draft roadmap for v3.x

ROADMAP.md

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+Complete tool reimplementation in python
+Segregate the processing into 4 main tasks
+
+  - Normalization of inputs. 
+    - Inputs can be:
+      - a PDF file
+      - one or several images of any type
+    - What preprocessing does:
+      - In case of PDF file:
+        - If the page needs to be OCRed:
+          - Extract the image corresponding to the page and save it in a tmp folder. 3 approaches to extract the image:
+            - extract raw image from pdf
+            - if not possible: identify resolution and rasterize page
+            - if not possible: use default resolution and rasterize
+        - If not:
+          - Save the page AS-IS in the tmp folder that should contained the final page
+      - In case of separate images:
+        - Just copy the images with standardized name into the tmp folder containing pages to be OCRed
+  - Preprocessing of normalized inputs (perform jobs in parallel)
+    - Identify orientation and skew angle
+    - deskew / rotate image
+    - Clean image
+  - OCRing (perform jobs in parallel)
+    - Just perform OCR in save resulting hocr file for each respective page (to be 
+  - Build output (currently only PDF file generation will be supported)
+    
+
+    
+New temp folder structure:
+
+  - tmp_xxxxx/
+    - a_raw_images (either from images or extracted from pdf file)
+      - page_<xxxx>.<extension>
+    - b_preprocessed_images (after deswing anf cleaning)
+      - page_<xxxx>.<extension>
+    - c_hocr_files
+      - page_<xxxx>.hocr
+    - d_output_pages (one file per page (at first 1 pdf file per page. Later on other formats might be supported)
+      - page_<xxxx>.<extension>
+    - e_final_output (concatenate output pages and conversion into PDF/1-a standard, Later on support other formats)
+      - final.<extension>