Image sharpness

When finest grain stmcture and maximum image sharpness are required, the original is photographed in a large-format camera using a separate sheet of film for each exposure. These cameras are heavier than roll-film cameras and usually require a tripod and/or a controlled studio environment. Common sheet film sizes include 102 x 127 mm (4x5 in.) and 203 x 254 mm (8 x 10 in.). 

Depth of field is an important concept when photographing an image. It refers to the range of position for an object in which image sharpness does not change. As illustrated in Figure 1.6, an object image is only accurately in focus when the object lies in a plane within a certain... 

Donofrio, R. 1972. Image sharpness of a color picture tube by MTF techniques. IEEE Trans. Broadcast TV Rec. BTR-18(l) l-6. 

The RPE cells contain melanosomes that provide pigment to absorb stray light -essential for image sharpness by minimizing light scatter [23]. 

High quality of images (sharp depth discrimination)... 

Vibrations that occur for example when driving on cobblestones could result in an error in the image display of CMS. Test drives on uneven road surfaces (here cobblestones in Fig. 21), however, showed no impairment with regard to image sharpness or blurred images. The monitor always displayed a sharp camera image. Only the relative motion between the driver and the monitor or between the driver and the mirror, that occur when driving on uneven road surfaces, resulted in a blurry perception of the rear field of vision. However, this blurriness was equal in mirrors and monitors and can never be fully avoided on uneven roads. 

Statement on image quality (brightness/contrast, colour rendering, image sharpness) ... 

Since the MTF measurement was only performed once, due to the fixed aperture of the applied camera, the image sharpness did not change over the course of this work and was not optimized. The measurement however was performed by positioning the wedges in the middle and comers of the image. This was done to determine the sharpness drop introduced by the form of the camera lens. The results of the measurement can be seen in Table 1, which as predicted, shows a slight sharpness drop in the comers of the image. 

The largest MTF value occurs for = 0,0 = a /2 Equation 15.24 yields MTF = 1.0. Higher frequencies have lower MTF those higher frequencies are rolled off in the image. The spatial frequency for which the MTF is 50% is a good indicator of perceived image sharpness. 

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