--- /dev/null
+/*
+ * Auto gain algorithm for camera's with a coarse exposure control
+ *
+ * Copyright (C) 2010 Hans de Goede <hdegoede@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+/* Autogain + exposure algorithm for cameras with a coarse exposure control
+ (usually this means we can only control the clockdiv to change exposure)
+ As changing the clockdiv so that the fps drops from 30 to 15 fps for
+ example, will lead to a huge exposure change (it effectively doubles),
+ this algorithm normally tries to only adjust the gain (between 40 and
+ 80 %) and if that does not help, only then changes exposure. This leads
+ to a much more stable image then using the knee algorithm which at
+ certain points of the knee graph will only try to adjust exposure,
+ which leads to oscilating as one exposure step is huge.
+
+ Note this assumes that the sd struct for the cam in question has
+ exp_too_high_cnt and exp_too_high_cnt int members for use by this function.
+
+ Returns 0 if no changes were made, 1 if the gain and or exposure settings
+ where changed. */
+static int gspca_coarse_grained_expo_autogain(struct gspca_dev *gspca_dev,
+ int avg_lum, int desired_avg_lum, int deadzone)
+{
+ int i, steps, gain, orig_gain, exposure, orig_exposure;
+ int gain_low, gain_high;
+ const struct ctrl *gain_ctrl = NULL;
+ const struct ctrl *exposure_ctrl = NULL;
+ struct sd *sd = (struct sd *) gspca_dev;
+ int retval = 0;
+
+ for (i = 0; i < gspca_dev->sd_desc->nctrls; i++) {
+ if (gspca_dev->ctrl_dis & (1 << i))
+ continue;
+ if (gspca_dev->sd_desc->ctrls[i].qctrl.id == V4L2_CID_GAIN)
+ gain_ctrl = &gspca_dev->sd_desc->ctrls[i];
+ if (gspca_dev->sd_desc->ctrls[i].qctrl.id == V4L2_CID_EXPOSURE)
+ exposure_ctrl = &gspca_dev->sd_desc->ctrls[i];
+ }
+ if (!gain_ctrl || !exposure_ctrl) {
+ PDEBUG(D_ERR, "Error: gspca_coarse_grained_expo_autogain "
+ "called on cam without gain or exposure");
+ return 0;
+ }
+
+ if (gain_ctrl->get(gspca_dev, &gain) ||
+ exposure_ctrl->get(gspca_dev, &exposure))
+ return 0;
+
+ orig_gain = gain;
+ orig_exposure = exposure;
+ gain_low =
+ (gain_ctrl->qctrl.maximum - gain_ctrl->qctrl.minimum) / 5 * 2;
+ gain_low += gain_ctrl->qctrl.minimum;
+ gain_high =
+ (gain_ctrl->qctrl.maximum - gain_ctrl->qctrl.minimum) / 5 * 4;
+ gain_high += gain_ctrl->qctrl.minimum;
+
+ /* If we are of a multiple of deadzone, do multiple steps to reach the
+ desired lumination fast (with the risc of a slight overshoot) */
+ steps = (desired_avg_lum - avg_lum) / deadzone;
+
+ PDEBUG(D_FRAM, "autogain: lum: %d, desired: %d, steps: %d",
+ avg_lum, desired_avg_lum, steps);
+
+ if ((gain + steps) > gain_high &&
+ sd->exposure < exposure_ctrl->qctrl.maximum) {
+ gain = gain_high;
+ sd->exp_too_low_cnt++;
+ } else if ((gain + steps) < gain_low &&
+ sd->exposure > exposure_ctrl->qctrl.minimum) {
+ gain = gain_low;
+ sd->exp_too_high_cnt++;
+ } else {
+ gain += steps;
+ if (gain > gain_ctrl->qctrl.maximum)
+ gain = gain_ctrl->qctrl.maximum;
+ else if (gain < gain_ctrl->qctrl.minimum)
+ gain = gain_ctrl->qctrl.minimum;
+ sd->exp_too_high_cnt = 0;
+ sd->exp_too_low_cnt = 0;
+ }
+
+ if (sd->exp_too_high_cnt > 3) {
+ exposure--;
+ sd->exp_too_high_cnt = 0;
+ } else if (sd->exp_too_low_cnt > 3) {
+ exposure++;
+ sd->exp_too_low_cnt = 0;
+ }
+
+ if (gain != orig_gain) {
+ gain_ctrl->set(gspca_dev, gain);
+ retval = 1;
+ }
+ if (exposure != orig_exposure) {
+ exposure_ctrl->set(gspca_dev, exposure);
+ retval = 1;
+ }
+
+ return retval;
+}
struct gspca_dev gspca_dev; /* !! must be the first item */
atomic_t avg_lum;
int prev_avg_lum;
+ int exp_too_low_cnt;
+ int exp_too_high_cnt;
+ unsigned short exposure;
unsigned char gain;
- unsigned char exposure;
unsigned char brightness;
unsigned char autogain;
unsigned char autogain_ignore_frames;
/* sensor_data flags */
#define F_GAIN 0x01 /* has gain */
#define F_SIF 0x02 /* sif or vga */
+#define F_COARSE_EXPO 0x04 /* exposure control is coarse */
/* priv field of struct v4l2_pix_format flags (do not use low nibble!) */
#define MODE_RAW 0x10 /* raw bayer mode */
#define MODE_REDUCED_SIF 0x20 /* vga mode (320x240 / 160x120) on sif cam */
/* ctrl_dis helper macros */
-#define NO_EXPO ((1 << EXPOSURE_IDX) | (1 << AUTOGAIN_IDX))
+#define NO_EXPO ((1 << EXPOSURE_IDX) | (1 << COARSE_EXPOSURE_IDX) | \
+ (1 << AUTOGAIN_IDX))
#define NO_FREQ (1 << FREQ_IDX)
#define NO_BRIGHTNESS (1 << BRIGHTNESS_IDX)
}
/* We calculate the autogain at the end of the transfer of a frame, at this
- moment a frame with the old settings is being transmitted, and a frame is
- being captured with the old settings. So if we adjust the autogain we must
- ignore atleast the 2 next frames for the new settings to come into effect
- before doing any other adjustments */
-#define AUTOGAIN_IGNORE_FRAMES 3
+ moment a frame with the old settings is being captured and transmitted. So
+ if we adjust the gain or exposure we must ignore atleast the next frame for
+ the new settings to come into effect before doing any other adjustments. */
+#define AUTOGAIN_IGNORE_FRAMES 1
/* V4L2 controls supported by the driver */
static int sd_setbrightness(struct gspca_dev *gspca_dev, __s32 val);
.id = V4L2_CID_EXPOSURE,
.type = V4L2_CTRL_TYPE_INTEGER,
.name = "Exposure",
-#define EXPOSURE_DEF 16 /* 32 ms / 30 fps */
-#define EXPOSURE_KNEE 50 /* 100 ms / 10 fps */
+#define EXPOSURE_DEF 33 /* 33 ms / 30 fps */
+#define EXPOSURE_KNEE 100 /* 100 ms / 10 fps */
.minimum = 0,
- .maximum = 255,
+ .maximum = 511,
.step = 1,
.default_value = EXPOSURE_DEF,
.flags = 0,
.set = sd_setexposure,
.get = sd_getexposure,
},
-#define AUTOGAIN_IDX 3
+#define COARSE_EXPOSURE_IDX 3
+ {
+ {
+ .id = V4L2_CID_EXPOSURE,
+ .type = V4L2_CTRL_TYPE_INTEGER,
+ .name = "Exposure",
+#define COARSE_EXPOSURE_DEF 2 /* 30 fps */
+ .minimum = 2,
+ .maximum = 15,
+ .step = 1,
+ .default_value = COARSE_EXPOSURE_DEF,
+ .flags = 0,
+ },
+ .set = sd_setexposure,
+ .get = sd_getexposure,
+ },
+#define AUTOGAIN_IDX 4
{
{
.id = V4L2_CID_AUTOGAIN,
.set = sd_setautogain,
.get = sd_getautogain,
},
-#define FREQ_IDX 4
+#define FREQ_IDX 5
{
{
.id = V4L2_CID_POWER_LINE_FREQUENCY,
0),
SENS(initPas202, initPas202, pas202_sensor_init, NULL, NULL, 0,
NO_EXPO|NO_FREQ, 0),
-SENS(initTas5110c, NULL, tas5110_sensor_init, NULL, NULL, F_GAIN|F_SIF,
- NO_BRIGHTNESS|NO_FREQ, 0),
-SENS(initTas5110d, NULL, tas5110_sensor_init, NULL, NULL, F_GAIN|F_SIF,
- NO_BRIGHTNESS|NO_FREQ, 0),
+SENS(initTas5110c, NULL, tas5110_sensor_init, NULL, NULL,
+ F_GAIN|F_SIF|F_COARSE_EXPO, NO_BRIGHTNESS|NO_FREQ, 0),
+SENS(initTas5110d, NULL, tas5110_sensor_init, NULL, NULL,
+ F_GAIN|F_SIF|F_COARSE_EXPO, NO_BRIGHTNESS|NO_FREQ, 0),
SENS(initTas5130, NULL, tas5130_sensor_init, NULL, NULL, 0, NO_EXPO|NO_FREQ,
0),
};
switch (sd->sensor) {
case SENSOR_TAS5110C:
case SENSOR_TAS5110D: {
- __u8 reg;
-
/* register 19's high nibble contains the sn9c10x clock divider
The high nibble configures the no fps according to the
formula: 60 / high_nibble. With a maximum of 30 fps */
- reg = 120 * sd->exposure / 1000;
- if (reg < 2)
- reg = 2;
- else if (reg > 15)
- reg = 15;
+ __u8 reg = sd->exposure;
reg = (reg << 4) | 0x0b;
reg_w(gspca_dev, 0x19, ®, 1);
break;
} else
reg10_max = 0x41;
- reg11 = (60 * sd->exposure + 999) / 1000;
+ reg11 = (30 * sd->exposure + 999) / 1000;
if (reg11 < 1)
reg11 = 1;
else if (reg11 > 16)
reg11 = 3;
/* frame exposure time in ms = 1000 * reg11 / 30 ->
- reg10 = sd->exposure * 2 * reg10_max / (1000 * reg11 / 30) */
- reg10 = (sd->exposure * 60 * reg10_max) / (1000 * reg11);
+ reg10 = sd->exposure * reg10_max / (1000 * reg11 / 30) */
+ reg10 = (sd->exposure * 30 * reg10_max) / (1000 * reg11);
/* Don't allow this to get below 10 when using autogain, the
steps become very large (relatively) when below 10 causing
}
}
+#include "coarse_expo_autogain.h"
+
static void do_autogain(struct gspca_dev *gspca_dev)
{
- int deadzone, desired_avg_lum;
+ int deadzone, desired_avg_lum, result;
struct sd *sd = (struct sd *) gspca_dev;
int avg_lum = atomic_read(&sd->avg_lum);
- if (avg_lum == -1)
+ if (avg_lum == -1 || !sd->autogain)
+ return;
+
+ if (sd->autogain_ignore_frames > 0) {
+ sd->autogain_ignore_frames--;
return;
+ }
/* SIF / VGA sensors have a different autoexposure area and thus
different avg_lum values for the same picture brightness */
if (sensor_data[sd->sensor].flags & F_SIF) {
- deadzone = 1000;
- desired_avg_lum = 7000;
+ deadzone = 500;
+ /* SIF sensors tend to overexpose, so keep this small */
+ desired_avg_lum = 5000;
} else {
- deadzone = 3000;
+ deadzone = 1500;
desired_avg_lum = 23000;
}
- if (sd->autogain_ignore_frames > 0)
- sd->autogain_ignore_frames--;
- else if (gspca_auto_gain_n_exposure(gspca_dev, avg_lum,
- sd->brightness * desired_avg_lum / 127,
- deadzone, GAIN_KNEE, EXPOSURE_KNEE)) {
+ if (sensor_data[sd->sensor].flags & F_COARSE_EXPO)
+ result = gspca_coarse_grained_expo_autogain(gspca_dev, avg_lum,
+ sd->brightness * desired_avg_lum / 127,
+ deadzone);
+ else
+ result = gspca_auto_gain_n_exposure(gspca_dev, avg_lum,
+ sd->brightness * desired_avg_lum / 127,
+ deadzone, GAIN_KNEE, EXPOSURE_KNEE);
+
+ if (result) {
PDEBUG(D_FRAM, "autogain: gain changed: gain: %d expo: %d",
(int)sd->gain, (int)sd->exposure);
sd->autogain_ignore_frames = AUTOGAIN_IGNORE_FRAMES;
sd->brightness = BRIGHTNESS_DEF;
sd->gain = GAIN_DEF;
- sd->exposure = EXPOSURE_DEF;
+ if (sensor_data[sd->sensor].flags & F_COARSE_EXPO) {
+ sd->exposure = COARSE_EXPOSURE_DEF;
+ gspca_dev->ctrl_dis |= (1 << EXPOSURE_IDX);
+ } else {
+ sd->exposure = EXPOSURE_DEF;
+ gspca_dev->ctrl_dis |= (1 << COARSE_EXPOSURE_IDX);
+ }
if (gspca_dev->ctrl_dis & (1 << AUTOGAIN_IDX))
sd->autogain = 0; /* Disable do_autogain callback */
else
sd->frames_to_drop = 0;
sd->autogain_ignore_frames = 0;
+ sd->exp_too_high_cnt = 0;
+ sd->exp_too_low_cnt = 0;
atomic_set(&sd->avg_lum, -1);
return 0;
}
struct sd *sd = (struct sd *) gspca_dev;
sd->autogain = val;
+ sd->exp_too_high_cnt = 0;
+ sd->exp_too_low_cnt = 0;
+
/* when switching to autogain set defaults to make sure
we are on a valid point of the autogain gain /
exposure knee graph, and give this change time to
take effect before doing autogain. */
- if (sd->autogain) {
+ if (sd->autogain && !(sensor_data[sd->sensor].flags & F_COARSE_EXPO)) {
sd->exposure = EXPOSURE_DEF;
sd->gain = GAIN_DEF;
if (gspca_dev->streaming) {
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