Thermal Infrared Camera - Photon

1. Can lenses be interchanged on the Photon?

We advise against customers changing Photon lenses. Each Photon is calibrated with its associated lens at the factory. The calibration data is stored in camera memory, but there is only enough memory for a single lens. It is physically possible to change lenses, however, if a different lens is installed, the original calibration is no longer valid. If a Photon lens is changed without recalibrating the camera, it will work but the image performance will be degraded. In addition, several of the available lenses use different adapters to attach to the Photon camera body, so changing lenses often requires more than just the lens itself. Finally, changing lenses can only be done by opening the Photon, and the warranty will be voided if this done by a customer.

2. How can I figure out which lens version will work best for my application?

There are three variables that need to be known in order to determine the most appropriate lens for an application:

1. The distance from the camera to the object being imaged. This is usually expressed in feet or meters.
2. The size of the object being imaged. This is usually the largest dimension, also in feet or meters, as long as the same units are used.
3. The number of pixels that the object needs to cover in the image, usually using the larger of the horizontal or vertical dimension.

Using these variables, it is possible to calculate the optimal lens, since the sensor resolution of 320x240 and the pixel size of 38 microns are known values. We provide a calculator for anyone to use at www.corebyindigo.com/tools/LensCalculator/new/ or by clicking the Lens Help button at the Photon home page.

3. What is included with a Photon delivery?

This depends on what is ordered. The Photon OEM camera core by itself is positioned as a high-volume thermal imaging component that customers integrate into products or systems of their own design. Most OEM customers interface directly to the Photon’s 30-pin electrical connector for power (in), video (out), and other select functions. This connector also facilitates camera control and serial digital data if needed. Therefore the Photon core by itself is typically what is ordered by and delivered to OEM customers.

For evaluation purposes, FLIR offers an optional OEM Accessory Kit that enables customers to operate a Photon until such time as they develop their own interface. This Kit contains a power supply, break-out box (called an I/O Module), an interface cable to the Photon, and a small adapter circuit (called a wearsaver) that attaches between the camera connector and the interface cable. A rear cover is also supplied that encloses the wearsaver adapter and allows for secure attachment to the interface cable. It is the customer’s responsibility to provide a video cable and monitor, and an RS-232 cable if remote control of the Photon is desired.

A picture of a Photon with accessory kit items can be seen here.

A Photon camera control software program (GUI) is available for download here.

The accessory kit part number is 421-0021-00. The kit includes the following items, which may also be ordered individually:

Part Number	Description
333-0005-00	I/O Module
206-0001-20	AC/DC Power Supply
208-0004-02	Line Cord
308-0076-00-02	Interface Cable
250-0194-00	Wearsaver
261-1273-00	Wearsaver Cover

4. What is needed to use Photon cameras?

This depends on the use, and whether or not camera control is desired. At a minimum, a cable is needed from the camera that provides power in to the camera and video out from the camera. We offer such a cable, called a “power/video cable”, as an optional accessory. Power/video cables require that the Photon be configured with a wearsaver connector and wearsaver rear cover, both of which are technically accessory items. An image of a Photon with the wearsaver and its cover can be seen on the Photon 320 page by clicking on the ‘Wearsaver rear cover’ view. The maximum length of the available Photon interface cables is 10 feet. If camera control is desired or required, then an “interface cable” is needed that goes from the camera into a break-out-box (called an I/O module). The I/O module accessory includes a standard DB-9 connector to allow a PC to communicate with a Photon via RS-232 protocol. Customers must arrange to get power to the input power jack of the power/video cable or the I/O module, or otherwise get power directly to the camera. FLIR offers an AC/DC power supply as a Photon accessory, as well as a rechargeable battery that will run a camera for 5-6 hours. Typically customers take the video out signal to a monitor or display of some sort.

5. Can I just hook a Photon up to power and a monitor?

Yes. Many customers use Photon cameras in a stand-alone fashion, and typically use all or part of our accessory kit items, and/or optional accessories, for connectivity with the camera. FLIR’s standard and optional Photon accessories include cables that enable connection to the camera in a straightforward, user-friendly fashion. Our high-volume integrators are more likely to build a custom wiring harness that directly interfaces to the Photon OEM connector to achieve a specific functionality. Answers to other FAQs on this page describe the connector pin functions and vendor information needed to build custom cabling.

6. Is it possible to get the Photon camera with an athermal lens?

All of the currently advertised Photon lenses are of a passive athermal design. This means that the lenses mechanically self-adjust to changes in temperature such that the lens remains in focus over wide ambient temperature ranges.

7. How much does the Photon camera weigh?

Photon Weight Information

The camera weight will depend on which type of cover is installed, if any, and whether or not a wearsaver adapter is used. The table below shows the approximate weight of the different camera/lens configurations, as well as the weights for the covers and wearsaver connector. There can be some variation in the actual weight, but the figures shown for the Core + Lens should be accurate to within +/- 2 grams.

Weight Table For Photon 320 and 160

	No Lens	6.3mm¹	14.25mm²	19mm	35mm²	50mm²
Core	97g	132g	153g	130g	185.5g	225g
Wearsaver Cover	16g	16g	16g	16g	16g	16g
Wearsaver	7g	7g	7g	7g	7g	7g
Core + Wearsaver + Cover	120g	155g	182g	158g	212g	253g

¹ Only available for Photon 160
² Only available for Photon 320

Weight Table For Photon 640

	No Lens	35mm	50mm
Core	113g	227g
Wearsaver cover	22g	22g	22g
Wearsaver	24g	24g	24g
Core + Wearsaver + Cover	159g	273g

8. Can the Photon rear cover be removed?

Unless otherwise specified by an OEM agreement, all Photons with lenses are delivered with a rear cover. This cover affords some protection to the electronics, but it can be removed by the customer. There is no credit given for unused rear covers. The standard rear cover has a cut-out to allow access to the SAMTEC 30-pin connector. This cut-out is sized to enable the wearsaver adapter to be installed.

Some customers have expressed concern about the integrity of the cable-to-camera connections in environments where vibration or low g-forces may exist. An optional rear cover is available for Photon that encloses the wearsaver adapter, and jack posts are provided to which the interface cable can be securely attached. The optional rear cover is furnished as part of the Photon Accessory Kit, or may be ordered separately using part number 261-1273-00. The optional cover is provided as a separate item in addition to the standard cover when delivered.

9. How are FLIR's microbolometer arrays packaged? Are they under vacuum? Why?

The microbolometer sensing elements are thermistors that are suspended, as bridge structures, above a readout integrated circuit (ROIC). The sensing elements need to be able to change temperature individually in response to small amounts of heat energy. In order to allow this response to small changes in radiant energy, the sensing elements must be thermally isolated from the ROIC. To achieve the thermal isolation, we put the sensor in a high-quality vacuum to eliminate the air gap that would otherwise exist between the thermistors and ROIC, creating a conduction path that would effectively dampen the sensor responsivity.

10. Is the Photon a rolling shutter camera or a framing camera?

The Photon camera is more like a rolling shutter camera than a framing camera, but does not perform exactly the same way that a typical rolling shutter camera performs. In typical electronic shutter cameras, each pixel in the sensor cyclically goes through the following functions during one frame period: integration of signal onto a collector (analogous to exposure time onto film); sample and readout of signal; reset (to “zero”) of the integration collector. In a framing camera, the integration of signal function occurs for all pixels at the same time, while in a rolling shutter camera, the integration period occurs at different times for pixels in different rows. The actively integrating rows in a rolling shutter camera “roll” down the sensor from top to bottom during the course of the frame period. For a rolling shutter camera, the sampling and readout operation occurs directly following the conclusion of integration, and as a result also rolls from top to bottom of the sensor during a frame period; and likewise with the integrator reset function.

The differences between a Photon camera and a typical rolling shutter camera are the following:

The Photon camera’s pixels are continually integrating on the signal (IR light) from the scene, and unlike a rolling shutter camera have no integration time adjustment. The pixels in the Photon camera register integrated signal via their temperature (get hotter when more signal arrives, and colder when less signal arrives). As IR signal arrives, it contributes to the pixel heating, while at the same time there are inherent mechanisms that also allow heat to escape from a pixel. A good analogy for this is a water bucket with a hole in the bottom. Signal is continually filling the bucket with water from the top (heating), while cooling is continually allowing some water out from the bottom.
Because the integration of signal is a physical rather than electronic mechanism, unlike a typical rolling shutter camera, in a Photon camera there is no way to reset the integrated signal from an earlier frame. As a result, a bolometer pixel will have memory of the signal that was collected in previous frames. Due to the pixel’s of cooling mechanism, the contribution from past frames decays over time. The heating and cooling occur at a rate that is defined by the pixel’s time constant. Image artifacts such as tails on hot moving objects are a result of this property of the camera.
Because there is no integration period on the Photon camera and no reset of the integration, the only function that rolls down the rows in the Photon camera is the sampling of the temperature of each pixel.

11. What is the occasional clicking sound made by the camera? What is FFC?

There is a shutter between the camera lens and the sensor package. This shutter is used to perform a flat-field correction, or FFC. During FFC, the shutter presents a uniform temperature source to each detector element in the array. While imaging the flat-field source, the camera updates the offset correction coefficients, resulting in a more uniform image after the process is complete. The FFC process takes 0.7 second. While the shutter is in the field of view of the sensor, the image just prior to the shutter moving is frozen and displayed until the FFC process finishes and the shutter moves out of the field of view of the sensor. The FFC functionality can be manipulated by the user via the GUI or by serial command to the camera. A faint click is produced when the shutter moves in front of the sensor.

12. I need to use the Photon to image an object at close range. Is it possible to adjust the focus of Photon lenses manually? What is the range of focus? What is the close focus distance?

We describe the range of focus to mean the hyperfocal range, that is, the range between infinity and some point less than infinity through which the lens remains in focus. All Photons with lenses are factory-calibrated with the lens locked at infinity focus.

All of the currently available Photon lenses use a screw-thread mount. The lens focus is locked by a small setscrew.

To adjust the lens focus to something other than infinity focus, or to achieve the shortest possible focus, requires that the setscrew be loosened. It may not be possible to lock the focus at a close focus point since in some cases the lens in almost out of its holder. FLIR does not offer spacers for macro focus.

The table below shows the approximate minimum focus distance for each lens type. Although Photon lenses are capable of focusing to shorter object distances, it is important to note that they are not designed, calibrated, or specified for this purpose. All Photon camera/lens calibrations are performed at infinity focus. Image space f/numbers can change under extreme finite conjugates. Very close focus applications using a Photon calibrated at infinity focus may result in possible image anomalies, non-uniformities, and/or degraded performance. Customers should be aware of these limitations and evaluate the images for issues.

Lens Focal Length	14.25mm Lens	19mm Lens	35mm Lens	50mm Lens
Close Focus Distance	~5 inches	~12 inches	~27 inches	~72 inches

13. What is the I/O module and how does it differ from going directly into a monitor or PC?

I/O = Input/Output. The I/O module is essentially a break-out box, in the form of a molded plastic accessory. There are connectors on four sides of the accessory: 1) interface connector to the camera; 2) RS-232 connector; 3) Power-in & Video-out connectors; 4) serial digital data connector. Photon cameras are configured with a single connector on the back, rather than providing discrete connectors for power, video, communication, etc., which would take up more space if they were built into the camera. The I/O module provides a way to access commonly used interfaces outside of the camera itself.

14. Is the Photon tripod adapter necessary?

The Photon has a total of 7 attach points on the top and sides of the camera. Because there are no attach points on the bottom, the tripod adapter was designed as an optional accessory to provide a ¼”x20 mounting interface to the bottom of the camera.

15. Does the PathFindIR come with the same accessories as Photon?

PathFindIR accessories are separate and distinct from those of Photon.

16. Is an export license required for Photon?

Yes, however, if the video frame rate is factory set to be less than 10 frames per second, Photon does not require any export license. An example of “slow” Photon imagery can be seen here.

Otherwise, export of Photon is under the jurisdiction of the U.S. Department of Commerce. In most cases, FLIR / Indigo will apply for the export licenses. In order to obtain an export license, the ultimate consignee or end user of the infrared product must furnish an end-use statement on company letterhead to FLIR / Indigo. The end user must also complete a BIS-711, Statement by Ultimate Consignee and Purchaser. This form is available on the internet at http://www.bis.doc.gov/Forms/FormsList.html. Quoted delivery times are based upon receipt of the validated export license from the Dept. of Commerce, which takes 8-10 weeks on average, depending on the end-use application, completeness of the end-use statement, and verification of the end-user.

17. What is the Export Control Classification Number (ECCN) for Photon?

The ECCN is 6A003b.4

18. What is the function of the 30-pin connector and the optional 15-pin connector on the Photon?

The 30-pin SAMTEC connector is the primary electrical interface to the Photon camera. This connector passes input power, output video, RS-232 commands, and serial digital data. The 15-pin connector passes these same signals and voltages. The 30-pin connector provisions for external sync as well as a few spare leads that are reserved for factory and OEM customer use. A description of the pin assignments for both connectors can be found at this link.

19. The Photon interface control drawing shows the pin numbers reversed for the interface connector J1 (SAMTEC TFML-115-02-S-D-P), in comparison with SAMTEC’s drawing for TFML-115-02-S-D-P. Which reference is correct?

At the time we designed around this interface connector, SAMTEC was just introducing this part and a pin numbering scheme was not available. Unfortunately, when SAMTEC released their pin numbering scheme, it differed from the one we had established. We elected to follow our own scheme, already released in our documentation. Our ICD correctly calls out pin function and pin location/ID.

Please do not use SAMTEC's drawing; this will result in a failure of Photon's power conditioning board.

20. Is there a recommended connector or cable harness that can be used to interface to the SAMTEC 30-pin connector?

SAMTEC now makes an SFSD Series mating connector that enables discrete wires to be brought out from the Photon 30-pin interface connector. The part number of a mating connector fully populated with wires is SFSD-15-28-S-10.00-S. However, a cable harness can be made using only the wires needed. Power and video leads would likely be the minimum, then RS-232, then digital video.

The 10.00 designates 10" leads. The leads could be made any (practical) length desired since these cables are custom-built.

www.samtec.com/technical_specifications/overview.aspx?series=SFSD

For more information, or to request pricing for a cable harness, contact:
SAMTEC USA
520 Park East Blvd.
New Albany, IN 47150-7251
800-726-8329

21. Can two cameras be set up as master and slave for synchronization purposes?

Photon was designed to accept a 3-Volt signal and send a 3-Volt signal, so one Photon can drive one or more Photons in slave mode. There are serial commands to designate a Photon as the master or slave camera.

Photon provides the capability to synchronize the frame start sequence using an external input. The camera completes the frame sequence using internal timing and then waits for the synchronization pulse before starting the next frame. If the sync pulse rate exceeds the maximum FPA frame rate (nominally 30Hz), sync pulses will be ignored and there will be frames dropped from the stream. (Note: this will result in lost data). While operating in slave mode, the analog video output signal is dependent upon the input frame sync rate for compliance with video standards.

Slave mode in slow video mode cameras continues to require an external sync pulse at the nominal 30Hz/ 25Hz frame rate. Digital output frame rate and analog video update rate are both at one fourth the input external frame sync rate independent of video modes (NTSC/PAL).

22. What is the voltage on the serial port? Do I need to access the serial port for normal operation? I am trying to connect to the camera via HyperTerminal and I can’t seem to get any control or response. I’ve tried a Null modem cable and a straight-thru cable and can’t seem to connect.

The serial port is only required to operate the camera in a non-autonomous mode. The camera is capable of being controlled remotely through an asynchronous serial interface consisting of the signals named RX, TX, and GND using 3.3 volt signal levels.

Note: The camera is compatible with most all RS-232 drivers/receivers but does not implement signaling levels (voltages) compliant with the RS-232 industry standard. However, it has been found fully functional in almost all implementations to date. There is no need for a NULL modem or to change the polarity when connecting Photon to a PC.

The Photon camera can understand camera commands set by the Photon Graphical User Interface (GUI) over an RS-232 link. The GUI can be downloaded here.

If you experience problems trying to communicate with a Photon over a serial port, we recommend trying another PC before contacting our Client Services group for help. The most common diagnosis we have seen is an anomaly with the serial port of the PC being used.

23. What would be needed to integrate Photon on a vehicle and run it?

Since Photon is not environmentally sealed, the first step would be to build some sort of enclosure for it. The enclosure would need to provision for mounting points. There would need to be a way to get power to the enclosure (and camera), and video from the camera out through the enclosure and back into the vehicle where it would be routed to a display. FLIR does not offer an environmental enclosure for Photon at this time. PathFindIR would be a better option since it is already sealed, and in fact designed for integration into a vehicle. The PathFindIR aftermarket kit that includes a display also furnishes some mounting bracketry.

24. For Photons used on vehicles for driver vision enhancement or situational awareness, how would the operator inside view the scene?

The video from the camera would need to be wired to a monitor or display that is mounted inside the vehicle where the operator can see it. PathFindIR offers an LCD display as an aftermarket option, along with a 20’ interface cable. FLIR does not offer specific aftermarket accessories for vehicle-mounted applications in support of Photon.

25. Is Photon available with PAL video?

Yes, Photon may be ordered in either NTSC or PAL video format. We use different part numbers to designate the video format. Both NTSC and PAL formats are fully compliant with their respective video standards. The video format (NTSC or PAL) programmed into the Photon is a factory setting that cannot be changed by the customer.

26. Can the Photon video format be changed from NTSC to PAL (or PAL to NTSC) ?

The video format is hard-coded into each camera at the factory and cannot be changed in the field. Cameras are calibrated differently depending on the video format, therefore customers must specify either PAL or NTSC at the time of purchase.

27. Does operating the Photon at 9 Hz reduce the camera power consumption?

There is no difference in power consumption. The FPA, AGC, and NUC are all still running at full rate. The video output is still running at full rate, however the data is updating at a rate less than 10 Hz.

28. Is there any price difference between the 9 Hz Photon and the 30 Hz (NTSC) or 25 Hz (PAL) versions?

The price of the slow video version of Photon is discounted approximately 3-5% from the full-rate video version, depending on the quantity of cameras ordered.

29. Does FLIR have any specifications as to the drive capability of the analog video out of the Photon camera?

We have empirically demonstrated the ability to drive analog video over 325 feet of coaxial cable with Photon. Longer cable runs may be possible, but not guaranteed.

30. Is the Photon video interlaced or non-interlaced?

Photon generates analog video that complies with NTSC video standards, or PAL video standards if so configured. Each video frame is comprised of two interlaced video fields (odd and even). As in traditional video systems, fields are sampled every 1/60th of a second (1/50th second PAL), one odd and one even. These fields are recombined into a video frame every 1/30th of a second (1/25th second PAL) to conform to NTSC and PAL standards for interlacing and display.

In traditional video systems, each odd and even field is sampled 1/60th of a second apart. For Photon, both odd and even video fields are sampled at the same time. But even though the fields are then interlaced to generate a frame, the data in each Photon video field (odd & even) is identical. Since each odd and even field contains exactly the same data, Photon's video display, while fully compliant to NTSC standards, is consistent with a progressive scan mode with the video sampling benefits of more detail and less flicker. The digital output of Photon is exclusively progressive scan.

31. There is a reference to the aspect ratio of the Photon video as being 4:3, however the image on our monitor is 5:4. Is this a problem?

There are 324x256 active pixels in the Photon's focal plane array.

For a Photon configured to display NTSC video, the pixel array format is 320x240, with an aspect ratio of 4:3.

For a Photon configured to display PAL video, the pixel array format is 320x255, so the aspect ratio is in fact very close to 5:4.

32. What methods are available to acquire digital data using Photon?

Currently there are three possible ways to acquire digital data:

1) Photon outputs digital data in a serial low-voltage differential signal (LVDS) format. This data is available at the 30-pin connector on the camera core. In addition, serial LVDS is available at the 15-pin wearsaver connector as well as the digital data port on the I/O module. The wearsaver connector and I/O module are accessory kit items. The Photon User's Guide provides the necessary pinouts and timing diagrams for interfacing directly to the Photon camera core electrical functions, including digital data.

2) FLIR / Indigo’s Ethernet Module for Photon provides camera control functions, and converts serial LVDS into real-time streaming uncompressed video data. The Module interfaces into a standard RJ-45 Ethernet network and runs at standard 100 megabit or full gigabit Ethernet speed. The Module includes the Ethernet interface adapter, camera cabling. The Module allows capture of both 8-bit digital data and the full 14-bit digital data. Analog video is also output via separate BNC connector. The Photon control software (GUI) now supports the Ethernet Module to allow camera control and video display in a host computer window. The Photon SDK also provides this functionality. The Photon Ethernet Module part number is 421-0025-00.

3) FLIR / Indigo’s optional serial-in, parallel-out (SIPO) module (part number 333-0008-00) converts the serial LVDS into a parallel data format that can be accessed via a frame grabber. The SIPO mates directly to the I/O module’s digital data port, and furnishes a 68-pin connector that can be attached to a frame grabber via a digital interface cable. One frame grabber possibility is the National Instruments IMAQ PCI-1422 board using digital interface cable part number 308-0013-00. Another frame grabber option is the Bit Flow RoadRunner Model 14 board using digital interface cable part number 308-0016-00-03. Both of these frame grab boards require third-party software not offered or supported by FLIR / Indigo. Setupfiles for the NI IMAQ and Bit FLow Road Runner frame grabbers can be downloaded from the Software Updates page, however, we do not formally support their use, nor do we claim or guarantee that these setup files will be suitable for any particular use or application. It is important to note that FLIR does not market the Photon as a scientific or R&D camera. We intentionally limit the information in this third option to avoid having customers perceive Photon as a science camera, since there is a natural tendency for challenging questions to otherwise result.

33. Is Photon’s 14-bit digital output (serial LVDS) true usable 14-bit data from the array?

The output of Photon is true 14-bit resolution (Non-Uniformity Compensated and bad pixel replaced).

34. Is the digital data from Photon signed or unsigned integer?

It is unsigned 16-bit data. The range is 0 to 16383. Higher counts equal higher relative temperature.

35. Can the camera be completely controlled using a PCI-1422 frame grabber card?

No. Only digital data passes through the SIPO.

36. Can the camera accept an external sync from the PCI-1422 to command the camera to digitize imagery at 30 frames per second?

No. Only digital data passes through the SIPO. External sync is only available via the 30-pin SAMTEC connector, which is the primary electrical interface to the camera.

37. Is there another way for the camera to accept an external sync using the PCI-1422?

A custom cable could be developed by the customer that interfaces from the SAMTEC connector directly to the frame grabber, thus obviating the SIPO limitations. This is necessary because there is no SYNC signal through the 15-pin connector. Such a cable would need to be bifurcated to provide a path for input power to the camera.

38. Can the frame grabber be used to command the camera to perform a NUC ‘on demand’?

No. Only digital data passes through the SIPO.

39. Can the frame grabber be used to turn on and off AGC and adjust contrast and brightness? Can we read out the NUC parameters from the camera?

No. Only digital data passes through the SIPO.

40. Can the camera data be streamed to disk over the PCI-1422 card and displayed real time?

This is up to the type of application that’s grabbing the frames. An application could be written in LabVIEW that would do this.

41. I have lost / can’t find / don’t remember receiving the Photon camera control software / User’s Guide. How can I get a copy?

Photon cameras are delivered with instructions that provide a link to the Photon camera control software (GUI). The software can be downloaded at www.corebyindigo.com/service/softwareupdates.cfm. The User’s Guide is also available as a download, at www.corebyindigo.com/service/currentmanuals.cfm.

42. What is needed in order to create my own application to control and/or acquire digital data using Photon?

The SDK enables camera control using one of several programming languages, including VB6, VB.net, C#, and C++ (MFC). Code examples are included to help illustrate how some of the camera control functions can be used.

The Photon OEM GUI (refer to http://www.corebyindigo.com/service/softwareupdates.cfm) is an example of an application created using the Photon SDK.

43. As for Photon software, what does FLIR offer and what are the capabilities?

Many customers use the Photon Graphical User Interface (GUI). The GUI is a PC program that enables remote command and control of the most commonly used Photon functions and features through an RS-232 serial interface to the camera. The GUI is available as a free download on the Software Updates page. A Photon is not required in order to run the GUI and view its capabilities.

44. Can any of it run on a Mac?

Our software is designed to run on a PC. It might be possible to run on a Mac in a PC-emulation mode, but we have not attempted this. A USB to RS-232 converter would be required, since Macs do not have RS-232 ports.

45. Is the Photon SDK necessary?

The Photon SDK is only necessary for customers that want to create a custom control interface to the camera. The Photon GUI is an example of a control interface, it was created with the SDK. Most customers operate Photon in an autonomous mode, that is, power in and video out only. The Photon GUI is used by many other customers for controlling the camera features and functions, as well as to save camera setup preferences. Also refer to FAQ #42.

46. Does Photon, along with certain software, allow for thermography and temperature characterization?

No, there is no inherent thermography capability in the standard Photon camera itself. Photon was designed principally as a thermal imaging camera.

47. If a lens-less camera core is purchased, how can it be calibrated with a lens?

FLIR offers, for sale, a Windows^TM application program called Alt Lens Cal that allows users to perform a supplementary calibration of the camera with a lens. The part number is 110-0102-46. Typically this software is used by customers that furnish their own optics.

This calibration requires the use of at least one blackbody source. The calibration routine calculates gain terms on a per-pixel basis with the customer-supplied lens attached to the Photon core, and stores the customer-performed calibration in non-volatile camera memory.

Alt Lens Cal software requires a customer-furnished PC, which should be dedicated to this task. The original factory calibration coefficients are first downloaded from the camera into a file on the PC. Then, via the supplementary calibration process, the user uploads new calibration data directly into the camera. This can be done multiple times if needed, and the user can actually build a library of calibration files for a camera.

48. Is there Linux support for Photon?

The Photon embedded SDK contains ‘C’ source code to compile in other operating systems such as Linux. There is a basic example in the SDK that would work in the Linux environment. The example contains the commands needed for a customer to write their own Photon control application. The Photon SDK part number is 110-0102-46.

49. What are the lens options and the minimum focus lengths for the Photon? What is the range of focus? Is it possible to adjust the focus of Photon lenses manually?

Focal Length	6.3mm	14.25mm	19mm	35mm	50mm
f/number	1.2	1.3	1.4	1.4	1.7
Field of View¹
320x240	-	46° x 36°	36° x 27°	20° x 15°	14° x 11°
160x120	52° x 40°	-	18° x 14°	-	-
640x480	-	-	-	26° x 20°	18° x 14°
IFoV² (milliradians)
320, 160	6.032	2.667	2.000	1.086	0.760
640	-	-	-	0.714	0.500
Minimum Focus Distance	~5 inches	~5 inches	~12 inches	~27 inches	~72 inches
Hyperfocal Distance³	0.25m	5 meters	7.5 meters	26 meters	35 meters
Hyperfocal Depth of Field⁴	-	2.5 meters	3.8 meters	13 meters	18 meters
Weight (Lens & Lens Mount only)	55g	56g	33g	88.5g	128g
Length (Lens only)	0.377"	1.209"	0.769"	1.709"	2.632"
Diameter (maximum)	1.250"	1.654"	1.024"	1.654"	1.772"
Coating Type	High Efficiency	High Durability		Hard Carbon⁵
Nominal Wavelength	8.0 to 14.0 microns

1 Field of View describes the angular measure of a scene imaged with the given pixel array, expressed as degrees in horizontal by vertical directions.
2 Instantaneous Field of View is the angular measure of a single pixel. Small angles are usually measured in milliradians. The IFoV is the pixel size (in microns) divided by the lens focal length
3 Hyperfocal distance is the distance beyond which all objects are acceptably sharp, for a lens focused at infinity.
4 Hyperfocal depth of field is the zone of acceptable sharpness. Increasing the depth of field increases the sharpness of an image. Smaller apertures (higher f/numbers) increase the depth of field.
5 Coating Type for 35mm and 50mm configurations of Photon 640 will be High Durability, not Hard Carbon.

50. Is the spectral response of the microbolometer array 7.5µ to 13.5µ, or is the spectral response a function of the lens?

The spectral response of the microbolometer is influenced by all of the optical interfaces between the focal plane array and the object being imaged. These include the sensor vacuum package front window, the lens, any protective windows in front of the lens, and finally atmospheric transmission between the object and the camera. Standard configuration vacuum packages (as of Jan 2007) have front windows that define the short wavelength cut-on of 7.5 um, while the bolometer itself defines the long wavelength cut-off of 13.5 um, assuming negligible atmospheric attenuation.

51. Should I clean the Photon lens, and how?

A light dusting of air should be enough to dislodge any dust particles, although small amounts of dust will not affect image quality noticeably. The antireflection coating on the germanium optics is easily scratched and the lens should only be cleaned according to the following procedure: If it is absolutely necessary to clean the lens surface, use 75% isopropyl alcohol and lens tissue, and use extremely light wiping motions. Use a fresh section of tissue with each swipe so as not to drag a piece of dirt back over the lens surface.

52. How do water droplets on the camera lens affect the image? Do they affect the image as much as a on a visible light range camera?

Water droplets are entirely opaque in the thermal IR. How they affect the image will depend on several factors. Lens focal length and focus position are two of the important ones after total percent of coverage. If the lens is focused at infinity, rain or water drops will be more out of focus than if the lens is focused up close. A longer focal length lens will also generally cause the droplets to be more out of focus. If the droplets are sufficiently out of focus (they should be if the lens is focused at infinity) then water drops on the lens will reduce the image contrast in proportion to the ratio of obscured area to total lens front surface area.

53. Is there a good reflector for IR? Can a standard front surface mirror be used or are there other materials available?

The best choice for a reflector is a front surface gold coated mirror. The next best choice is aluminum – a common material for front surface mirrors. Other polished metals would also work, but they tend to be slightly less reflective or are prone to oxidation.

54. What are the detection ranges for the various Photon/lens versions?

This question has many variables that must be considered, and some of those variables are inter-related. We make some assumptions to simplify the problem, but it is important to note that this type of question (what can be seen at what distance with an particular IR camera system) is typically approached in terms of target detection, recognition & identification ranges, along with an associated probability of success. Typically the result will be communicated in terms of a percentage probability of a particular target being detected, recognized and identified and certain ranges. There is a standard set of conditions regarding targets and defined meaning for the results that allows some simple test measurements to be fed into models that provide range outputs. Where applicable, our assumptions are consistent with standard range modeling.

We have compiled two charts that provide the nominal detection, recognition, and identification ranges for the different Photon versions. One chart is based on a person-sized object the other on a 2.3 meter vehicle-sized object.

1) Detection, Recognition, & ID of Human Target
2) Detection, Recognition, ID of 2.3m Vehicle

55. What is the Digital Detail Enhancement (DDE) filter?

DDE is basically a spatial filter designed to enhance the high spatial frequencies (edges etc.) and appears as boosted lens MTF. Enabling, disabling, and adjusting DDE can be accomplished by the user via the Photon GUI or by serial command to the camera. Experimentation may be necessary to see if or how much DDE is beneficial to a particular application.

Photon cameras with software versions prior to 2.2 (i.e., most cameras delivered prior to 2008) have factory-set DDE values that may not be optimal. Specifically, if the DDE values are too high in certain scene situations, the image may appear to exhibit a noticeable amount of fixed-pattern noise. We recommend resetting the Filter Gain value to 16 (not higher) and the Spatial Control value to 4, then save the changed values by clicking the "Set" button. Next, save the camera settings by clicking the Save settings button under the Camera tab. Try these new settings for awhile and adjust them as necessary to see if any improvement results.

56. Is a protective enclosure available for Photon?

FLIR's PathFindIR product is one option. PathFindIR comprises a Photon/19mm lens in a magnesium housing that is completely sealed. The field of view is 36 degrees horizontal. A hermetic connector provides the electrical interface for input power and output video. For more information, refer to the PathFindIR page. There are no PathFindIR lens options offered other than the 19mm (36-degree FOV).

There are also several FLIR Security & Surveillance products available that incorporate Photon cores into environmentally sealed systems, including the ThermoVision Integration Series (TVIS), Wide Eye, Security HD, and Sentinel. Please refer to CVS Security Products for more information.

57. Does Photon have requirements for electromagnetic interference (EMI) attenuation?

FLIR / Indigo does not make any specific claims about EMI with respect to Photon. Photon exhibits an EMI "spike" at about 290 MHz. The standard rear cover does not mitigate Photon's EMI emission.

There is an optional rear cover availabe for Photon that, with appropriate grounding, cable shielding, and power considerations, mitigates the resulting radiated EMI emissions to near-CE class A performance levels (~0dB margin). The EMI Rear Enclosure Assembly part number is 500-0312-00. This accessory includes a circuit board that must be installed onto the power conditioning board, resulting in an increase to the overall camera length of about 3/8". The power dissipation of the camera increases by a negligible amount, approximately 0.05W when the EMI rear cover is installed.

58. Does Photon meet any military environmental specifications or requirements?

Photon is intended as a thermal imaging camera core for integration into higher-level systems. It is not sealed, and therefore not IP-rated. Photon is much better resistant to shock and vibration than its predecessor (Omega / Micron / A10) due to its superior design, which uses two discrete PCBs rather than a flex cable. Many thousands of Photon cores are used in automotive applications as a nighttime driving aid. The environmental requirements imposed by automobile manufacturers are generally far more stringent than for military systems. Many more thousands of Photons are used as thermal imaging payloads in small unmanned vehicles used by the military, which frequently crash-land. We have been told by our customers that Photons experience forces of hundreds and in some cases thousands of G’s, yet in most cases keep on working well beyond the product design specifications. We think these are the best testimonials to the ruggedness and reliability of Photon. FLIR uses the term “commercially-developed, military-qualified” (CDMQ) to define such use. Positioning Photon as a CDMQ product helps FLIR keep Photon prices low, because to MIL-qual any product adds cost which has to be passed on to customers that require it.

59. What Power density will saturate the pixels on the Photon camera?

This question typically comes up in the context of illuminating the Photon camera with a laser source. The answer provided assumes the source is CW, and NOT pulsed. The Photon camera’s pixels will saturate at approximately 1E-7 watts per pixel at the FPA. This is a typical value for room temperature operation in the camera’s default operating mode, and will vary depending on parameters such as sensor operating temperature as well as the responsivity of a specific sensor. For pulsed laser applications, the amount of energy applied to the pixel over a readout frame period to achieve saturation will be significantly less than 1E-7Watts*3.3E-3 Seconds = 3.3E-9 joules, assuming that the applied energy arrives over a time period significantly less that the thermal time constant of roughly 2.0E-2 seconds.

60. What is the mean time between failure (MTBF) for Photon?

The most recent estimate for Photon's MTBF is > 4.5 years. Specific configurations can be made that more than double the MTBF – email oem@indigosystems.com.

61. Can the Photon camera be pointed at the sun?

We do not recommend intentionally viewing the sun, but looking at the sun will not permanently damage the sensor. It will, however, take some time for the camera to recover. The amount of time needed for recovery will depend on how long the camera was exposed to the sun. The longer the exposure, the longer the recovery time needed.