RTC - Revision history

Polto: /* Absolute date/time in Elphel cameras */

2010-10-03T15:23:22Z

Absolute date/time in Elphel cameras

← Older revision		Revision as of 15:23, 3 October 2010
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	== Real Time Clock ==		== Real Time Clock ==
	=== Absolute date/time in Elphel cameras ===		=== Absolute date/time in Elphel cameras ===
	Elphel model ~~333~~ (as well as older ones) camera does not have a hardware clock with battery backup so each time it wakes up it is January, 1 1970. We made a simple hack to automatically setup date and time - camera web interface uses javascript code that sends host computer time (UTC) to the camera as one parameters for image acquisitions (originally the purpose was just to make all URLs unique to prevent caching of images by the browser).		Elphel model NC353L (as well as older ones) camera does not have a hardware clock with battery backup so each time it wakes up it is January, 1 1970. (NC353L-369* models have cmos clock). We made a simple hack to automatically setup date and time - camera web interface uses javascript code that sends host computer time (UTC) to the camera as one parameters for image acquisitions (originally the purpose was just to make all URLs unique to prevent caching of images by the browser).

	=== Timekeeping in Elphel cameras ===		=== Timekeeping in Elphel cameras ===
	After the date/time are set cameras use internal CPU timer (baased on the master crystal oscillator) to maintain current time. There are several restrictions of these method:		After the date/time are set cameras use internal CPU timer (baased on the master crystal oscillator) to maintain current time. There are several restrictions of these method:

Polto: /* Timestamping frame data */

2007-08-24T00:22:31Z

Timestamping frame data

← Older revision		Revision as of 00:22, 24 August 2007
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	There is a way to specify timestamp mode with the http request by adding &ts=<0..2> to the image URL, you may als..		There is a way to specify timestamp mode with the http request by adding &ts=<0..2> to the image URL, you may als..
	== Timestamping frame data ==		== Timestamping frame data ==
	In ~~333~~ cameras now - starting from the fpga revision 0333100f (it can be read as "fpcf -r 13" from telnet session) the timestamp data is embedded into each frame transferred from the FPGA to the system memory. It comes right before the frame length data as 8-byte sequence - 4 bytes of seconds and then 4 of microseconds.		In 353 cameras now - starting from the fpga revision 0333100f (it can be read as "fpcf -r 13" from telnet session) the timestamp data is embedded into each frame transferred from the FPGA to the system memory. It comes right before the frame length data as 8-byte sequence - 4 bytes of seconds and then 4 of microseconds.

	This data is ~~not yet~~ embedded as EXIF into the file header~~, but it will be soon~~.		This data is also embedded as EXIF into the file header.


	----		----
	''Free Software and Open Hardware. Elphel, Inc., 2005-2006''		''Free Software and Open Hardware. Elphel, Inc., 2005-2006''

Andrey.filippov at 13:10, 21 September 2006

2006-09-21T13:10:12Z

← Older revision		Revision as of 13:10, 21 September 2006
Line 50:		Line 50:

	There is a way to specify timestamp mode with the http request by adding &ts=<0..2> to the image URL, you may als..		There is a way to specify timestamp mode with the http request by adding &ts=<0..2> to the image URL, you may als..
			== Timestamping frame data ==
			In 333 cameras now - starting from the fpga revision 0333100f (it can be read as "fpcf -r 13" from telnet session) the timestamp data is embedded into each frame transferred from the FPGA to the system memory. It comes right before the frame length data as 8-byte sequence - 4 bytes of seconds and then 4 of microseconds.

			This data is not yet embedded as EXIF into the file header, but it will be soon.


	----		----
	''Free Software and Open Hardware. Elphel, Inc., 2005''		''Free Software and Open Hardware. Elphel, Inc., 2005-2006''

Ilya at 20:36, 23 September 2005

2005-09-23T20:36:06Z

← Older revision		Revision as of 20:36, 23 September 2005
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	~~'''''Elphel Network Cameras Manual'''''~~
	~~----~~
	~~[[Using the cameras]] \|~~
	~~[[Camera software]] \|~~
	~~[[Camera hardware]] \|~~
	~~[[Diagnostic and repair]] \|~~
	~~[[Development documentation]] \|~~
	~~[[Information]] \|~~
	~~[[Glossary]] \|~~
	~~[[About Elphel, Inc]]~~
	~~----~~
	~~[[Board design]] \|~~
	~~[[Logics]] \|~~
	[[RTC]] \|		[[RTC]] \|
	[[10331]] \|		[[10331]] \|

Ilya at 05:13, 23 September 2005

2005-09-23T05:13:12Z

← Older revision		Revision as of 05:13, 23 September 2005
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	[[Logics]] \|		[[Logics]] \|
	[[RTC]] \|		[[RTC]] \|
			[[10331]] \|
			[[10332]] \|
	[[10334]]		[[10334]]
	----		----

Ilya at 15:29, 22 September 2005

2005-09-22T15:29:23Z

← Older revision		Revision as of 15:29, 22 September 2005
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	[[About Elphel, Inc]]		[[About Elphel, Inc]]
	----		----
	[[RTC]]		[[Board design]] \|
			[[Logics]] \|
			[[RTC]] \|
			[[10334]]
	----		----

Ilya at 08:44, 22 September 2005

2005-09-22T08:44:10Z

@@ Line 1: / Line 1: @@
 == Real Time Clock ==
 === Absolute date/time in Elphel cameras ===
@@ Line 44: / Line 58: @@
 There is a way to specify timestamp mode with the http request by adding &ts=<0..2> to the image URL, you may als..

Andrey.filippov: /* Timestamps */

2005-09-22T06:38:41Z

Timestamps

← Older revision		Revision as of 06:38, 22 September 2005
Line 44:		Line 44:

	There is a way to specify timestamp mode with the http request by adding &ts=<0..2> to the image URL, you may als..		There is a way to specify timestamp mode with the http request by adding &ts=<0..2> to the image URL, you may als..
	~~to the normal image mode you~~
	~~need to specify &pfh=0).~~

Andrey.filippov: /* Timestamps */

2005-09-22T06:38:10Z

Timestamps

← Older revision		Revision as of 06:38, 22 September 2005
Line 39:		Line 39:
	0 - timestampos off		0 - timestampos off

	1 - timestamps are embedded into the upper-left corner of the image. Currently while demosaic algorithm uses 3x3 pixel interpolation first row and first column are skipped. When the 5x5 conversion will be implemented the time stamp will be in the very corner (or maybe not to simplify reversing de-mosaic processing of the timestamp data).		1 - timestamps are embedded into the upper-left corner of the image. Currently while demosaic algorithm uses 3x3 pixel interpolation first row and first column are skipped. When the 5x5 conversion will be implemented the time stamp will be in the very corner (or maybe not to simplify reversing de-mosaic processing of the timestamp data). The frame size will not increase in that mode - timestamp will be embedded over the part of an image.

	2 - timestamps are embedded after the sensor data in each column (sensor row), this mode is needed for the photo-finish application.		2 - timestamps are embedded after the sensor data in each column (sensor row), this mode is needed for the photo-finish application. The image size will be increased by 28 pixels tgo accomodate the timestamps.

			There is a way to specify timestamp mode with the http request by adding &ts=<0..2> to the image URL, you may als..
			to the normal image mode you
			need to specify &pfh=0).

Andrey.filippov: /* Timestamps */

2005-09-22T06:23:26Z

Timestamps

← Older revision		Revision as of 06:23, 22 September 2005
Line 39:		Line 39:
	0 - timestampos off		0 - timestampos off

	1 - timestamps are embedded into the upper-left corner of the image. Currently while demosaic algorithm uses 3x3 pixel interpolation first row and first column		1 - timestamps are embedded into the upper-left corner of the image. Currently while demosaic algorithm uses 3x3 pixel interpolation first row and first column are skipped. When the 5x5 conversion will be implemented the time stamp will be in the very corner (or maybe not to simplify reversing de-mosaic processing of the timestamp data).
	are skipped. When the 5x5 conversion will be implemented the time stamp will be in the very corner (or maybe not to simplify reversing de-mosaic processing of the timestamp data).

	2 - timestamps are embedded after the sensor data in each column (sensor row), this mode is needed for the photo-finish application.		2 - timestamps are embedded after the sensor data in each column (sensor row), this mode is needed for the photo-finish application.

← Older revision		Revision as of 20:36, 23 September 2005
Line 1:		Line 1:
	~~'''''Elphel Network Cameras Manual'''''~~
	~~----~~
	~~[[Using the cameras]] \|~~
	~~[[Camera software]] \|~~
	~~[[Camera hardware]] \|~~
	~~[[Diagnostic and repair]] \|~~
	~~[[Development documentation]] \|~~
	~~[[Information]] \|~~
	~~[[Glossary]] \|~~
	~~[[About Elphel, Inc]]~~
	~~----~~
	~~[[Board design]] \|~~
	~~[[Logics]] \|~~
	[[RTC]] \|		[[RTC]] \|
	[[10331]] \|		[[10331]] \|