HDR images with Elphel cameras - Revision history

OneArtPlease at 16:18, 23 January 2012

2012-01-23T16:18:47Z

← Older revision		Revision as of 16:18, 23 January 2012
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	# AUTOEXP_ON - set to 0 to turn off automatic exposure time adjustments		# AUTOEXP_ON - set to 0 to turn off automatic exposure time adjustments
	# TRIG - Switch from free-running-mode(default) to triggered mode:TRIG_CONDITION=0x0, set the TRIG_PERIOD, TRIG=0x4		# TRIG - Switch from free-running-mode(default) to triggered mode:TRIG_CONDITION=0x0, set the TRIG_PERIOD, TRIG=0x4
	# TRIG_PERIOD - defines FPS		# TRIG_PERIOD - defines FPS (1/frame period; FPS = 96000000 / TRIG_PERIOD); 3840000 [decimal] for 25FPS)
			# EXPOS - Exposure time in µseconds (10000 = 10 ms) Note that in triggered mode not the entire frame period can be used for exposing
			# HDR_DUR - 0 = HDR ON, 1 = HDR ON
			# HDR_VEXPOS - defines the exposure difference between the 2 alternating exposure times.


	Also very handy is the "Last aquired images" link on top/bottom of the parsedit table as it shows a table of the last 9 images (total number, number per row can be altered in the URL) and the matching exposure time values. Please be aware though that mismatching parameters will lead to the exposure not alternating with each frame but every second, thirds, etc. frame while the exposure time displayed in the table will seem correct but is actually wrong.		Also very handy is the "Last aquired images" link on top/bottom of the parsedit table as it shows a table of the last 9 images (total number, number per row can be altered in the URL) and the matching exposure time values. Please be aware though that mismatching parameters will lead to the exposure not alternating with each frame but every second, thirds, etc. frame while the exposure time displayed in the table will seem correct but is actually wrong.

OneArtPlease at 16:03, 23 January 2012

2012-01-23T16:03:11Z

← Older revision		Revision as of 16:03, 23 January 2012
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	This HDR-video can be recorded just like any other normal video with the harddisk-recorder, camogm or captured over the network.		This HDR-video can be recorded just like any other normal video with the harddisk-recorder, camogm or captured over the network.

	Due to limitations in how fast the exposure time change can be propagated to the image sensor, HDR mode works best in Triggered mode([http://www.mail-archive.com/support-list@support.elphel.com/msg00533.html]); And by altering the http://CameraIP/tuneseq.php?mode=latency- page, setting the EXPOS value to "0". ([http://www.mail-archive.com/support-list@support.elphel.com/msg00492.html]).		Due to limitations in how fast the exposure time change can be propagated to the image sensor, HDR mode works best in [[Trigger\| Triggered]] mode([http://www.mail-archive.com/support-list@support.elphel.com/msg00533.html]); And by altering the http://CameraIP/tuneseq.php?mode=latency- page, setting the EXPOS value to "0". ([http://www.mail-archive.com/support-list@support.elphel.com/msg00492.html]).

	Below is a parsedit url that provides quick access to the required parameters for frame sequential HDR in triggered mode:		Below is a parsedit url that provides quick access to the required parameters for frame sequential HDR in triggered mode:
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	http://192.168.0.8/parsedit.php?embed=0.15&title=Parameters+for+groups:+autoexposure+whiteBalance+trigger+&WB_EN&AUTOEXP_ON&TRIG&TRIG_PERIOD&EXPOS&HDR_DUR&HDR_VEXPOS		http://192.168.0.8/parsedit.php?embed=0.15&title=Parameters+for+groups:+autoexposure+whiteBalance+trigger+&WB_EN&AUTOEXP_ON&TRIG&TRIG_PERIOD&EXPOS&HDR_DUR&HDR_VEXPOS

			[[File:HDRTrigMode.png]]
			# WB_EN - set to 0 to turn off automatic white balance adjustment
			# AUTOEXP_ON - set to 0 to turn off automatic exposure time adjustments
			# TRIG - Switch from free-running-mode(default) to triggered mode:TRIG_CONDITION=0x0, set the TRIG_PERIOD, TRIG=0x4
			# TRIG_PERIOD - defines FPS

			Also very handy is the "Last aquired images" link on top/bottom of the parsedit table as it shows a table of the last 9 images (total number, number per row can be altered in the URL) and the matching exposure time values. Please be aware though that mismatching parameters will lead to the exposure not alternating with each frame but every second, thirds, etc. frame while the exposure time displayed in the table will seem correct but is actually wrong.

			[[File:Hdr_alternating.jpg]]
	==Manual Bracketing==		==Manual Bracketing==
	You can do exposure bracketing manually with a PHP script. Just set exposure time -> capture a single frame -> change exposure time -> capture another image, etc.		You can do exposure bracketing manually with a PHP script. Just set exposure time -> capture a single frame -> change exposure time -> capture another image, etc.

Floating.Point: /* Autoexposure Daemon HDR Functions */

2012-01-23T15:30:08Z

Autoexposure Daemon HDR Functions

← Older revision		Revision as of 15:30, 23 January 2012
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	Due to limitations in how fast the exposure time change can be propagated to the image sensor, HDR mode works best in Triggered mode([http://www.mail-archive.com/support-list@support.elphel.com/msg00533.html]); And by altering the http://CameraIP/tuneseq.php?mode=latency- page, setting the EXPOS value to "0". ([http://www.mail-archive.com/support-list@support.elphel.com/msg00492.html]).		Due to limitations in how fast the exposure time change can be propagated to the image sensor, HDR mode works best in Triggered mode([http://www.mail-archive.com/support-list@support.elphel.com/msg00533.html]); And by altering the http://CameraIP/tuneseq.php?mode=latency- page, setting the EXPOS value to "0". ([http://www.mail-archive.com/support-list@support.elphel.com/msg00492.html]).

			Below is a parsedit url that provides quick access to the required parameters for frame sequential HDR in triggered mode:
			(replace the IP address with that of your camera)

			http://192.168.0.8/parsedit.php?embed=0.15&title=Parameters+for+groups:+autoexposure+whiteBalance+trigger+&WB_EN&AUTOEXP_ON&TRIG&TRIG_PERIOD&EXPOS&HDR_DUR&HDR_VEXPOS

	==Manual Bracketing==		==Manual Bracketing==

Floating.Point: /* Autoexposure Daemon HDR Functions */

2012-01-23T15:26:09Z

Autoexposure Daemon HDR Functions

← Older revision		Revision as of 15:26, 23 January 2012
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	==Autoexposure Daemon HDR Functions==		==Autoexposure Daemon HDR Functions==
	The autoexposure daemon running in the camera can alternate exposure times ~~quickly meaning~~		The autoexposure daemon running in the camera can rapidly alternate between multiple exposure times, allowing a single video stream with over / under exposed sequential frames. In post, these frames can be separated into individual streams and finally combined into a single HDR sequence.
	~~recording at maximal FPS~~ with ~~2 alternating exposure times is possible~~.		This HDR-video can be recorded just like any other normal video with the harddisk-recorder, camogm or captured over the network.
	This HDR-video can be ~~record~~ just like any other normal video with the harddisk-recorder camogm or ~~streamed~~ over the network.

	Due to ~~limitation~~ how fast the exposure time change can be propagated to the image sensor HDR mode works best in Triggered mode([http://www.mail-archive.com/support-list@support.elphel.com/msg00533.html]). by altering the http://CameraIP/tuneseq.php?mode=latency- page, setting the EXPOS value to "0". ([http://www.mail-archive.com/support-list@support.elphel.com/msg00492.html]).		Due to limitations in how fast the exposure time change can be propagated to the image sensor, HDR mode works best in Triggered mode([http://www.mail-archive.com/support-list@support.elphel.com/msg00533.html]); And by altering the http://CameraIP/tuneseq.php?mode=latency- page, setting the EXPOS value to "0". ([http://www.mail-archive.com/support-list@support.elphel.com/msg00492.html]).

	==Manual Bracketing==		==Manual Bracketing==

OneArtPlease at 14:47, 23 January 2012

2012-01-23T14:47:16Z

← Older revision		Revision as of 14:47, 23 January 2012
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	recording at maximal FPS with 2 alternating exposure times is possible.		recording at maximal FPS with 2 alternating exposure times is possible.
	This HDR-video can be record just like any other normal video with the harddisk-recorder camogm or streamed over the network.		This HDR-video can be record just like any other normal video with the harddisk-recorder camogm or streamed over the network.

			Due to limitation how fast the exposure time change can be propagated to the image sensor HDR mode works best in Triggered mode([http://www.mail-archive.com/support-list@support.elphel.com/msg00533.html]). by altering the http://CameraIP/tuneseq.php?mode=latency- page, setting the EXPOS value to "0". ([http://www.mail-archive.com/support-list@support.elphel.com/msg00492.html]).

	==Manual Bracketing==		==Manual Bracketing==

OneArtPlease at 14:42, 23 January 2012

2012-01-23T14:42:35Z

← Older revision		Revision as of 14:42, 23 January 2012
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	This HDR-video can be record just like any other normal video with the harddisk-recorder camogm or streamed over the network.		This HDR-video can be record just like any other normal video with the harddisk-recorder camogm or streamed over the network.

	==Manual Bracketing		==Manual Bracketing==
	You can do exposure bracketing manually with a PHP script. Just set exposure time -> capture a single frame -> change exposure time -> capture another image, etc.		You can do exposure bracketing manually with a PHP script. Just set exposure time -> capture a single frame -> change exposure time -> capture another image, etc.
	This will be slower than using the daemon but you have finer control over how many brackets you want and how big the EV steps between the brackets are, etc.		This will be slower than using the daemon but you have finer control over how many brackets you want and how big the EV steps between the brackets are, etc.

OneArtPlease at 14:42, 23 January 2012

2012-01-23T14:42:24Z

@@ Line 3: / Line 3: @@
 For informations about HDR imaging see: [http://en.wikipedia.org/wiki/High_dynamic_range_imaging Wikipedia.org]. For informations about HDR imaging algorithms see: [http://www.debevec.org/ Debevec.org] and [http://www1.cs.columbia.edu/CAVE/ Columbia.edu].
-----
+=Exposure Bracketing=
-=INTRODUCTION=
+==Manual Bracketing
-In computer graphics and photography, high dynamic range imaging (HDRI) is a set of techniques that allows a greater dynamic range of exposures than normal digital imaging techniques. The intention of HDRI is to accurately represent the wide range of intensity levels found in real scenes ranging from direct sunlight to shadows.
+=Gain Bracketing=
+[[JP4 HDR]] is a special raw color format that can capture a higher dynamic range in an image without introducing any artifacts as result from combining images captured at different times (exposure bracketing). Though the post processing code to develop the images is still experimental.

Polto: /* PHP PROGRAMMING */

2009-04-27T00:40:32Z

PHP PROGRAMMING

@@ Line 38: / Line 38: @@
 (under development)
-<pre>
+Using [[parsedit.php]] you can request images with altered exposure times as show in this example: http://community.elphel.com/pictures/8.0/9images.html
 ----

Polto at 00:27, 27 April 2009

2009-04-27T00:27:25Z

← Older revision		Revision as of 00:27, 27 April 2009
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	The purpose of this project is to get HDR images using an Elphel camera~~. The project development is supported by [http://www.waveng.com Waveng]~~.		The purpose of this project is to get HDR images using an Elphel camera.

	For informations about HDR imaging see: [http://en.wikipedia.org/wiki/High_dynamic_range_imaging Wikipedia.org]. For informations about HDR imaging algorithms see: [http://www.debevec.org/ Debevec.org] and [http://www1.cs.columbia.edu/CAVE/ Columbia.edu].		For informations about HDR imaging see: [http://en.wikipedia.org/wiki/High_dynamic_range_imaging Wikipedia.org]. For informations about HDR imaging algorithms see: [http://www.debevec.org/ Debevec.org] and [http://www1.cs.columbia.edu/CAVE/ Columbia.edu].
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	----		----


	~~=CGI PROGRAMMING AND LINUX SOFTWARE=~~
	~~(under development)~~


	~~----~~


	=FPGA ALGORITHM=		=FPGA ALGORITHM=
	~~(under development)~~


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	=~~EXTERNAL GPU ALGORITHM~~=		=Post-processing=
	~~(under development)~~

Polto at 18:31, 16 February 2008

2008-02-16T18:31:54Z

← Older revision		Revision as of 18:31, 16 February 2008
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	~~'''~~INTRODUCTION~~'''~~		=INTRODUCTION=

	In computer graphics and photography, high dynamic range imaging (HDRI) is a set of techniques that allows a greater dynamic range of exposures than normal digital imaging techniques. The intention of HDRI is to accurately represent the wide range of intensity levels found in real scenes ranging from direct sunlight to shadows.		In computer graphics and photography, high dynamic range imaging (HDRI) is a set of techniques that allows a greater dynamic range of exposures than normal digital imaging techniques. The intention of HDRI is to accurately represent the wide range of intensity levels found in real scenes ranging from direct sunlight to shadows.
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	~~'''~~PHP PROGRAMMING~~'''~~		=PHP PROGRAMMING=
	(under development)		(under development)

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	~~'''~~CGI PROGRAMMING AND LINUX SOFTWARE~~'''~~		=CGI PROGRAMMING AND LINUX SOFTWARE=
	(under development)		(under development)

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	~~'''~~FPGA ALGORITHM~~'''~~		=FPGA ALGORITHM=
	(under development)		(under development)

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	~~'''~~EXTERNAL GPU ALGORITHM~~'''~~		=EXTERNAL GPU ALGORITHM=
	(under development)		(under development)