Secure & Advanced Sheet Identification for OMR Process
In high-stakes examinations, data collection and results integrity matter critically. With typical barcode technology facing scanning and accuracy limitations on OMR answer sheets, the lithocode emerges as a more secure, robust alternative.
At Addmen Group, our OMR software with Lithocode Reading module is designed to:
Enable secret code encoding on answer sheets, reducing risks of sheet replacement and identity tampering.
Use larger “star” (“*”) marks recognisable like standard filled bubbles rather than fine printed lines — improving detection reliability.
Restrict readability to only the OMR system, disguising sequential patterns and enhancing confidentiality.
| Advantages | Disadvantages / Limitations |
|---|---|
| Enhanced Security: Only readable by the OMR system, making it impossible for candidates or third parties to interpret or manipulate sheet identity. | Requires Special Printing Utility: Lithocode generation needs a proprietary binary encoding tool, not easily done using standard Word or Excel mail merge. |
| High Accuracy in Scanning: Uses bold, filled marks similar to bubbles, which are less error-prone than narrow barcode lines. | Specialised Print Vendors Needed: Precise lithocode placement requires professional printing to maintain positional accuracy. |
| Confidential Sheet Identification: Lithocode disguises sheet numbers or candidate IDs, preventing leakage of sequential order. | Cannot Be Self-Generated by End Users: End-users cannot independently create lithocode without the proper utility or software module. |
| Seamless OMR Integration: Works with existing Addmen OMR workflows and modules without disrupting setup. | Slightly Higher Setup Cost: Initial cost of adding the B4 module and binary printing software is higher than barcode-only setups. |
| Supports Large-Scale Exams: Best suited for secure, multi-center assessments and government exams where identity masking is essential. | Not Always Needed: For low-risk or internal tests, barcode systems might suffice and be simpler to deploy. |
Enhanced Security: Only the OMR system can decode lithocode, ensuring sheet identity remains hidden.
Bubble-Read Friendly Format: Lithocode marks act like filled bubbles, avoiding scanning issues associated with barcodes.
Full Workflow Integration: Easily incorporated as Module B4 within Addmen’s OMR software suite.
The Basic Reader (B0) is the core module; lithocode reading is implemented via Module B4 (Lithocode Reader).
During scanning, the software decodes the lithocode zone and maps it to candidate IDs automatically.
The lithocode is printed from binary code converted from a predefined number series (Excel or database).
Scanning captures both answers and lithocode data in a single pass, ensuring secure and accurate result mapping.
Design OMR sheets with a clearly defined lithocode block and sufficient spacing.
Use Addmen-recommended scanner settings (TIFF/JPG, 200–300 DPI) for best results.
Ensure your printing vendor supports binary lithocode generation.
Conduct pilot scanning to validate lithocode decoding before full-scale use.
Combine lithocode with barcodes or QR codes for additional redundancy and layered security.
Proprietary Technology: Developed and maintained entirely in-house for reliability and support.
Modular & Scalable: Add or remove modules (B2 Barcode, B3 QR, B4 Lithocode) as per requirement.
ISO 27001 & ISO 9001 Certified: Compliant with global standards for data security and quality.
Proven Performance: Trusted by 5,000+ clients across 20+ countries in education, recruitment, and certification sectors.
Q1: What is lithocode and how is it different from barcode?
Lithocode uses binary encoding represented as bold bubble marks instead of fine lines, making it readable only by OMR systems and not by barcode scanners.
Q2: Can I generate lithocode using Word or Excel?
No. Lithocode needs a dedicated binary generation utility, not available in common office software.
Q3: Is lithocode faster or slower than barcode in reading?
Reading speed is the same as standard OMR scanning since the lithocode is decoded in the same scan pass.
Q4: Can lithocode and barcode be used together?
Yes. Many institutions use both — lithocode for internal security and barcode for logistical or external tracking.
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