radon.jl

function radon(img::AbstractArray, theta=range(0,stop=pi,length=minimum(size(img))))
    ilength, iwidth = size(img)
    idiag = sqrt(ilength^2 + iwidth^2)
    length_pad = ceil(idiag-ilength) + 2
    width_pad = ceil(idiag-iwidth) + 2

    # Make enough padding so we don't loose anything on rotation 
    pad_image = zeros(Int(ilength+length_pad), Int(iwidth+width_pad))
    pad_image[Int(ceil(length_pad/2)):Int(ceil(length_pad/2)+ilength-1),
    Int(ceil(width_pad/2)):Int(ceil(width_pad/2)+iwidth-1)] = img;
    

    n = length(theta);
    radon_img = zeros(size(pad_image,2), n)

    # loop over all the angles
    for i in 1:1
        # rotate the padded image
        rotated = imrotate(pad_image, theta[i], axes(pad_image))
        # take the sum along 1 dim to get projection
        radon_img[:, i] = sum(rotated, dims=1)
    end
    return radon_img
end