Image flicker control by CCD-chip-shift and wobble operation at double-enhanced Nyquist regions

CCD-chip-shift operation can double the Nyquist limit to give a high-resolution CCD imager. Image flickers, however, are apt to appear at highly resolved images near the double-enhanced Nyquist limit. The flickers are, in nature, field-time-dependent image flickers inherent in the operation principle. In order to suppress image flickers, a CCD-chip wobbling was superimposed at swung sites for the CCD-chip-shift imager by utilizing piezoelectric bimorph acutators, on which the CCD chip was mounted. By wobbling, apparent horizontal pixel apertures were enlarged to overlap each other, resulting in MTF control at the double-enhanced Nyquist regions.