append_ocr_trainf🔗
Short description🔗
append_ocr_trainf — Add characters to a training file.
Signature🔗
append_ocr_trainf( region Character, image Image, string Class, filename.write TrainingFile )
Description🔗
The operator append_ocr_trainf serves to prepare the
training with the operator trainf_ocr_class_mlp or
trainf_ocr_class_svm. Hereby
regions, representing characters, including their gray values (region
and pixel) and the corresponding class name will be written into a
file. An arbitrary number of regions within one image is supported.
For each character (region) in Character the corresponding
class name must be specified in Class. The gray values are
passed via the parameter Image. In
contrast to the operator write_ocr_trainf the
characters are appended to an existing file using the same training file
format as this file. If
the file does not exist, a new file is generated. In this case, the
file format can be chosen by the parameter
'ocr_trainf_version' of the operator set_system. If no
file extension is specified in TrainingFile, the extension ‘.trf’
is appended to the name.
Execution information🔗
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🔗
Character (input_object) region(-array) → object
Characters to be trained.
Image (input_object) singlechannelimage → object (byte / uint2)
Gray values of the characters.
Class (input_control) string(-array) → (string)
Class (name) of the characters.
TrainingFile (input_control) filename.write → (string)
Name of the training file.
Default: 'train_ocr'
File extension: .trf, .otr
Example🔗
(C)
char name[128]\;
char class[128]\;
read_image(&Image,"character.tiff")\;
binary_threshold(Image,&Dark, 'otsu', 'dark', &UsedThreshold)\;
connection(Dark,&Character)\;
count_obj(Character,&num)\;
create_tuple(&Class,num)\;
open_window(0,0,-1,-1,0,"","",&WindowHandle)\;
set_color(WindowHandle,"red")\;
for (i=0\; i<num\; i++) {
select_obj(Character,&SingleCharacter,i)\;
disp_region(SingleCharacter,WindowHandle)\;
printf("class of character %d ?\n",i)\;
scanf("%s\n",class)\;
append_ocr_trainf(Character,Image,name,class)\;
}
Result🔗
If the parameters are correct, the operator
append_ocr_trainf returns the value 2 (H_MSG_TRUE).
Otherwise an exception will be raised.
Combinations with other operators🔗
Combinations
Possible predecessors
threshold, connection, read_ocr_trainf
Possible successors
trainf_ocr_class_mlp, trainf_ocr_class_svm, write_ocr_trainf
Alternatives
Module🔗
OCR/OCV