- (
`ren1`) The original image.

- (
`ren1sob1`) Result of applying the Sobel edge detector to

`ren1`.- (
`ren1sob2`) The normalized result of applying the Sobel edge detector to a scaled version (

*i.e.*intensity reduction by a factor of 4) of`ren1`.- (
`ren1can1`) Result of applying the Canny edge detector (Gaussian smoothing standard deviation = 1, upper threshold = 255, lower threshold = 1) to

`ren1`.- (
`ren1can2`) Result of applying the Canny edge detector (Gaussian smoothing standard deviation = 1.8, upper threshold = 255, lower threshold = 1) to

`ren1`.- (
`ren1can3`) Result of applying the Canny edge detector (Gaussian smoothing standard deviation = 1.8, upper threshold = 200, lower threshold = 1) to a scaled version (

*i.e.*intensity reduction by a factor of 4) of`ren1`.