Image meta data

[stevedee]

Although the text overlay module is super useful, I like to capture 'clean' images, free of clutter, once the system has been properly setup.
So wondered if you could implement the addition of image EXIF data.

I notice in the c++ file: capture_RPi.cpp some notes to implement this:-

/* TODO: what exif fields should we use?
if (myModeMeanSetting.meanAuto != MEAN_AUTO_OFF) {
stringstream strExposureTime;
stringstream strReinforcement;
strExposureTime << myRaspistillSetting.shutter_us;
strReinforcement << myRaspistillSetting.analoggain;

	command += " --exif IFD0.Artist=li_" + strExposureTime.str() + "_" + strReinforcement.str();
}

*/

I'd suggest as a minimum:-
exposure: number (ms)
gain: number
auto exposure: yes/no
auto gain: yes/no

Nice-to-have:-
author: text
camera: text
lens: text
camera temperature: 'C
focus metric: number
longitude:
latitude:

Many thanks!

[stevedee]

It looks like there is not too much interest in this. But for my own use, I've modified the code to add a few EXIF tags to my images.

Obviously 'Gain' is not ISO speed, but it is easier to use existing tags than to create new ones. This tag is an integer, so if bothered about having a more precise value (e.g. 12.75) then either create a new tag definition or use a multiplier (e.g. display 127 or something).

The tag 'Exposure Time' automatically translates decimal time into fractions for some values (e.g. for 5ms, but not for 9ms)

To implement this, I've just added a few lines of code to the bash script: saveImage.sh

This is what my mods look like:-

# Get passed-in variables.

while [[ $# -gt 0 ]]; do
	VARIABLE="AS_${1%=*}"		# everything before the "="
	VALUE="${1##*=}"			# everything after  the "="
	shift
	# Export the variable so other scripts we call can use it.
	# shellcheck disable=SC2086
	
	#steve mod+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
	if [[ ${VARIABLE} = "AS_sEXPOSURE" ]]; then
		SD_EXPOSURE=${VALUE% ms*}	#we just need value in ms
		SD_EXPOSURE=$(echo "scale=3; ${SD_EXPOSURE}/1000" | bc -l)	#convert to seconds
		#echo " ${PI_OS}" " ${VARIABLE}" " ${VALUE}" "Trim & convert(s): ${SD_EXPOSURE}" >> "/home/steve/allsky/tmp/steve.log"	#debug
	fi
	if [[ ${VARIABLE} = "AS_GAIN" ]]; then
		SD_GAIN=$(echo "${VALUE}" | bc -l | xargs printf %.0f)	#round the gain value
		#echo " ${PI_OS}" " ${VARIABLE}" " ${VALUE}" " ${SD_GAIN}" >> "/home/steve/allsky/tmp/steve.log"		#debug
	fi	
	#end------------------------------------------------------------

	export ${VARIABLE}="${VALUE}"	# need "export" to get indirection to work
done

...and:-

	if [[ ${IMG_CREATE_THUMBNAILS} == "true" ]]; then
		THUMBNAILS_DIR="${DATE_DIR}/thumbnails"
		mkdir -p "${THUMBNAILS_DIR}"
		# Create a thumbnail of the image for faster load in the WebUI.
		# If we resized above, this will be a resize of a resize,
		# but for thumbnails that should be ok.
		convert "${CURRENT_IMAGE}" -resize "${THUMBNAIL_SIZE_X}x${THUMBNAIL_SIZE_Y}" "${THUMBNAILS_DIR}/${IMAGE_NAME}"
		if [ $? -ne 0 ] ; then
			echo -e "${YELLOW}*** ${ME}: WARNING: THUMBNAIL resize failed; continuing.${NC}"
		fi
	fi
	#steve mod++++++++++++++++++++++++++++++++++++++++++++++
	#add meta data to image
	exiftool -copyright="stevedee" -software="AllSky" -CameraLabel="${CAMERA_TYPE} ${CAMERA_MODEL}" -ExposureTime="${SD_EXPOSURE}" -ISOspeed="${SD_GAIN}" "${CURRENT_IMAGE}"
	# The web server can't handle symbolic links so we need to make a copy of the file for
	# it to use.
	FINAL_FILE="${DATE_DIR}/${IMAGE_NAME}"
	if cp "${CURRENT_IMAGE}" "${FINAL_FILE}" ; then
		rm -f "${CURRENT_IMAGE}_original"	#remove exiftool generated file copy
	#end----------------------------------------------------

		if [[ ${TIMELAPSE_MINI_IMAGES} -ne 0 && ${TIMELAPSE_MINI_FREQUENCY} -ne 1 ]]; then
			# We are creating mini-timelapses; see if we should create one now.

[Alex-developer]

It looks like there is not too much interest in this. But for my own use, I've modified the code to add a few EXIF tags to my images.

Obviously 'Gain' is not ISO speed, but it is easier to use existing tags than to create new ones. This tag is an integer, so if bothered about having a more precise value (e.g. 12.75) then either create a new tag definition or use a multiplier (e.g. display 127 or something).

The tag 'Exposure Time' automatically translates decimal time into fractions for some values (e.g. for 5ms, but not for 9ms)

To implement this, I've just added a few lines of code to the bash script: saveImage.sh

This is what my mods look like:-

`# Get passed-in variables.

while [[ $# -gt 0 ]]; do VARIABLE="AS_${1%=}" # everything before the "=" VALUE="${1##=}" # everything after the "=" shift # Export the variable so other scripts we call can use it. # shellcheck disable=SC2086

#steve mod+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
if [[ ${VARIABLE} = "AS_sEXPOSURE" ]]; then
	SD_EXPOSURE=${VALUE% ms*}	#we just need value in ms
	SD_EXPOSURE=$(echo "scale=3; ${SD_EXPOSURE}/1000" | bc -l)	#convert to seconds
	#echo " ${PI_OS}" " ${VARIABLE}" " ${VALUE}" "Trim & convert(s): ${SD_EXPOSURE}" >> "/home/steve/allsky/tmp/steve.log"	#debug
fi
if [[ ${VARIABLE} = "AS_GAIN" ]]; then
	SD_GAIN=$(echo "${VALUE}" | bc -l | xargs printf %.0f)	#round the gain value
	#echo " ${PI_OS}" " ${VARIABLE}" " ${VALUE}" " ${SD_GAIN}" >> "/home/steve/allsky/tmp/steve.log"		#debug
fi	
#end------------------------------------------------------------

export ${VARIABLE}="${VALUE}"	# need "export" to get indirection to work

done `

...and:-

` if [[ ${IMG_CREATE_THUMBNAILS} == "true" ]]; then THUMBNAILS_DIR="${DATE_DIR}/thumbnails" mkdir -p "${THUMBNAILS_DIR}" # Create a thumbnail of the image for faster load in the WebUI. # If we resized above, this will be a resize of a resize, # but for thumbnails that should be ok. convert "${CURRENT_IMAGE}" -resize "${THUMBNAIL_SIZE_X}x${THUMBNAIL_SIZE_Y}" "${THUMBNAILS_DIR}/${IMAGE_NAME}" if [ $? -ne 0 ] ; then echo -e "${YELLOW}*** ${ME}: WARNING: THUMBNAIL resize failed; continuing.${NC}" fi fi #steve mod++++++++++++++++++++++++++++++++++++++++++++++ #add meta data to image exiftool -copyright="stevedee" -software="AllSky" -CameraLabel="${CAMERA_TYPE} ${CAMERA_MODEL}" -ExposureTime="${SD_EXPOSURE}" -ISOspeed="${SD_GAIN}" "${CURRENT_IMAGE}" # The web server can't handle symbolic links so we need to make a copy of the file for # it to use. FINAL_FILE="${DATE_DIR}/${IMAGE_NAME}" if cp "${CURRENT_IMAGE}" "${FINAL_FILE}" ; then rm -f "${CURRENT_IMAGE}_original" #remove exiftool generated file copy #end----------------------------------------------------

	if [[ ${TIMELAPSE_MINI_IMAGES} -ne 0 && ${TIMELAPSE_MINI_FREQUENCY} -ne 1 ]]; then
		# We are creating mini-timelapses; see if we should create one now.

`

I like it :-)

We are in the middle of testing the next release so a little tied up at the moment, apologies for not replying sooner.

I'll create an issue for this and we will see what we can do

Cheers

Alex

[stevedee]

Thanks Alex.

Re: my previous 2 posts:-
I no longer think 'exposure/gain auto' meta data is necessary.
However, I have added the moon phase, as the current full moon was affecting my images, even though it was well out of shot (yes, I'm still learning the basics!).

I used Kevin Boones moonphase.sh script: https://github.com/kevinboone/moonphase.sh and assigned this to an available string exif tag: ImageDescription

For the Exposure Time, my code didn't account for the value being returned in either seconds or milliseconds, so I've now added something like this;

if [[ ${VARIABLE} = "AS_sEXPOSURE" ]]; then
	if [[ ${VALUE} == *"sec"* ]]; then
		SD_EXPOSURE=${VALUE% sec*}	#value is in seconds
	fi
	if [[ ${VALUE} == *"ms"* ]]; then
		SD_EXPOSURE=${VALUE% ms*}	#value is in milliseconds
		SD_EXPOSURE=$(echo "scale=3; ${SD_EXPOSURE}/1000" | bc -l)	#convert to seconds
	fi	

[EricClaeys]

@stevedee,
for moon phase, why not use the ${MOON_ILLUMINATION} variable that Allsky already provides? It's the % full.

The ${AS_s....} variables are a string representation of the same variable without the lowercase "s". Try ${AS_EXPOSURE_US}

[stevedee]

Doh!!!
Thanks Eric.
I'm still very new to this and I'm blind to the obvious (...and I'm the wrong side of 70).

BTW: what's the easiest way to manually generate a startrails image?

[EricClaeys]

generateForDay.sh --startrails 20240820 or whatever date you want.
Ditto for --keogram and --timelapse.

[stevedee]

Sorry, probably being very dim, but I can't get any data from ${MOON_ILLUMINATION}

And doing a text-search-in-files I get:-

steve@pi-AllSky:~ $ grep -Rnw '/home/steve/allsky/' -e 'MOON_ILLUMINATION'
/home/steve/allsky/html/documentation/overlays/overlays.html:1959: ${MOON_ILLUMINATION}
/home/steve/allsky/config_repo/overlay/config/fields.json:239: "name": "${MOON_ILLUMINATION}",
/home/steve/allsky/config/overlay/config/overlay.json:18: "label": "Moon: ${MOON_ILLUMINATION}",
/home/steve/allsky/config/overlay/config/fields.json:239: "name": "${MOON_ILLUMINATION}",

...so it doesn't look like MOON_ILLUMINATION being used.