TIEMultiBitmap.RemoveDuplicates

Declaration

function RemoveDuplicates(): Integer; overload;
function RemoveDuplicates(Threshold: Double; Algorithm: TIEVisionImageHashAlgorithm = ievHashPHash): Integer; overload;

Description

Locate images with duplicate content in the TIEMultiBitmap and remove other instances. The first image of each group of duplicates is kept.
Returns the number of removed pages.

The first overload only finds images with exactly the same pixels (using an MD5 Hash).
The second overload (requires IEVision) uses a perceptual hash, so it also removes near-duplicates, such as resized, recompressed or slightly edited copies. An image is a duplicate if its similarity to an earlier image is Threshold or higher (0 to 1, where 0.75 is a good value. See similarity).

Examples

// Ensure there are no duplicate images in our TIEMultiBitmap after filling it from a folder
MBitmap.Clear();
MBitmap.FillFromDirectory('C:\Images');
MBitmap.RemoveDuplicates();

// Also remove resized and recompressed copies
MBitmap.RemoveDuplicates( 0.75 );

TIEMultiBitmap.RemoveDuplicates