What is the technical explanation of this satellite photography of an airplane moving fast

Question

This screenshot was taken on Apple Maps on August 2024 at this location : 45,18727° N, 0,34439° W

We can see "2 airplanes".

1. The first is the white one. RGB colors seems separated. I understand that the sensor captures colors sequentially : Red, then Green, then Blue. As the plane is moving fast during the shot, colors appears shifted in the direction of the move. This question has an awnser to this point.

2. The second airplane though is myterious to me. It is darker and surprinsingly sharp. How can the focus point be on the ground and at the same time tens of kilometers above ? Why is there a "second plane" ? Is this a specificity of satellite photography ?

Answer 1

The second airplane though is myterious to me. It is darker and surprinsingly sharp

This image has almost certainly been pansharpened. The process of pansharpening combines intensity taken from a high-resolution image having a single channel, with hue taken from a lower-resolution image having multiple channels, to produce an image with more information than either of its inputs alone.

Notice in particular that the sharp airplane image is colored in brown and green — the colors of the field, path, and trees below it. I don't know why it's so dark, but I'd guess that the particular algorithm used refrains from making an output pixel much brighter than the input color was, to avoid amplifying noise from dark pixels when edges don't perfectly align.

Answer 2

The cameras used on satellites uses different techniques. Multiple shots are taken in quick suspension, each imaging at different wavelengths of light. Likely, one exposure captures the image in monochrome followed by multiple exposures, each taken through colored filters imposed atop the camera lens. Some shots could be in the infrared region to penetrate cloud cover. These image a heat signature and convert it to false colors. The final image is likely a composite image.

Our ordinary digital cameras make three exposures via red, green and blue filters. The three images are taken simultaneously. The satellite camera need not image these different wavelengths simultaneously.