Operator Reference
get_deep_ocr_param (Operator)
get_deep_ocr_param — Return the parameters of a Deep OCR model.
Signature
get_deep_ocr_param( : : DeepOcrHandle, GenParamName : GenParamValue)
Description
get_deep_ocr_param returns the parameter values
GenParamValue of GenParamName for the Deep OCR model
DeepOcrHandle.
Parameters can apply to the whole model or be specific for a given component. The following table gives an overview, which parameters can be set and which ones retrieved as well as for which model part they apply.
GenParamName |
Model | Det. comp. | Recog. comp. |
|---|---|---|---|
| 'device' | |||
| 'detection_device' | |||
| 'detection_image_dimensions' | |||
| 'detection_image_height' | |||
| 'detection_image_size' | |||
| 'detection_image_width' | |||
| 'detection_min_character_score' | |||
| 'detection_min_link_score' | |||
| 'detection_min_word_area' | |||
| 'detection_min_word_score' | |||
| 'detection_model' | |||
| 'detection_orientation' | |||
| 'detection_sort_by_line' | |||
| 'detection_tiling' | |||
| 'detection_tiling_overlap' | |||
| 'recognition_alphabet' | |||
| 'recognition_alphabet_internal' | |||
| 'recognition_alphabet_mapping' | |||
| 'recognition_batch_size' | |||
| 'recognition_device' | |||
| 'recognition_image_dimensions' | |||
| 'recognition_image_height' | |||
| 'recognition_image_width' | |||
| 'recognition_model' | |||
| 'recognition_num_char_candidates' | |||
-
's': The parameter can be set using
set_deep_ocr_param. -
'g': The parameter can be retrieved using
get_deep_ocr_param. -
'-': The parameter is not applicable.
-
Model: Entire Deep OCR model with all its components.
-
Det. comp.: Detection component.
-
Recog. comp.: Recognition component.
Only parameters that do not change the model architecture can be set after
the model has been optimized with optimize_dl_model_for_inference.
A list of these parameters can be found at
optimize_dl_model_for_inference.
In the following the parameters are described, sorted according to the part
of the model they apply to:
- Entire model:
-
- 'device':
-
Handle of the device on which the model will be executed. To get a tuple of handles of all available potentially Deep-OCR-capable compute devices use
query_available_dl_devices.Note, the device can be reset for an individual component, in which case only the possibly remaining part of the model (e.g., the remaining component) will be executed on the device of this handle.
Default: Handle of the default device, thus the GPU with index 0 when querying a list using
get_systemwith 'cuda_devices'. If no device is available, this is an empty tuple.
- Detection component:
-
- 'detection_device':
-
This parameter will set the device on which the detection component of the Deep OCR model is executed. For a further description, see 'device'.
Default: The same value as for 'device'.
- 'detection_image_dimensions':
-
Tuple containing the image dimensions ('detection_image_width', 'detection_image_height', number of channels) the detection component will process.
The input image is scaled to 'detection_image_dimensions' such that the original aspect ratio is preserved. The scaled image is padded with gray value 0 if necessary. Therefore, changing the 'detection_image_height' or 'detection_image_width' can influence the results.
Default: [1024, 1024, 3]
- 'detection_image_height':
-
Height of the images the detection component will process. This means, the network preserves the aspect ratio of the input image by scaling it to a maximum of this height before processing it. Thus this size can influence the results.
The model architecture requires that the height is a multiple of 32. If this is not the case, the height is rounded up to the nearest integer multiple of 32.
Suggested values: 768, 1024, 1280
Default: 1024
- 'detection_image_size':
-
Tuple containing the image size ('detection_image_width', 'detection_image_height') the detection component will process.
Default: [1024, 1024]
- 'detection_image_width':
-
Width of the images the detection component will process. This means, the network preserves the aspect ratio of the input image by scaling it to a maximum of this width before processing it. Thus this size can influence the results.
The model architecture requires that the width is a multiple of 32. If this is not the case, the width is rounded up to the nearest integer multiple of 32.
Suggested values: 768, 1024, 1280
Default: 1024
- 'detection_min_character_score':
-
The parameter 'detection_min_character_score' specifies the lower threshold used for the character score map to estimate the dimensions of the characters. By adjusting the parameter, suggested instances can be split up or neighboring instances can be merged.
Value range: .
Default: 0.5
- 'detection_min_link_score':
-
The parameter 'detection_min_link_score' defines the minimum link score required between two localized characters to recognize these characters as coherent word.
Value range: .
Default: 0.3
- 'detection_min_word_area':
-
The parameter 'detection_min_word_area' defines the minimum size that a localized word must have in order to be suggested. This parameter can be used to filter suggestions that are too small.
Value range: .
Default: 10.
- 'detection_min_word_score':
-
The parameter 'detection_min_word_score' defines the minimum score a localized instance must contain to be suggested as valid word. With this parameter uncertain words can be filtered out.
Value range: .
Default: 0.7
- 'detection_model':
-
The operator
get_deep_ocr_paramreturns the handle of the Deep OCR model component for word detection. Usingset_deep_ocr_paramit is possible to either specify a handle, filename or special string. As a special string only 'default' and 'compact' are allowed. In case of 'default' the default pretrained word detection component is loaded (i.e. 'pretrained_deep_ocr_detection.hdl'). In case of 'compact', a more efficient word detection component is loaded (i.e. 'pretrained_deep_ocr_detection_compact.hdl'). If the given value is a string the model is loaded internally and the batch size is set to 1.Suggested values: 'default', 'compact', filename.
Default: 'default'
- 'detection_orientation':
-
This parameter allows to set a predefined orientation angle for the word detection. To revert to default behavior using the internal orientation estimation, 'detection_orientation' is set to 'auto'.
Value range: .
Default: 'auto'
- 'detection_sort_by_line':
-
The words are sorted line-wise based on the orientation of the localized word instances. If the parameter 'detection_sort_by_line' is set to 'false', the results will not be sorted.
Default: 'true'
- 'detection_tiling':
-
The input image is automatically split into overlapping tile images of size 'detection_image_size', which are processed separately by the detection component. This allows processing images that are much larger than the actual 'detection_image_size' without having to zoom the input image. Thus, if 'detection_tiling' = {'true'}, the input image will not be zoomed before processing it.
Default: 'false'
- 'detection_tiling_overlap':
-
This parameter defines how much neighboring tiles overlap when input images are split (see 'detection_tiling'). The overlap is given in pixels.
Value range: .
Default: 64
- Recognition component:
-
- 'recognition_alphabet':
-
The character set that can be recognized by the Deep OCR model.
It contains all characters that are not mapped to the Blank character of the internal alphabet (see parameters 'recognition_alphabet_mapping' and 'recognition_alphabet_internal').
The alphabet can be changed or extended if needed. Changing the alphabet with this parameter will edit the internal alphabet and mapping in such a way that it tries to keep the length of the internal alphabet unchanged. After changing the alphabet, it is recommended to retrain the model on application specific data (see the HDevelop example
deep_ocr_recognition_training_workflow.hdev). Previously unknown characters will need more training data.Note, that if the length of the internal alphabet changes, the last model layers have to be randomly initialized and thus the output of the model will be random strings (see 'recognition_alphabet_internal'). In that case it is required to retrain the model.
- 'recognition_alphabet_internal':
-
The full character set which the Deep OCR recognition component has been trained on.
The first character of the internal alphabet is a special character. In the pretrained model this character is specified as Blank (U+2800) and is not to be confused with a space. The Blank is never returned in a word output but can occur in the reported character candidates. It is required and cannot be omitted. If the internal alphabet is changed, the first character has to be the Blank. Furthermore, if 'recognition_alphabet' is used to change the alphabet, the Blank symbol is added automatically to the character set.
The length of this tuple corresponds to the depth of the last convolution layer in the model. If the length changes, the last convolution layer and all layers after it have to be resized and potentially reinitialized randomly. After such a change, it is required to retrain the model (see HDevelop example
deep_ocr_recognition_training_workflow.hdev).It is recommend to use the parameter 'recognition_alphabet' to change the alphabet, as it will automatically try to preserve the length of the internal alphabet.
- 'recognition_alphabet_mapping':
-
Tuple of integer indices.
It is a mapping that is applied by the model during the decoding step of each word. The mapping overwrites a character of 'recognition_alphabet_internal' with the character at the specified index in 'recognition_alphabet_internal'.
In the decoding step each prediction is mapped according to the index specified in this tuple. The tuple has to be of same length as the tuple 'recognition_alphabet_internal'. Each integer index of the mapping has to be within 0 and |'recognition_alphabet_internal'|-1.
In some applications it can be helpful to map certain characters onto other characters. E.g. if only numeric words occur in an application it might be helpful to map the character "O" to the "0" character without the need to retrain the model.
If an entry contains a 0, the corresponding character in 'recognition_alphabet_internal' will not be decoded in the word.
- 'recognition_batch_size':
-
Number of images in a batch that is transferred to device memory and processed in parallel in the recognition component. For further details, please refer to the reference documentation of
apply_dl_modelwith respect to the parameter 'batch_size'. This parameter can be used to optimize the runtime ofapply_deep_ocron a given dl device. If the recognition component has to process multiple inputs (words), processing multiple inputs in parallel can result in a faster execution ofapply_deep_ocr. Note, however, that a higher 'recognition_batch_size' will require more device memory.Default: 1
- 'recognition_device':
-
This parameter will set the device on which the recognition component of the Deep OCR model is executed. For a further description, see 'device'.
Default: The same value as for 'device'.
- 'recognition_image_dimensions':
-
Tuple containing the image dimensions ('recognition_image_width', 'recognition_image_height', number of channels) the recognition component will process.
This means, the network will first zoom the input image part to 'recognition_image_height' while maintaining the aspect ratio of the input. If the width of the resulting image is smaller than 'recognition_image_width', the image part is padded with gray value 0 on the right. If it is larger, the image is zoomed to 'recognition_image_width'.
Default: [120, 32, 1]
- 'recognition_image_height':
-
Height of the images the recognition component will process.
Default: 32
- 'recognition_image_width':
-
Width of the images the recognition component will process.
Default: 120
- 'recognition_model':
-
The operator
get_deep_ocr_paramreturns the handle of the Deep OCR model component for word recognition.Using
set_deep_ocr_paramit is possible to either specify a handle, filename or 'default'. In case of 'default' the pretrained word recognition component is loaded (i.e. 'pretrained_deep_ocr_recognition.hdl'). If the given value is a string the model is loaded internally and the batch size is set to 1.Suggested values: 'default', filename.
Default: 'default'
- 'recognition_num_char_candidates':
-
Controls the number of reported character candidates in the result of the operator
apply_deep_ocr.Default: 3
Execution Information
- Multithreading type: reentrant (runs in parallel with non-exclusive operators).
- Multithreading scope: global (may be called from any thread).
- Processed without parallelization.
Parameters
DeepOcrHandle (input_control) deep_ocr → (handle)
Handle of the Deep OCR model.
GenParamName (input_control) attribute.name → (string)
Name of the generic parameter.
Default: 'recognition_model'
List of values: 'detection_device', 'detection_image_dimensions', 'detection_image_height', 'detection_image_size', 'detection_image_width', 'detection_min_character_score', 'detection_min_link_score', 'detection_min_word_area', 'detection_min_word_score', 'detection_model', 'detection_orientation', 'detection_sort_by_line', 'detection_tiling', 'detection_tiling_overlap', 'recognition_alphabet', 'recognition_alphabet_internal', 'recognition_alphabet_mapping', 'recognition_batch_size', 'recognition_device', 'recognition_image_dimensions', 'recognition_image_height', 'recognition_image_width', 'recognition_model', 'recognition_num_char_candidates'
GenParamValue (output_control) attribute.value(-array) → (integer / handle / string / real)
Value of the generic parameter.
Result
If the parameters are valid, the operator get_deep_ocr_param
returns the value 2 (
H_MSG_TRUE)
. If necessary, an exception is raised.
Possible Predecessors
create_deep_ocr,
set_deep_ocr_param
Possible Successors
set_deep_ocr_param,
apply_deep_ocr
See also
Module
OCR/OCV