What is tilt photography? How different is it from traditional orthography in imaging?

The traditional image is the image data obtained by taking photos of the ground continuously through the aerial camera carried on the plane and then through a series of indoor processing. The only result obtained is the information of the overlooking angle of the ground object, that is, the viewing angle is perpendicular to the ground. In the tilt photogrammetry experiment, an airplane or unmanned aerial vehicle is equipped with five cameras to shoot ground objects from four vertical directions, and then through a series of indoor processing such as geometric correction, adjustment and multi-view image matching, data with all-round information of ground objects are obtained. The simple understanding is that the ground objects in the image are on a plane, and the ground objects measured by oblique photography have real heights. (The above is not original)