Porovnání vad

Testovaná technika

Testované objektivy

Testované drony

Testované fotoaparáty

Summary

The aim of the bachelor thesis was to analyze the optical properties and characteristics of selected cameras for photogrammetry purposes. Testing of the technique in the form of an experiment under conditions identical for all devices was carried out. The selected devices were tested for basic defects, namely vignetting, chromatic aberration, Modular Transfer Function, lens distortion and image noise level. Testing was carried out for different aperture numbers, focal lengths and sensor sensitivities. The images produced were analyzed and evaluated according to the type of defect.
Each device (lens, drone, mobile phone) was tested at the maximum combination of settings it allowed. The focal lengths tested were 24 mm; 28 mm; 35 mm; 40 mm and 50 mm. The tested aperture numbers ranged from f/1.4 to f/7.1. For the zoom lenses, both the focal length and aperture number were varied, for the other devices only the aperture numbers were varied, and always all the tested ones that could be set for the device.
Vignetting testing was performed by photographing a uniformly illuminated white area, which was then analyzed in ArcGIS Pro by subtracting the maximum and minimum pixel brightness values. For chromatic aberration testing, a test chart based on the eSFR ISO 12233 standard was created and imaged with all devices tested. On the images thus created, the defect was examined and evaluated mainly in the corners of the image. The measurements were carried out in Adobe Photoshop. The images created for chromatic aberration were used to evaluate the MTF defect. MTF was measured and evaluated separately in the corners and in the center of the image. The measurements were performed in Imatest Master. Lens distortion was measured on a regular grid that was projected in Agisoft Metashape. This grid was taken from five angles and analysed in the same program. The noise level in the image was tested on a standardised ColorChecker test target, which was photographed with the test devices for ISO values of 100; 200; 400; 800; 1600 and 3200. The images were then analyzed in Imatest Master. Noise was examined in the Y-Luminance channel.
As a main output, a series of graphs across all tested defects for all devices and each focal length is presented. The next output is a website that is divided by devices for clarity. Due to the large combination of settings and the variety of techniques, it is not possible to determine that one device outperforms the others in all defects, so a table was created where devices are divided by focal length and ranked from best. However, according to the results it can be evaluated that the lens with the least vignetting is the Olympus M.Zuiko Digital ED 12-200 mm f/3.5-6.3. The lens that suffers the least from chromatic aberration in most cases is the Olympus M.Zuiko Digital ED 12-40 mm f/2.8 Pro. The sharpest lens among the tested devices is the Sigma Art 35 mm f/1.4, both in the centre of the frame and in its corners. The least distortion of the lens was measured when using a focal length of 25 mm (50 mm equivalent), when using a wider focal length each device behaves quite differently. The noise level was evaluated to be the lowest for all devices when the ISO sensitivity was set to ISO 400. In all cases, noise is lowest on the Nikon D750.
For photogrammetric purposes, it is essential to know how the device behaves and what defects are present. This information is then taken into account in flight planning, for example when calculating image overlaps or flight altitudes. Defects such as vignetting or lens distortion can then be corrected in programs, so they may not be as important as sharpness in the corners of the image when selecting a device.