The recognized image may contain a large amount of "dust" (i.e. excess dots) if the original is medium–to–low print quality. Dust, when it resides close to character outlines, may adversely affect recognition quality. To decrease the number of dots:
To despeckle a particular block:
Note: Despeckling may decrease recognition quality if the original document is very faint or contains a light font. Very small characters, such as periods or commas, and parts of very thin characters may disappear.
Change image resolution
Image resolution shows the fineness of detail that can be distinguished in an image and is measured in dots per inch (dpi). ABBYY FineReader shows best OCR performance when vertical and horizontal resolution is the same and is in the range from 50 to 3200 dpi. The recommended range is 200-600 dpi, and the recommended setting is 300 dpi.
If image resolution is too small or too large, this may have an adverse effect on the quality of OCR.
Some image formats, e.g. *.bmp files, have no resolution. Sometimes an image may have non-standard resolution, e.g. 204*96 dpi, which may also adversely affect the quality of OCR.
ABBYY FineReader checks the resolution of each image and corrects if required, leaving the image dimensions unchanged. Images whose resolution has been corrected by the program are marked with in the Batch window. Place the mouse cursor over such an image to see a pop-up tip.
If OCR quality for a particular image is poor, changing its resolution may help improve the quality. To change the resolution of an image marked with :
Straighten text lines
When scanning very thick books, the text close to the binding may be distorted. Similarly, when photographing text with a digital camera, the text close to the margin may be distorted. To remedy such distortions:
- Click or select Image>Image Adjustment>Straighten text lines.
Note: Straightening text lines may take some time.
Some scanners invert images (turning black into white and vice versa) during scanning.
You may wish to apply the Invert Image option to create a uniform or standard appearance (e.g. a black font against a white background) among the documents. To do this:
Note: If you scan or open inverted images, select the Invert image item in the Scan/Open group in the Legacy Options dialog prior to adding these images to the batch. To open the Legacy Options dialog, click the Legacy Options... button on the General tab in the Options dialog.
Rotate or flip image
Recognition quality relies on the image having a standard orientation (the text should be read from top to bottom and all lines should be horizontal). ABBYY FineReader automatically detects page orientation during the recognition stage. If the program detects page orientation incorrectly, clear Detect image orientation (during recognition) on the Scan/Open tab and rotate the image manually. To do this:
Click or select Rotate Clockwise from the Image>Rotate /Flip Image menu to rotate the image 90° clockwise.
To flip the image:
You may choose to skip recognizing a particular image area or eradicate large areas of dust on the image by erasing them. To do this:
Sometimes a scanned image may have dark borders. You can crop the unwanted black areas before running OCR. You can also use the Crop Image tool to reduce the image to a standard paper size, such as A4 or A5.
In the drop down-list to the left, you can select the scale at which the image must be displayed in the window;
To crop the image, rest the mouse cursor on the color border and drag it to the desired location. Alternatively, you can rest the mouse cursor in one of the corners and drag it diagonally. The part of the image that will be removed will be displayed in gray. Click the Crop button;
To reduce the image to a standard paper size, select the desired paper size from the Crop to list to the right;
To skip cropping the current image and go to the next one, click the Skip button;
Clear the Move to next image box if you do not wish ABBYY FineReader to automatically move to the next image once you are finished working with the current image.
Increase/Decrease image scale
Get image information
You can obtain a number of parameters about your image: image width and height in pixels; vertical and horizontal resolution per inch (dpi); and image type. To do this:
Tip: To reverse an Undo action, click the Redo button on the Standard bar .