For the Dead Leaves fields, we therefore compare the camera‘s image with the original picture on the test chart. Thus, the low contrast structures for example deliver a measurement value for the preservation of fine textures without maximum contrast in the image.Īs part of image optimization, a camera software can add artefacts as additional and hence erroneous structures into the image. So the boundary of the Dead Leaves resolution is reached when the image contrast drops to 50% of the initial contrast (MTF50). On the Dead Leaves fields we measure the resolution of the coloured structures against a threshold contrast value of 50%. After all, the world is not only colourful, but also full of different contrasts. On these coloured structures, we also determine the resolution for both high as well as low contrast textures. Transversal from the Dead Leaves field with high contrast (3 in test chart shown at the top of this page), the test chart contains a Dead Leaves field with low contrast (4). For badly centered lenses, we measure differences of up to several hundred line pairs per image height. For this reason, we compare the resolution of the four Siemens stars in the image‘s corners. Also, transportation of the device can lead to misalignments. But when a manufacturer applys these techniques too aggressively, the result is an unnatural, too hard and artificial visual impression.Įspecially in smart phones, the optical lens is not always perfectly adjusted directly in front of the sensor. This typically leads to higher resolutions in the corners as in the image center. Because with re-sharpening and edge boosting, the resolution can be influenced overall. But signal processing again plays a role in this as well. Under normal circumstances, the resolution drops more or less at the edges, depending on the quality of the optical lens. This is first of all a property of the optical lens.

As the Siemens stars are located at three different distances to the center of the image, we can identify the trimming of the resulution.

Siemens star char