Editing text in an image

Abstract

Character level text editing is performed on an image without recognizing characters, by operating on a character-size array obtained from a two-dimensional array defining an image region. A processor, in response to a request for a text editing operation, accesses an edit data structure that includes the image region array and performs the operation. The character-size array is obtained by dividing the image region array when necessary. An image region array that includes more than one line is divided along interline spaces. An image region array that includes one line is divided along intercharacter spaces. Character-size arrays are divided out of larger arrays by finding connected component bounding boxes, and then determining from the bounding boxes whether the connected components are likely to form a character. If so, the connected components are used to obtain the character-size array and spatial data about position, size, and shape of the character. Smaller arrays and spatial data can replace a larger array in the edit data structure. Smaller arrays are obtained only as necessary to perform a requested text editing operation, and if the edit data structure is not otherwise modified, obtaining a smaller array does not necessitate redrawing of the display. In addition to character level editing, a text editing operation can be performed on a sequence of arrays, such as a word, line, or a sequence that begins on one line and ends on another. The spatial data can be used to position arrays after insertion or deletion, to advance a cursor through the text, and to justify a line of arrays. A character-size array can be assigned to a keyboard key, and the key may then be used to insert that array into the text or to request a search for other arrays matching that array.