How to choose the face recognition camera module?

With the increasing popularity of the mature intelligent hardware of the face recognition algorithm, its product types are also more diversified to adapt to more demand scenarios. Channel gate, bank monitoring, industrial medical, institutional Windows, smart cities, face recognition camera modules are not only different in application price and interface, but also monocular and binocular differentiation, horizontal screen, vertical screen. So how should end customers choose the face recognition camera module?

The following is analyzed by the old beam who has more than 10 years of experience in the industry engineering platform micro-image of the camera module.

How to choose a face recognition camera

The first is the hardware confirmation of the equipment, the general channel gate, the panel machine, the building intelligence and other motherboard equipment is mostly based on Rui core micro, low cost, mature program, determine the choice of the motherboard model, to see whether the connection interface is MIPI interface or USB interface, face recognition on the market is mainly these two kinds of camera interface, but due to the price cost problem, More and more integrated manufacturers choose MIPI camera, another reason is the data transmission bandwidth problem, but also an important reason to choose MIPI camera.

The author interviewed that Shenzhen micro image do face recognition camera module and MIPI camera module has more than 15 years of experience in the old beam, he has a face camera recognition algorithm, product matching selection, wide dynamic scene testing, production process has very sufficient experience, they launched a lot of low-cost binocular camera module according to customer needs, Caused a great response in the market, through the side to learn that other camera module manufacturers have said that the price of 10% of the gross profit, they can not do.

Why can the price be very low compared with peers? Lao Liang finally said why:

The long-term accumulation of supplier resources, the lens characteristics of hundreds of different sizes of lens manufacturers in Shenzhen, the characteristics of all the main control schemes in the market, sensor manufacturers are very familiar with, which lays a solid foundation for better hardware selection, can be customized for customers with low cost prices and the best results of the material.

Rapid feedback customer order demand, most of the materials are in stock, to meet the customer's small batch shipment needs, because many customers several times are hundreds, thousands of orders, and some customers even dozens of orders have, so in response to this situation, in the material preparation to achieve batch procurement, batch patch, scattered order countermeasures, making the cost is much lower than scattered procurement.

Product standardization management and production are equally important, responsible for each product, each process, strict control of quality, reduce after-sales costs, Lao Liang said that because many customers received the camera module will not be tested twice, it may also be the condition of the reason, if the product is installed to the customer's side of the machine, the test is not good, for the customer to remove and replace. Not only waste a lot of customer labor time, but also some machine screen is not easy to remove resulting in high scrap rate.

Long-term experience accumulated in the camera module technology, face recognition multiple indoor and outdoor environment application problems, have their own understanding, CRA matching, backlight, downlight, side light, skin color, depth of field, focal length, shooting distance to the Angle of light adaptation, etc., have a unique solution experience.

They can be customized for customers, together with customers to explore the feasibility of custom programs, for customers to solve problems together attitude is worth our serious learning, face recognition camera is mainly RGB camera +IR infrared camera + infrared light board form, with the algorithm can quickly complete the acquisition, high-quality images sent to the back end for identification and comparison, Applicable to face recognition, face defense, accurate promotion, passenger flow statistics, access control management and other application scenarios.

The binocular wide dynamic camera module has better defense capability against false face attack than monocular. Based on the infrared imaging principle and the high robustness of deep learning algorithm, it has excellent defense against paper photos and screen photos.

At present, some customers do false binocular (that is, monocular) through the algorithm can also do face recognition, but due to hardware differences, binocular living detection compared to monocular RGB living costs are relatively increased.

In general, the monocular face recognition solution is easy to deploy and low cost; The binocular face recognition scheme has higher accuracy in living detection, and is more adaptable to factors such as light changes and complex background environment, which can support true unattended. Therefore, in the selection process, specific considerations should be made according to the actual application scenario, the live effect you want to achieve, and the final cost, to balance the needs of all parties, and cannot be generalized.

Face camera imaging core components and key parameters

The working principle of the camera is to convert the light signal into an image signal, so the complex light environment such as strong light, backlight, and dark light will directly affect the image quality of the camera. The quality of the camera imaging will also directly affect the effect and experience of face recognition and living detection. Therefore, when making product selection, developers should also pay attention to the core components and key parameters of the camera imaging to ensure that the quality of the image collected by the front-end meets the requirements of face recognition.

In the three core components of the face recognition camera module, lens, image sensor and DSP image processor, the lens mainly assumes the task of capturing the object and focusing the shot image on the image sensor, and its main parameters are field of view Angle, aperture, CRA, distortion, glare and so on. The face recognition camera module generally adopts a fixed focus lens with fast focusing speed, stable imaging quality and accurate metering.

For the image sensor which is responsible for converting optical signal into digital signal output, its main parameters include sensor size, effective pixel, pixel element size, etc., CMOS sensor with high integration, low power consumption, fast speed and low cost is recommended. Finally, the digital image signal is optimized and transmitted to the face recognition device DSP image processor, high-quality DSP can improve the original chip wide dynamic range by more than 30%.

In order to further facilitate developers, Taiwan Micro image launched the integration of dynamic scene, backlight scene, highlight scene and up to 6 scenes of the "multi-scene mode", the multiple scene modes are compatible with a camera, through the camera to automatically judge the light environment in the scene, and then call the corresponding mode, in order to achieve the best face recognition effect in a particular scene.

Test the basic function and reliability of the product

In order to ensure that the product can be used smoothly after mass production, production testing is a very important link. Pre-production reliability testing and routine testing of mass production process: For the face recognition camera module, its basic performance test includes the analytical force test in the normal shooting test environment, the screen test, the line test, the color test and the dark corner test in the whiteboard test environment, the dirt test, the bad spot test, the infrared light test, and the reliability test such as the power aging test, the plug test, and the vibration test.

Among them, the resolution power refers to the clarity that the camera module can achieve and the detail expression ability of the image. A more intuitive evaluation method is to visually identify the black and white line pairs in the figure by shooting the ISO chart test, and human eyes can identify the limit line values of the black and white line pairs. In the same environment, it is also necessary to check the image for abnormalities such as flower screen, lines, and color bias. In the whiteboard test environment, the dark Angle is usually checked to detect the brightness uniformity of the module, detect whether there is dirt abnormal in the lens, and detect whether the chip has bright spots and bad spots abnormal.

Therefore, it is very necessary to choose a manufacturer specializing in the production of camera modules similar to the image table microimaging to improve product quality and shorten the product landing cycle.