Convert image to pencil drawing (Not pencil sketch) using imagemagick

Question

I need an application which converts any image to pencil drawing (Not sketch ) like artist does. Exactly like the step2 from step 1 in this question. I have tried the following options.

• Tried the charcol effect + color in effect but it only fits perfectly for sharp color change images. But mine is mostly not.
• Tried canny edge detector and inverting the image: But not getting desired output as it changes according to the clarity of the image.
• Tried the photo copy example here : This suites the purpose but I don't want the shade effect and unwanted pixel dots just need proper outline only.

1- What is the best approach for my requirement ?

2- What are we specifying with the argument string 0x1+10%+20% in cany detection ?

3- How can I remove the pencil shades in photocopy and just get the important outline only ?

4- Is there any other image editing tools out there which fits best ?

Answer 1

I hope the following helps. The functions used below are readily available in OpenCV. You can give it a try.

This is the image I am using for reference:

Pencil Sketching:

sketch_gray, sketch_color = cv2.pencilSketch(img, sigma_s=60, sigma_r=0.07, shade_factor=0.05)

Output of sketch_gray, which is the pencil sketch of the gray scale image:

Output of sketch_color, which is the pencil sketch of the color image:

You can limit the amount of shade in the output by varying the shade_factor in the function cv2.pencilSketch.

And as a bonus cv2.stylization:

stylize = cv2.stylization(img, sigma_s=60, sigma_r=0.07)