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lib: use normalized error to make decision about movement direction

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Height is not a good determinant in movement direction, normalized
error is much better. Should fix aes1610 and aes2501 driver issues.
This commit is contained in:
Vasily Khoruzhick
2015-09-19 15:27:19 -07:00
parent 0f0a4b2da6
commit f7d00a828d
4 changed files with 26 additions and 30 deletions
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29
libfprint/assembling.c
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@@ -88,7 +88,7 @@ static void find_overlap(struct fpi_frame_asmbl_ctx *ctx,
{
int dx, dy;
unsigned int err;
*min_error = INT_MAX;
*min_error = 255 * ctx->frame_height * ctx->frame_width;
/* Seeking in horizontal and vertical dimensions,
* for horizontal dimension we'll check only 8 pixels
@@ -108,16 +108,20 @@ static void find_overlap(struct fpi_frame_asmbl_ctx *ctx,
}
}
unsigned int fpi_do_movement_estimation(struct fpi_frame_asmbl_ctx *ctx,
static unsigned int do_movement_estimation(struct fpi_frame_asmbl_ctx *ctx,
GSList *stripes, size_t num_stripes,
gboolean reverse)
{
GSList *list_entry = stripes;
GTimer *timer;
int frame = 1;
int height = 0;
struct fpi_frame *prev_stripe = list_entry->data;
unsigned int min_error;
/* Max error is width * height * 255, for AES2501 which has the largest
* sensor its 192*16*255 = 783360. So for 32bit value it's ~5482 frame before
* we might get int overflow. Use 64bit value here to prevent integer overflow
*/
unsigned long long total_error = 0;
list_entry = g_slist_next(list_entry);
@@ -132,22 +136,31 @@ unsigned int fpi_do_movement_estimation(struct fpi_frame_asmbl_ctx *ctx,
}
else
find_overlap(ctx, cur_stripe, prev_stripe, &min_error);
total_error += min_error;
frame++;
height += prev_stripe->delta_y;
prev_stripe = cur_stripe;
list_entry = g_slist_next(list_entry);
} while (frame < num_stripes);
if (height < 0)
height = -height;
height += ctx->frame_height;
g_timer_stop(timer);
fp_dbg("calc delta completed in %f secs", g_timer_elapsed(timer, NULL));
g_timer_destroy(timer);
return height;
return total_error / num_stripes;
}
void fpi_do_movement_estimation(struct fpi_frame_asmbl_ctx *ctx,
GSList *stripes, size_t num_stripes)
{
int err, rev_err;
err = do_movement_estimation(ctx, stripes, num_stripes, FALSE);
rev_err = do_movement_estimation(ctx, stripes, num_stripes, TRUE);
fp_dbg("errors: %d rev: %d", err, rev_err);
if (err < rev_err) {
do_movement_estimation(ctx, stripes, num_stripes, FALSE);
}
}
static inline void aes_blit_stripe(struct fpi_frame_asmbl_ctx *ctx,