J
Jasen Betts
Guest
On 2015-05-01, N_Cook <diverse@tcp.co.uk> wrote:
plane mirror and sunlight (heliostat)
--
umop apisdn
plane mirror and sunlight (heliostat)
--
umop apisdn
N
N_Cook
Guest
On 02/05/2015 07:23, Charlie+ wrote:
No. If my reduced apaeratures , close coupled heater in cone and pyro
thermometer does not resolve 6mm wide lettering I may have another go.
Perhaps indirect bounce from a large distributed heater, using some
sort of diffusing surface to bounce off.
No. If my reduced apaeratures , close coupled heater in cone and pyro
thermometer does not resolve 6mm wide lettering I may have another go.
Perhaps indirect bounce from a large distributed heater, using some
sort of diffusing surface to bounce off.
N
N_Cook
Guest
On 02/05/2015 07:57, Jasen Betts wrote:
Now that is an interesting idea, for this application , may require 2
mirrors, but feasible.
Now that is an interesting idea, for this application , may require 2
mirrors, but feasible.
N
N_Cook
Guest
I got back to this project yesterday. I' d tried oblique lighting with
NIR and modded webcam before and not seen anything. This time I could
make out lettering under pattern-free areas but not convincingly under
patterning. But I remembered I'd painted letters
NCE
V
I could quite plainly see the N and V and the curve of the C but also
curve in the E area. I dug out the paper I'd written down the letters
and it was
NCQ
V
So without patterning, in the real application, it may be possible,
"brass-rubbing" optically.
I'll also have a go with mark3 close-coupled heater cone and cut down
pyro thermometer,tomorrow , on a grid of readings and repeat for
different temperatures and hopefully improve on the 0.7 deg F differential.
I tried the modded webcam , with no floppy disc filter,viewing a Weller
magnastat soldering iron barrel. The heater area glowed bright and
dulled to nearly no discernable pixels , and the thick part of the
barrel stayed at some intermediary luminosity, brightening and dimming
but observable in space by its conical shape at all times , with a 700
deg F magnastat in place.
NIR and modded webcam before and not seen anything. This time I could
make out lettering under pattern-free areas but not convincingly under
patterning. But I remembered I'd painted letters
NCE
V
I could quite plainly see the N and V and the curve of the C but also
curve in the E area. I dug out the paper I'd written down the letters
and it was
NCQ
V
So without patterning, in the real application, it may be possible,
"brass-rubbing" optically.
I'll also have a go with mark3 close-coupled heater cone and cut down
pyro thermometer,tomorrow , on a grid of readings and repeat for
different temperatures and hopefully improve on the 0.7 deg F differential.
I tried the modded webcam , with no floppy disc filter,viewing a Weller
magnastat soldering iron barrel. The heater area glowed bright and
dulled to nearly no discernable pixels , and the thick part of the
barrel stayed at some intermediary luminosity, brightening and dimming
but observable in space by its conical shape at all times , with a 700
deg F magnastat in place.
C
Charlie+
Guest
On Sat, 16 May 2015 20:04:48 +0100, N_Cook <diverse@tcp.co.uk> wrote as
underneath :
Thanks for continuing your experimentation story! C+
underneath :
Thanks for continuing your experimentation story! C+
N
N_Cook
Guest
On 17/05/2015 08:02, Charlie+ wrote:
I've now got some convincing AVI of the N followed by a circular letter
not complete as an O , could be C or G . With floppy disc material over
the webcam lens , so I can work in room light and laptop screen is black
with no IR torch on. With all controls on the webcam driver set to min
brightness and max for contrast, saturation and mid white balance. As
only 5 frames per second, sweeping the NIR LED torch gives a better
chance of reading the letters then snapshots.
In the real application the context of words should make distinguishing
the likes of Q and C, or E and F easier.
In the next hour or two I'll give the heater and pyro method another go
over 1/4 inch steps horizontal and vertical at a few heater settings,
but stick to 3 seconds per position, for optimum of speed of capture and
one level of consistency. Could increase to 10 seconds or so if
required for greater resolution later, over questionable letters.
I've now got some convincing AVI of the N followed by a circular letter
not complete as an O , could be C or G . With floppy disc material over
the webcam lens , so I can work in room light and laptop screen is black
with no IR torch on. With all controls on the webcam driver set to min
brightness and max for contrast, saturation and mid white balance. As
only 5 frames per second, sweeping the NIR LED torch gives a better
chance of reading the letters then snapshots.
In the real application the context of words should make distinguishing
the likes of Q and C, or E and F easier.
In the next hour or two I'll give the heater and pyro method another go
over 1/4 inch steps horizontal and vertical at a few heater settings,
but stick to 3 seconds per position, for optimum of speed of capture and
one level of consistency. Could increase to 10 seconds or so if
required for greater resolution later, over questionable letters.
N
N_Cook
Guest
Got nowhere on the heater cone and pyro.
I even tried a rubber hot water bottle with hot water ,held against the
test wall for 10 minutes. Loads of temp variation but nothing to do with
black paint, just change of heat capacity of different thickness of
plaster over brick presumably.
So I'm wondering if even an expensive thermal imaging camera and some
sort of diffuse and even heat source would work either, unless just
flashed over the paper and not hanging around enough to deep heat.
The NIR webcam is relying on "brass-rubbing" relief in all probability.
The \ part of the N is evident in raking white light but not the rest of
the N or any of the next letter or any of the other 2 letters so bit of
a mystery why the NIR+webcam is picking up so much differentiation.
With no patterning on the paper it would probably resolve the likes of C
and G, Q and O, E and F ,P and R, B and 8 etc.
I tried polarizing filters as well
I've run out of ideas, what I would like to try was a long IR, 5 to 10
micron LED to direct heat energy onto a small spot, the pyro seems to be
reacting to heat radiating off the close by metal heater cone rather
than heat bouncing off the paper. All the parabolic reflectors I have
are too big to direct a little halogen bulb or similar "point" heat source.
I even tried a rubber hot water bottle with hot water ,held against the
test wall for 10 minutes. Loads of temp variation but nothing to do with
black paint, just change of heat capacity of different thickness of
plaster over brick presumably.
So I'm wondering if even an expensive thermal imaging camera and some
sort of diffuse and even heat source would work either, unless just
flashed over the paper and not hanging around enough to deep heat.
The NIR webcam is relying on "brass-rubbing" relief in all probability.
The \ part of the N is evident in raking white light but not the rest of
the N or any of the next letter or any of the other 2 letters so bit of
a mystery why the NIR+webcam is picking up so much differentiation.
With no patterning on the paper it would probably resolve the likes of C
and G, Q and O, E and F ,P and R, B and 8 etc.
I tried polarizing filters as well
I've run out of ideas, what I would like to try was a long IR, 5 to 10
micron LED to direct heat energy onto a small spot, the pyro seems to be
reacting to heat radiating off the close by metal heater cone rather
than heat bouncing off the paper. All the parabolic reflectors I have
are too big to direct a little halogen bulb or similar "point" heat source.
C
Carl Ijames
Guest
Put a small halogen bulb, 5-20 watts and 12 VDC like those used for under
cabinet kitchen lighting, in one end of a short piece of copper tubing. The
inside of new tubing is pretty shiny in the visible and should be a great
reflector at 10 um, and something like 1/4 or 3/8" tubing a few inches long
should give a pretty good spot that size when held against or almost
touching the wall paper. Probably comparable to a small parabolic reflector
but with a closer working distance. The longer the tube the more directed
the beam, and the more light lost to the walls. I would start with 1.5 or
2" of tubing but you might need to try even shorter. Good part is it's
cheap
.
Have you called a few of those companies that use ir cameras to map heat
leakage from a house, to see if they would be willing to try a quick
experiment for free in return for whatever publicity you can give when you
examine the final target?
-----
Regards,
Carl Ijames carl.ijames aat deletethis verizon dott net
"N_Cook" wrote in message news:mja3p3$lbh$1@dont-email.me...
Got nowhere on the heater cone and pyro.
I even tried a rubber hot water bottle with hot water ,held against the
test wall for 10 minutes. Loads of temp variation but nothing to do with
black paint, just change of heat capacity of different thickness of
plaster over brick presumably.
So I'm wondering if even an expensive thermal imaging camera and some
sort of diffuse and even heat source would work either, unless just
flashed over the paper and not hanging around enough to deep heat.
The NIR webcam is relying on "brass-rubbing" relief in all probability.
The \ part of the N is evident in raking white light but not the rest of
the N or any of the next letter or any of the other 2 letters so bit of
a mystery why the NIR+webcam is picking up so much differentiation.
With no patterning on the paper it would probably resolve the likes of C
and G, Q and O, E and F ,P and R, B and 8 etc.
I tried polarizing filters as well
I've run out of ideas, what I would like to try was a long IR, 5 to 10
micron LED to direct heat energy onto a small spot, the pyro seems to be
reacting to heat radiating off the close by metal heater cone rather
than heat bouncing off the paper. All the parabolic reflectors I have
are too big to direct a little halogen bulb or similar "point" heat source.
cabinet kitchen lighting, in one end of a short piece of copper tubing. The
inside of new tubing is pretty shiny in the visible and should be a great
reflector at 10 um, and something like 1/4 or 3/8" tubing a few inches long
should give a pretty good spot that size when held against or almost
touching the wall paper. Probably comparable to a small parabolic reflector
but with a closer working distance. The longer the tube the more directed
the beam, and the more light lost to the walls. I would start with 1.5 or
2" of tubing but you might need to try even shorter. Good part is it's
cheap
.Have you called a few of those companies that use ir cameras to map heat
leakage from a house, to see if they would be willing to try a quick
experiment for free in return for whatever publicity you can give when you
examine the final target?
-----
Regards,
Carl Ijames carl.ijames aat deletethis verizon dott net
"N_Cook" wrote in message news:mja3p3$lbh$1@dont-email.me...
Got nowhere on the heater cone and pyro.
I even tried a rubber hot water bottle with hot water ,held against the
test wall for 10 minutes. Loads of temp variation but nothing to do with
black paint, just change of heat capacity of different thickness of
plaster over brick presumably.
So I'm wondering if even an expensive thermal imaging camera and some
sort of diffuse and even heat source would work either, unless just
flashed over the paper and not hanging around enough to deep heat.
The NIR webcam is relying on "brass-rubbing" relief in all probability.
The \ part of the N is evident in raking white light but not the rest of
the N or any of the next letter or any of the other 2 letters so bit of
a mystery why the NIR+webcam is picking up so much differentiation.
With no patterning on the paper it would probably resolve the likes of C
and G, Q and O, E and F ,P and R, B and 8 etc.
I tried polarizing filters as well
I've run out of ideas, what I would like to try was a long IR, 5 to 10
micron LED to direct heat energy onto a small spot, the pyro seems to be
reacting to heat radiating off the close by metal heater cone rather
than heat bouncing off the paper. All the parabolic reflectors I have
are too big to direct a little halogen bulb or similar "point" heat source.
N
N_Cook
Guest
On 17/05/2015 14:53, Carl Ijames wrote:
Great minds ...
I'd just removed a 6V 10W halogen bulb from its reflector, I was going
to roll up some polished tin-plate, soldered on the outside.
Put a small halogen bulb, 5-20 watts and 12 VDC like those used for under
cabinet kitchen lighting, in one end of a short piece of copper tubing. The
inside of new tubing is pretty shiny in the visible and should be a great
reflector at 10 um, and something like 1/4 or 3/8" tubing a few inches long
should give a pretty good spot that size when held against or almost
touching the wall paper. Probably comparable to a small parabolic reflector
but with a closer working distance. The longer the tube the more directed
the beam, and the more light lost to the walls. I would start with 1.5 or
2" of tubing but you might need to try even shorter. Good part is it's
cheap
Have you called a few of those companies that use ir cameras to map heat
leakage from a house, to see if they would be willing to try a quick
experiment for free in return for whatever publicity you can give when you
examine the final target?
-----
Regards,
Carl Ijames carl.ijames aat deletethis verizon dott net
"N_Cook" wrote in message news:mja3p3$lbh$1@dont-email.me...
Got nowhere on the heater cone and pyro.
I even tried a rubber hot water bottle with hot water ,held against the
test wall for 10 minutes. Loads of temp variation but nothing to do with
black paint, just change of heat capacity of different thickness of
plaster over brick presumably.
So I'm wondering if even an expensive thermal imaging camera and some
sort of diffuse and even heat source would work either, unless just
flashed over the paper and not hanging around enough to deep heat.
The NIR webcam is relying on "brass-rubbing" relief in all probability.
The \ part of the N is evident in raking white light but not the rest of
the N or any of the next letter or any of the other 2 letters so bit of
a mystery why the NIR+webcam is picking up so much differentiation.
With no patterning on the paper it would probably resolve the likes of C
and G, Q and O, E and F ,P and R, B and 8 etc.
I tried polarizing filters as well
I've run out of ideas, what I would like to try was a long IR, 5 to 10
micron LED to direct heat energy onto a small spot, the pyro seems to be
reacting to heat radiating off the close by metal heater cone rather
than heat bouncing off the paper. All the parabolic reflectors I have
are too big to direct a little halogen bulb or similar "point" heat source.
Great minds ...
I'd just removed a 6V 10W halogen bulb from its reflector, I was going
to roll up some polished tin-plate, soldered on the outside.
N
N_Cook
Guest
I'll have to abandon the close coupled heater and pyro thermometer. Even
overdriving the 6V bulb to 8V and 8 deg C nominal over ambient on the
pyro thermometer , nothing convincing found. That 8 deg C is the reading
on the scale with my cut down brass cone, probably corresponds to 15 deg
C or more for the proper cone that it is properly calibrated to.
Whether a FLIR device and heat source would work, is a bit questionable.
But the IR filter removed web cam and 5 degree or so raking angle NIR
torch, video image recorded to laptop, is worth trying.
overdriving the 6V bulb to 8V and 8 deg C nominal over ambient on the
pyro thermometer , nothing convincing found. That 8 deg C is the reading
on the scale with my cut down brass cone, probably corresponds to 15 deg
C or more for the proper cone that it is properly calibrated to.
Whether a FLIR device and heat source would work, is a bit questionable.
But the IR filter removed web cam and 5 degree or so raking angle NIR
torch, video image recorded to laptop, is worth trying.
C
Carl Ijames
Guest
I came across something that sounds pretty intriguing and might be within
your budget, a long wave IR camera chip that responds to 7-14 um IR and
delivers 80x60 pixel images at about 2 frames per second. Here is where I
found it: https://www.sparkfun.com/products/13233, they have links you can
follow for more info. This plus a Raspberry PI and their free demo software
gets you an IR video camera for under $400 (not including a TV monitor) that
stands a good chance of being able to read your hidden lettering. Watch the
video, it's very impressive. After you finish your project I'm sure you
could sell it on craigslist for most of what you paid for it.
-----
Regards,
Carl Ijames carl.ijames aat deletethis verizon dott net
your budget, a long wave IR camera chip that responds to 7-14 um IR and
delivers 80x60 pixel images at about 2 frames per second. Here is where I
found it: https://www.sparkfun.com/products/13233, they have links you can
follow for more info. This plus a Raspberry PI and their free demo software
gets you an IR video camera for under $400 (not including a TV monitor) that
stands a good chance of being able to read your hidden lettering. Watch the
video, it's very impressive. After you finish your project I'm sure you
could sell it on craigslist for most of what you paid for it
.-----
Regards,
Carl Ijames carl.ijames aat deletethis verizon dott net
N
N_Cook
Guest
On 22/05/2015 06:02, Carl Ijames wrote:
The off the shelf FLIR 60x80 camera is not much more in cost.
Next week I'll take my modded webcam + NIR torch to the site and have a
go on site. I'll also take high quality pics of the wallpaper along with
architects colour swatches and ruler. If my NIR webcam does not show
anything then the next pricewise plan of campaign is look into
custom-made wallpaper (usually for kids bedrooms) and permission to
remove and replace a patch of wallpaper. Luckily the relevant patch of
wall is isolated from the rest of the room , so an absolutely colour and
texture matched patch should not be noticeable.
I came across something that sounds pretty intriguing and might be within
your budget, a long wave IR camera chip that responds to 7-14 um IR and
delivers 80x60 pixel images at about 2 frames per second. Here is where I
found it: https://www.sparkfun.com/products/13233, they have links you can
follow for more info. This plus a Raspberry PI and their free demo software
gets you an IR video camera for under $400 (not including a TV monitor) that
stands a good chance of being able to read your hidden lettering. Watch the
video, it's very impressive. After you finish your project I'm sure you
could sell it on craigslist for most of what you paid for it
-----
Regards,
Carl Ijames carl.ijames aat deletethis verizon dott net
The off the shelf FLIR 60x80 camera is not much more in cost.
Next week I'll take my modded webcam + NIR torch to the site and have a
go on site. I'll also take high quality pics of the wallpaper along with
architects colour swatches and ruler. If my NIR webcam does not show
anything then the next pricewise plan of campaign is look into
custom-made wallpaper (usually for kids bedrooms) and permission to
remove and replace a patch of wallpaper. Luckily the relevant patch of
wall is isolated from the rest of the room , so an absolutely colour and
texture matched patch should not be noticeable.
N
N_Cook
Guest
I'm hoping, if not fully readable image, to have enough image to show
something is under there, intriguing enough to get permission to remove
a section of wallpaper.
As it should be very localised text then knowing where it is then
perhaps simply remove the patch of wallpaper and move one of the
pictures to cover the spot, may even be possible. Because of the
significance of the text they may wish to have it accessible, but not
necessarily on show, for the odd academic visitor.
something is under there, intriguing enough to get permission to remove
a section of wallpaper.
As it should be very localised text then knowing where it is then
perhaps simply remove the patch of wallpaper and move one of the
pictures to cover the spot, may even be possible. Because of the
significance of the text they may wish to have it accessible, but not
necessarily on show, for the odd academic visitor.
Guest
On Fri, 22 May 2015 09:24:21 +0100, N_Cook <diverse@tcp.co.uk> wrote:
modding a camera in order to see NIR. I did this mod to a Canon SD
300 Powershot camera. It not only sees NIR but also near UV. I have
been using the camera to look through stuff that is opaque to my eyes,
in both NIR and NUV. Is it possible that NUV might go through the
wallpaper?
Eric
Since you first brought this subject up I have been intrigued with
modding a camera in order to see NIR. I did this mod to a Canon SD
300 Powershot camera. It not only sees NIR but also near UV. I have
been using the camera to look through stuff that is opaque to my eyes,
in both NIR and NUV. Is it possible that NUV might go through the
wallpaper?
Eric
N
N_Cook
Guest
On 22/05/2015 17:48, etpm@whidbey.com wrote:
A assume it was near UV, 20 LED cluster only labelled UV , numerous
materials flourescing under it. I returned to the test wallpaper patch
and tried straight on and oblique with various visibly opaque or going
on opaque "filters" over the webcam lens , passing the UV image, mylar,
polyester , black polythene, CD in overprinted-free area of label,
floppy disc material blocked the uv illuminated image. Could see not the
slightest hint of any letters under the paper wiht any of them, or
absent filter, but could see the wallpaper printed design in each case,
but nothing in the background room light illumination.
A assume it was near UV, 20 LED cluster only labelled UV , numerous
materials flourescing under it. I returned to the test wallpaper patch
and tried straight on and oblique with various visibly opaque or going
on opaque "filters" over the webcam lens , passing the UV image, mylar,
polyester , black polythene, CD in overprinted-free area of label,
floppy disc material blocked the uv illuminated image. Could see not the
slightest hint of any letters under the paper wiht any of them, or
absent filter, but could see the wallpaper printed design in each case,
but nothing in the background room light illumination.
R
Rich Webb
Guest
On Fri, 22 May 2015 08:58:57 +0100, N_Cook <diverse@tcp.co.uk> wrote:
The best value (not the lowest price) in consumer thermal IR imagers
is still the FLIR E4. It's only 80x60 out of the box but anyone active
on s.e.d or s.e.r can probably follow the thread over at
http://www.eevblog.com/forum/testgear/flir-e4-thermal-imaging-camera-teardown/
and unlock the 320x240 native capability.
With the advent of the Lepton and similar low resolution sensors it's
unlikely FLIR (or anyone else) will release a 320x240 imager that's
software-crippled to a lower res anytime soon so this is pretty much
it for bargain sensors, until maybe the next gen.
It's also possible to add a ZnSe close-up aux lens which makes it
quite useable for PCB inspection. FLIR doesn't supply them, so it's
ebay for the lenses and 3D printing for the holders. Works, though.
https://www.dropbox.com/s/cca4mu28b11ilpt/FLIR.jpg?dl=0
On 22/05/2015 06:02, Carl Ijames wrote:
I came across something that sounds pretty intriguing and might be within
your budget, a long wave IR camera chip that responds to 7-14 um IR and
delivers 80x60 pixel images at about 2 frames per second. Here is where I
found it: https://www.sparkfun.com/products/13233, they have links you can
follow for more info. This plus a Raspberry PI and their free demo software
gets you an IR video camera for under $400 (not including a TV monitor) that
stands a good chance of being able to read your hidden lettering. Watch the
video, it's very impressive. After you finish your project I'm sure you
could sell it on craigslist for most of what you paid for it
-----
Regards,
Carl Ijames carl.ijames aat deletethis verizon dott net
The off the shelf FLIR 60x80 camera is not much more in cost.
Next week I'll take my modded webcam + NIR torch to the site and have a
go on site. I'll also take high quality pics of the wallpaper along with
architects colour swatches and ruler. If my NIR webcam does not show
anything then the next pricewise plan of campaign is look into
custom-made wallpaper (usually for kids bedrooms) and permission to
remove and replace a patch of wallpaper. Luckily the relevant patch of
wall is isolated from the rest of the room , so an absolutely colour and
texture matched patch should not be noticeable.
The best value (not the lowest price) in consumer thermal IR imagers
is still the FLIR E4. It's only 80x60 out of the box but anyone active
on s.e.d or s.e.r can probably follow the thread over at
http://www.eevblog.com/forum/testgear/flir-e4-thermal-imaging-camera-teardown/
and unlock the 320x240 native capability.
With the advent of the Lepton and similar low resolution sensors it's
unlikely FLIR (or anyone else) will release a 320x240 imager that's
software-crippled to a lower res anytime soon so this is pretty much
it for bargain sensors, until maybe the next gen.
It's also possible to add a ZnSe close-up aux lens which makes it
quite useable for PCB inspection. FLIR doesn't supply them, so it's
ebay for the lenses and 3D printing for the holders. Works, though.
https://www.dropbox.com/s/cca4mu28b11ilpt/FLIR.jpg?dl=0
N
N_Cook
Guest
On 25/05/2015 13:16, Rich Webb wrote:
The trouble with thermal imaging cameras is I'm not sure they would work
for this purpose. I've not found an image of something that is natively
at the same temperature to its surroundings , hidden under something
visibly opaque. I'm assuming some sort of search heat source would be
required to highlight hidden black from white, but I've not found a pic
of someone doing that . My coupled use of non contact pyro thermometer
and external heat sourse seemed to just show differences in the thermal
capacity of the underlying structure. to differentiate , it would
probably require a very specific wavelength of IR, specific for picking
up paint v plaster difference.
On Fri, 22 May 2015 08:58:57 +0100, N_Cook <diverse@tcp.co.uk> wrote:
On 22/05/2015 06:02, Carl Ijames wrote:
I came across something that sounds pretty intriguing and might be within
your budget, a long wave IR camera chip that responds to 7-14 um IR and
delivers 80x60 pixel images at about 2 frames per second. Here is where I
found it: https://www.sparkfun.com/products/13233, they have links you can
follow for more info. This plus a Raspberry PI and their free demo software
gets you an IR video camera for under $400 (not including a TV monitor) that
stands a good chance of being able to read your hidden lettering. Watch the
video, it's very impressive. After you finish your project I'm sure you
could sell it on craigslist for most of what you paid for it
-----
Regards,
Carl Ijames carl.ijames aat deletethis verizon dott net
The off the shelf FLIR 60x80 camera is not much more in cost.
Next week I'll take my modded webcam + NIR torch to the site and have a
go on site. I'll also take high quality pics of the wallpaper along with
architects colour swatches and ruler. If my NIR webcam does not show
anything then the next pricewise plan of campaign is look into
custom-made wallpaper (usually for kids bedrooms) and permission to
remove and replace a patch of wallpaper. Luckily the relevant patch of
wall is isolated from the rest of the room , so an absolutely colour and
texture matched patch should not be noticeable.
The best value (not the lowest price) in consumer thermal IR imagers
is still the FLIR E4. It's only 80x60 out of the box but anyone active
on s.e.d or s.e.r can probably follow the thread over at
http://www.eevblog.com/forum/testgear/flir-e4-thermal-imaging-camera-teardown/
and unlock the 320x240 native capability.
With the advent of the Lepton and similar low resolution sensors it's
unlikely FLIR (or anyone else) will release a 320x240 imager that's
software-crippled to a lower res anytime soon so this is pretty much
it for bargain sensors, until maybe the next gen.
It's also possible to add a ZnSe close-up aux lens which makes it
quite useable for PCB inspection. FLIR doesn't supply them, so it's
ebay for the lenses and 3D printing for the holders. Works, though.
https://www.dropbox.com/s/cca4mu28b11ilpt/FLIR.jpg?dl=0
The trouble with thermal imaging cameras is I'm not sure they would work
for this purpose. I've not found an image of something that is natively
at the same temperature to its surroundings , hidden under something
visibly opaque. I'm assuming some sort of search heat source would be
required to highlight hidden black from white, but I've not found a pic
of someone doing that . My coupled use of non contact pyro thermometer
and external heat sourse seemed to just show differences in the thermal
capacity of the underlying structure. to differentiate , it would
probably require a very specific wavelength of IR, specific for picking
up paint v plaster difference.
A
Arfa Daily
Guest
I was going to suggest the FLIR one. But how about the local fire brigade ?
They like to get involved in 'projects' and have probably the most advanced
thermal imaging cameras available. They can see bodies through walls, so how
about 'illuminating' the area with infra red from the opposite side, and
then seeing if the letters 'obstruct' the infra red passing through the wall
enough to be able to read them with such an item ?
Arfa
N
N_Cook
Guest
On 09/06/2015 09:25, Arfa Daily wrote:
Events have overtaken this project. Since my last visit they've removed
the wallpaper, not surprising as a horrible green.
On the negative side the walls had been emulsioned with white emulsion
paint some years before the wallpaper went on.
On the positive side , as standard white emulsion, it should be easier
to get permission to strip back this top layer of paint, and easily
repaint if nothing there.
I've tried oblique NIR on it and nothing seen. A youngster around
reckoned he could see a letter under the paint with his young eyesight
but not myself or the NIR video capture with waving torch. But we now
know exactly where to strip back the paint as 2 bits of the text, top
and bottom of it, were not painted over in effect, which shows there is
likely more text for any doubting Thomases. Top bit not covered and
lower bit emerged with routine daily cleaning rubbing back the paint
enough to make out some letters. I've tried diluting none
methyl-chloride paint stripper 1 to 3 with meths and that gently removes
emulsion but leaves any gloss paint underneath, untouched.
Just need permission now
Events have overtaken this project. Since my last visit they've removed
the wallpaper, not surprising as a horrible green.
On the negative side the walls had been emulsioned with white emulsion
paint some years before the wallpaper went on.
On the positive side , as standard white emulsion, it should be easier
to get permission to strip back this top layer of paint, and easily
repaint if nothing there.
I've tried oblique NIR on it and nothing seen. A youngster around
reckoned he could see a letter under the paint with his young eyesight
but not myself or the NIR video capture with waving torch. But we now
know exactly where to strip back the paint as 2 bits of the text, top
and bottom of it, were not painted over in effect, which shows there is
likely more text for any doubting Thomases. Top bit not covered and
lower bit emerged with routine daily cleaning rubbing back the paint
enough to make out some letters. I've tried diluting none
methyl-chloride paint stripper 1 to 3 with meths and that gently removes
emulsion but leaves any gloss paint underneath, untouched.
Just need permission now