Added manual exposure settings

Author: dudeofea

examples/glview.c

@@ -217,6 +217,8 @@ void keyPressed(unsigned char key, int x, int y)
 	if (key == 'e') {
 		static freenect_flag_value auto_exposure = FREENECT_ON;
 		freenect_set_flag(f_dev, FREENECT_AUTO_EXPOSURE, auto_exposure);
+		freenect_set_flag(f_dev, FREENECT_AUTO_FLICKER, auto_exposure);
+		freenect_set_flag(f_dev, FREENECT_AUTO_WHITE_BALANCE, auto_exposure);
 		auto_exposure = auto_exposure ? FREENECT_OFF : FREENECT_ON;
 	}
 	if (key == 'b') {

include/libfreenect.h

@@ -110,6 +110,7 @@ typedef enum {
 typedef enum {
 	// values written to the CMOS register
 	FREENECT_AUTO_EXPOSURE      = 1 << 14,
+	FREENECT_AUTO_FLICKER       = 1 << 7,
 	FREENECT_AUTO_WHITE_BALANCE = 1 << 1,
 	FREENECT_RAW_COLOR          = 1 << 4,
 	// arbitrary bitfields to support flag combination
@@ -670,6 +671,34 @@ FREENECTAPI int freenect_set_depth_mode(freenect_device* dev, const freenect_fra
  */
 FREENECTAPI int freenect_set_flag(freenect_device *dev, freenect_flag flag, freenect_flag_value value);
 
+/**
+ * Get the current exposure in microseconds
+ *
+ * @param dev Device to set exposure
+ * @param time_us exposure time in microseconds
+ *
+ * @return 0 on success, < 0 if error
+ */
+FREENECTAPI int freenect_get_exposure(freenect_device *dev, int *time_us);
+
+/**
+ * Sets a static exposure time in microseconds
+ * note: you must turn off auto-exposure before calling this function
+ *
+ * Sample usage with 33.333ms exposure:
+ *
+ *   freenect_set_flag(fn_dev, FREENECT_AUTO_EXPOSURE, FREENECT_OFF);
+ *   freenect_set_flag(fn_dev, FREENECT_AUTO_FLICKER, FREENECT_OFF);
+ *   freenect_set_flag(fn_dev, FREENECT_AUTO_WHITE_BALANCE, FREENECT_OFF);
+ *   freenect_set_exposure(fn_dev, 33333);
+ *
+ * @param dev Device to set exposure
+ * @param time_us exposure time in microseconds
+ *
+ * @return 0 on success, < 0 if error
+ */
+FREENECTAPI int freenect_set_exposure(freenect_device *dev, int time_us);
+
 /**
  * Returns the brightness of the IR sensor.
  *

src/flags.c

@@ -93,6 +93,58 @@ int freenect_set_flag(freenect_device *dev, freenect_flag flag, freenect_flag_va
 	return write_cmos_register(dev, 0x0106, cmos_value);
 }
 
+int freenect_get_exposure(freenect_device *dev, int *time_us)
+{
+	freenect_context *ctx = dev->parent;
+
+	uint16_t shutter_width = read_cmos_register(dev, 0x0009);
+	if (shutter_width == UINT16_MAX)
+	{
+		return -1;
+	}
+	switch (dev->video_format) {
+		case FREENECT_VIDEO_RGB:
+		case FREENECT_VIDEO_BAYER:
+			*time_us = shutter_width * SHUTTER_WIDTH_TO_EXP_RGB;
+			break;
+		case FREENECT_VIDEO_YUV_RGB:
+		case FREENECT_VIDEO_YUV_RAW:
+			*time_us = shutter_width * SHUTTER_WIDTH_TO_EXP_YUV;
+			break;
+		case FREENECT_VIDEO_DUMMY:
+		case FREENECT_VIDEO_IR_8BIT:
+		case FREENECT_VIDEO_IR_10BIT:
+		case FREENECT_VIDEO_IR_10BIT_PACKED:
+			FN_WARNING("Could not get exposure, invalid video format");
+			return -1;
+	}
+	return 0;
+}
+
+int freenect_set_exposure(freenect_device *dev, int time_us)
+{
+	freenect_context *ctx = dev->parent;
+
+	uint16_t cmos_value = 0;
+	switch (dev->video_format) {
+		case FREENECT_VIDEO_RGB:
+		case FREENECT_VIDEO_BAYER:
+			cmos_value = time_us / SHUTTER_WIDTH_TO_EXP_RGB;
+			break;
+		case FREENECT_VIDEO_YUV_RGB:
+		case FREENECT_VIDEO_YUV_RAW:
+			cmos_value = time_us / SHUTTER_WIDTH_TO_EXP_YUV;
+			break;
+		case FREENECT_VIDEO_DUMMY:
+		case FREENECT_VIDEO_IR_8BIT:
+		case FREENECT_VIDEO_IR_10BIT:
+		case FREENECT_VIDEO_IR_10BIT_PACKED:
+			FN_WARNING("Could not set exposure, invalid video format");
+			return -1;
+	}
+	return write_cmos_register(dev, 0x0009, cmos_value);;
+}
+
 int freenect_get_ir_brightness(freenect_device *dev)
 {
 	freenect_context *ctx = dev->parent;

src/freenect_internal.h

@@ -148,6 +148,12 @@ static inline int32_t fn_le32s(int32_t s)
 #define PID_K4W_AUDIO_ALT_1 0x02c3
 #define PID_K4W_AUDIO_ALT_2 0x02bb
 
+// Conversion from shutter width to exposure in microseconds
+// Measured using camtest.c with various very long exposure times
+// TODO: calculate this from camera registers instead of magic numbers
+#define SHUTTER_WIDTH_TO_EXP_RGB 54.21
+#define SHUTTER_WIDTH_TO_EXP_YUV 63.25
+
 typedef struct {
 	int running;
 	uint8_t flag;