Smear performance comparison using various Kodak 35 mm format interline transfer sensors

Comparing the smear performance of Kodak KAI-16000, -16050, -16070 and -29050 sensors

Why do we need to know about smear?
Some of the highest-resolution cameras are designed using the KAI-16000, KAI-16070, KAI-16050 and the KAI-29050 sensors and in many applications, the performance of the interline transfer CCD is hindered by the smear performance of the sensor.

What is "smear?"
Smear happens when light leaks into the vertical CCD as the image is read out and is most apparent when the exposure is very small and the read-out time is very large. This is an issue in aerial-imaging applications because exposures must be very short in order to limit motion blur, and because the light source (ie, the sun) is very bright.

Smear is influenced by the design of the interline pixel and some designs are better than others. Kodak's 5.5um design used in the KAI-16050 and -29050 sensors) produces an extremely low smear and they list the smear performance to be 20dB better than their older KAI-11002 and KAI-16000 sensors; the new KAI-16070 boasting a smear performance of 32dB better than the KAI-16000.

The comparison
Four RMV cameras were tested using the same lens and aperture, the same light source and working distance. The anti blooming (substrate) bias was adjusted for each camera to eliminate blooming. Each camera was set to approximately the same exposure and the smear was qualitatively measured using the RMV’s built-in line plot feature.

	RMV 16MP smear test. 55mm lens at F32. 1ms exposure
KAI-29050 sensor Pixel size = 5.5 um	KAI-16000 sensor Pixel size = 7.4 um	KAI-16070 sensor Pixel size = 7.4 um	KAI-16050 sensor Pixel size = 7.4 um
Note: Timing diagram are not to scale and certain pulses have been enlarged to aid the inclusion of labels

Conclusion
• The new KAI-29050 and KAI-16050 sensors exhibit 10X less smear than the KAI-16000 sensors.
• The the new KAI-16070 sensor exhibits 40X less smear than the older KAI-16000 sensors.

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