Why are the photos of Ukraine taken by US satellites in color but China in black and white?

赵玉田

Why are the photos of Ukraine taken by US satellites in color but China in black and white? [Copy link]

Recently, a group of photos have attracted widespread attention. One of them was taken by my country's "Maritime Silk Road No. 1" satellite, and the other was taken by a foreign satellite. The foreign satellite's photos are in color, while China's satellite photos are in black and white. Netizens have questioned whether China's satellite technology is inferior to that of foreign countries. In fact, this is not the case.

01The imaging principles of satellite photography are different

Satellite images are taken in black and white, not because China's satellite technology is inferior to that of foreign countries, but because China and foreign countries use different satellite imaging technologies. China uses radar imaging, while foreign countries use optical imaging.

Optical imaging uses visible waves to form images, and with the help of infrared imaging technology, it can present a colorful observation picture. Radar imaging actively emits electromagnetic waves and uses the reflected electromagnetic waves to form images, so the images are colorless.

02Optical imaging and radar imaging satellites have their own advantages

Although the effect of optical imaging looks more "beautiful", it is greatly affected by weather and light. If there are thick clouds or the satellite enters the shadow side of the earth, clear images cannot be obtained.

Although radar imaging satellite images are colorless, they are not affected by sunlight and climate, can be used for all-weather detection, and have a certain degree of penetration into clouds, light rain, vegetation, and dry objects. In addition, by adjusting the optimal observation angle, the stereoscopic effect of its imaging can effectively detect the spatial morphological characteristics of the target objects. Moreover, the accuracy of radar imaging satellites will be more accurate. my country's radar imaging level has reached the international advanced level. At present, the accuracy of the "Maritime Silk Road No. 1" satellite has reached 1 meter, and the accuracy of the next generation of satellites will reach 0.5 meters.

In fact, China not only has radar imaging satellites, but also optical imaging satellites. This time, it just happened to choose radar imaging images.

03China's "Jilin-1" satellite can take color satellite images

Jilin-1 is my country's optical remote sensing satellite, capable of taking color satellite images. The Jilin-1 satellite was developed by the Changchun Institute of Optics, Fine Mechanics and Physics of the Chinese Academy of Sciences. The first satellite's index parameter is a ground pixel resolution of 0.72 meters for full color, and the Jilin-1 video satellite has a ground pixel resolution of 1.12 meters. It can automatically identify buildings, roads, water bodies, trees and different types of crops online, with an identification accuracy of more than 95%.

The National Bird's Nest photographed by "Jilin-1"

Overall, my country's current satellite level is in an internationally leading position. And my country is still constantly building and improving the satellite network, which may bring great changes to our lives in the near future.

wangerxian

It seems like it’s not working, but it’s actually KO!

Verifone

The function settings are different, and different settings reflect different outputs. There is no comparison at all.

wl08

There is no comparison

UUC

Thanks for sharing, thanks for the popular science

Chad4133

The Google satellite map we are familiar with is a picture taken with optical remote sensing technology, because the pictures taken with optical remote sensing technology are more intuitive, spectacular, and have a high degree of restoration. The principle of optical remote sensing technology imaging is the same as that of mobile phone photography, which is to synthesize images through the reflection of light. Therefore, there is a relatively large defect in optical imaging remote sensing technology, that is, it is impossible to perform normal shooting in environments such as fog, heavy rain, and night. The imaging principle of aperture radar remote sensing satellite technology is relatively complex. It mainly forms images visible to the naked eye by emitting radio electromagnetic waves, recovering signals, and post-processing. The radio electromagnetic waves emitted by aperture radar remote sensing satellite technology have the characteristics of strong penetration, can penetrate rain, fog, clouds, etc., and have a strong ability to obtain information. In the early days of the US-Soviet Cold War, aperture radar satellites were used in military detection aircraft to detect enemy strategic targets. Therefore, aperture radar remote sensing satellite technology is of high value!

花鼓舞

The function settings are different, and different settings reflect different outputs. There is no comparison at all.