diff --git a/libfprint/drivers/aes1610.c b/libfprint/drivers/aes1610.c
index df5b5695..5a29080f 100644
--- a/libfprint/drivers/aes1610.c
+++ b/libfprint/drivers/aes1610.c
@@ -611,7 +611,7 @@ static void capture_read_strip_cb(struct libusb_transfer *transfer)
 		/* 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);
-		fpi_do_movement_estimation(&assembling_ctx, aesdev->strips, aesdev->strips_len);
+		fpi_do_movement_estimation(&assembling_ctx, aesdev->strips);
 		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 91e02a39..ef705e7b 100644
--- a/libfprint/drivers/aes2501.c
+++ b/libfprint/drivers/aes2501.c
@@ -482,8 +482,7 @@ static void capture_read_strip_cb(struct libusb_transfer *transfer,
 			struct fp_img *img;
 
 			aesdev->strips = g_slist_reverse(aesdev->strips);
-			fpi_do_movement_estimation(&assembling_ctx,
-					aesdev->strips, aesdev->strips_len);
+			fpi_do_movement_estimation(&assembling_ctx, aesdev->strips);
 			img = fpi_assemble_frames(&assembling_ctx,
 						  aesdev->strips, aesdev->strips_len);
 			img->flags |= FP_IMG_PARTIAL;
diff --git a/libfprint/drivers/elan.c b/libfprint/drivers/elan.c
index 897f34f9..8bc7e505 100644
--- a/libfprint/drivers/elan.c
+++ b/libfprint/drivers/elan.c
@@ -307,7 +307,7 @@ static void elan_submit_image(struct fp_img_dev *dev)
 	assembling_ctx.frame_height = elandev->frame_height;
 	assembling_ctx.image_width = elandev->frame_width * 3 / 2;
 	g_slist_foreach(raw_frames, (GFunc) elandev->process_frame, &frames);
-	fpi_do_movement_estimation(&assembling_ctx, frames, num_frames);
+	fpi_do_movement_estimation(&assembling_ctx, frames);
 	img = fpi_assemble_frames(&assembling_ctx, frames, num_frames);
 
 	img->flags |= FP_IMG_PARTIAL;
diff --git a/libfprint/fpi-assembling.c b/libfprint/fpi-assembling.c
index 9ff29c0b..cb911a8c 100644
--- a/libfprint/fpi-assembling.c
+++ b/libfprint/fpi-assembling.c
@@ -162,7 +162,6 @@ static unsigned int do_movement_estimation(struct fpi_frame_asmbl_ctx *ctx,
  * fpi_do_movement_estimation:
  * @ctx: #fpi_frame_asmbl_ctx - frame assembling context
  * @stripes: a singly-linked list of #fpi_frame
- * @num_stripes: number of items in @stripes to process
  *
  * fpi_do_movement_estimation() estimates the movement between adjacent
  * frames, populating @delta_x and @delta_y values for each #fpi_frame.
@@ -170,17 +169,12 @@ static unsigned int do_movement_estimation(struct fpi_frame_asmbl_ctx *ctx,
  * This function is used for devices that don't do movement estimation
  * in hardware. If hardware movement estimation is supported, the driver
  * should populate @delta_x and @delta_y instead.
- *
- * Note that @num_stripes might be shorter than the length of the list,
- * if some stripes should be skipped.
  */
 void fpi_do_movement_estimation(struct fpi_frame_asmbl_ctx *ctx,
-			    GSList *stripes, size_t num_stripes)
+				GSList                     *stripes)
 {
 	int err, rev_err;
 
-	g_return_if_fail (g_slist_length(stripes) != num_stripes);
-
 	err = do_movement_estimation(ctx, stripes, FALSE);
 	rev_err = do_movement_estimation(ctx, stripes, TRUE);
 	fp_dbg("errors: %d rev: %d", err, rev_err);
diff --git a/libfprint/fpi-assembling.h b/libfprint/fpi-assembling.h
index d2a66515..1425e7a6 100644
--- a/libfprint/fpi-assembling.h
+++ b/libfprint/fpi-assembling.h
@@ -63,7 +63,7 @@ struct fpi_frame_asmbl_ctx {
 };
 
 void fpi_do_movement_estimation(struct fpi_frame_asmbl_ctx *ctx,
-			    GSList *stripes, size_t num_stripes);
+				GSList                     *stripes);
 
 struct fp_img *fpi_assemble_frames(struct fpi_frame_asmbl_ctx *ctx,
 			    GSList *stripes, size_t num_stripes);