Dual camera system with improved video smooth transition by image blending

A method of zooming in a zoom dual-camera that includes a first sub-camera and a second sub-camera, the method comprising:

• during switching in video mode from output images of the first sub-camera to output images of the second sub-camera,
• a) applying scaling on the output images of the first sub-camera according to a changing zoom factor (ZF) when the ZF changes from a lower ZF to a higher ZF or vice versa to obtain a first image stream with scaled images;
• b) applying shifting on the output images of the second sub-camera according to the changing ZF to obtain a second image stream with shifted images;
• c) when a ZF-transition-threshold is reached, generating a third image stream comprising a predefined number of images, wherein each image of the predefined number of images is based on a weighted combination On(x,y) of values of corresponding pixels in an image from the first image stream and a corresponding image from the second image stream
• On(x,y)=αn(n,x,y,ZF,Wn(x,y),Tn(x,y) . . . )Pn{Wn(x,y)}+(1−αn(n,x,y,ZF,Wn(x,y),Tn(x,y) . . . ))Qn{Tn(x,y)}
• wherein x and y are spatial coordinates, n ≥1, Wn and Tn are nth frames in the third image stream, Pn and Qn are spatial transformations and an, is a weighting factor dependent on n, x, y and ZF;
• d) switching an output image stream of the dual-camera from the first image stream to the third image stream;
• and
• e) further switching the output image stream of the dual-camera from the third image stream to the second image stream.