How to take photos with a mobile phone? OPPO may have found the right direction.

In June 2000, 165438+ 10, Sharp launched J-SH04 in Japan. Although the appearance of this model was not beautiful even at that time, and its performance was nothing compared with that of Nokia 9 1 10 at that time, it remained in history forever with an extremely important technological innovation.

Because it is the first mobile phone with camera function in the world.

Looking back at history, it is not difficult to find that since the mobile phone joined the camera, the major manufacturers have basically gone through three stages on the issue of "how to make mobile phones take pictures better". That is, the earliest stage of crazy superstition of pixels, the later stage of algorithm and AI supremacy, and now the stage of returning to hardware exploration and attaching importance to outsole and high-quality lens.

To tell the truth, in fact, we can't blame the manufacturers for the detours in the image design of mobile phones in the past. After all, every era has its objective technical conditions at that time. But the question is, for today's top camera phones, when the customized CMOS is close to 1 inch, when the AI algorithm has almost stretched the capabilities of ISP to the limit, and when the color format of 10bit or even 12bit beyond the capabilities of civilian display devices is used in the image system of mobile phones, what other methods can bring great breakthroughs to the image performance of mobile phones?

On the afternoon of 20021August 19, OPPO announced their latest batch of imaging technologies that will be put into mass production with a "future imaging technology conference" of only 19 minutes. Except for the new generation of off-screen camera solutions that we reported and analyzed before, the other three technologies are all made public for the first time.

What's more interesting is that after carefully tasting OPPO's three new imaging technologies, we found that the R&D direction revealed by OPPO from these technologies probably represents the next stage of smartphone image development, which is more pragmatic and more familiar to photographers.

First, OPPO announced their brand-new sensor pixel design.

First of all, let's start with the new CMOS sensor from OPPO. As we all know, for today's smart phones, the development of "extra large bottom" has basically reached the bottleneck, because a larger sensor area will inevitably increase the flange distance, which leads to the need for thicker practical lens modules, more convex camera modules and thicker body. However, if the area of CMOS sensor is not increased, it will be difficult to improve the light sensitivity of a single pixel on the physical level.

So is there any new way to increase the photosensitive capacity without increasing the CMOS area? The answer is yes. That is to say, the pixel layout of the sensor is modified, and W white pixels that do not perceive color but only perceive light intensity are "stuffed" into the gap of traditional RGGB pixels, which becomes RGBW structure, which can greatly enhance the photosensitive ability of CMOS.

Of course, adding W white pixels is not without cost. On the one hand, it will reduce the number of pixels that CMOS actually participates in RGB imaging, which means that the RGBW sensor itself must be large enough to have enough pixels to maintain the resolution. On the other hand, the traditional CMOS sensor is a group of RGGB four pixels, but after adding white pixels, the four adjacent pixels will not contain RGB primary colors at the same time, which will affect the imaging quality and even produce pseudo color and Moire fringes.

In order to solve these problems, on the one hand, OPPO has adopted the design of "hardware four pixels in one" in their new RGBW CMOS sensor, which combines the traditional four groups of pixels (that is, the actual 16 photosensitive units) into a composite image, thus ensuring that each group of pixel units has complete RGB three primary colors and W pixels with greatly increased photosensitive capacity, so as to eliminate Moire phenomenon. On the other hand, by adding pixel isolation layers between photosensitive units, the problem of mutual interference between different color units is solved, and the imaging purity is improved. Moreover, it is worth mentioning that the calculation of "hardware four pixels in one" is directly completed on CMOS, so it can be compatible with various models without specially adapting to the mobile platform of mobile phones.

Secondly, OPPO has brought great changes to the telephoto of smart phones.

In terms of mobile phone lens design, OPPO also announced a "big move" today, that is, a periscope zoom lens that really supports continuous optical zoom between 85 mm and 200 mm equivalent focal length.

You know, although many models now adopt the design of "zoom multi-camera", for almost all mobile phones, the so-called "zoom" is just switching between several lenses with different fixed focal lengths. But this will bring two obvious disadvantages. First, the optical quality of different lenses is different, which will cause the color of the photo to change after zooming and look unnatural; Secondly, for those focal segments located between two lenses, it is actually a "digital zoom" that is cut and enlarged by an algorithm, so it will inevitably lead to a certain decline in image quality. For example, if a mobile phone has three zoom lenses of 1 x, 3 x and1x, the loss of picture details will be more obvious when shooting these "intermediate focal lengths" of 2 or 5 times.

However, OPPO's "continuous optical zoom lens" can solve this problem. Because it is really designed with a series of movable optical zoom lenses, driven by a long-stroke zoom motor, the zoom lens can move inside the lens, and the real optical zoom effect can be achieved without cutting and algorithmic amplification.

Not only that, in this "continuous optical zoom lens", OPPO also uses two real glass lenses to improve the light transmittance. In fact, for smart phones at this stage, almost all lenses are made of light plastic lenses, and the frequent use of glass lenses is a great improvement in quality.

Finally, OPPO also pioneered a new hardware scheme for smartphone anti-shake.

The last new mobile phone image technology announced by OPPO today is about anti-shake. As we all know, at present, the optical anti-shake structure of mobile phones can be basically divided into three types. The first one is "lens anti-shake", which can be realized by designing an anti-shake lens inside the lens. Its advantage is that the anti-shake lens is very light, so the anti-shake driving mechanism can be small and the cost is not high, so it is also the most common design. But its disadvantage is that the anti-shake lens can only move in four directions, so it can only achieve two-axis anti-shake.

The second design is to install anti-shake driving device around CMOS at the end of the camera system, and realize "sensor anti-shake" by driving CMOS to rotate, tilt and deflect. Therefore, a more powerful anti-shake motor is needed, and the cost is higher than that of the first design, but the advantage is that the movable range of the sensor is larger than that of the lens, and it can cope with the type of jitter that the lens anti-shake cannot cope with, that is, three-axis anti-shake.

The third design is to wrap the whole camera module and use four groups of magnetic modules outside the module to make it "suspended", so as to realize "pan-tilt anti-shake". The advantage of this kind of anti-shake is that it will not cause optical axis deviation at all, which is beneficial to achieve higher image quality, but the disadvantage is also obvious, which will limit the weight and area of the whole camera module and make it difficult to realize the design of super-large bottom and super-large multi-lens of mobile phones.

To this end, OPPO proposed the fourth anti-shake method for smart phones today, which is the dual optical anti-shake design of lens+sensor. By arranging the active anti-shake structure on the mirror group and CMOS at the same time, OPPO's optical anti-shake technology can achieve 65% higher performance than traditional anti-shake technology. At the same time, it can also handle the jitter on up to five axes at the same time, and the anti-shake compensation accuracy is 3.5 times higher than that of the traditional model with only lens anti-shake

None of the above is "new technology", but why can only OPPO do it?

RGBW sensor's pixel structure, built-in motor, continuous variable telephoto lens, lens and sensor have five-axis optical anti-shake structure. Among the three new imaging technologies announced by OPPO today, I wonder if you have found any similarities?

Yes, they are obviously inspired by the excellent design in the field of traditional cameras. For example, RGBW sensor was exposed by Sony and Canon at 20 12 and 20 16 respectively. For example, the built-in zoom motor and the "built-in zoom lens" with the same overall length during zooming are actually classic designs on many high-end SLR telephoto lenses; Not to mention the anti-shake design that the lens and the fuselage can work together, which is one of the most proud innovative designs of M43 camps such as Olympus and Panasonic in recent years.

In other words, OPPO is actually using their design and technology to successfully miniaturize the promising or proven imaging technologies on traditional cameras and accurately "transplant" them to smart phones. Compared with the "outsole" that is difficult to continue to develop, or the mysterious "AI" that may have side effects, these technologies from high-end cameras at least seem to be much more reliable, and it is indeed possible to bring great changes to the future smartphone image experience.

However, as a result, new problems have emerged. These imaging technologies are nothing new in the field of cameras. In principle, other manufacturers can learn from it. But why didn't we see a similar technical announcement before OPPO's future video conference?

On the one hand, cost and production difficulty may be one of the important reasons. On the other hand, it is not difficult to find out from some details announced by OPPO at today's conference that they have been exploring and commercializing pixel arrangement scheme, optical anti-shake structure and telephoto zoom technology for a long time. As far as zoom is concerned, OPPO has launched two generations of ultra-telephoto zoom models so far, and tried several telephoto lens "relay" schemes, and finally made up its mind to make a continuous optical zoom module.

Therefore, OPPO obviously not only has the financial resources and courage to take the lead in mass production of new technologies, but more importantly, they started early enough in the matter of "taking photos with mobile phones" and accumulated enough experience. Perhaps because of this, OPPO finally chose a "return to nature" image design road, and these may be one of the most reliable image design schemes we have seen on mobile phones so far.