More than 1,700 "beautiful photos" of the Earth were taken from space, and the Zheyan polarization three-dimensional satellite payload successfully completed its mission!

How many steps are needed to take a stereoscopic image of the Earth from space?

Unlike the past where you had to take photos from multiple angles to synthesize a three-dimensional image, now there is a new answer -

Recently, the world's first polarization 3D imaging payload developed by the research team of the Advanced Vision Research Institute of Xidian University Hangzhou Research Institute (hereinafter referred to as "Xidian Hangzhou Research Institute") completed its mission and bid farewell to the boundless starry sky. During its time in orbit, it took more than 1,700 polarization images of the Earth from a high-dimensional perspective.

Compared with the traditional method of taking three-dimensional images of the earth, which requires "multiple integration", the polarization three-dimensional imaging camera payload only needs to shoot at a single perspective, and then use the polarization data that is invisible to the human eye to enter the calculation model, so as to achieve more accurate and efficient three-dimensional imaging.

| Polarization 3D imaging payload carried on Donghai-1 satellite

Three-dimensional imaging records, opening up a new dimension of observation

"Our payload is like putting '3D glasses' on the earth!" Li Xuan, deputy director of the Advanced Vision Institute of Xidian Hangzhou Research Institute and associate researcher of Shao Xiaopeng's PI team, excitedly told reporters that the system can obtain the three-dimensional contour of an object by capturing physical information such as the polarization degree and polarization angle of light reflected from surface objects.

In the past, satellites used the stereo intersection method to first perform remote sensing imaging and then combine photos from different angles into a 3D image. Li Xuan said: "Usually, 4 to 5 pictures are needed to obtain high-precision 3D imaging. We only need to take one picture, which is a fast and high-precision stereo reconstruction."

The payload was launched into space on the Donghai-1 satellite on August 9, 2022. During its approximately 21,155 hours in orbit, it was like a tireless interstellar messenger, taking 1,735 polarized images, recording the magnificence of the Earth in detail from a high-dimensional perspective.

| Pearl River Buildings

| Lop Nur Desert

The Himalayas, Qinling Mountains, Lop Nur, Pearl River, Xiayunling Mountains, the South China Sea around Taiwan, China... Whether it is the magnificent mountains, rivers, lakes and seas, or the magnificent cultural buildings, they are all faithfully recorded and encoded by it, showing the rich details and characteristics of the different landforms and regions of the earth, providing a unique perspective for mankind to explore the mysteries of the earth.

Internationally leading level, empowering multiple fields in the future

"As the world's first polarization 3D imaging payload, experts have rated us as 'internationally leading'!" Li Xuan is very confident that as an important branch of computational imaging, polarization 3D imaging technology has great potential application value in the future, and is expected to play an important role in mobile photography, industrial inspection, smart medical care, smart driving, resource exploration, emergency disaster reduction and other fields.

For example, in the field of resource exploration, the research team has provided a new type of high-precision and high-efficiency mapping method for terrain mapping through payloads. "This can enhance our country's ability to obtain geographic information and provide more accurate data support for urban planning, land and resources management and other work," said Li Xuan.

| 3D imaging of the Yesanpo area in Beijing

| 3D imaging of the Himalayas region

In addition, in terms of emergency disaster reduction, the research team can use on-orbit satellites to quickly obtain high-resolution polarization feature images and three-dimensional contours of the disaster-stricken areas and timely estimate earthwork information. This method is like giving rescue workers a pair of "perspective glasses" to help them accurately monitor the development of disasters, provide key basis for emergency rescue decisions, effectively reduce disaster losses, and protect people's lives and property.

Li Xuan said that the on-orbit test results showed that the payload can greatly improve the accuracy and efficiency of three-dimensional remote sensing detection, enable space remote sensing detection to obtain richer and more accurate information, and provide strong technical support for my country's stereoscopic surveying and mapping, disaster assessment and other work.

| 3D contours of mountains near Shidu and estimation of earthwork volume

Assisting deep space exploration, stereo imaging is worth looking forward to

Polarization three-dimensional imaging cameras are also present in China's space launches.

"We capture video of the moment the rocket takes off, and then we can quickly calculate the rocket's attitude to provide support for the safety of the entire launch, including the next launch mission," said Li Xuan.

Today, the polarization 3D imaging camera payload has successfully completed its mission, marking a breakthrough from scratch in my country's field of satellite-borne passive polarization 3D imaging of earth targets, and a key progress in computational imaging technology in space application research.

Li Xuan said that in the next step, the polarization 3D imaging camera payload will solve the problem of deep space exploration. The detection, sampling and return of extraterrestrial bodies are difficult problems that humans need to overcome, and China is focusing on planetary exploration. Next, the polarization 3D imaging camera payload may be carried in major national space missions to help my country in deep space exploration and the development of space technology.

(The above text is from Chao News, and the pictures are from Xidian Hangzhou Research Institute)