how does imresize work in matlab?

how does matlab implement the command: imresize(<image>,<scaling factor>,'bicubic');

the other types of interpolations are easy to understand and implement. but in case of bicubic, when the scaling factor is less than 1, it does the anti-aliasing filter operation. how does this operation work?

Answer 1

[Image Analyst]

2 points define a line, 3 define a quadratic, and 4 define a cubic. So if you have just the two adjacent pixels, you can do a bilinear interpolation, a bicubic interpolation uses two pixels on each side, in each direction. Same things as bilinear, just using 4 pixels instead of two to get the value of the pixel "in the middle". Not sure how it does antialiasing - perhaps it blurs it a little after the interpolation. Why do you ask?

[Utkarsh Deshmukh]

Thank You sir, I was really trying to understand the process of resizing. For the part of antialiasing, can i use simple gaussian filter? i am unable to understand how to get the kernel for the anti-aliasing filter.

[Utkarsh Deshmukh]

also sir, i wanted to know when does it do the antialiasing? before the interpolation or after the interpolation?