In the original image used to generate the three

blurred images shown, the vertical bars are $5$ pixels wide, $100$ pixels high, and their separation is

$20$ pixels. The image was blurred using square box

kernels of sizes $23,25,$ and $45$ elements on the side,

respectively. The vertical bars on the left, lower

part of $($a$)$ and $($c$)$ are blurred, but a clear sseparation exists between them.