It is best to find a company with its own R&D team to understand. If you sell other people's products, others will tell you some basic knowledge of operation and technology, but the only way to learn cutting-edge technology is to be a training institution outside the school. For example, Hikvision, Dahua, Tiandi Ye Wei, Locke Wei Tuo and other companies with their own R&D teams will not disclose their technologies.