Thin multi-aperture imaging system with auto-focus and methods for using same

A dual-aperture digital camera with auto-focus (AF) for imaging an object or scene, comprising:

• a) a first sub-camera that includes a first optics bloc and a color image sensor with a first number of pixels, the first camera operative to provide a color image of the object or scene;
• b) a second sub-camera that includes a second optics bloc and a clear image sensor having a second number of pixels, the second sub-camera operative to provide a luminance image of the object or scene, wherein the first and second sub-cameras have substantially the same field of view;
• c) an AF mechanism coupled mechanically at least to the first optics bloc;
• and
• d) a camera controller coupled to the AF mechanism and to the two image sensors and configured to control the AF mechanism, to calculate a scaling difference and a sharpness difference between the color and luminance images, the scaling and sharpness differences being due to the AF mechanism, and to process the color and luminance images into a fused color image using the calculated differences.