At CMKL University, innovation isn’t just about writing code—it’s about solving real-world problems. One of the most inspiring examples is SONAR, a mobile phone application developed by CMKL undergraduate students that transforms printed Thai books into audio, designed specifically to support people with visual impairments.
“The long-term goal? A platform that can serve both individuals and institutions in need of reliable, inclusive reading alternatives — from schools for the blind to public libraries.”
— Khant Phyo Wai, SONAR Project Team
What’s the Goal?
Accessing printed books can be a major challenge for the visually impaired community, particularly in Thailand where accessible reading tools for the visually impaired are limited. The SONAR team set out to address this gap by building an app that could read Thai books aloud—clearly, accurately, and naturally—using only a smartphone.
“We took on this project because it offers a steep learning curve: it brings together several cutting-edge technologies, and the resulting product is both versatile and highly adaptable. I’m confident it can scale into something much bigger and deliver real value to an often underrepresented audience.” — Khant Phyo Wai
SONAR was designed from the ground up to be user-friendly for those with limited or no vision. It features screen reader support, audio-based feedback, and live reading feature to ensure ease of use.
How Does the App Work?
Users simply point their phone’s camera at a printed page. The app then processes the image, reads the text using Optical Character Recognition (OCR), and converts it into natural Thai speech using AI-powered Text-to-Speech (TTS) synthesis. Users can pause, rewind, or replay sections just like a traditional audiobook.
With a current accuracy rate of approximately 95%, SONAR represents a significant step forward in Thai-language accessibility.
Behind the Technology
SONAR combines modern AI and deep learning technologies into an efficient and accessible mobile platform. The system features OCR powered by EasyOCR for Thai text recognition, Text-to-Speech capabilities using VITS models, and deep learning frameworks like PyTorch. It also includes a cross-platform mobile app built with Flutter, and a robust backend architecture that utilizes PostgreSQL, FastAPI, and Celery to enable smooth, asynchronous processing.
“The hard part? Not a lot of people develop apps for the visually impaired. We had to constantly learn how users navigate their phones and go to our partners at CFBT (Christian Foundation for the Blind in Thailand) to do real-time testing.” — Thiri Htet Thwe, Sonar Team Member
OCR Pipeline: From Page to Voice
A key feature of SONAR is its custom-built OCR pipeline, tailored specifically for Thai-language texts. The pipeline includes:
1. Image Preprocessing
- Grayscale conversion for clarity
- Resizing input for consistent processing
- Quality checks on brightness, contrast, and sharpness
2. OCR Extraction
- Uses EasyOCR to extract text, bounding boxes, and confidence levels
- Optimized for the complexity of Thai script
3. Postprocessing
- Basic correction using PyThaiNLP for grammar and character normalization
- Advanced correction using large language models (LLMs) to refine sentence structure and context
Why It Matters
SONAR is more than a student project—it’s a real-world solution with meaningful social impact. It helps users access any printed Thai book, supports mobile and on-the-go learning, and is built specifically for the Thai language.
Its accessibility-first design ensures that it is easy to navigate for those with visual impairments. By focusing on natural-sounding Thai speech and accurate OCR, the app bridges the gap left by many global platforms.
What’s Next?
The SONAR team is already looking ahead, with exciting updates on the horizon. Future plans include expanded voice options that convey emotional tones, hands-free controls through voice commands, and a growing library of pre-recorded Thai audiobooks. Their ultimate vision is to make SONAR a widely adopted tool across schools, libraries, and public institutions in Thailand—bringing inclusive literacy within reach for all.
At CMKL, this is what we stand for: blending heart, knowledge, and technology to create real change. SONAR isn’t just a student project — it’s a step toward a more inclusive future, led by students like the SONAR team, whose commitment to social impact is shaping a better tomorrow.
