Document scanning workflows often involve processing multi-page documents that contain separator pages or blank pages used for organizational purposes. Manually identifying and removing these blank pages while splitting documents can be time-consuming and error-prone. In this tutorial, we'll explore how to implement intelligent document splitting using Dynamic Web TWAIN's powerful blank page detection capabilities.
Demo Video: Blank Image Detection for Document Management
Online Demo
https://yushulx.me/web-twain-document-scan-management/examples/split_merge_document/
Prerequisites
The Challenge of Blank Pages in Document Scanning
In professional document scanning environments, blank pages serve various purposes:
- Document Separators: Used to divide different documents in a batch scan
- Page Padding: Added to ensure proper document alignment in feeders
- Organizational Markers: Inserted between sections for filing purposes
- Accidental Inclusions: Blank pages mixed in with content pages
Manual processing of these documents requires:
- Human review of each page
- Manual identification of blank pages
- Time-consuming splitting and reorganization
- Risk of human error in document classification
Why Dynamic Web TWAIN for Blank Detection
Dynamic Web TWAIN provides several advantages for implementing intelligent blank page detection:
JavaScript Blank Detection API
- Built-in IsBlankImageAsync() method for accurate detection
- Handles various image qualities and scanning conditions
Browser-Based Scanner Control
- Cross-platform compatibility (Windows, macOS, Linux)
- Supports TWAIN, WIA, ICA, and SANE scanners
Understanding the Auto Split Feature
Our implementation provides an intelligent Auto Split feature that:
- Analyzes each page using Dynamic Web TWAIN's blank detection
- Identifies separator pages based on blank content detection
- Splits documents at blank page boundaries
- Removes blank pages from the final output
- Creates organized document groups automatically
Key Benefits:
- Automated Workflow: Eliminates manual intervention
- Improved Accuracy: Reduces human error in document organization
- Time Savings: Processes hundreds of pages in seconds
- Clean Output: Removes unwanted blank pages automatically
Implementation Guide
Before implementing blank page detection, ensure you have included the Dynamic Web TWAIN SDK in your project.
<!-- Dynamic Web TWAIN SDK --> <script src="https://unpkg.com/dwt/dist/dynamsoft.webtwain.min.js"></script> Basic Setup
Initialize the Dynamic Web TWAIN environment with your license key:
Dynamsoft.DWT.ProductKey = licenseKey; Dynamsoft.DWT.ResourcesPath = 'https://unpkg.com/dwt/dist/'; Dynamsoft.DWT.CreateDWTObjectEx({ WebTwainId: 'mydwt-' + Date.now() }, (dwtObject) => { console.log('Dynamic Web TWAIN initialized successfully'); }, (error) => { console.error('DWT initialization failed:', error); }); Auto Split Function with Blank Page Detection
Here's the complete implementation of our intelligent auto split feature:
async autoSplit() { if (!DWTObject || imageCount === 0) { Utils.showNotification('No images to analyze for auto split', 'error'); return; } Utils.showNotification('Analyzing images for blank pages...', 'info'); let splitsPerformed = 0; let blankPagesRemoved = 0; const imageBoxContainer = document.querySelector('#imagebox-1 .ds-imagebox'); if (!imageBoxContainer) { Utils.showNotification('No images found to analyze', 'error'); return; } for (let i = imageCount - 1; i >= 0; i--) { try { let isBlank = await DWTObject.IsBlankImageAsync(i); if (isBlank) { const imageID = DWTObject.IndexToImageID(i); const imgElement = document.querySelector(`img[imageid="${imageID}"]`); if (imgElement) { const imageWrapper = imgElement.parentNode; const previousWrapper = imageWrapper.previousElementSibling; if (previousWrapper) { this.splitImage(imgElement); splitsPerformed++; console.log(`Split performed before blank page (image index: ${i})`); } FileManager.deleteOneImage(imgElement); blankPagesRemoved++; console.log(`Blank page removed (image index: ${i})`); } } } catch (error) { console.error('Error analyzing image at index', i, ':', error); } } FileManager.deleteEmptyDocs(); if (splitsPerformed > 0 || blankPagesRemoved > 0) { let message = 'Auto split completed! '; if (splitsPerformed > 0) message += `${splitsPerformed} split(s) performed. `; if (blankPagesRemoved > 0) message += `${blankPagesRemoved} blank page(s) removed.`; Utils.showNotification(message, 'success'); PageManager.updateAll(); } else { Utils.showNotification('No blank pages detected for splitting', 'info'); } } Implementation Details
1. Reverse Processing Strategy
for (let i = imageCount - 1; i >= 0; i--) { } Processing images in reverse order prevents index shifting issues when documents are split or pages are removed.
2. Blank Page Detection
let isBlank = await DWTObject.IsBlankImageAsync(i); Dynamic Web TWAIN's IsBlankImageAsync() method provides accurate blank page detection algorithm.
3. Smart Document Splitting
if (previousWrapper) { this.splitImage(imgElement); splitsPerformed++; } The algorithm intelligently splits documents only when blank pages have preceding content, preventing empty document creation.
4. Cleanup and Removal
FileManager.deleteOneImage(imgElement); blankPagesRemoved++; Blank pages are completely removed from the document workflow, ensuring clean output.
Document Splitting Logic
The splitImage() method handles the creation of new document groups:
splitImage(imageEl) { const imageWrapperDiv = imageEl.parentNode; const previousDivEl = imageWrapperDiv.previousSibling; if (previousDivEl) { this.createNextDocument(previousDivEl); } } This method:
- Identifies the split point before the blank page
- Creates a new document group
- Moves subsequent pages to the new group
- Updates the UI to reflect the new document structure
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