Thicken Pixels

Before After

 

Thicken Pixels fills white pixels that are surrounded by a user-defined number of colored pixels. It is particularly useful for improving the quality of “dithered” images like the “Before” image above and for filling cracks in raster lines.

Although Thicken Pixels can improve raster image quality and therefore vectorization results spectacularly it should be used with care. It can also deteriorate the quality of an image by thickening it to the extent that lines that are close to each other become joined.

 

Thicken the whole image

1. Click or select Raster Effects Menu > Thicken > Pixels.
2. In the Preview Window, zoom into the image so that you will be able to clearly see the effects of the thickening.
Warning: If you display a large section of your raster image in the Preview Window this function may operate very slowly.
3. Select a minimum number of Proximity Pixels by moving the slider.

This number can be between 2 and 8 inclusive and works as follows:

 

Before After: Proximity Pixels = 2

If you select 2, Scan2CAD fills each white pixel that is touched by 2 or more colored pixels.

 

Before After: Proximity Pixels = 5

If you select 5, Scan2CAD fills each white pixel that is touched by 5 or more colored pixels.

 

Before After: Proximity Pixels = 8

If you select 8, Scan2CAD fills each white pixel that is touched by 8 colored pixels, i.e. that is completely surrounded.

 

As you move the slider you will see the image in the Preview Window thickening as you move the slider to 2 and then thinning as you move the slider up towards 8.

If you are using Thicken Pixels to mend a dithered image you will need a small value like 2. If you are using it to mend indentations in otherwise solid lines you will need a higher value like 5.

4. Zoom and pan around the image in the Preview Window to make sure the number of Proximity Pixels you have chosen is appropriate to other parts of the image.

In particular, ensure that the number of Proximity Pixels you have chosen has not thickened the image to the extent that lines that are close to each other have become joined. Also check to ensure that areas that are supposed to be white, like the white triangle in the upper half of the letter A, have not been filled.

Adjust the number of Proximity Pixels if necessary.

5. Ensure the Apply changes to Full Image option is selected.
6. Click OK.

 

Click to undo.

 

You will often need to use Thicken Pixels at least twice to significantly improve the quality of a raster image. For example:

Dithered image

After first use of Thicken Pixels

After second use of Thicken Pixels

Vectorized image after using Thicken Pixels twice

 

Thicken part of the image

If you only want to thicken part of the image, choose the part you want to thicken by windowing it or zooming into it, then follow the steps above. In Step 5, ensure the Apply changes to Full Image option is not selected.

 

Special note for color images

If you are working with a color raster image you can modify the way that Thicken Pixels works by selecting a Pick Color.

 

Before

After: no Pick Color

If no Pick Color is selected Scan2CAD fills white pixels that touch pixels of any color.

 

Before

After: Pick Color = blue

If a Pick Color is selected Scan2CAD only fills white pixels that touch Pick Colored pixels.

 

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