Can PaddleOCR only detect special style character or digit?

[Github-Polaris]

I mean that the OCR model should only detect the style I want. For example, black character or some character with specific background.

[GreatV]

PaddleOCR doesn’t natively support selecting or detecting characters based solely on visual styles such as color (e.g., black characters only) or background features directly during inference. However, what you're trying to achieve—making the model detect only specific styled characters or digits—is possible, but it requires customization, particularly during model training.

From a technical perspective, here are some strategies you can consider:

1. Filtering through Data Labeling:
   You can train a detection or recognition model using only the styles you want (e.g., black text, specific background types). By labeling and training with only these styled characters, the model will learn to focus on similar patterns and potentially ignore other styles.

2. Ignore Certain Styles via Preprocessing:
   You can preprocess input images to filter out unwanted styles. For example, using color masking techniques to highlight only the desired black characters or specific backgrounds before passing the image to the OCR model.

3. Negative Sampling (Optional Annotation):
   As discussed in this related issue (训练 det模型时，不让模型检测90° 180° 270°的字符 #14229), unwanted styles (like rotated characters) can be included in training images but left unannotated. The model can then learn to ignore these unlabelled regions. You could use a similar technique: include undesired styled text in your training images without annotations, so the model learns to ignore them.

4. Post-processing Based on Style:
   After inference, use additional logic to filter out texts that do not match your required visual characteristics (e.g., discarding results that don’t have a black font style).

To summarize, while PaddleOCR doesn't provide an out-of-the-box feature for detecting only specific character styles, you can achieve this through dataset preparation, training strategy, and image preprocessing or post-processing.

Let me know if you need implementation suggestions for any of these approaches.

---

Response generated by 🤖 feifei-bot | chatgpt-4o-latest

⚠️ This is an AI-generated response. Please verify any critical information.