Image Box Filtering to Remove Form Boxes Before OCR

The patent applies preliminary action by performing box detection and removal operations on the scanned form image before the OCR process. The system identifies box boundaries using image processing techniques (such as detecting horizontal and vertical lines or using projection profiles) and removes or masks these box elements from the image. This preprocessing step eliminates the harmful effect of boxes on OCR accuracy while preserving the original form structure for user guidance, thereby resolving the contradiction between ease of operation and measurement precision.

The patent applies parameter changes by adjusting key detection parameters such as threshold values for line detection, width and height tolerances for box identification, and margin calculations. The system dynamically modifies these parameters based on the specific form characteristics being processed, allowing it to adapt to varying box sizes and shapes without requiring a completely different detection algorithm for each case. This approach maintains adaptability while controlling complexity through parameter adjustment rather than structural complexity.