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Identification infrastructure

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This commit is contained in:
Daniel Drake 2007-11-20 21:52:10 +00:00
parent dbcd293ab3
commit 3f70d6f794
3 changed files with 141 additions and 15 deletions
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94
libfprint/core.c
View file

@ -747,6 +747,18 @@ API_EXPORTED int fp_dev_supports_imaging(struct fp_dev *dev)
return dev->drv->type == DRIVER_IMAGING;
}
/** \ingroup dev
* Determines if a device is capable of \ref identification "identification"
* through fp_identify_finger() and similar. Not all devices support this
* functionality.
* \param dev the fingerprint device
* \returns 1 if the device is capable of identification, 0 otherwise.
*/
API_EXPORTED int fp_dev_supports_identification(struct fp_dev *dev)
{
return dev->drv->identify != NULL;
}
/** \ingroup dev
* Captures an \ref img "image" from a device. The returned image is the raw
* image provided by the device, you may wish to \ref img_std "standardize" it.
@ -1020,6 +1032,88 @@ API_EXPORTED int fp_verify_finger_img(struct fp_dev *dev,
return r;
}
/** \ingroup dev
* Performs a new scan and attempts to identify the scanned finger against
* a collection of previously enrolled fingerprints.
* If the device is an imaging device, it can also return the image from
* the scan, even when identification fails with a RETRY code. It is legal to
* call this function even on non-imaging devices, just don't expect them to
* provide images.
*
* This function returns codes from #fp_verify_result. The return code
* fp_verify_result#FP_VERIFY_MATCH indicates that the scanned fingerprint
* does appear in the print gallery, and the match_offset output parameter
* will indicate the index into the print gallery array of the matched print.
*
* This function will not necessarily examine the whole print gallery, it
* will return as soon as it finds a matching print.
*
* Not all devices support identification. -ENOTSUP will be returned when
* this is the case.
*
* \param dev the device to perform the scan.
* \param print_gallery NULL-terminated array of pointers to the prints to
* identify against. Each one must have been previously enrolled with a device
* compatible to the device selected to perform the scan.
* \param match_offset output location to store the array index of the matched
* gallery print (if any was found). Only valid if FP_VERIFY_MATCH was
* returned.
* \param img location to store the scan image. accepts NULL for no image
* storage. If an image is returned, it must be freed with fp_img_free() after
* use.
* \return negative code on error, otherwise a code from #fp_verify_result
*/
API_EXPORTED int fp_identify_finger_img(struct fp_dev *dev,
struct fp_print_data **print_gallery, size_t *match_offset,
struct fp_img **img)
{
struct fp_driver *drv = dev->drv;
struct fp_img *_img;
int r;
if (!drv->identify) {
fp_dbg("driver %s has no identify func", drv->name);
return -ENOTSUP;
}
fp_dbg("to be handled by %s", drv->name);
r = drv->identify(dev, print_gallery, match_offset, &_img);
if (r < 0) {
fp_dbg("identify error %d", r);
return r;
}
if (img)
*img = _img;
else
fp_img_free(_img);
switch (r) {
case FP_VERIFY_NO_MATCH:
fp_dbg("result: no match");
break;
case FP_VERIFY_MATCH:
fp_dbg("result: match at offset %zd", match_offset);
break;
case FP_VERIFY_RETRY:
fp_dbg("verify should retry");
break;
case FP_VERIFY_RETRY_TOO_SHORT:
fp_dbg("swipe was too short, verify should retry");
break;
case FP_VERIFY_RETRY_CENTER_FINGER:
fp_dbg("finger was not centered, verify should retry");
break;
case FP_VERIFY_RETRY_REMOVE_FINGER:
fp_dbg("scan failed, remove finger and retry");
break;
default:
fp_err("unrecognised return code %d", r);
return -EINVAL;
}
return r;
}
/** \ingroup core
* Initialise libfprint. This function must be called before you attempt to
* use the library in any way.

2
libfprint/fp_internal.h
View file

@ -113,6 +113,8 @@ struct fp_driver {
struct fp_print_data **print_data, struct fp_img **img);
int (*verify)(struct fp_dev *dev, struct fp_print_data *data,
struct fp_img **img);
int (*identify)(struct fp_dev *dev, struct fp_print_data **print_gallery,
size_t *match_offset, struct fp_img **img);
};
enum fp_print_data_type fpi_driver_get_data_type(struct fp_driver *drv);

60
libfprint/fprint.h
View file

@ -150,30 +150,32 @@ static inline int fp_enroll_finger(struct fp_dev *dev,
}
/** \ingroup dev
* Verification result codes returned from fp_verify_finger().
* Verification result codes returned from fp_verify_finger(). Return codes
* are also shared with fp_identify_finger().
* Result codes with RETRY in the name suggest that the scan failed due to
* user error. Applications will generally want to inform the user of the
* problem and then retry the verify operation.
*/
enum fp_verify_result {
/** The verification scan completed successfully, but the newly scanned
* fingerprint does not match the fingerprint being verified against. */
/** The scan completed successfully, but the newly scanned fingerprint
* does not match the fingerprint being verified against.
* In the case of identification, this return code indicates that the
* scanned finger could not be found in the print gallery. */
FP_VERIFY_NO_MATCH = 0,
/** The verification scan completed successfully and the newly scanned
* fingerprint does match the fingerprint being verified. */
/** The scan completed successfully and the newly scanned fingerprint does
* match the fingerprint being verified, or in the case of identification,
* the scanned fingerprint was found in the print gallery. */
FP_VERIFY_MATCH = 1,
/** The verification scan did not succeed due to poor scan quality or
* other general user scanning problem. */
/** The scan did not succeed due to poor scan quality or other general
* user scanning problem. */
FP_VERIFY_RETRY = FP_ENROLL_RETRY,
/** The verification scan did not succeed because the finger swipe was
* too short. */
/** The scan did not succeed because the finger swipe was too short. */
FP_VERIFY_RETRY_TOO_SHORT = FP_ENROLL_RETRY_TOO_SHORT,
/** The verification scan did not succeed because the finger was not
* centered on the scanner. */
/** The scan did not succeed because the finger was not centered on the
* scanner. */
FP_VERIFY_RETRY_CENTER_FINGER = FP_ENROLL_RETRY_CENTER_FINGER,
/** The verification scan did not succeed due to quality or pressure
* problems; the user should remove their finger from the scanner before
* retrying. */
/** The scan did not succeed due to quality or pressure problems; the user
* should remove their finger from the scanner before retrying. */
FP_VERIFY_RETRY_REMOVE_FINGER = FP_ENROLL_RETRY_REMOVE_FINGER,
};
@ -181,7 +183,9 @@ int fp_verify_finger_img(struct fp_dev *dev,
struct fp_print_data *enrolled_print, struct fp_img **img);
/** \ingroup dev
* Performs a new scan and verify it against a previously enrolled print.
* Performs a new scan and verify it against a previously enrolled print. This
* function is just a shortcut to calling fp_verify_finger_img() with a NULL
* image output parameter.
* \param dev the device to perform the scan.
* \param enrolled_print the print to verify against. Must have been previously
* enrolled with a device compatible to the device selected to perform the scan.
@ -194,6 +198,32 @@ static inline int fp_verify_finger(struct fp_dev *dev,
return fp_verify_finger_img(dev, enrolled_print, NULL);
}
int fp_dev_supports_identification(struct fp_dev *dev);
int fp_identify_finger_img(struct fp_dev *dev,
struct fp_print_data **print_gallery, size_t *match_offset,
struct fp_img **img);
/** \ingroup dev
* Performs a new scan and attempts to identify the scanned finger against a
* collection of previously enrolled fingerprints. This function is just a
* shortcut to calling fp_identify_finger_img() with a NULL image output
* parameter.
* \param dev the device to perform the scan.
* \param print_gallery NULL-terminated array of pointers to the prints to
* identify against. Each one must have been previously enrolled with a device
* compatible to the device selected to perform the scan.
* \param match_offset output location to store the array index of the matched
* gallery print (if any was found). Only valid if FP_VERIFY_MATCH was
* returned.
* \return negative code on error, otherwise a code from #fp_verify_result
* \sa fp_identify_finger_img()
*/
static inline int fp_identify_finger(struct fp_dev *dev,
struct fp_print_data **print_gallery, size_t *match_offset)
{
return fp_identify_finger_img(dev, print_gallery, match_offset, NULL);
}
/* Data handling */
int fp_print_data_load(struct fp_dev *dev, enum fp_finger finger,
struct fp_print_data **data);