Mi 10 Ultra’s OmniVision OV48C CMOS and Dual-Native ISO Technology Explained

Mi 10 Ultra Camera Technology

Mi 10 Ultra uses OmniVision OV48C CMOS

According to the report Mi 10 Ultra’s main camera is powered by OmniVision OV48C CMOS. Xiaomi Mi 10 Ultra supersized bottom main camera comes from OmniVision’s 48-megapixel OV48C. Officially, the 1/1.32-inch optically-spec sensor features OmniVision’s PureCel Plus chip stacking technology to deliver high-quality still image capture and video performance for the flagship smartphone.

According to OmniVision, the OV48C is a DCG HDR-powered HD mobile image sensor and a flagship mobile image sensor that offers simultaneous 48-megapixel resolution, a 1.2-micron pixel size, high speed, and high on-chip dynamic range.

The OV48C also integrates an on-chip 4-in-1 color filter array and hardware pixel reduction algorithms to deliver real-timeHigh-quality 48MP output 8K Bayer video, which also brings premium 8K video recording capabilities to the Mi 10 Ultra.

The OV48C is also an HD mobile phone camera image sensor with DCG HDR functionality. This feature effectively removes motion artifacts for a better signal-to-noise ratio (SNR). The OV48C also offers an interleaved HDR solution with on-chip compositing, which gives developers the flexibility to choose HDR methods for specific scenarios.

Xiaomi Mi 10 Ultra Dual-native ISO Technology

Why your phone can’t take good pictures of light and dark details.

This is The Summons of St. Matthew, a painting by the famous Italian painter Caravaggio painted in the late 16th century.

In this painting, Caravaggio recreates a typical high dynamic range scene. From the near-black corners to the highlights on the faces. In this way, we are more inclined to believe that these paintings come from a real scene than from myth. However, this effect that can be achieved with a brush and paint is difficult to do with a mobile phone. When we take a picture of the same scene with our phone, we get either a blurred shadow or a white highlight, which is a waste.

When you press the shutter; How does the camera acquire what it sees in front of you?

With conventional film cameras, when the shutter is pressed, a large number of photons hit the film, causing the silver halide crystals on top to become light-sensitive, creating a latent image that is invisible to the naked eye. This is then developed to obtain an image composed of ferrous silver metal particles.

Xiaomi Mi 10 Ultra In-depth Review – Suggested Reading.

However, in these low-brightness corners, where the number of photons is relatively small, the silver halide crystals are less likely to be hit, and the image is not as clear as it should be, and dark details are lost.

In addition to adjusting the shutter speed and aperture size, it was necessary to replace the film with a more sensitive film. The crystals on these films are larger, and there is a greater chance that photons will hit them and be absorbed to complete the sensitization.

Moving into the digital age, the camera’s sensor changed from film to a CMOS sensor. Adjusting the sensor’s sensitivity is more complicated than adjusting the size of the halide crystal in the film era. The top layer of the widely used back-illuminated CMOS today is a microlens that is used to concentrate the light. The second layer is a Bayer array filter matrix to collect the red, green, and blue light. The third layer is a photodiode, followed by a metal wiring layer and a storage layer.

The most critical structure of all is the photodiode. It converts the light signal into an electrical signal, i.e., a photon into a photogenerated charge, and stores it in an electric field. This electric field is called a potential trap, and the photogenerated charge in the potential trap is converted into a voltage signal and then amplified. This process of converting the charge quantity into a voltage signal and amplifying it is the native ISO of a digital camera, which, like the ISO of film, is a factory setting and cannot be adjusted.

The amplified voltage signal, then, is transmitted through a circuit to an analog-to-digital converter and converted into a digital signal. This allows the light intensity information for each pixel to be recorded, which, when combined with the color information, yields a photograph.

Why some photos, Either overexposed or pitch black?

If the light is very dim, i.e. the number of photons entering the sensor is very small, it is difficult to count the differences in light intensity between the pixels and it will appear as pitch black in the photo. What can be done about this?

One idea is to add a digital signal amplifier after the analog-to-digital converter to increase the gain multiplier of the digital signal. This way, you can compare the differences between individual pixels, even in very low light. This is what you achieve when you turn up the ISO when taking a picture with your phone – amplifying the digital signal. In the process, however, the system inevitably introduces noise, which manifests itself as noise in the photo.

So is it possible to take photos in low light without introducing a lot of noise? Yes, it is to have two kinds of potential traps on the CMOS. We can compare the potential trap to a bucket, and take pictures as if rainwater is dripping into the bucket. By reducing the size of the bucket, we can more accurately measure changes in water volume, meaning that the difference in water volume between buckets can be compared even when the volume is small.

The same principle applies to photography. Using a smaller potential trap means that it is more sensitive to light, which corresponds to a higher ISO so that details are preserved in low light and reading noise is reduced. The existence of two potential wells is like a film camera loaded with two types of film at the same time, which can be switched automatically according to the brightness of the scene.

High Native ISO is turned on in low light to address increased noise and loss of detail. Low native ISO is turned on in high light to solve the problem of over-exposure. This is the dual native ISO technology that comes from professional cameras.

However, in a cave-like this, if only Low Native ISO is used, dark details are lost, and if only High Native ISO is used, the bright areas are over-exposed. In other words, using only one of the dual native ISOs at the same time still won’t accurately reproduce scenes with a high dynamic range.

Mi 10 Ultra’s OmniVision OV48C CMOS and Dual-Native ISO Technology Explained

Xiaomi Mi 10 Ultra, How do you shoot super high motion images?

To overcome this problem, the Mi 10 Ultra’s 1/1.32-inch extra-large bottom sensor enables, for the first time on a phone, ultra-dynamic technology with dual native ISO Fusion, which means that two potential trap shooting techniques using CMOS are simultaneously utilized and merged in real-time.

In addition to the high dynamic range output in photography, the Mi 10 Ultra can also record HDR video, giving every frame a high dynamic range. It was hard to do when shooting videos with the phone before.

On top of that, the phone’s image sensor also features chip-level single-frame progressive HDR technology. Chip-level single-frame progressive HDR is faster than conventional HDR, which requires three frames to be shoot and three separate exposures. This technique allows for three consecutive short, medium, and long exposures for each line of pixels, requiring almost a single frame to complete the three exposures. It avoids ghosting and allows for a higher dynamic range.

From brushes and film to digital cameras and cell phones, rapidly evolving imaging technology is making the real world clearer and clearer in your cell phone’s lens, and allowing your story to travel farther and farther into the corners of the world.

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