From f7d00a828dd0af5db75a80415758c848d48d11f8 Mon Sep 17 00:00:00 2001 From: Vasily Khoruzhick Date: Sat, 19 Sep 2015 15:27:19 -0700 Subject: [PATCH] lib: use normalized error to make decision about movement direction Height is not a good determinant in movement direction, normalized error is much better. Should fix aes1610 and aes2501 driver issues. --- libfprint/assembling.c | 29 +++++++++++++++++++++-------- libfprint/assembling.h | 5 ++--- libfprint/drivers/aes1610.c | 9 +-------- libfprint/drivers/aes2501.c | 13 ++----------- 4 files changed, 26 insertions(+), 30 deletions(-) diff --git a/libfprint/assembling.c b/libfprint/assembling.c index 87711bd..cde4eaf 100644 --- a/libfprint/assembling.c +++ b/libfprint/assembling.c @@ -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, diff --git a/libfprint/assembling.h b/libfprint/assembling.h index 4525006..3bcab2f 100644 --- a/libfprint/assembling.h +++ b/libfprint/assembling.h @@ -40,9 +40,8 @@ struct fpi_frame_asmbl_ctx { unsigned y); }; -unsigned int fpi_do_movement_estimation(struct fpi_frame_asmbl_ctx *ctx, - GSList *stripes, size_t stripes_len, - gboolean reverse); +void fpi_do_movement_estimation(struct fpi_frame_asmbl_ctx *ctx, + GSList *stripes, size_t stripes_len); struct fp_img *fpi_assemble_frames(struct fpi_frame_asmbl_ctx *ctx, GSList *stripes, size_t stripes_len); diff --git a/libfprint/drivers/aes1610.c b/libfprint/drivers/aes1610.c index b4de1a2..afd0dbb 100644 --- a/libfprint/drivers/aes1610.c +++ b/libfprint/drivers/aes1610.c @@ -621,19 +621,12 @@ static void capture_read_strip_cb(struct libusb_transfer *transfer) /* stop capturing if MAX_FRAMES is reached */ if (aesdev->blanks_count > 10 || g_slist_length(aesdev->strips) >= MAX_FRAMES) { struct fp_img *img; - unsigned int height, rev_height; fp_dbg("sending stop capture.... blanks=%d frames=%d", aesdev->blanks_count, g_slist_length(aesdev->strips)); /* send stop capture bits */ aes_write_regv(dev, capture_stop, G_N_ELEMENTS(capture_stop), stub_capture_stop_cb, NULL); aesdev->strips = g_slist_reverse(aesdev->strips); - height = fpi_do_movement_estimation(&assembling_ctx, aesdev->strips, aesdev->strips_len, FALSE); - rev_height = fpi_do_movement_estimation(&assembling_ctx, aesdev->strips, aesdev->strips_len, TRUE); - fp_dbg("heights: %d rev: %d", height, rev_height); - if (rev_height < height) { - fp_dbg("Reversed direction"); - height = fpi_do_movement_estimation(&assembling_ctx, aesdev->strips, aesdev->strips_len, FALSE); - } + fpi_do_movement_estimation(&assembling_ctx, aesdev->strips, aesdev->strips_len); img = fpi_assemble_frames(&assembling_ctx, aesdev->strips, aesdev->strips_len); img->flags |= FP_IMG_PARTIAL; g_slist_free_full(aesdev->strips, g_free); diff --git a/libfprint/drivers/aes2501.c b/libfprint/drivers/aes2501.c index 8729740..6c852a5 100644 --- a/libfprint/drivers/aes2501.c +++ b/libfprint/drivers/aes2501.c @@ -490,19 +490,10 @@ static void capture_read_strip_cb(struct libusb_transfer *transfer) aesdev->no_finger_cnt++; if (aesdev->no_finger_cnt == 3) { struct fp_img *img; - unsigned int height, rev_height; aesdev->strips = g_slist_reverse(aesdev->strips); - height = fpi_do_movement_estimation(&assembling_ctx, - aesdev->strips, aesdev->strips_len, FALSE); - rev_height = fpi_do_movement_estimation(&assembling_ctx, - aesdev->strips, aesdev->strips_len, TRUE); - fp_dbg("heights: %d rev: %d", height, rev_height); - if (rev_height < height) { - fp_dbg("Reversed direction"); - height = fpi_do_movement_estimation(&assembling_ctx, - aesdev->strips, aesdev->strips_len, FALSE); - } + fpi_do_movement_estimation(&assembling_ctx, + aesdev->strips, aesdev->strips_len); img = fpi_assemble_frames(&assembling_ctx, aesdev->strips, aesdev->strips_len); img->flags |= FP_IMG_PARTIAL;