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aes2501: Improve image contrast

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When scanning, check the histogram sum, and increase the
ADREFHI register value if the sum is too low, or decrease
it if it's too high.

https://bugs.freedesktop.org/show_bug.cgi?id=56715
This commit is contained in:
Vasily Khoruzhick 2012-11-03 16:13:05 +03:00 committed by Bastien Nocera
parent d8aae30a67
commit e32fa8cc38
2 changed files with 21 additions and 2 deletions
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17
libfprint/drivers/aes2501.c
View file

@ -515,13 +515,13 @@ static const struct aes_regwrite capture_reqs_2[] = {
{ AES2501_REG_CTRL2, AES2501_CTRL2_SET_ONE_SHOT },
};
static const struct aes_regwrite strip_scan_reqs[] = {
static struct aes_regwrite strip_scan_reqs[] = {
{ AES2501_REG_IMAGCTRL,
AES2501_IMAGCTRL_TST_REG_ENABLE | AES2501_IMAGCTRL_HISTO_DATA_ENABLE },
{ AES2501_REG_STRTCOL, 0x00 },
{ AES2501_REG_ENDCOL, 0x2f },
{ AES2501_REG_CHANGAIN, AES2501_CHANGAIN_STAGE1_16X },
{ AES2501_REG_ADREFHI, 0x5b },
{ AES2501_REG_ADREFHI, AES2501_ADREFHI_MAX_VALUE },
{ AES2501_REG_ADREFLO, 0x20 },
{ AES2501_REG_CTRL2, AES2501_CTRL2_SET_ONE_SHOT },
};
@ -574,6 +574,17 @@ static void capture_read_strip_cb(struct libusb_transfer *transfer)
}
fp_dbg("sum=%d", sum);
if (sum < AES2501_SUM_LOW_THRESH) {
strip_scan_reqs[4].value -= 0x8;
if (strip_scan_reqs[4].value < AES2501_ADREFHI_MIN_VALUE)
strip_scan_reqs[4].value = AES2501_ADREFHI_MIN_VALUE;
} else if (sum > AES2501_SUM_HIGH_THRESH) {
strip_scan_reqs[4].value += 0x8;
if (strip_scan_reqs[4].value > AES2501_ADREFHI_MAX_VALUE)
strip_scan_reqs[4].value = AES2501_ADREFHI_MAX_VALUE;
}
fp_dbg("ADREFHI is %.2x", strip_scan_reqs[4].value);
/* Sum is 0, maybe finger was removed? Wait for 3 empty frames
* to ensure
*/
@ -682,6 +693,8 @@ static void start_capture(struct fp_img_dev *dev)
}
aesdev->no_finger_cnt = 0;
/* Reset gain */
strip_scan_reqs[4].value = AES2501_ADREFHI_MAX_VALUE;
ssm = fpi_ssm_new(dev->dev, capture_run_state, CAPTURE_NUM_STATES);
fp_dbg("");
ssm->priv = dev;

6
libfprint/drivers/aes2501.h
View file

@ -167,4 +167,10 @@ enum aes2501_sensor_gain2 {
#define AES2501_LPONT_MIN_VALUE 0x00 /* 0 ms */
#define AES2501_LPONT_MAX_VALUE 0x1f /* About 16 ms */
#define AES2501_ADREFHI_MIN_VALUE 0x28
#define AES2501_ADREFHI_MAX_VALUE 0x58
#define AES2501_SUM_HIGH_THRESH 1000
#define AES2501_SUM_LOW_THRESH 700
#endif /* __AES2501_H */