diff --git a/src/drivers/optical_flow/pmw3901/PMW3901.cpp b/src/drivers/optical_flow/pmw3901/PMW3901.cpp
index b4df95cb3e..1bdc45cd2e 100644
--- a/src/drivers/optical_flow/pmw3901/PMW3901.cpp
+++ b/src/drivers/optical_flow/pmw3901/PMW3901.cpp
@@ -314,8 +314,12 @@ PMW3901::Run()
 
 	readMotionCount(delta_x_raw, delta_y_raw, qual);
 
-	_flow_sum_x += delta_x_raw;
-	_flow_sum_y += delta_y_raw;
+	if (qual > 0) {
+		_flow_sum_x += delta_x_raw;
+		_flow_sum_y += delta_y_raw;
+		_flow_sample_counter ++;
+		_flow_quality_sum += qual;
+	}
 
 	// returns if the collect time has not been reached
 	if (_flow_dt_sum_usec < _collect_time) {
@@ -336,19 +340,12 @@ PMW3901::Run()
 	rotate_3f(_yaw_rotation, report.pixel_flow_x_integral, report.pixel_flow_y_integral, zeroval);
 	rotate_3f(_yaw_rotation, report.gyro_x_rate_integral, report.gyro_y_rate_integral, report.gyro_z_rate_integral);
 
-	report.frame_count_since_last_readout = 4;		// microseconds
+	report.frame_count_since_last_readout = _flow_sample_counter;	// number of frames
 	report.integration_timespan = _flow_dt_sum_usec; 	// microseconds
 
 	report.sensor_id = 0;
+	report.quality = _flow_sample_counter > 0 ? _flow_quality_sum / _flow_sample_counter : 0;
 
-	// This sensor doesn't provide any quality metric. However if the sensor is unable to calculate the optical flow it will
-	// output 0 for the delta. Hence, we set the measurement to "invalid" (quality = 0) if the values are smaller than FLT_EPSILON
-	if (fabsf(report.pixel_flow_x_integral) < FLT_EPSILON && fabsf(report.pixel_flow_y_integral) < FLT_EPSILON) {
-		report.quality = 0;
-
-	} else {
-		report.quality = qual;
-	}
 
 	/* No gyro on this board */
 	report.gyro_x_rate_integral = NAN;
@@ -363,6 +360,8 @@ PMW3901::Run()
 	_flow_dt_sum_usec = 0;
 	_flow_sum_x = 0;
 	_flow_sum_y = 0;
+	_flow_sample_counter = 0;
+	_flow_quality_sum = 0;
 
 	_optical_flow_pub.publish(report);
 
@@ -379,6 +378,7 @@ PMW3901::readMotionCount(int16_t &deltaX, int16_t &deltaY, uint8_t &qual)
 	int ret = transfer(&data[0], &data[0], 12);
 
 	if (OK != ret) {
+		qual = 0;
 		perf_count(_comms_errors);
 		DEVICE_LOG("spi::transfer returned %d", ret);
 		return ret;
@@ -386,7 +386,14 @@ PMW3901::readMotionCount(int16_t &deltaX, int16_t &deltaY, uint8_t &qual)
 
 	deltaX = ((int16_t)data[5] << 8) | data[3];
 	deltaY = ((int16_t)data[9] << 8) | data[7];
-	qual = data[11];
+
+	// If the reported flow is impossibly large, we just got garbage from the SPI
+	if (deltaX > 240 || deltaY > 240 || deltaX < -240 || deltaY < -240) {
+		qual = 0;
+
+	} else {
+		qual = data[11];
+	}
 
 	ret = OK;
 
diff --git a/src/drivers/optical_flow/pmw3901/PMW3901.hpp b/src/drivers/optical_flow/pmw3901/PMW3901.hpp
index 09d5768bae..942495d401 100644
--- a/src/drivers/optical_flow/pmw3901/PMW3901.hpp
+++ b/src/drivers/optical_flow/pmw3901/PMW3901.hpp
@@ -103,7 +103,7 @@ protected:
 
 private:
 
-	const uint64_t _collect_time{15000}; // usecs, optical flow data publish rate
+	const uint64_t _collect_time{15000}; // usecs, ensures flow data is published every second iteration of Run() (100Hz -> 50Hz)
 
 	uORB::PublicationMulti<optical_flow_s> _optical_flow_pub{ORB_ID(optical_flow)};
 
@@ -117,6 +117,8 @@ private:
 	int _flow_sum_x{0};
 	int _flow_sum_y{0};
 	uint64_t _flow_dt_sum_usec{0};
+	uint16_t _flow_quality_sum{0};
+	uint8_t _flow_sample_counter{0};
 
 	/**
 	* Initialise the automatic measurement state machine and start it.