A device and method are described for capturing an image of a document using a
digital camera. The invention includes a resolution analyzer for analyzing the
resolution of text characters in the image, to assess whether the resolution is
suitable for OCR. In one aspect, if the resolution is too small or too large, an
indicator is generated to guide the user as to the corrective movement of the camera
to improve the resolution for OCR. In a second aspect, an electronic zoom control
is controlled to alter the magnification of the captured image, to correct the
resolution. In a third aspect, a method is described for analyzing the image to
determine the resolution according to the height of text characters in the image.
The method includes analyzing the run lengths of pixels in the image to identify
a predominant length corresponding to the average character height (in pixels).
