Construct Your Personal OCR Engine for Wingdings

Optical Character Recognition (OCR) has revolutionized the best way we work together with textual information in actual life, enabling machines to learn and interpret textual content from photos, scanned paperwork, and handwritten notes. From digitizing books and automating information entry to real-time textual content translation in augmented actuality, OCR functions are extremely various and impactful. A few of its software could embody:

• Doc Digitization: Converts bodily paperwork into editable and searchable digital codecs.
• Bill Scanning: Extracts particulars like quantities, dates, and vendor names for automated processing.
• Knowledge Entry Automation: Hastens workflows by extracting textual content from varieties and receipts.
• Actual-Time Translation: Interprets international textual content from photos or video streams in augmented actuality.
• License Plate Recognition: Identifies autos in site visitors programs and parking administration.
• Accessibility Instruments: Converts textual content to speech for visually impaired people.
• Archiving and Preservation: Digitizes historic paperwork for storage and analysis.

On this submit, we take OCR a step additional by constructing a customized OCR mannequin for recognizing textual content within the Wingdings font—a symbolic font with distinctive characters typically utilized in artistic and technical contexts. Whereas conventional OCR fashions are skilled for traditional textual content, this tradition mannequin bridges the hole for area of interest functions, unlocking potentialities for translating symbolic textual content into readable English, whether or not for accessibility, design, or archival functions. By this, we reveal the ability of OCR to adapt and cater to specialised use instances within the trendy world.

Is There a Want for Customized OCR within the Age of Imaginative and prescient-Language Fashions?

Imaginative and prescient-language fashions, reminiscent of Flamingo, Qwen2-VL, have revolutionized how machines perceive photos and textual content by bridging the hole between the 2 modalities. They’ll course of and motive about photos and related textual content in a extra generalized method.

Regardless of their spectacular capabilities, there stays a necessity for customized OCR programs in particular eventualities, primarily as a consequence of:

• Accuracy for Particular Languages or Scripts: Many vision-language fashions deal with widely-used languages. Customized OCR can handle low-resource or regional languages, together with Indic scripts, calligraphy, or underrepresented dialects.
• Light-weight and Useful resource-Constrained Environments: Customized OCR fashions may be optimized for edge units with restricted computational energy, reminiscent of embedded programs or cell functions. Imaginative and prescient-language fashions, in distinction, are sometimes too resource-intensive for such use instances. For real-time or high-volume functions, reminiscent of bill processing or automated doc evaluation, customized OCR options may be tailor-made for pace and accuracy.
• Knowledge Privateness and Safety: Sure industries, reminiscent of healthcare or finance, require OCR options that function offline or inside non-public infrastructures to fulfill strict information privateness laws. Customized OCR ensures compliance, whereas cloud-based vision-language fashions may introduce safety issues.
• Value-Effectiveness: Deploying and fine-tuning huge vision-language fashions may be cost-prohibitive for small-scale companies or particular initiatives. Customized OCR is usually a extra inexpensive and targeted various.

Construct a Customized OCR Mannequin for Wingdings

To discover the potential of customized OCR programs, we’ll construct an OCR engine particularly for the Wingdings font.

Beneath are the steps and parts we’ll comply with:

• Generate a customized dataset of Wingdings font photos paired with their corresponding labels in English phrases.
• Create a customized OCR mannequin able to recognizing symbols within the Wingdings font. We are going to use the Imaginative and prescient Transformer for Scene Textual content Recognition (ViTSTR), a state-of-the-art structure designed for image-captioning duties. Not like conventional CNN-based fashions, ViTSTR leverages the transformer structure, which excels at capturing long-range dependencies in photos, making it very best for recognizing advanced textual content buildings, together with the intricate patterns of Wingdings fonts.
• Prepare the mannequin on the customized dataset of Wingdings symbols.
• Take a look at the mannequin on unseen information to guage its accuracy.

For this undertaking, we’ll make the most of Google Colab for coaching, leveraging its 16 GB T4 GPU for quicker computation.

Making a Wingdings Dataset

What’s Wingdings?

Wingdings is a symbolic font developed by Microsoft that consists of a set of icons, shapes, and pictograms as a substitute of conventional alphanumeric characters. Launched in 1990, Wingdings maps keyboard inputs to graphical symbols, reminiscent of arrows, smiley faces, checkmarks, and different ornamental icons. It’s typically used for design functions, visible communication, or as a playful font in digital content material.

As a consequence of its symbolic nature, deciphering Wingdings textual content programmatically poses a problem, making it an fascinating use case for customized OCR programs.

Dataset Creation

Since no present dataset is accessible for Optical Character Recognition (OCR) in Wingdings font, we created one from scratch. The method includes producing photos of phrases within the Wingdings font and mapping them to their corresponding English phrases.

To attain this, we used the Wingdings Translator to transform English phrases into their Wingdings representations. For every transformed phrase, a picture was manually generated and saved in a folder named “wingdings_word_images”.

Moreover, we create a “metadata.csv” file to take care of a structured file of the dataset together with the picture path. This file accommodates two columns:

1. Picture Path: Specifies the file path for every picture within the dataset.
2. English Phrase: Lists the corresponding English phrase for every Wingdings illustration.

The dataset may be downloaded from this hyperlink.

Preprocessing the Dataset

The photographs within the dataset range in dimension as a result of handbook creation course of. To make sure uniformity and compatibility with OCR fashions, we preprocess the photographs by resizing and padding them.

import pandas as pd
import numpy as np
from PIL import Picture
import os
from tqdm import tqdm

def pad_image(picture, target_size=(224, 224)):
    """Pad picture to focus on dimension whereas sustaining side ratio"""
    if picture.mode != 'RGB':
        picture = picture.convert('RGB')
    
    # Get present dimension
    width, peak = picture.dimension
    
    # Calculate padding
    aspect_ratio = width / peak
    if aspect_ratio > 1:
        # Width is bigger
        new_width = target_size[0]
        new_height = int(new_width / aspect_ratio)
    else:
        # Peak is bigger
        new_height = target_size[1]
        new_width = int(new_height * aspect_ratio)
    
    # Resize picture sustaining side ratio
    picture = picture.resize((new_width, new_height), Picture.Resampling.LANCZOS)
    
    # Create new picture with padding
    new_image = Picture.new('RGB', target_size, (255, 255, 255))
    
    # Paste resized picture in middle
    paste_x = (target_size[0] - new_width) // 2
    paste_y = (target_size[1] - new_height) // 2
    new_image.paste(picture, (paste_x, paste_y))
    
    return new_image

# Learn the metadata
df = pd.read_csv('metadata.csv')

# Create output listing for processed photos
processed_dir="processed_images"
os.makedirs(processed_dir, exist_ok=True)

# Course of every picture
new_paths = []
for idx, row in tqdm(df.iterrows(), whole=len(df), desc="Processing photos"):
    # Load picture
    img_path = row['image_path']
    img = Picture.open(img_path)
    
    # Pad picture
    processed_img = pad_image(img)
    
    # Save processed picture
    new_path = os.path.be a part of(processed_dir, f'processed_{os.path.basename(img_path)}')
    processed_img.save(new_path)
    new_paths.append(new_path)

# Replace dataframe with new paths
df['processed_image_path'] = new_paths
df.to_csv('processed_metadata.csv', index=False)

print("Picture preprocessing accomplished!")
print(f"Whole photos processed: {len(df)}")

First, every picture is resized to a set peak whereas sustaining its side ratio to protect the visible construction of the Wingdings characters. Subsequent, we apply padding to make all photos the identical dimensions, usually a sq. form, to suit the enter necessities of neural networks. The padding is added symmetrically across the resized picture, with the background colour matching the unique picture’s background.

Splitting the Dataset

The dataset is split into three subsets: coaching (70%), validation (dev) (15%), and testing (15%). The coaching set is used to show the mannequin, the validation set helps fine-tune hyperparameters and monitor overfitting, and the take a look at set evaluates the mannequin’s efficiency on unseen information. This random break up ensures every subset is various and consultant, selling efficient generalization.

import pandas as pd
from sklearn.model_selection import train_test_split

# Learn the processed metadata
df = pd.read_csv('processed_metadata.csv')

# First break up: practice and short-term
train_df, temp_df = train_test_split(df, train_size=0.7, random_state=42)

# Second break up: validation and take a look at from short-term
val_df, test_df = train_test_split(temp_df, train_size=0.5, random_state=42)

# Save splits to CSV
train_df.to_csv('practice.csv', index=False)
val_df.to_csv('val.csv', index=False)
test_df.to_csv('take a look at.csv', index=False)

print("Knowledge break up statistics:")
print(f"Coaching samples: {len(train_df)}")
print(f"Validation samples: {len(val_df)}")
print(f"Take a look at samples: {len(test_df)}")

Visualizing the Dataset

To raised perceive the dataset, we visualize samples from every break up. Particularly, we show 5 examples from the coaching set, 5 from the validation set, and 5 from the take a look at set. Every visualization contains the Wingdings textual content as a picture alongside its corresponding label in English. This step offers a transparent overview of the info distribution throughout the splits and ensures the correctness of the dataset mappings.

import matplotlib.pyplot as plt
from PIL import Picture
import pandas as pd

def plot_samples(df, num_samples=5, title="Pattern Pictures"):
    # Set bigger font sizes
    plt.rcParams.replace({
        'font.dimension': 14,          # Base font dimension
        'axes.titlesize': 16,     # Subplot title font dimension
        'determine.titlesize': 20    # Important title font dimension
    })
    
    fig, axes = plt.subplots(1, num_samples, figsize=(20, 4))
    fig.suptitle(title, fontsize=20, y=1.05)
    
    # Randomly pattern photos
    sample_df = df.pattern(n=num_samples)
    
    for idx, (_, row) in enumerate(sample_df.iterrows()):
        img = Picture.open(row['processed_image_path'])
        axes[idx].imshow(img)
        axes[idx].set_title(f"Label: {row['english_word_label']}", fontsize=16, pad=10)
        axes[idx].axis('off')
    
    plt.tight_layout()
    plt.present()

# Load splits
train_df = pd.read_csv('practice.csv')
val_df = pd.read_csv('val.csv')
test_df = pd.read_csv('take a look at.csv')

# Plot samples from every break up
plot_samples(train_df, title="Coaching Samples")
plot_samples(val_df, title="Validation Samples")
plot_samples(test_df, title="Take a look at Samples")

Samples from the info are visualised as:

Prepare an OCR Mannequin

First we have to import the required libraries and dependencies:

import torch
import torch.nn as nn
from torch.utils.information import Dataset, DataLoader
from transformers import VisionEncoderDecoderModel, ViTImageProcessor, AutoTokenizer
from PIL import Picture
import pandas as pd
from tqdm import tqdm

Mannequin Coaching with ViTSTR

We use a Imaginative and prescient Encoder-Decoder mannequin, particularly ViTSTR (Imaginative and prescient Transformer for Scene Textual content Recognition). We fine-tune it for our Wingdings OCR activity. The encoder processes the Wingdings textual content photos utilizing a ViT (Imaginative and prescient Transformer) spine, whereas the decoder generates the corresponding English phrase labels.

Throughout coaching, the mannequin learns to map pixel-level info from the photographs to significant English textual content. The coaching and validation losses are monitored to evaluate mannequin efficiency, guaranteeing it generalizes properly. After coaching, the fine-tuned mannequin is saved for inference on unseen Wingdings textual content photos. We use pre-trained parts from Hugging Face for our OCR pipeline and nice tune them. The ViTImageProcessor prepares photos for the Imaginative and prescient Transformer (ViT) encoder, whereas the bert-base-uncased tokenizer processes English textual content labels for the decoder. The VisionEncoderDecoderModel, combining a ViT encoder and GPT-2 decoder, is fine-tuned for picture captioning duties, making it very best for studying the Wingdings-to-English mapping.

class WingdingsDataset(Dataset):
    def __init__(self, csv_path, processor, tokenizer):
        self.df = pd.read_csv(csv_path)
        self.processor = processor
        self.tokenizer = tokenizer
    
    def __len__(self):
        return len(self.df)
    
    def __getitem__(self, idx):
        row = self.df.iloc[idx]
        picture = Picture.open(row['processed_image_path'])
        label = row['english_word_label']
        
        # Course of picture
        pixel_values = self.processor(picture, return_tensors="pt").pixel_values
        
        # Course of label
        encoding = self.tokenizer(
            label,
            padding="max_length",
            max_length=16,
            truncation=True,
            return_tensors="pt"
        )
        
        return {
            'pixel_values': pixel_values.squeeze(),
            'labels': encoding.input_ids.squeeze(),
            'textual content': label
        }

def train_epoch(mannequin, dataloader, optimizer, system):
    mannequin.practice()
    total_loss = 0
    progress_bar = tqdm(dataloader, desc="Coaching")
    
    for batch in progress_bar:
        pixel_values = batch['pixel_values'].to(system)
        labels = batch['labels'].to(system)
        
        outputs = mannequin(pixel_values=pixel_values, labels=labels)
        loss = outputs.loss
        
        optimizer.zero_grad()
        loss.backward()
        optimizer.step()
        
        total_loss += loss.merchandise()
        progress_bar.set_postfix({'loss': loss.merchandise()})
    
    return total_loss / len(dataloader)

def validate(mannequin, dataloader, system):
    mannequin.eval()
    total_loss = 0
    
    with torch.no_grad():
        for batch in tqdm(dataloader, desc="Validating"):
            pixel_values = batch['pixel_values'].to(system)
            labels = batch['labels'].to(system)
            
            outputs = mannequin(pixel_values=pixel_values, labels=labels)
            loss = outputs.loss
            total_loss += loss.merchandise()
    
    return total_loss / len(dataloader)

# Initialize fashions and tokenizers
processor = ViTImageProcessor.from_pretrained("google/vit-base-patch16-224-in21k")
tokenizer = AutoTokenizer.from_pretrained("bert-base-uncased")
mannequin = VisionEncoderDecoderModel.from_pretrained("nlpconnect/vit-gpt2-image-captioning")

# Create datasets
train_dataset = WingdingsDataset('practice.csv', processor, tokenizer)
val_dataset = WingdingsDataset('val.csv', processor, tokenizer)

# Create dataloaders
train_loader = DataLoader(train_dataset, batch_size=32, shuffle=True)
val_loader = DataLoader(val_dataset, batch_size=32)

# Setup coaching
system = torch.system('cuda' if torch.cuda.is_available() else 'cpu')
mannequin = mannequin.to(system)
optimizer = torch.optim.AdamW(mannequin.parameters(), lr=5e-5)
num_epochs = 20 #(change in keeping with want)

# Coaching loop
for epoch in vary(num_epochs):
    print(f"nEpoch {epoch+1}/{num_epochs}")
    
    train_loss = train_epoch(mannequin, train_loader, optimizer, system)
    val_loss = validate(mannequin, val_loader, system)
    
    print(f"Coaching Loss: {train_loss:.4f}")
    print(f"Validation Loss: {val_loss:.4f}")

# Save the mannequin
mannequin.save_pretrained('wingdings_ocr_model')
print("nTraining accomplished and mannequin saved!")

The coaching is carried for 20 epochs in Google Colab. Though it offers truthful consequence with 20 epochs, it is a hyper parameter and may be elevated to realize higher accuracy. Dropout, Picture Augmentation and Batch Normalization are a couple of extra hyper-parameters one can play with to make sure mannequin will not be overfitting. The coaching stats and the loss and accuracy curve for practice and validation units on first and final epochs are given under:

Epoch 1/20
Coaching: 100%|██████████| 22/22 [00:36<00:00,  1.64s/it, loss=1.13]
Validating: 100%|██████████| 5/5 [00:02<00:00,  1.71it/s]
Coaching Loss: 2.2776
Validation Loss: 1.0183

..........
..........
..........
..........

Epoch 20/20
Coaching: 100%|██████████| 22/22 [00:35<00:00,  1.61s/it, loss=0.0316]
Validating: 100%|██████████| 5/5 [00:02<00:00,  1.73it/s]
Coaching Loss: 0.0246
Validation Loss: 0.5970

Coaching accomplished and mannequin saved!

Utilizing the Saved Mannequin

As soon as the mannequin has been skilled and saved, you may simply load it for inference on new Wingdings photos. The take a look at.csv file created throughout preprocessing is used to create the test_dataset. Right here’s the code to load the saved mannequin and make predictions:

# Load the skilled mannequin
mannequin = VisionEncoderDecoderModel.from_pretrained('wingdings_ocr_model')
processor = ViTImageProcessor.from_pretrained("google/vit-base-patch16-224-in21k")
tokenizer = AutoTokenizer.from_pretrained("bert-base-uncased")

# Create take a look at dataset and dataloader
test_dataset = WingdingsDataset('take a look at.csv', processor, tokenizer)
test_loader = DataLoader(test_dataset, batch_size=32)

Mannequin Analysis

After coaching, we consider the mannequin’s efficiency on the take a look at break up to measure its efficiency. To achieve insights into the mannequin’s efficiency, we randomly choose 10 samples from the take a look at break up. For every pattern, we show the true label (English phrase) alongside the mannequin’s prediction and verify in the event that they match.

import seaborn as sns
import matplotlib.pyplot as plt
from PIL import Picture

def plot_prediction_samples(image_paths, true_labels, pred_labels, num_samples=10):
    # Set determine dimension and font sizes
    plt.rcParams.replace({
        'font.dimension': 14,
        'axes.titlesize': 18,
        'determine.titlesize': 22
    })
    
    # Calculate grid dimensions
    num_rows = 2
    num_cols = 5
    num_samples = min(num_samples, len(image_paths))
    
    # Create determine
    fig, axes = plt.subplots(num_rows, num_cols, figsize=(20, 8))
    fig.suptitle('Pattern Predictions from Take a look at Set', fontsize=22, y=1.05)
    
    # Flatten axes for simpler indexing
    axes_flat = axes.flatten()
    
    for i in vary(num_samples):
        ax = axes_flat[i]
        
        # Load and show picture
        img = Picture.open(image_paths[i])
        ax.imshow(img)
        
        # Create label textual content
        true_text = f"True: {true_labels[i]}"
        pred_text = f"Pred: {pred_labels[i]}"
        
        # Set colour primarily based on correctness
        colour="inexperienced" if true_labels[i] == pred_labels[i] else 'crimson'
        
        # Add textual content above picture
        ax.set_title(f"{true_text}n{pred_text}", 
                    fontsize=14,
                    colour=colour,
                    pad=10,
                    bbox=dict(facecolor="white", 
                             alpha=0.8,
                             edgecolor="none",
                             pad=3))
        
        # Take away axes
        ax.axis('off')
    
    # Take away any empty subplots
    for i in vary(num_samples, num_rows * num_cols):
        fig.delaxes(axes_flat[i])
    
    plt.tight_layout()
    plt.present()
    
# Analysis
system = torch.system('cuda' if torch.cuda.is_available() else 'cpu')
mannequin = mannequin.to(system)
mannequin.eval()

predictions = []
ground_truth = []
image_paths = []

with torch.no_grad():
    for batch in tqdm(test_loader, desc="Evaluating"):
        pixel_values = batch['pixel_values'].to(system)
        texts = batch['text']
        
        outputs = mannequin.generate(pixel_values)
        pred_texts = tokenizer.batch_decode(outputs, skip_special_tokens=True)
        
        predictions.lengthen(pred_texts)
        ground_truth.lengthen(texts)
        image_paths.lengthen([row['processed_image_path'] for _, row in test_dataset.df.iterrows()])

# Calculate and print accuracy
accuracy = accuracy_score(ground_truth, predictions)
print(f"nTest Accuracy: {accuracy:.4f}")

# Show pattern predictions in grid
print("nDisplaying pattern predictions:")
plot_prediction_samples(image_paths, ground_truth, predictions)    

The analysis offers the next output:

Analysing the output given by the mannequin, we discover that the predictions match the reference/authentic labels pretty properly. Though the final prediction is right it’s displayed in crimson due to the areas within the generated textual content.

All of the code and dataset used above may be discovered on this Github repository. And the tip to finish coaching may be discovered within the following colab pocket book

Dialogue

After we see the outputs, it turns into clear that the mannequin performs rather well. The expected labels are correct, and the visible comparability with the true labels demonstrates the mannequin’s sturdy functionality in recognizing the proper lessons.

The mannequin’s wonderful efficiency might be attributed to the sturdy structure of the Imaginative and prescient Transformer for Scene Textual content Recognition (ViTSTR). ViTSTR stands out as a consequence of its potential to seamlessly mix the ability of Imaginative and prescient Transformers (ViT) with language fashions for textual content recognition duties.

A comparability might be made by experimenting with completely different ViT structure sizes, reminiscent of various the variety of layers, embedding dimensions, or the variety of consideration heads. Fashions like ViT-Base, ViT-Giant, and ViT-Big may be examined, together with various architectures like:

• DeiT (Knowledge-efficient Picture Transformer)
• Swin Transformer

By evaluating these fashions of various scales, we are able to determine which structure is probably the most environment friendly by way of efficiency and computational sources. This may assist decide the optimum mannequin dimension that balances accuracy and effectivity for the given activity.

For duties like extracting info from paperwork, instruments reminiscent of Nanonets’ Chat with PDF have evaluated and used a number of state of the LLMs together with customized in-house skilled fashions and may provide a dependable option to work together with content material, guaranteeing correct information extraction with out danger of misrepresentation.