Extract Lines of Images Import from Camera

Extract Lines of Images Import from Camera or Scanner

If you want to extract lines from analog art, take a picture of the illustration with your smartphone or camera and extract the lines. In this article, we will talk about “extracting lines”.

Image. Extracting lines from an analog art

Take a picture of the analog art with smartphone/camera

First, take a picture of the hand-drawn illustration. If you pay attention to the following points, you can get an ideal line art.

  • Draw lines as clear as possible
  • Clean up the paper by erasing unnecessary lines and dust
  • Keep the paper wrinkle-free

Also, pay attention to the following when taking pictures with your smartphone/camera.

  • take pictures from above
  • try to avoid shadows
Image. Good and bad examples for extracting lines

The importance of extracting lines and how it works

Ideal lines for digital painting is that all areas except the lines are transparent. If you draw lines digitally on paint tools, you may get such ideal lines easily.

However, since the picture taken by the camera is opaque (Lines are black and the rest is in white), “lines extraction” is necessary to make it suitable for digital painting.

Image. Good and bad examples of line art for digital painting

Lines Extraction

Lines extraction is a process of extracting lines from an opaque image taken from a camera or scanner. It keeps the lines in black and changes the background to transparent.

It is important to adjust the parameters so that lines are clearly extracted and the surrounding area is transparent.

Let’s try it out! Select [Filter] > [Extracting Lines] from the menu.

Image. Click “Extracting Lines” from “Filter”

Adjust the parameter in the window to reduce the noise.

Image. By adjusting the parameter well, you can reduce the noise.

This time, we need to erase the texture of the paper and the  unnecessary draft lines. Therefore, after erasing the texture of the paper, adjust the sharpness of the line. The line extraction is now complete.

Image. The result of line extraction


I colored the extracted line art. Since the line was hand-drawn, it shows a different atmosphere from the digital one.

Image. Colored analog line art
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