A system and process of nearsighted (myopia) camera object detection involves detecting the objects through edge detection and outlining or thickening them with a heavy border. Thickening may include making the object bold in the case of text characters. The bold characters are then much more apparent and heaver weighted than the background. Thresholding operations are then applied (usually multiple times) to the grayscale image to remove all but the darkest foreground objects in the background resulting in a nearsighted (myopic) image. Additional processes may be applied to the nearsighted image, such as morphological closing, contour tracing and bounding of the objects or characters. The bound objects or characters can then be averaged to provide repositioning feedback for the camera user. Processed images can then be captured and subjected to OCR to extract relevant information from the image.

This application provides a method of detecting printing defects. The method includes obtaining a first image of each character in a reference image. A third image of each character is obtained based on the first image of each character, a fourth image of each character is obtained based on a second image of each character obtained from an image to be detected. Once a fifth image of each character is obtained based on the third image of each character, a sixth image of each character is obtained according to the fourth image and the fifth image of each character, a detection result of each character in the image to be detected is determined according to the fifth image and the sixth image of the each character.

A technical data detection method in a technical drawing image. The technical drawing includes a view of a technical object and a technical annotation. The method includes identifying one or more views in the technical drawing. The method includes identifying one or more technical annotations in each view. The method includes identifying characters in each technical annotation. The method includes determining a graph representation of each view. The graph representation includes nodes each corresponding to a classification of pixels in the view into a semantic class and edges each connects two nodes either if the two nodes represent neighboring pixels or if the two nodes represent pixels distant from each other below a threshold. The method includes, for each identified view, using the graph topology and the identified characters to associate nodes corresponding to the dimension-related symbol or dimension classes to nodes corresponding to the geometry class.