Automatically Digitize Graph Using Luminosity Recognition Method - ByteScout

Automatically Digitize Graph Using Luminosity Recognition Method

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How to digitize graph using luminosity recognition method in Graph Digitizer Scout

This page contains step-by-step tutorial that will teach you how to digitize graph using luminosity recognition method in Graph Digitizer Scout software.

First download, install and run Graph Digitizer Scout

This tutorial will show step by step how to digitize graph on the picture using luminosity recognition method

In this example we will digitize the following picture scanned from a journal:

Source scanned picture for chart digitizing

Run Graph Digitizer Scout:

Graph Digitizer Scout software main window

Open file with the scanned picture (you can also directly scan picture from Graph Digitizer Scout):

Open command in File menu lets to open image file for auto digitizing

Open picture with scanned graph to digitize

Now use “Coordinates Binding” tool to bind graph to 4 points so program will properly recognize X and Y coordinates without additional rotation of the image. Click on tool button and select By 4 Points mode:

Set binding by 4 points

Now click on this points to set them: minX, maxX, minY, maxY

Set Xmin, Xmax, Ymin and Ymax points to bind grid to source grid

After you’ve pointed all 4 base points, the program will show Set Coordinates confirmation window.

Enter coordinates of Xmin, Xmax, Ymin, Ymax points as you see them on the original picture.

Click OK

Enter real values of Xmin, Xmax, Ymin and Ymax

Program will rotate picture automatically according to base points:

Automatically rotated source image

Then we should apply blur effect graph the picture for better graph recognition. Change Blur on Picture tab to 2:

Blur effect applied to a picture for better results in automatic digitizing

Now we should set digitization region. Use Set Digitization Region tool button.

Click Select Digitization Region tool button

Select Region option and click button and select rectangle region using mouse

Digitization region on the source image

IMPORTANT: set minimum region and try to set graph only without original grid on the source picture.

Incorrect digitization regionCorrect digitization region

As we are going to use luminosity recognition method so we should invert picture colors by checking “Negative” parameter on Picture tab:

Negative effect applied to the image

Set recognition method to By Max Brightness by pressing F5

Then press F9 to digitize graph:

Digitized graph automatically recognized using brightness recognition method

Save generated data to the file when correction is done:

Save Data command in File menu to save digitized graph data to file

Select folder and filename to save data:

Select filename to save output data to

You can also simply copy this data to the clipboard for use in MS Excel:

Copy command in Edit menu to copy digitized data to clipboard

In Excel use Edit | Paste to insert data from clipboard:

Paste from clipboard command in Edit menu in MS Excel

Points coordinates pasted to the worksheet:

Data copied and pasted from Graph Digitizer Scout to MS Excel

Then you you can create a chart using pasted data (A column in Excel contains X coordinates, B column in Excel contains Y coordinates)

To add a chart just use Chart command in the Insert menu:

Insert new chart based on the selected data in Excel

For example select XY chart type and click OK

Selecting a new chart type

Excel will add a chart to the worksheet:

New chart generated using data copied from Graph Digitizer Scout

You can also paste data to Mathlab.