Image reader having height distribution correction for a read document

摘要

An image reading apparatus which reads document surfaces of open book-like documents placed on a document platen in a face upward condition and detects height of the document to control an image reading operation. An image reader reads the document platen on which the document is placed and outputs image data. A height detector detects height distribution of the document, and a discrimination device determines whether or not abnormalities occur in the height distribution of the document. A memory stores the height distribution of the document, and a update device updates the height distribution of the document stored in the memory when the abnormalities do not occur in the height distribution of the document. A correcting device corrects distortion of the image data caused by the height of the document in accordance with the height distribution of the document stored in the memory.