What are the working principles of photography, scanning and radar imaging?

Photography, scanning and radar imaging work differently as follows:

1. Photography mode is to focus the light reflected by the target on the substrate or electronic photosensitive plate through an optical lens and record it to form a photo or video with visual information. The principle of this imaging method is to record the image of the object by using the light reflected by the object.

2. Scanning mode refers to scanning the whole target plane regularly or irregularly in some way, and reconstructing the image of the target through the data recorded in the scanning process. Scanning methods can be divided into mechanical scanning and electronic scanning. Mechanical scanning uses a mechanical scanner to image, while electronic scanning uses an electron beam to directly transmit image information to a display or storage medium. The principle of this imaging method is to obtain the characteristic information of the target by using the radiation signal of the target (such as sunlight radiation, infrared radiation, microwave radiation, etc.). ).

3. Radar mode is a technology to detect a specific target by transmitting high-frequency electromagnetic waves to the target, and to determine the position and shape of the target by receiving reflected signals. The principle of this imaging method is to use the interaction between electromagnetic waves and objects to obtain target feature information. Radar imaging is widely used in weather forecast, military reconnaissance, environmental protection and other fields because of its characteristics of no need for the target to emit illumination light and high imaging reliability under complex conditions.