What is the difference between EIS electronic anti shake and OIS optical anti shake?

When you read the pictures in the photo album of the smart machine, you often see some photos or videos that have been pasted. The problem is that even a smart phone with a price of 1000 yuan can now use a high-end sonyIMX586 sensor with 48 million pixels. Why is it still impossible to ensure that every photo and video is extremely clear?

The reason why the film is burnt

First of all, we must establish an awareness that even professional shooters can't help but shake a little under the direct influence of heart rate, and can reduce the shaking force of hands at the moment of shooting with a gun to what level, which will affect the final shooting test results.

The trained professionals are still like this. As ordinary people, the moment you take a photo on your mobile phone certainly cannot solve the danger of shaking hands.

Generally speaking, as long as the natural environment light source is sufficient and good, you can take a clear picture with a little steady hand.

As we all know, the golden time for taking pictures has been fleeting. For example, it is difficult to control the shaking of hands when taking pictures, and it is also the most easily "filmed" scene. In addition, when the light source is not enough (such as at night or in low light situations), the slow shutter speed of the SLR will double the danger of shaking hands.

When the lens focal length is lengthened (such as entering the 2X, 5X, 10X focusing mode), a little bit of jitter will cause a sharp change in the far end, and it is very easy to lose the overall goal of focusing in addition to pasting.

If you often shake your hands when taking photos, it will be more difficult to control the shaking of the picture when taking photos, especially when tracking the dynamic scene of the photo. Viewing the video that sways from side to side not only seriously affects the perception, but also continues to cause dizziness and other health problems after watching it for a long time. In order to minimize the harm of photo blurring or video screen shaking caused by hand shaking, "anti shake technicality" has become a professional skill that every intelligent aircraft must master, otherwise, it will not be qualified to be awarded the real identity of "new product".

CFan has introduced anti shake technology related to photography in detail in the past. In this article, we will mainly introduce the basic principle and practical significance of anti shake technology when taking photos.

A totally free EIS meal

Everybody, do you still remember the "super definition technicality"? According to the optimization algorithm of mobile phone software, the 16 million definition camera can take 64 million pixel pictures. That is to say, software engineers can take higher definition photos on mobile phones according to the code. Can we use the code to end the period of "anti shake key depends on feeling"?

The answer, of course, is unquestionable. Many years ago, the smart phone industry became fashionable in the anti shake technology of electronic devices called "EIS", which is also an anti shake ability based on coding, that is, mobile phone software optimization algorithm.

Its mechanism is to dynamically adjust the ISO, fast gate and 3D imaging optimization algorithm to make ambiguous adjustments by using the "G-sensor" and mobile phone gyroscope (most new mobile phones have it) control module, which are essential for each smart phone, to detect the frequency of tremor on the mobile phone, The anti shake technology of electronic devices can now perfectly ensure that the photos are not pasted - the "handheld extraordinary city night scene" applicable to many new mobile phones, that is, the city night scene photos with brighter and more critical points can be taken without tripods, is a final evolution of the anti shake technology of electronic devices.

With the popularity of Tiktok short videos and other apps, short video photography has long become the next "ignition point" of smart machines, and the anti shake technology of electronic devices is slowly contributing to video photography. However, taking a picture is different from taking a picture. In order to apply anti shake to electronic devices, the first one must be based on giving up some interfaces. You can open the camera app on your mobile phone. When you switch from "taking a picture" to "recording", is the scene taking interface of the latter one "larger"?

For video photography in the anti shake mode of electronic devices, only the interface located at the core of the viewfinder is considered reasonable content, and the interface at the edge is automatically "cut" (the same is true when taking photos, and only the interface with cutting damage accounts for a smaller proportion).

It must be noted that the cut scene content has not been "discarded". The camera APP will compensate for the camera shake in the opposite direction based on the gesture data information recorded on the mobile phone gyroscope, and the cut scene content is the material content used for compensation.

That is to say, the major problem of anti shake of electronic devices is interface clipping. Only today, when high-definition ultra wide-angle lenses are becoming more popular and AI optimization algorithms are more excellent, it has been able to save more screen content. In addition to video content that is relatively stable in photography, it is also suitable for ultra-high definition video recording with higher pixel and frame rate.

However, this kind of technology is still unable to deal with the deformation problem caused by relatively large jitters after the interface is stretched. After all, it belongs to the role that can be completed according to a piece of coding. This kind of "zero hardware configuration cost" solution must have limitations.

So, how can we take more stable video content?

Anti shake of PTZ camera

From the Stanikon system software, photographers all over the world are looking for faster anti shake technology and lighter control service platform, and the generation of handheld PTZ has become one of the most satisfactory solutions, which can help all fixed video camera equipment such as smart machines, digital cameras and motion cameras to obtain nearly extreme anti shake characteristics.

In simple terms, most handheld PTZ are embedded with multi axis (widely three axis) mobile phone gyroscopes and multi axis acceleration sensors, as well as X, Y, Z radial motors. Under the control of the embedded optimization algorithm, the hand-held PTZ can push the motor amplitude derived from the rotation of the mobile phone according to the weight of the mobile phone, and use the inductor to continuously check the vibration or rotation generated by a part of the rocker, and then compensate for the harm caused to the video recording interface by the vibration of a part of the rocker according to the rotation of the motor in the opposite direction.

Unfortunately, the handheld PTZ belongs to an external device with a large body size, which is inconvenient to carry or install on a fixed mobile phone. As the saying goes, "tempering needs to be hard", why can't a smart machine be born with a "Buff" with a built-in PTZ camera?

Attraction from OIS

Just like focusing technology has digital technology (electronic devices) focusing and optical zoom, the anti shake technology field also has the difference between EIS electronic device anti shake and "OIS" electronic optical anti shake. When the camera on the mobile phone and OIS are technically married, whether taking pictures or video recording can more than offset the harm from shaking hands, making the photos and videos taken more extreme.

If we say that the actual effect of EIS electronic device anti shake is the "innovation ability" derived from coding, then OIS electronic optical anti shake is the "hard indicator" of hard and soft integration.

As we all know, every picture of an intelligent machine is composed of many parts, such as circuit board, CMOS sensor, support frame, glasses, focus, etc.

In order to obtain OIS electronic optical anti shake effect, micro motors that can move in several directions must be modified in the internal structure of the picture. When people use the camera APP to take photos/record videos, the system software can convert the instant jitter information detected by the mobile phone gyroscope and acceleration sensor into electronic signals. The OIS control controller will predict the image offset caused by the skew based on this data, and then report the results to the motor, so that it can promote the sensor to move by predicting and analyzing the image offset with the same size but relative angle offset, Then offset the image offset caused by shaking.

There is no mistake. We can think of the pictures applicable to OIS as camera modules embedded with pan tilt cameras. Because micro motors and corresponding control loops occupy a lot of indoor space, the specifications of such OIS pictures are one circle larger than those of traditional sensors but incompatible with OIS.

IPhone 11 Pro picture module, wide angle lens and telephoto are applicable to OIS, and the specification is significantly expanded

It must be noted that OIS images are all available, but there may still be differences in the electro-optical anti shake function of everyone, and the key elements that endanger their anti shake ability include the following aspects.

"Multi axis" war: to what direction can the embedded motor offset, and the two axes can offset X and Y vibrations in opposite directions; The three axes can offset the X, Y and Z azimuths; The four axes can adjust the vibration in eight directions, namely, horizontal, vertical, forward extension and roll; The five axes can offset the horizontal offset, vertical offset, left and right swing, sway and Z axis rotation. The larger the axis applicable to the electronic optical anti shake, it means that the telecom version mobile phone can offset a large number of azimuth jitters.

Inductor characteristics: There are also many levels of acceleration sensor and gyroscope sensor embedded in the smart machine, such as sensitivity and output power. The higher the frequency, the more dexterous the sensor, which can collect more accurate flutter information content, thus allowing the motor to complete more accurate offset repair.

The mobile phone gyroscope on the mobile phone is all stored in the shape of the processing chip

Electronic optical anti shake optimization algorithm: the optimization algorithm between hardware and software is harmonious. Generally, only the camera APP built in the official website can guarantee the anti shake feeling. After the third-party APP has obtained the management authority for taking pictures or video recording, it is very likely that the OIS motor control module cannot be further enabled.

During the period when mobile phones were used for taking pictures, OIS technology was applicable to the "main camera" of the flagship machine; With more and more customers gradually caring about focusing and taking photos, many flagship mobile phones gradually tend to shift the OIS technology from main photography to "telephoto lens" images; In today's increasingly popular video, OIS technology has a development trend of returning to the main camera from the long focus, and very few products will continue to use the more high-end "dual OIS" drainage matrix, that is, both the main camera and the long focus are suitable for OIS. The high-end means Apple iPhone 11, and the mid-range means the honor V30 PRO is dominant.

Joint operation is the development trend

With the popularization of new sensors and SoCs with stronger AI characteristics, there is a view in the industry that the anti shake technology of EIS electronic devices is sufficient, and hard OIS is actually a consumption. In fact, this is also a very evasive attitude. Saying that the OIS motor will significantly increase the volume of the camera control module, causing the cell phone camera to thicken, is a perfunctory thing. The source of OIS not widely used or comes from a higher cost - only primary and secondary school students can choose between OIS and EIS. Real users will definitely say "I want everything"!

The reason is very simple. If the video is out of focus, it is not enough to rely only on the anti shake of EIS electronic devices. In the video recording process of roller coaster riding, cycling, galloping, etc., which is likely to have a large amplitude of jitter, OIS electronic optical anti jitter can not guarantee perfection. Therefore, the "HIS" mixed anti shake of EIS OIS integration in the mobile terminal industry will become the future development trend.

HIS hybrid anti shake introduces the technology of multi-source sensor information fusion and anti shake scenario data analysis system, and increases the number of mobile phone gyroscopes from the traditional 400Hz to 800Hz, which can more dexterously sense the motion state on the mobile phone, thus completing the unusual anti shake in video photography.