Preprocessor package¶
Submodules¶
Preprocessor.PreprocessImages module¶
This module is responsible for preprocessing images to make them more suitable for Tesseract-OCR.
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class
Preprocessor.PreprocessImages.
Preprocess
¶ Bases:
object
This class preprocesses the image by applying filters and manipulations.
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gray_scale
(image)¶ Applies grayscale on the image.
Parameters: image – The image to be preprocessed. Returns: Grayscaled image.
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gaussian_blur
(image)¶ Applies gaussian blur on the image.
Parameters: image – The image to be preprocessed. Returns: Gaussian blurred image.
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filter2d
(image)¶ Applies 2D convolution on the image.
Parameters: image – The image to be preprocessed. Returns: 2D Convoluted image.
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binary_threshold
(image)¶ Applies a binary threshold combined with Otsu’s binarization on the image.
Parameters: image – The image to be preprocessed. Returns: Binary thresholded image (i.e. black and white).
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binary_adaptive_threshold
(image)¶ Applies a adaptive binary threshold.
Parameters: image – The image to be preprocessed. Returns: Binary thresholded image (i.e. black and white).
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normalisation
(image)¶ Applies a histogram based normalisation to image to increase contrast.
Parameters: image – The image to be preprocessed. Returns: Normalisated image
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white_boarder
(image)¶ Applies a white boarder to image the size of the hight of the given image
Parameters: image – The image to be preprocessed. Returns: Image with white boarder
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median_blur
(image)¶ Applies a median blur on the image.
Parameters: image – The image to be preprocessed. Returns: Median blurred image.
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erosion
(image)¶ Applies erosion on the image.
Parameters: image – The image to be preprocessed. Returns: Eroded image.
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perspective_transform
(image)¶ Corrects for deformations created by the camera.
Parameters: image – the (color) image to be preprocessed. Returns: Corrected image
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preprocess_image
(pp_sequence, image)¶ This function runs the preprocessing based on a supplied selection and sequence.
The getattr() function is used to call a function based on a String value. For example, the string ‘erosion’ can be used to call the method erosion() in this module.
Parameters: - pp_sequence – The selection and sequence of the preprocessor operations
- image – The image to be preprocessed.
Returns: Preprocessed image.
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