What are the requirements of photogrammetry for aerial photos and flight quality?

The requirements of photogrammetry for aerial photos and flight quality are as follows: image tone, photo overlap, photo tilt, route bend and photo rotation angle.

1, color of image:

The image should be clear, the tone should be consistent and the contrast should be moderate. There should be no shadows in the photo that hinder the mapping.

2. Overlapping photos:

It is required that two adjacent photos overlap on the same route, which is called heading overlap. Overlap of courses: 60%~65%, with a minimum of 53%.

There should also be enough overlap between adjacent routes, which is called lateral overlap. Horizontal overlap: 30%~40%, and the minimum shall not be less than 15%.

3. Photo inclination:

At the moment of photography, the camera axis is tilted, and the angle between the camera axis and the vertical direction is called the photo tilt angle, which is not more than 2 and not more than 3.

4, route bending:

Limited by technical and natural conditions, aircraft often cannot fly on the scheduled route, resulting in bending, which leads to missed shots or too small lateral overlap, thus making the image map in the industry. Generally speaking, the ratio of the maximum offset of aerial photography to the length of the whole route does not exceed 3%.

5, photo rotation angle:

The included angle between the line connecting the main points of adjacent photos and the line connecting two frames of image along the route direction is called photo rotation angle, which generally requires that the photo rotation angle should not exceed 6 and the maximum rotation angle should not exceed 8.

Basic principles of photography:

Exposure process:

When taking pictures, light enters the cassette through a small hole (more often, a lens group) and forms an image on the medium on the back of the cassette (relative to the incident direction of light). According to the actual light intensity and the photosensitive ability of the medium, the required light time is also different. In the process of illumination, the medium is irradiated by light.

Post production:

After photography is completed, the image information stored in the medium must be read by human eyes again through conversion. The specific method depends on the photosensitive means and medium characteristics. For film cameras, there will be chemical processes such as fixing, developing and enlarging. For a digital camera, a processor is needed to calculate the data and then output it through electronic equipment.

Equipment used:

Generally speaking, people take pictures with visible light, and cameras are the most commonly used. Because of different scenes and uses, cameras have many classifications. Generally speaking, a camera must have several basic components to ensure the exposure process, including: photosensitive medium, imaging lens, exposure time control mechanism, film cassette and storage medium.