Scanning Grid Frame - Paper Template

[bwente]

I read a great article by Tim Deagan in issue #90 of Make magazine (no free online version, yet.)

Here is a PDF I made from the article he used for straightening photos for engraving and tracing.

Deskewing Frame - Print Out.pdf (2.1 KB)

Here are my best guess on how to use it on other programs… Once you have it cleaned-up you can take it further in make it a vector.

GIMP

1. Open the Image:

• Open GIMP and load your image.

2. Select the Perspective Tool:

• Choose the “Perspective Tool” from the toolbox or press Shift + P.

3. Align the Fiducial Frame:

• Click and drag the corners of the image until the fiducial frame aligns with the grid lines, making sure the corner marks (black circles) form a perfect rectangle.

4. Apply the Transformation:

• Press “Transform” to apply the perspective correction.

5. Measure the Current Size of Corner Marks:

• Use the “Measure Tool” (found under the Tools menu or by pressing Shift + M) to check the current size of the rectangle formed by the corner marks.

6. Scale the Image:

• Select the “Scale Tool” (Shift + T). In the tool options, set the width to 7.25 inches and the height to 9.75 inches, ensuring the aspect ratio is locked. Adjust the size until the measurements match these values.

7. Crop the Image (Optional):

• Use the “Crop Tool” (Shift + C) to remove any unnecessary parts outside the fiducial frame.

8. Export the Image:

• Save your corrected and scaled image.

Affinity Photo

1. Open the Image:

• Open Affinity Photo and load your image.

2. Use the Perspective Tool:

• Select the “Perspective Tool” from the toolbar.

3. Adjust the Perspective:

• Drag the corners of the grid to align with the fiducial frame, ensuring the corner marks form a perfect rectangle.

4. Apply the Changes:

• Click “Apply” to set the transformation.

5. Measure the Current Size of Corner Marks:

• Use the “Rectangle Tool” to draw a rectangle over the corner marks, then check the size in the transform panel.

6. Scale the Image:

• With the “Move Tool” (V), adjust the dimensions so the rectangle measures 7.25 inches by 9.75 inches. Lock the aspect ratio if necessary.

7. Crop the Image (Optional):

• Use the “Crop Tool” (C) to trim any excess areas outside the fiducial frame.

8. Export the Image:

• Save your corrected and scaled image.

Adobe Photoshop

1. Open the Image:

• Open Adobe Photoshop and load your image.

2. Use the Perspective Warp Tool:

• Go to Edit > Perspective Warp.

3. Create a Grid:

• Create a grid around the fiducial frame, ensuring the corner marks form a perfect rectangle.

4. Warp the Image:

• Switch to “Warp” mode and fine-tune the grid to align perfectly with the fiducial frame.

5. Confirm the Changes:

• Press “Enter” to apply the perspective warp.

6. Measure the Current Size of Corner Marks:

• Use the “Ruler Tool” (found under the Eyedropper Tool) to measure the distance between the corner marks.

7. Scale the Image:

• Go to Edit > Transform > Scale or press Ctrl + T (Cmd + T on Mac). Adjust the size until the rectangle measures 7.25 inches by 9.75 inches. Lock the aspect ratio to maintain proportional scaling.

8. Crop the Image (Optional):

• Use the “Crop Tool” (C) to remove any parts outside the fiducial frame.

9. Save the Image:

• Save your corrected and scaled image.

[evansd2]

Nice process.

Wouldn’t using a scanner app instead of the bare camera app do this automatically? I wonder about the performance compared to using this method?

This also relies on the idea that your paper is flat, yeah?

[bwente]

Unfortunately, I can’t post the article here. In the article he mentions products like Trace form Shaper for people who need to do this often. This is more for a one time, quick and free (open source) solution.

[rvogt]

Thanks for the write up and the share!

[ekla]

@evansd2

This also relies on the idea that your paper is flat, yeah?

In the Photoshop section - using Warp would be able to account for non flat paper which standard camera wouldn’t be able to do.

[cynd11]

Thank you!