Name

filt_tophatb - top-hat band-pass Fourier filter (truncation of a Fourier series)

Usage

output = filt_tophatb(image, freql, freqh, pad)

Input

image

input image (can be either real or Fourier)

freql

low-end frequency of the filter pass-band

freqh

high-end frequency of the filter pass-band

pad

logical flag specifying whether before filtering the image should be padded with zeroes in real space to twice the size (this helps avoiding aliasing artifacts). (Default pad = False).

• All frequencies are in absolute frequency units `f_a` and their valid range is [0:0.5].

Output

output

filtered image. Output image is real when input image is real or Fourier when input image is Fourier

Method

Fourier transform of the input image is set to zero for spatial frequencies smaller than freql and larger than freqh.

Reference

Gonzalez, R. F., Woods, R. E., 2002. Digital Image Processing. Prentice Hall, Upper Saddle River, NJ.

Author / Maintainer

Pawel A. Penczek

Keywords

category 1

FILTER

category 2

FOURIER

Files

filter.py

Maturity

stable

works for most people, has been tested; test cases/examples available.

Bugs

None. It is perfect.