AP_Camera: add time based triggering support

libraries/AP_Camera/AP_Camera.cpp

@@ -87,6 +87,18 @@ void AP_Camera::take_picture()
     primary->take_picture();
 }
 
+// take multiple pictures, time_interval between two consecutive pictures is in miliseconds
+// total_num is number of pictures to be taken, -1 means capture forever
+void AP_Camera::take_multiple_pictures(uint32_t time_interval_ms, int16_t total_num)
+{
+    WITH_SEMAPHORE(_rsem);
+
+    if (primary == nullptr) {
+        return;
+    }
+    primary->take_multiple_pictures(time_interval_ms, total_num);
+}
+
 // start/stop recording video
 // start_recording should be true to start recording, false to stop recording
 bool AP_Camera::record_video(bool start_recording)
@@ -240,10 +252,13 @@ MAV_RESULT AP_Camera::handle_command_long(const mavlink_command_long_t &packet)
         return MAV_RESULT_DENIED;
     case MAV_CMD_IMAGE_START_CAPTURE:
         if (!is_zero(packet.param2) || !is_equal(packet.param3, 1.0f) || !is_zero(packet.param4)) {
-            // time interval is not supported
-            // multiple image capture is not supported
-            // capture sequence number is not supported
-            return MAV_RESULT_UNSUPPORTED;
+            // Its a multiple picture request
+            if (is_equal(packet.param3, 0.0f)) {
+                take_multiple_pictures(packet.param2*1000, -1);
+            } else {
+                take_multiple_pictures(packet.param2*1000, packet.param3);
+            }
+            return MAV_RESULT_ACCEPTED;
         }
         take_picture();
         return MAV_RESULT_ACCEPTED;

libraries/AP_Camera/AP_Camera.h

@@ -115,6 +115,10 @@ public:
     void take_picture();
     void take_picture(uint8_t instance);
 
+    // take multiple pictures, time_interval between two consecutive pictures is in miliseconds
+    // total_num is number of pictures to be taken, -1 means capture forever
+    void take_multiple_pictures(uint32_t time_interval_ms, int16_t total_num);
+
     // start/stop recording video
     // start_recording should be true to start recording, false to stop recording
     bool record_video(bool start_recording);

libraries/AP_Camera/AP_Camera_Backend.cpp

@@ -32,6 +32,21 @@ void AP_Camera_Backend::update()
     // check feedback pin
     check_feedback();
 
+    // time based triggering
+    // if time and distance triggering both are enabled then we only do time based triggering
+    if (time_interval_settings.num_remaining != 0) {
+        uint32_t delta_ms = AP_HAL::millis() - last_picture_time_ms;
+        if (delta_ms > time_interval_settings.time_interval_ms) {
+            if (take_picture()) {
+                // decrease num_remaining except when its -1 i.e. capture forever
+                if (time_interval_settings.num_remaining > 0) {
+                    time_interval_settings.num_remaining--;
+                }
+            }
+        }
+        return;
+    }
+
     // implement trigger distance
     if (!is_positive(_params.trigg_dist)) {
         last_location.lat = 0;
@@ -86,7 +101,7 @@ bool AP_Camera_Backend::take_picture()
 
     // check minimum time interval since last picture taken
     uint32_t now_ms = AP_HAL::millis();
-    if (now_ms - last_photo_time_ms < (uint32_t)(_params.interval_min * 1000)) {
+    if (now_ms - last_picture_time_ms < (uint32_t)(_params.interval_min * 1000)) {
         trigger_pending = true;
         return false;
     }
@@ -96,7 +111,7 @@ bool AP_Camera_Backend::take_picture()
     // trigger actually taking picture and update image count
     if (trigger_pic()) {
         image_index++;
-        last_photo_time_ms = now_ms;
+        last_picture_time_ms = now_ms;
         IGNORE_RETURN(AP::ahrs().get_location(last_location));
         log_picture();
         return true;
@@ -105,6 +120,13 @@ bool AP_Camera_Backend::take_picture()
     return false;
 }
 
+// take multiple pictures, time_interval between two consecutive pictures is in miliseconds
+// total_num is number of pictures to be taken, -1 means capture forever
+void AP_Camera_Backend::take_multiple_pictures(uint32_t time_interval_ms, int16_t total_num)
+{
+    time_interval_settings = {time_interval_ms, total_num};
+}
+
 // handle camera control
 void AP_Camera_Backend::control(float session, float zoom_pos, float zoom_step, float focus_lock, float shooting_cmd, float cmd_id)
 {

libraries/AP_Camera/AP_Camera_Backend.h

@@ -56,6 +56,10 @@ public:
     // take a picture.  returns true on success
     bool take_picture();
 
+    // take multiple pictures, time_interval between two consecutive pictures is in miliseconds
+    // total_num is number of pictures to be taken, -1 means capture forever
+    void take_multiple_pictures(uint32_t time_interval_ms, int16_t total_num);
+
     // entry point to actually take a picture.  returns true on success
     virtual bool trigger_pic() = 0;
 
@@ -128,6 +132,12 @@ protected:
         uint32_t feedback_trigger_logged_count; // ID sequence number
     } camera_feedback;
 
+    // Picture settings
+    struct {
+        uint32_t time_interval_ms;     // time interval (in miliseconds) between two consecutive pictures
+        int16_t num_remaining;      // number of pictures still to be taken, -1 means take unlimited pictures
+    } time_interval_settings;
+
     // Logging Function
     void log_picture();
     void Write_Camera(uint64_t timestamp_us=0);
@@ -143,7 +153,7 @@ protected:
     uint32_t feedback_trigger_timestamp_us; // system time (in microseconds) that timer detected the feedback pin changed
     uint32_t feedback_trigger_logged_count; // number of times the feedback has been logged
     bool trigger_pending;           // true if a call to take_pic() was delayed due to the minimum time interval time
-    uint32_t last_photo_time_ms;    // system time that photo was last taken
+    uint32_t last_picture_time_ms;    // system time that photo was last taken
     Location last_location;         // Location that last picture was taken at (used for trigg_dist calculation)
     uint16_t image_index;           // number of pictures taken since boot
     bool last_is_armed;             // stores last arm/disarm state. true if it was armed lastly