Mask Classification

We developed a simple classifier that roughly uses the same strategy as PDFBox, namely:

• define a "mask" on the PDF documents ;
• keep every text bloc within that mask, tag everything else as pollution.

Factories

Two factories are available in the classifiers registry: mask.v1 and custom_masks.v1.

mask.v1

The simplest form. You define the mask, everything else is tagged as a pollution.

Example configuration :

[classifier]
@classifiers = "mask.v1"
x0 = 0.1
y0 = 0.1
x1 = 0.9
y1 = 0.9
threshold = 0.9

custom_masks.v1

A generalisation, wherein the user defines a number of regions.

The following configuration produces exactly the same classifier as mask.v1 example above.

[classifier]
@classifiers = "custom_masks.v1"

[classifier.body]
label = "body"
x0 = 0.1
y0 = 0.1
x1 = 0.9
y1 = 0.9
threshold = 0.9

The following configuration defines a header region.

[classifier]
@classifiers = "custom_masks.v1"

[classifier.header]
label = "header"
x0 = 0.1
y0 = 0.1
x1 = 0.9
y1 = 0.3
threshold = 0.9

[classifier.body]
label = "body"
x0 = 0.1
y0 = 0.3
x1 = 0.9
y1 = 0.9
threshold = 0.9

Any bloc that is not part of a mask is tagged as pollution.