself was uncertain. If Jiang Yuan did not make any adjustments, the system would automatically estimate a center point.

Jiang Yuan watched the direction of the lines, repositioned the center point, then put it back into the software, changed the conditions, and pressed OK again.

Another 20 fingerprints failed to match.

Fine-tune the center point again, and compare again...

This time, Jiang Yuan picked the third-ranked fingerprint at a glance.

When ordinary people look at fingerprints, they think they are similar at first glance, especially when they are bow-shaped or bucket-shaped patterns, they often have to be distinguished very hard.

But for people who have been looking at fingerprints, different fingerprint features are like freckles on the face of an old sow. After looking for a long time, they will feel familiar.

Jiang Yuan directly clicked on the third fingerprint, enlarged it and placed it on the right side of the computer screen, then opened the original fingerprint and placed it on the left side of the screen.

When the two fingerprints were placed together, the similarities were immediately apparent.

At this time, it is not just a matter of looking at the feature points, but directly looking at the similarity of the fingerprints to make a judgment. In a one-on-one situation, the human eye's ability to distinguish is much stronger than that of a computer.

"It matches!" Jiang Yuan muttered to himself, and was also relaxed for a while, and submitted the matching fingerprint.

According to the rules, the fingerprints he submitted will be submitted to the experts of the provincial department. After the latter reviews and confirms that they are correct, they click submit, and someone will notify the corresponding front-line units, and then the local authorities will arrange the arrest.

Of course, it is no problem for the local criminal police team to arrest people.

Jiang Yuan didn't care so much, stretched his waist, got up to stretch his muscles, looked at the time, and waited for the end of get off work with peace of mind.

The life of a forensic doctor without a corpse is simple and pure.