Saying the ICDAR 2023 Competitors on Hierarchical Textual content Detection and Recognition – Google AI Weblog


The previous couple of many years have witnessed the speedy improvement of Optical Character Recognition (OCR) expertise, which has developed from an tutorial benchmark process utilized in early breakthroughs of deep studying analysis to tangible merchandise obtainable in shopper gadgets and to third celebration builders for day by day use. These OCR merchandise digitize and democratize the dear data that’s saved in paper or image-based sources (e.g., books, magazines, newspapers, kinds, road indicators, restaurant menus) in order that they are often listed, searched, translated, and additional processed by state-of-the-art pure language processing methods.

Analysis in scene textual content detection and recognition (or scene textual content recognizing) has been the foremost driver of this speedy improvement via adapting OCR to pure photos which have extra complicated backgrounds than doc photos. These analysis efforts, nevertheless, deal with the detection and recognition of every particular person phrase in photos, with out understanding how these phrases compose sentences and articles.

Structure evaluation is one other related line of analysis that takes a doc picture and extracts its construction, i.e., title, paragraphs, headings, figures, tables and captions. These structure evaluation efforts are parallel to OCR and have been largely developed as impartial methods which are usually evaluated solely on doc photos. As such, the synergy between OCR and structure evaluation stays largely under-explored. We consider that OCR and structure evaluation are mutually complementary duties that allow machine studying to interpret textual content in photos and, when mixed, may enhance the accuracy and effectivity of each duties.

With this in thoughts, we announce the Competitors on Hierarchical Textual content Detection and Recognition (the HierText Problem), hosted as a part of the seventeenth annual Worldwide Convention on Doc Evaluation and Recognition (ICDAR 2023). The competitors is hosted on the Strong Studying Competitors web site, and represents the primary main effort to unify OCR and structure evaluation. On this competitors, we invite researchers from around the globe to construct methods that may produce hierarchical annotations of textual content in photos utilizing phrases clustered into traces and paragraphs. We hope this competitors may have a major and long-term impression on image-based textual content understanding with the objective to consolidate the analysis efforts throughout OCR and structure evaluation, and create new indicators for downstream data processing duties.

The idea of hierarchical textual content illustration.

Setting up a hierarchical textual content dataset

On this competitors, we use the HierText dataset that we printed at CVPR 2022 with our paper “In direction of Finish-to-Finish Unified Scene Textual content Detection and Structure Evaluation”. It’s the primary real-image dataset that gives hierarchical annotations of textual content, containing phrase, line, and paragraph degree annotations. Right here, “phrases” are outlined as sequences of textual characters not interrupted by areas. “Strains” are then interpreted as “area“-separated clusters of “phrases” which are logically linked in a single route, and aligned in spatial proximity. Lastly, “paragraphs” are composed of “traces” that share the identical semantic subject and are geometrically coherent.

To construct this dataset, we first annotated photos from the Open Pictures dataset utilizing the Google Cloud Platform (GCP) Textual content Detection API. We filtered via these annotated photos, maintaining solely photos wealthy in textual content content material and structure construction. Then, we labored with our third-party companions to manually right all transcriptions and to label phrases, traces and paragraph composition. Because of this, we obtained 11,639 transcribed photos, break up into three subsets: (1) a prepare set with 8,281 photos, (2) a validation set with 1,724 photos, and (3) a check set with 1,634 photos. As detailed within the paper, we additionally checked the overlap between our dataset, TextOCR, and Intel OCR (each of which additionally extracted annotated photos from Open Pictures), ensuring that the check photos within the HierText dataset weren’t additionally included within the TextOCR or Intel OCR coaching and validation splits and vice versa. Beneath, we visualize examples utilizing the HierText dataset and exhibit the idea of hierarchical textual content by shading every textual content entity with totally different colours. We will see that HierText has a range of picture area, textual content structure, and excessive textual content density.

Samples from the HierText dataset. Left: Illustration of every phrase entity. Center: Illustration of line clustering. Proper: Illustration paragraph clustering.

Dataset with highest density of textual content

Along with the novel hierarchical illustration, HierText represents a brand new area of textual content photos. We be aware that HierText is at the moment essentially the most dense publicly obtainable OCR dataset. Beneath we summarize the traits of HierText compared with different OCR datasets. HierText identifies 103.8 phrases per picture on common, which is greater than 3x the density of TextOCR and 25x extra dense than ICDAR-2015. This excessive density poses distinctive challenges for detection and recognition, and as a consequence HierText is used as one of many main datasets for OCR analysis at Google.

Dataset       Coaching break up       Validation break up       Testing break up       Phrases per picture      
ICDAR-2015       1,000       0       500       4.4      
TextOCR       21,778       3,124       3,232       32.1      
Intel OCR       19,1059       16,731       0       10.0      
HierText       8,281       1,724       1,634       103.8

Evaluating a number of OCR datasets to the HierText dataset.

Spatial distribution

We additionally discover that textual content within the HierText dataset has a way more even spatial distribution than different OCR datasets, together with TextOCR, Intel OCR, IC19 MLT, COCO-Textual content and IC19 LSVT. These earlier datasets are inclined to have well-composed photos, the place textual content is positioned in the midst of the photographs, and are thus simpler to determine. Quite the opposite, textual content entities in HierText are broadly distributed throughout the photographs. It is proof that our photos are from extra various domains. This attribute makes HierText uniquely difficult amongst public OCR datasets.

Spatial distribution of textual content situations in several datasets.

The HierText problem

The HierText Problem represents a novel process and with distinctive challenges for OCR fashions. We invite researchers to take part on this problem and be part of us in ICDAR 2023 this 12 months in San Jose, CA. We hope this competitors will spark analysis neighborhood curiosity in OCR fashions with wealthy data representations which are helpful for novel down-stream duties.


The core contributors to this challenge are Shangbang Lengthy, Siyang Qin, Dmitry Panteleev, Alessandro Bissacco, Yasuhisa Fujii and Michalis Raptis. Ashok Popat and Jake Walker offered beneficial recommendation. We additionally thank Dimosthenis Karatzas and Sergi Robles from Autonomous College of Barcelona for serving to us arrange the competitors web site.


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