Xiaomi 11 Ultra dToF Laser Focusing System and Dual Native ISO Fusion Detailed

Xiaomi 11 Ultra dToF Laser Focusing System and Dual Native ISO Fusion Detailed

Xiaomi 11 Ultra dToF Laser Focusing System and Dual Native ISO Fusion

Slow focus, inaccurate focus, two problems solved in one step.
Xiaomi 11 Ultra is equipped with 64 dot matrix dToF laser focusing technology, through the transmission and reception of laser light, while acquiring different depth information of 64 locations, to get the accurate distance between and focus object, thus significantly improving the focusing performance in various usage scenarios.

Besides, dToF on Xiaomi 11 Ultra, Xiaomi 11 Pro & Ultra both feature dual native ISO fusion. When Xiaomi 11 Pro & Ultra shoot large light ratio scenes, it uses dual native ISO to image separately, low native ISO for highlights without overexposure, and high native ISO for details in the dark, blending the two photos into one super dynamic photo with greater dynamic range, better tolerance, and excellent noise control. Here we will talk about both technologies in detail.

Xiaomi 11 Ultra dToF Laser Focusing

XIAOMI 11 UItra dark light focusing and fast and accurate secret dToF 64 dot matrix laser focusing system detailed by Xiaomi official.

When shouting into a valley, the distance to the opposite wall can be calculated based on the time it takes to hear the echo. If you replace the sound with a more accurate and faster laser, you can get more accurate distance information in a very short time, and this is where the dToF laser focusing system that comes with the Xiaomi 11 Ultra comes in.

What is the dToF laser focusing system?

Why do you need dToF laser focusing when the phone’s focusing system is already very powerful? Because with existing focusing systems, the sensor does not feed enough light when the ambient light is too low and focusing by detecting phase difference alone may fail. dToF is actually an acronym for Direct-Time of flight, which directly translates to “direct time of flight,” and the name of this technology directly reflects its essence, measuring distance by directly measuring the time of flight back from laser reflections.

In the dToF laser focusing system, it can be roughly divided into the VCSEL laser, VCSEL driver, SPAD detector, and TDC time digital converter components. During focusing, the driver drives a signal through the electric current so that the VCSEL laser emits an infrared laser invisible to the human eye, which is reflected by the object and then receives the light signal through the SPAD detector, and then the laser time of flight is recorded by the TDC.

By transmitting and receiving the light signal several times in a very short period of time and doing histogram statistics on the recorded flight time, the accuracy of the results can be greatly improved to get an accurate distance between the phone and the focused object.

After getting the precise distance between the phone and the focused object, the camera then focuses according to the distance obtained by dToF, which will not only make the focusing speed significantly improved but also the focusing accuracy will be more accurate.

Compared to the single point dToF laser focusing used in Xiaomi 10 Ultra, Xiaomi 11 Ultra upgrades the dToF focusing system to an 8×8 point array, by firing the laser at up to 64 points, it can obtain different depth information of 64 areas, thus achieving accurate focusing in a wide range within 61° field of view angle, with an effective distance of up to 400cm.

By dToF laser focusing system, the dToF laser focusing system enhances the mid-distance focusing performance and solves the problem of slow and easily inaccurate focusing in the dark light environment of the phone, thus enhancing the entire dark light photography experience of Xiaomi 11 Ultra.

Xiaomi 11 Pro and Ultra’s HDR dual native ISO Fusion

We all want to pick up our phones, press the shutter, and get the picture we want. However, in some scenes with a strong contrast between light and dark, cell phone photos are either bright places a white, or dark areas a dead black, it is difficult to take into account both bright and dark details, this scene is generally called high dynamic range scenes, High-Dynamic Range, referred to as on HDR.

Why is it so difficult to shoot light and dark details?

To explain this phenomenon, we go back to the original source to see. In the process of pressing the shutter with the phone to generate a photo, the light signal in the environment will be converted into an electrical signal, and then from the electrical signal to a digital signal, resulting in a digital photo that records the light intensity of each pixel point.

The light signal is converted into an electrical signal by a photodiode under the pixel of the photoreceptor, which transforms photons into photogenerated charges and stores them in an electric field, which is called a potential well. The photogenerated charge stored in the potential well is then converted into a voltage signal and amplified, a process known in familiar terms as native ISO, and native ISO is a fixed parameter that cannot be adjusted.

When the ambient light is low and the sensor records fewer photons, the difference in light intensity between individual pixels becomes difficult to count. The general practice at this time is to add a digital signal amplifier to directly amplify the signal gain, which is expressed in the operating interface to increase ISO, but the process of amplifying the signal inevitably introduces a lot of noise, resulting in a large amount of noise in the final output photo.

A better solution is to increase the type of potential well, which is like a bucket of water, and when taking pictures, it is like rain dropping into a bucket. By reducing the volume of the bucket, we can measure the water volume variation more accurately, i.e., the difference in water volume between different buckets can be clearly compared when the water volume is very small.

Xiaomi 11 Pro & Ultra premiered Samsung GN2 supports dual native ISO Fusion technology, which also uses two potential wells of CMOS, and by using different two potential wells, it can record images at two different ISOs. Photos output in high ISO mode can retain the dark colors and details in the scene, while photos output using low ISO mode can avoid losing color information due to overexposure of the highlights.

Dual native ISO Fusion then blends these two modes to output photos while presenting richer details and a full range of colors.

By fusing low ISO and high ISO photos to enhance the dynamic range from low light to high light, the advantages of the two ISO modes can be maximized, resulting in a stunning HDR photo.

Source 1, Source 2

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