"Just around nine o'clock last night, Wang forced himself to have sex with the then 16-year-old victim Xiao Yao in a classroom on the east side of the sixth floor of a teaching building of a foreign language school in Changping District. Later, because he was afraid that Xiao Yao would report him, he strangled him They pressed Xiao Yao's neck, causing him to die of mechanical asphyxiation, and took away Xiao Yao's mobile phone."
This is a major criminal case that many people from the Changping District Public Security Bureau are currently involved in.
In the early hours of today, Xiao Yao's mother received a call from the school teacher, saying that during the bed check, she found that Xiao Yao had gone out with her boyfriend and was not in the dormitory.
The school will severely punish this matter, so we called the parents to discuss it.
Xiao Yao's mother was very angry at first, but soon began to feel uneasy.
Firstly, because he could never get through his daughter's phone, and secondly, he began to feel that something was wrong. His daughter wanted to study abroad and she usually focused on her studies.
She was far away from home and going to a boarding school to learn English. How could she have time to talk to friends at this time?
I was still chatting with my daughter during dinner, but my daughter stopped replying halfway through the conversation.
The uneasiness in her heart became more and more intense, and Xiao Yao's mother, Li, decided to drive from her hometown to Yanjing overnight.
During the journey, Li kept trying to contact the school, hoping that they could help find Xiao Yao.
But unfortunately, the final reply to Li this morning was the news of her daughter's death.
Xiao Yao's body was found around 6 o'clock on Thursday morning in Classroom 601 of the New Oriental Teaching Building.
The first person to discover Xiao Yao was his classmate Liu. Liu said that at that time, Xiao Yao's head was facing north and his feet were facing south, with his head covered by the school uniform.
After that, four students came to the door of Classroom 601 one after another. At first, everyone thought she was sleeping and asked those coming behind to keep their voices down so as not to wake her up.
They didn't know that Xiao Yao would never wake up again.
The perpetrator of the crime, Wang, was an ordinary student, and the murder was not planned for a long time. After the incident, only Wang among the students in the school was missing, so the police quickly identified him as the number one suspect.
"Many classmates have provided testimony and evidence. Wang has been pestering Xiao Yao repeatedly in the past few months. We have also found enough evidence in the surveillance video last night."
By the time Wang Kai was waiting outside, the police had all the witnesses and evidence, and they were just short of arresting him.
"This is not a difficult case. In terms of difficulty in solving it, it is in the very easy category." Director Tian took over and said, "The police were called within ten hours of the incident. We soon had enough The evidence has identified the number one suspect, and it is only a matter of time before the murderer is caught.”
"The faster we move, the shorter the distance the murderer can escape, and the fewer things we need to investigate, so I'm afraid it's not convenient to share your new technology today." Director Tian said as if he was seeing off the guests. .
"Our current task is to focus on the school and find Wang's traces through on-site visits and surveillance videos, and then arrest him in the shortest possible time."
Director Tian took this case very seriously. The impact of committing a crime on campus where middle school students and teachers usually attend class and work is completely different from that of committing a crime in the wilderness.
The most important thing is that it will make people feel insecure, so the murderer must be caught in the shortest possible time to calm public opinion.
Of course, on the other hand, Director Tian will be re-elected in two years, and he still hopes that he can go to the Municipal Public Security Bureau in 2015.
At present, public opinion has begun to ferment rapidly, and he must handle this matter no matter what.
As for new technologies and the like, although they are political achievements, let’s wait and see.
"Director Tian, are there many surveillance videos that we need to investigate?" At this moment, Wang Kai had already forgotten the unpleasantness he had been waiting for. He vaguely felt that this might be a good opportunity.
Although Baidu currently does not have the ability to add target tracking functions based on Meng Fanqi's technology, let alone achieve the multi-target vehicle tracking required by the government.
But it would be easy to add a function to Meng Fanqi's code that would issue a warning when a specified type of target (such as a human) appears.
For example, as long as a human is detected in the picture, some brightness changes will be made to the frame.
Dozens of monitoring screens, which are usually dark, will light up when a person is detected, which can greatly save manpower.
This is especially true in terms of security. If a criminal case of this nature occurs, the police often need to thoroughly investigate surrounding cameras, and time is often extremely tight.
Due to the tight time limit, high pressure, and bad nature of the incident, it is often inconvenient to fast forward and jump frequently when investigating and monitoring.
It would be a grave sin to miss a fleeting clue.
Wang Kai wants to directly apply Meng Fanqi's real-time detection technology to help investigate this case.
"From the time of the crime to now, each camera has about fifteen hours of content that needs to be checked. At present, there are at least close to a hundred surveillance videos related to the case that need to be checked. If you are unlucky, More is needed.”
Director Tian also had a headache. Even if he went to investigate at three times the speed, one person could only investigate a part of the surveillance video in five hours.
It may take twenty or thirty people a whole day to thoroughly check all these contents.
Of course, this is the worst case of luck. Once traces of the suspect are found, the time and place to be investigated can be determined, and the remaining workload can be reduced exponentially.
It's just that you are not always so lucky. You often check out 50 or 60% of the surveillance videos before initially discovering the suspect's traces.
If calculated as half, it would take twenty or thirty people to investigate until late tonight to initially discover the suspect.
"Director Tian, our technology can greatly speed up your investigation efficiency." After listening to Director Tian's words, Wang Kai felt that this was an excellent opportunity.
People can only watch videos at low magnification, but machines are different. As long as the computing speed is fast enough, the machine can observe the video at a hundred times and a thousand times without missing a single frame.
Now the whiteness-accelerated version of the lightweight YOLO real-time detection algorithm can achieve a detection speed of more than 300 FPS on lower resolution or single-channel videos.
The number of frames of surveillance video is often only 20-30, which means that a single graphics card can achieve ten times the speed of viewing.
Moreover, Baidu has more than twenty or thirty graphics cards.
In order to give the government a good impression, it was easy for Baidu to use a thousand graphics cards to do this.
Each video is broken down into ten parts, each of which is less than two hours long. If you analyze it with a single card, it only takes more than ten minutes to mark out all the clips in which people appear.
The results that might have required the entire team to investigate from noon to early morning could be obtained in just ten minutes.
Including mobile data, fine-tuning the code, and testing time, it will not exceed an hour and a half at most.
In the early hours of the morning, there won’t be many clips of people flashing through the video.
The police's investigation based on these key fragments requires less than one percent of the original energy.
