DESKEWDETECTION

typedef struct _DESKEWDETECTION 
{ 
   L_UINT uStructSize; 
   L_UINT uFlags; 
   L_INT32 pnDeskewAngle; 
   L_UINT uAngleRange; 
   L_UINT uAngleResolution; 
   COLORREF crBack; 
} DESKEWDETECTION, *pDESKEWDETECTION; 

The DESKEWDETECTION structure provides deskew detection information for the L_DetectBitmapDeskewOrientation function.

Members

uStructSize

Size of this structure in bytes, for versioning. Use the sizeof() operator to calculate this value.

uFlags

Flags that indicate whether or not to deskew the image and what background color to use. You can use a bitwise OR (|) to specify one flag from each group.

Value Meaning
Deskew the image after finding the skew angle:
DSKW_PROCESS [0x00000000] Deskew (rotate) the image.
DSKW_NOPROCESS [0x00000001] Do not deskew (rotate) the image. Generally this flag is used to find the angle of rotation.
Background color to use:
DSKW_FILL [0x00000000] Use the color in crBack to fill areas exposed by rotation.
DSKW_NOFILL [0x00000010] Let the function automatically find the suitable background color to fill areas exposed by rotation. crBack is ignored in this case.
Image type:
DSKW_DOCUMENTIMAGE [0x00000000] The image contains text only.
DSKW_DOCUMENTANDPICTURE [0x00010000] The image contains text and pictures, or light text.
Type of interpolation to perform:
DSKW_LINEAR [0x00000000] Do not perform interpolation when rotating.
DSKW_RESAMPLE [0x00001000] Perform bilinear interpolation when rotating.
DSKW_BICUBIC [0x00002000] Perform bicubic interpolation when rotating.
Rotation Type:
DSKW_NORMALSPEEDROTATE [0x00000000] Rotate the image at normal speed with a high rotation quality.
DSKW_HIGHSPEEDROTATE [0x00100000] Speed up image rotation with a moderate rotation quality (only for 1-bit images).
Perform preprocessing to enhance results:
DSKW_PERFORM_PREPROCESSING [0x00000000] Perform pre-processing operations. Use this with images that contain black borders as a result of scanning in order to enhance accuracy. Works only with 1-bit document images.
DSKW_DONT_PERFORM_PREPROCESSING [0x10000000] Do not perform pre-processing operations.
Detecting the skew angle:
DSKW_SELECTIVE_DETECTION [0x00000000] Detect the skew angle selectively using important features of the document, to enhance accuracy. Works only with 1-bit document images.
DSKW_NORMAL_DETECTION [0x20000000] Detect the skew angle normally using all the features of the document.
Perform deskewing using the bank check algorithms:
DSKW_DONT_USE_CHECK_DESKEW [0x00000000] Do not use any of the bank check algorithms. Perform ordinary deskewing. This is the default value.
DSKW_USE_CHECK_DESKEW [0x01000000] Use the bank check algorithm to deskew the bitmap. This algorithm considers many features common to standard bank checks in order to determine orientation.
DSKW_USE_CHECK_DESKEW_DETECT_LINES [0x02000000] Use the bank check line detection algorithm to deskew the image.

pnDeskewAngle

This value is updated with the angle that the image needs to be deskewed, in hundredths of degrees.

uAngleRange

this value indicates the maximum angle of deskew, in hundredths of degrees.

uAngleResolution

This value indicates the deskew angle precision on which the filter is applied.

crBack

The value indicates the color used to fill the background following rotation.

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