Add a function that generates .gt.txt from folder name to all images inside that folder

Makefile

@@ -119,6 +119,9 @@ endif
 
 LOG_FILE = $(OUTPUT_DIR)/training.log
 
+# Folder containing multiple subfolders for gt generation. Default: $(INPUT_DIR)
+INPUT_DIR = images_in_subfolder_has_content_matching_folder_name
+
 # BEGIN-EVAL makefile-parser --make-help Makefile
 
 help:
@@ -138,6 +141,7 @@ help:
 	@echo "    clean-lstmf      Clean generated .lstmf files"
 	@echo "    clean-output     Clean generated output files"
 	@echo "    clean            Clean all generated files"
+	@echo "    generate-gt-from-folder-name  Generate .gt.txt files for images based on their parent folder names and organize them in the Tesseract training directory structure or the specified output directory"
 	@echo ""
 	@echo "  Variables"
 	@echo ""
@@ -177,7 +181,7 @@ endif
 
 .PRECIOUS: $(LAST_CHECKPOINT)
 
-.PHONY: clean help lists proto-model tesseract-langdata training unicharset charfreq
+.PHONY: clean help lists proto-model tesseract-langdata training unicharset charfreq generate-gt-from-folder-name
 
 ALL_FILES = $(and $(wildcard $(GROUND_TRUTH_DIR)),$(shell find -L $(GROUND_TRUTH_DIR) -name '*.gt.txt'))
 unexport ALL_FILES # prevent adding this to envp in recipes (which can cause E2BIG if too long; cf. make #44853)
@@ -194,6 +198,37 @@ charfreq: $(ALL_GT)
 # Create lists of lstmf filenames for training and eval
 lists: $(OUTPUT_DIR)/list.train $(OUTPUT_DIR)/list.eval
 
+# Supported image extensions
+IMAGE_EXTENSIONS=-iname "*.jpg" -o -iname "*.jpeg" -o -iname "*.png" -o \
+                 -iname "*.tif" -o -iname "*.tiff" -o -iname "*.bmp" -o -iname "*.gif"
+
+# Generate .gt.txt files for images based on their parent folder names and organize them in the Tesseract training directory structure or the specified output directory
+generate-gt-from-folder-name:
+	@# Check if INPUT_DIR exists
+	@if [ ! -d "$(INPUT_DIR)" ]; then \
+		echo "Error: Input directory '$(INPUT_DIR)' does not exist!" >&2; \
+		exit 1; \
+	fi
+	@# Check that at least one subdirectory exists
+	@if [ $$(find "$(INPUT_DIR)" -mindepth 1 -maxdepth 1 -type d | wc -l) -eq 0 ]; then \
+		echo "Error: '$(INPUT_DIR)' must contain at least one subdirectory!" >&2; \
+		exit 1; \
+	fi
+	@# Check for valid image files
+	@if [ $$(find "$(INPUT_DIR)" -mindepth 2 -maxdepth 2 -type f \( $(IMAGE_EXTENSIONS) \) | wc -l) -eq 0 ]; then \
+		echo "Error: No valid images found in any subdirectory of '$(INPUT_DIR)'!" >&2; \
+		exit 1; \
+	fi
+	@# Create the output directory if it does not exist
+	@mkdir -p "$(GROUND_TRUTH_DIR)"
+	@# Execute the ground truth generation script
+	@$(PY_CMD) generate_gt_from_folder.py "$(INPUT_DIR)" "$(GROUND_TRUTH_DIR)"
+	@# Verify that output files were generated
+	@if [ $$(ls "$(GROUND_TRUTH_DIR)" | wc -l) -eq 0 ]; then \
+		echo "Warning: No ground truth files were generated in '$(GROUND_TRUTH_DIR)'!" >&2; \
+		exit 1; \
+	fi
+
 $(OUTPUT_DIR):
 	@mkdir -p $@
 

generate_gt_from_folder.py

@@ -0,0 +1,73 @@
+import shutil
+import argparse
+from pathlib import Path
+import sys
+from typing import List, Set
+
+
+def get_image_files(input_dir: Path, extensions: Set[str]) -> List[Path]:
+    """Get image files (only in first-level subdirectories) with matching extensions."""
+    return [
+        file
+        for folder in input_dir.iterdir() if folder.is_dir()
+        for file in folder.iterdir() if file.suffix.lower() in extensions
+    ]
+
+
+def get_unique_base(output_dir: Path, base: str, ext: str) -> str:
+    """Find a unique base name efficiently without excessive looping."""
+    candidate = base
+    counter = 1
+    existing_files = {f.stem for f in output_dir.glob("*")}  # Cache existing filenames for faster lookup
+
+    while candidate in existing_files:
+        candidate = f"{base}_{counter}"
+        counter += 1
+
+    return candidate
+
+
+def generate_gt_from_folders(input_dir: Path, output_dir: Path) -> int:
+    """Generate .gt.txt files for each image where the text file contains the parent folder's name."""
+    print("Ground-Truth generation beginning...")
+    output_dir.mkdir(parents=True, exist_ok=True)
+
+    image_extensions = {'.png', '.jpg', '.jpeg', '.tif', '.tiff', '.bmp', '.gif'}
+    image_files = get_image_files(input_dir, image_extensions)
+
+    total_files = 0
+
+    for file_path in image_files:
+        folder_name = file_path.parent.name
+        base_name = file_path.stem
+        ext = file_path.suffix.lower()
+
+        unique_base = get_unique_base(output_dir, base_name, ext)
+        dest_image = output_dir / f"{unique_base}{ext}"
+        txt_filepath = output_dir / f"{unique_base}.gt.txt"
+
+        try:
+            txt_filepath.write_text(folder_name, encoding='utf-8')
+            shutil.copy(file_path, dest_image)  # Faster than copy2()
+            total_files += 1
+            print(f"Processed: {file_path.name} -> {folder_name}")
+        except (IOError, OSError) as e:
+            print(f"Error processing {file_path}: {e}", file=sys.stderr)
+
+    print(f"Done! Processed {total_files} image files.")
+    return total_files
+
+
+def main():
+    parser = argparse.ArgumentParser(description="Generate .gt.txt files from folder names for Tesseract training")
+    parser.add_argument('input_dir', type=Path, help='Input directory containing subfolders with images')
+    parser.add_argument('output_dir', type=Path, help='Output directory')
+    args = parser.parse_args()
+
+    count = generate_gt_from_folders(args.input_dir.resolve(), args.output_dir.resolve())
+    if count == 0:
+        sys.exit(1)
+
+
+if __name__ == "__main__":
+    main()