text_createERFilterNM2

textfunctionOpenCV 5.0.0

import { text_createERFilterNM2 } from '@banou/opencv-wasm'

Use after await initOpenCV(). See the initialization and named imports guide.

Explore visually: Text-region detection →

Find candidate text regions before character recognition.

VISUAL WALKTHROUGHText

REFERENCE INPUTText in an image

Characters are pixels before a recognizer assigns text to them.

→

RESULTReturn a text region

Detection returns geometry. Recognition is a separate operation.

Illustrative example. The stages explain the method; they are not a live OpenCV execution.

Create an Extremal Region Filter for the 2nd stage classifier of N&M algorithm [Neumann12].

text_createERFilterNM2(cb: text_ERFilter_Callback | null, minProbability: number): text_ERFilter | null;

2 available overloads

text_createERFilterNM2(cb: text_ERFilter_Callback | null): text_ERFilter | null;

text_createERFilterNM2(cb: text_ERFilter_Callback | null, minProbability: number): text_ERFilter | null;

cb

: Callback with the classifier. Default classifier can be implicitly load with function loadClassifierNM2, e.g. from file in samples/cpp/trained_classifierNM2.xml

minProbability

: The minimum probability P(er|character) allowed for retreived ER's

In the second stage, the ERs that passed the first stage are classified into character and non-character classes using more informative but also more computationally expensive features. The classifier uses all the features calculated in the first stage and the following additional features: hole area ratio, convex hull ratio, and number of outer inflexion points.

Returns

The text_ERFilter | null result.

Upstream declaration ↗

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