WSQ_UNION

The WSQ_UNION structure describes the image and compression parameters for a WSQ image.

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typedef struct { DWORD Reserved0; BYTE PICHUGE* Reserved1; BYTE PICHUGE* Reserved2; BYTE PICHUGE* Reserved3; BYTE PICHUGE* Reserved4; BYTE PICHUGE* Reserved5; BYTE PICHUGE* Reserved6; BYTE PICHUGE* Reserved7; BYTE PICHUGE* Reserved8; PICFLAGS PicFlags; PICFLAGS PicFlags2 LONG Status; REGION Region; LONG StripSize; LONG Black; LONG White; Double Quant; } WSQ_UNION

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typedef struct {
   DWORD              Reserved0;
   BYTE PICHUGE*      Reserved1;
   BYTE PICHUGE*      Reserved2;
   BYTE PICHUGE*      Reserved3;
   BYTE PICHUGE*      Reserved4;
   BYTE PICHUGE*      Reserved5;
   BYTE PICHUGE*      Reserved6;
   BYTE PICHUGE*      Reserved7;
   BYTE PICHUGE*      Reserved8;
   PICFLAGS           PicFlags;
   PICFLAGS           PicFlags2
   LONG               Status;
   REGION             Region;
   LONG               StripSize;
   LONG               Black;
   LONG               White;
   Double             Quant;
} WSQ_UNION

Fields:

Name

Description

Reserved0

Reserved1

Reserved2

Reserved3

Reserved4

Reserved5

Reserved6

Reserved7

Reserved8

Used internally, MUST BE LEFT NULL.

PicFlags

Used to control aspects of the operation.

Value	Action
PF_Yield	Yield to caller during REQ_EXEC

PicFlags2

Used to control aspects of the operation.

Value	Action
PF2_ForceWSQv2Spec	Force strict IAFIS-IC-0110v2 compliance even for images that are inappropriate for IAFIS-IC-0110v2 modeling

WSQ's spec decides to exclude a wavelet subband if a central subrectangle of the subband coefficients (roughly equivalent to a subrectangle of the pixels) variance is less than 1.01. The subrectangle is 3/4 horizontally and 7/16 vertically. So if the significant fingerprint data are in the top or bottom 1/4 of the image, that data is not used in the decision to exclude. If the subrectangle is mostly smoothly one intensity, then enough of the wavelet subbands are excluded so that higher resolution detail about the fingerprints is not present no matter what bit rate is selected. For a WSQ-spec-compliant image, compression must occur in this way. But, catch-22, because of the resulting fingerprint quality resulting from the missing high resolution detail, the FBI can't use the compressed image. This flag forces spec-compliant compression even when for images when this occurs. Otherwise in cases like this, the entire subband rectangle is used in the decision instead so it doesn't matter where the fingerprint occurs in the image. Whether this flag is set, or not set, the FBI compliance test is still passed.

Status

Not currently used.

Region

See REGION above.

StripSize

Minimum size of buffer to hold a strip.

Black

Scanner black calibration value.

White

Scanner white calibration value.

Quant

Desired total bit rate per pixel.