L_INT LBitmap::AutoZone(phZones, puCount, uFlags = 0)
Automatically detects different zone types (Text, Graphics and Tables) in an image. Classifying by types, improves the recognition results from OCR pre-processing. This function is useful for any application that needs to automatically separate images, tables and text within mixed raster content (MRC) images.
Pointer to a handle to be updated with the detected zones. To retrieve the data of the detected zones cast the phZones to pLEADZONE and call the GlobalLock function.
Pointer to a variable to be updated with the number of detected zones.
Flags indicating how the function should behave. You can combine values when appropriate by using a bitwise OR ( | ). Possible values are:
Value | Meaning |
---|---|
AUTOZONE_DETECT_TEXT | [0x0001] Detect text zones. |
AUTOZONE_DETECT_GRAPHIC | [0x0002] Detect graphic zones. |
AUTOZONE_DETECT_TABLE | [0x0004] Detect table zones. |
AUTOZONE_DETECT_ALL | [0x00010007] Detect all zone types (Text, Graphics and tables). |
Value | Meaning |
---|---|
AUTOZONE_DONT_ALLOW_OVERLAP | [0x0000] Do not allow zones to overlap. |
AUTOZONE_ALLOW_OVERLAP | [0x0010] Allow zones to overlap. |
Value | Meaning |
---|---|
AUTOZONE_ACCURATE_ZONES | [0x0000] Do not merge text zones. Keep them separated (as paragraphs). |
AUTOZONE_GENERAL_ZONES | [0x0100] Merge text zones as much as possible. |
Value | Meaning |
---|---|
AUTOZONE_DONT_RECOGNIZE_ONE_CELL_TABLE | [0x0000] Ignore one-cell tables (borders). Detect what is inside. |
AUTOZONE_RECOGNIZE_ONE_CELL_TABLE | [0x1000] Consider borders to be one-cell tables. |
AUTOZONE_NORMAL_TABLE (version 17 or after) | [0x0000] Use normal table detection. |
AUTOZONE_ADVANCED_TABLE (version 17 or after) | [0x2000] Use advanced table detection which is more accurate and which can detect complex tables. |
AUTOZONE_LINES_RECONSTRUCTION (version 17 or after) | [0x4000] Use line reconstruction to connect broken lines and for patterned tables. |
Value | Meaning |
---|---|
AUTOZONE_USE_MULTITHREADING | [0x00000000] Use multi-threading (faster for multi-core CPUs). |
AUTOZONE_DONTUSE_MULTITHREADING | [0x80000000] Do not use multi-threading (Use this with single-core CPUs). |
Value | Meaning |
---|---|
AUTOZONE_TEXT_DETECTION | [0x8000] If set, the function does not return text zones in phZones. Instead, it modifies pBitmap to have text areas only: graphics and tables areas are deleted from the input image. |
NOTE: Make a copy of the original image if you want to keep it. When this function is set to AUTOZONE_TEXT_DETECTION, the original image is modified.
Value | Meaning |
---|---|
AUTOZONE_TEXTBOOK | [0x40000] Use improved zoning on a book's pages. |
AUTOZONE_FAVOR_GRAPHICS | [0x400000] Use improved detection of figure zones in documents. |
Value | Meaning |
---|---|
AUTOZONE_DETECT_VERTICAL_TEXT | [0x100000] Detect vertical text lines. |
Value | Meaning |
---|---|
AUTOZONE_DETECT_CHECKBOX | [0x10000] Set this flag to detect checkbox zones in the document. |
AUTOZONE_CHECKBOX_SENSITIVITY_HIGH | [0x00000000] The sensitivity of matching the checkboxes shape is high, and hence, the false negative detections is low. |
AUTOZONE_CHECKBOX_SENSITIVITY_LOW | [0x200000] The sensitivity of matching the checkboxes shape is low, and hence, the false negative detections is high. |
Value | Meaning |
---|---|
AUTOZONE_ASIAN_ZONING | [0x200] Detect Asian text (Japanese, Chinese, Korean, etc.) |
Value | Meaning |
---|---|
SUCCESS | The function was successful. |
< 1 | An error occurred. Refer to Return Codes. |
This function is useful for any application that needs to automatically separate images, tables and text within mixed raster content (MRC) images.
After using this function, free the phZones using the LBitmap::FreeZoneData function.
This function does not support 12 and 16-bit grayscale and 48 and 64-bit color images. If the image is 12 and 16-bit grayscale and 48 and 64-bit color, the function will not return an error.
This function does not support signed data images. It returns the ERROR_SIGNED_DATA_NOT_SUPPORTED error code if a signed data image is passed to this function.
This function does not support 32-bit grayscale images. It returns the ERROR_GRAY32_UNSUPPORTED error code if a 32-bit grayscale image is passed to this function.
The behavior of this function can be modified by overriding LBitmap::AutoZoneCallback.
Win32, x64.
Detects the image zones and return the results.
L_INT LBitmap__AutoZoneBitmapExample(LBitmap & LeadBitmap)
{
L_INT nRet;
HGLOBAL pointer = NULL;
L_UINT32 count;
L_INT TextZonesCount = 0;
L_INT GraphicZonesCount = 0;
L_INT TableZonesCount = 0;
L_INT CellsCount = 0;
L_UINT i;
nRet = LeadBitmap.Load(MAKE_IMAGE_PATH(TEXT("Clean.tif")));
if(nRet !=SUCCESS)
return nRet;
nRet = LeadBitmap.AutoZone(&pointer, &count, 0);
if(nRet !=SUCCESS)
return nRet;
LEADZONE * pZone = (LEADZONE *)GlobalLock(pointer);
for(i=0; i<count; i++)
{
if (pZone[i].uZoneType == LEAD_ZONE_TYPE_TEXT)
{
TextZonesCount++;
}
if (pZone[i].uZoneType == LEAD_ZONE_TYPE_GRAPHIC)
{
GraphicZonesCount++;
}
if (pZone[i].uZoneType == LEAD_ZONE_TYPE_TABLE)
{
TableZonesCount++;
TABLEZONE * pTable = (TABLEZONE *)GlobalLock(pZone[i].pZoneData);
CellsCount = pTable->Rows * pTable->Columns;
GlobalUnlock(pTable);
}
}
nRet = LeadBitmap.FreeZoneData(pointer, count);
if(nRet !=SUCCESS)
return nRet;
GlobalUnlock(pointer);
return SUCCESS;
}
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