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elanspi: Add PID 04F3:3128 support and enable SIGFM OpenCV matcher #43

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714ec03
elanspi: Add PID 04F3:3128 and tune swipe motion thresholds
Sep 13, 2026
3678a1f
elanspi: Enable OpenCV SIGFM matcher and improve swipe processing
Sep 13, 2026
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93 changes: 82 additions & 11 deletions libfprint/drivers/elanspi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1329,11 +1329,52 @@ elanspi_fp_assembling_get_pixel (struct fpi_frame_asmbl_ctx *ctx, struct fpi_fra
return frame->data[y * ctx->frame_width + x];
}

/* Separable gaussian smoothing pass (sigma ~1.2, radius 3). Suppresses
* sensor-noise speckle that otherwise produces spurious, non-repeatable
* image features on the eFSA80SC. */
static void
elanspi_smooth_image (FpImage *img)
{
/* gaussian kernel, sigma=1.2 */
static const guint kern[7] = { 34, 111, 218, 298, 218, 111, 34 };
guint w = img->width, h = img->height;
g_autofree guint8 *tmp = g_malloc (w * h);
guint8 *data = (guint8 *) img->data;

for (guint y = 0; y < h; y++)
for (guint x = 0; x < w; x++)
{
guint acc = 0, wsum = 0;
for (gint k = -3; k <= 3; k++)
{
gint xx = (gint) x + k;
if (xx < 0 || xx >= (gint) w)
continue;
acc += kern[k + 3] * data[y * w + xx];
wsum += kern[k + 3];
}
tmp[y * w + x] = acc / wsum;
}
for (guint y = 0; y < h; y++)
for (guint x = 0; x < w; x++)
{
guint acc = 0, wsum = 0;
for (gint k = -3; k <= 3; k++)
{
gint yy = (gint) y + k;
if (yy < 0 || yy >= (gint) h)
continue;
acc += kern[k + 3] * tmp[yy * w + x];
wsum += kern[k + 3];
}
data[y * w + x] = acc / wsum;
}
}

static void
elanspi_fp_frame_stitch_and_submit (FpiDeviceElanSpi *self)
{
g_autoptr(FpImage) img = NULL;
g_autoptr(FpImage) scaled = NULL;
struct fpi_frame_asmbl_ctx assembling_ctx = {
.image_width = (self->frame_width * 3) / 2,

Expand All @@ -1348,12 +1389,19 @@ elanspi_fp_frame_stitch_and_submit (FpiDeviceElanSpi *self)

fpi_do_movement_estimation (&assembling_ctx, frame_start);
img = fpi_assemble_frames (&assembling_ctx, frame_start);
scaled = fpi_image_resize (img, 2, 2);

scaled->flags |= FPI_IMAGE_PARTIAL | FPI_IMAGE_COLORS_INVERTED;
/* The assembled image is used at native scale: its ~10px ridge period is
* already in the matcher's expected band, and a 2x upscale only starves
* feature extraction. FPI_IMAGE_PARTIAL is not set since on these narrow
* strips it would cull most minutiae as perimeter points. Light smoothing
* suppresses sensor noise that otherwise creates spurious features. */
elanspi_smooth_image (img);
img->flags |= FPI_IMAGE_COLORS_INVERTED;

fp_dbg ("stitched image %dx%d submitted to SIGFM", img->width, img->height);

/* submit image */
fpi_image_device_image_captured (FP_IMAGE_DEVICE (self), g_steal_pointer (&scaled));
fpi_image_device_image_captured (FP_IMAGE_DEVICE (self), g_steal_pointer (&img));

/* clean out frame data */
g_slist_free_full (g_steal_pointer (&self->fp_frame_list), g_free);
Expand Down Expand Up @@ -1396,7 +1444,7 @@ elanspi_fp_frame_handler (FpiSsm *ssm, FpiDeviceElanSpi *self)
case ELANSPI_GUESS_EMPTY:
self->fp_empty_counter += 1;
fp_dbg ("<fp_frame> got empty");
if (self->fp_empty_counter > 1)
if (self->fp_empty_counter > 3)
{
fp_dbg ("<fp_frame> have enough debounce");
if (g_slist_length (self->fp_frame_list) >= ELANSPI_MIN_FRAMES_SWIPE)
Expand All @@ -1416,10 +1464,10 @@ elanspi_fp_frame_handler (FpiSsm *ssm, FpiDeviceElanSpi *self)
case ELANSPI_GUESS_FINGERPRINT:
if (self->fp_empty_counter && self->fp_frame_list)
{
if (self->fp_empty_counter < 1)
if (self->fp_empty_counter <= 2)
{
fp_dbg ("<fp_frame> possible bounced fp");
break;
fp_dbg ("<fp_frame> momentary gap during swipe, keeping list");
self->fp_empty_counter = 0;
}
else
{
Expand All @@ -1445,7 +1493,19 @@ elanspi_fp_frame_handler (FpiSsm *ssm, FpiDeviceElanSpi *self)
{
gint difference = elanspi_get_frame_diff_stddev_sq (self, self->last_image, self->prev_frame_image);
fp_dbg ("<fp_frame> diff = %d", difference);
if (difference < ELANSPI_MIN_FRAME_TO_FRAME_DIFF)
gboolean is_enroll =
fpi_device_get_current_action (FP_DEVICE (self)) ==
FPI_DEVICE_ACTION_ENROLL;
gint min_frame_diff =
is_enroll
? ELANSPI_MIN_FRAME_TO_FRAME_DIFF_ENROLL
: ELANSPI_MIN_FRAME_TO_FRAME_DIFF_VERIFY;

fp_dbg ("<fp_frame> threshold = %d, profile = %s",
min_frame_diff,
is_enroll ? "enroll" : "verify");

if (difference < min_frame_diff)
{
fp_dbg ("<fp_frame> ignoring b.c. difference is too small");
break;
Expand Down Expand Up @@ -1641,7 +1701,12 @@ elanspi_fp_capture_finish (FpiSsm *ssm, FpDevice *dev, GError *error)

/* if there was an error, report it */
if (error)
fpi_image_device_session_error (idev, error);
{
if (fpi_device_get_current_action (dev) != FPI_DEVICE_ACTION_NONE)
fpi_image_device_session_error (idev, error);
else
g_error_free (error);
}
}

static void
Expand Down Expand Up @@ -1701,7 +1766,13 @@ fpi_device_elanspi_class_init (FpiDeviceElanSpiClass *klass)
dev_class->scan_type = FP_SCAN_TYPE_SWIPE;
dev_class->nr_enroll_stages = 7; /* these sensors are very hit or miss, may as well record a few extras */

img_class->bz3_threshold = 24;
/* SIGFM (SIFT-based) matching: NBIS/bozorth3 cannot discriminate fingers
* on the narrow stitched strips these sensors produce (measured genuine
* and impostor score distributions fully overlap). SIGFM separates them
* by ~3 orders of magnitude. Threshold chosen from a measured corpus:
* impostor pairs scored <= 26, genuine pairs typically 10^3..10^7. */
img_class->algorithm = FPI_DEVICE_ALGO_SIGFM;
img_class->bz3_threshold = 30;
img_class->img_open = elanspi_open;
img_class->activate = elanspi_activate;
img_class->deactivate = elanspi_deactivate;
Expand Down
13 changes: 8 additions & 5 deletions libfprint/drivers/elanspi.h
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Original file line number Diff line number Diff line change
Expand Up @@ -340,6 +340,8 @@ static const struct elanspi_regtable elanspi_calibration_table_new_page1 = {

// using checkargs ACPI:HIDPID
static const FpIdEntry elanspi_id_table[] = {
{.udev_types = ELANSPI_UDEV_TYPES, .spi_acpi_id = "ELAN7001", .hid_id = {.vid = ELANSPI_TP_VID, .pid = 0x3128}, .driver_data = ELANSPI_180_ROTATE},
{.udev_types = ELANSPI_UDEV_TYPES, .spi_acpi_id = "ELAN70A1", .hid_id = {.vid = ELANSPI_TP_VID, .pid = 0x322d}, .driver_data = ELANSPI_90LEFT_ROTATE},
{.udev_types = ELANSPI_UDEV_TYPES, .spi_acpi_id = "ELAN7001", .hid_id = {.vid = ELANSPI_TP_VID, .pid = 0x3057}, .driver_data = ELANSPI_180_ROTATE},
{.udev_types = ELANSPI_UDEV_TYPES, .spi_acpi_id = "ELAN7001", .hid_id = {.vid = ELANSPI_TP_VID, .pid = 0x3087}, .driver_data = ELANSPI_180_ROTATE},
{.udev_types = ELANSPI_UDEV_TYPES, .spi_acpi_id = "ELAN7001", .hid_id = {.vid = ELANSPI_TP_VID, .pid = 0x30c6}, .driver_data = ELANSPI_180_ROTATE},
Expand All @@ -362,17 +364,18 @@ static const FpIdEntry elanspi_id_table[] = {
#define ELANSPI_MIN_EMPTY_INVALID_PERCENT 6
#define ELANSPI_MAX_REAL_INVALID_PERCENT 3

#define ELANSPI_MIN_REAL_STDDEV (592 * 592)
#define ELANSPI_MAX_EMPTY_STDDEV (350 * 350)
#define ELANSPI_MIN_REAL_STDDEV (250 * 250)
#define ELANSPI_MAX_EMPTY_STDDEV (180 * 180)

#define ELANSPI_MIN_FRAMES_DEBOUNCE 2

#define ELANSPI_SWIPE_FRAMES_DISCARD 1
#define ELANSPI_MIN_FRAMES_SWIPE (7 + ELANSPI_SWIPE_FRAMES_DISCARD)
#define ELANSPI_MAX_FRAMES_SWIPE (20 + ELANSPI_SWIPE_FRAMES_DISCARD)
#define ELANSPI_MIN_FRAMES_SWIPE (2 + ELANSPI_SWIPE_FRAMES_DISCARD)
#define ELANSPI_MAX_FRAMES_SWIPE (12 + ELANSPI_SWIPE_FRAMES_DISCARD)

#define ELANSPI_MAX_FRAME_HEIGHT 43
#define ELANSPI_MIN_FRAME_TO_FRAME_DIFF (250 * 250)
#define ELANSPI_MIN_FRAME_TO_FRAME_DIFF_VERIFY (100 * 100)
#define ELANSPI_MIN_FRAME_TO_FRAME_DIFF_ENROLL (100 * 100)

#define ELANSPI_HV_SENSOR_FRAME_DELAY 23

Expand Down
2 changes: 1 addition & 1 deletion libfprint/fp-image.c
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Expand Up @@ -316,7 +316,7 @@ fp_image_sigfm_extract_thread_func (GTask * task, void * src_obj,
g_timer_stop (timer);
fp_dbg ("sigfm extract completed in %f secs", g_timer_elapsed (timer, NULL));
g_timer_destroy (timer);
if (sigfm_keypoints_count (data->sigfm_info) < 25)
if (sigfm_keypoints_count (data->sigfm_info) < 5)
{
g_task_return_new_error (task, G_IO_ERROR, G_IO_ERROR_FAILED,
"No enough keypoints found");
Expand Down
3 changes: 2 additions & 1 deletion libfprint/fpi-print.c
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Expand Up @@ -305,7 +305,8 @@ fpi_print_sigfm_match (FpPrint * template, FpPrint * print,
"error in sigfm_match_score");
return FPI_MATCH_ERROR;
}
fp_dbg ("sigfm score %d/%d", score, bz3_threshold);
fp_dbg ("sigfm template %d/%d score %d/%d",
i + 1, template->prints->len, score, bz3_threshold);
if (score >= bz3_threshold)
return FPI_MATCH_SUCCESS;
}
Expand Down