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LEPTON Long Wave Infrared (LWIR) Camera ModuleKey Specifications3.0 Key SpecificationsThe key specifications of the Lepton camera module are listed in Table 1. See Figure 3 on page 8 for thecorresponding package pinout diagram.Table 1 Key SpecificationsSpecificationOverviewFunctionSensor technologySpectral rangeArray formatPixel sizeEffective frame rateThermal sensitivityTemperature compensationNon-uniformity correctionsFOV - horizontalFOV - diagonalDepth of fieldLens typeOutput formatSolar protectionElectricalInput clockVideo data interfaceControl portInput supply voltage (nominal)Power dissipationMechanicalPackage dimensions – socket versionWeightEnvironmentalOptimum operating temperaturerangeNon-operating temperature rangeShockVersion 1.2.1, September 23, 2014DescriptionPassive thermal imaging module for mobile equipmentUncooled VOx microbolometerLongwave infrared, 8 μm to 14 μm80 60, progressive scan17 μm8.6 Hz (exportable) 50 mK (0.050 C)Automatic. Output image independent of camera temperature(optional mode - see Radiometry Modes, page 20).Automatic (with scene motion)51 63.5 10 cm to infinityf/1.1 silicon doubletUser-selectable 14-bit, 8-bit (AGC applied)Integral25-MHz nominal, CMOS IO Voltage Levels(see Operating States and Modes, page 13)Video over SPI (see VoSPI Channel, page 25)CCI (I2C-like), CMOS IO Voltage Levels(see Command and Control Interface, page 24)2.8 V, 1.2 V, 2.5 V to 3.1 V IO(see DC and Logic Level Specifications, page 39)Nominally 150 mW at room temperature (operating),4 mW (standby)8.5 11.7 5.6 mm (w l h)0.55 grams (typ)-10 C to 65 C-40 C to 80 C1500 G @ 0.4 msProprietary to FLIR Systems, Inc7

Lepton Camera Module Pinout DiagramLEPTON Long Wave Infrared (LWIR) Camera Module4.0 Lepton Camera Module Pinout Diagram32 MIPI DATA P31 MIPI DATA N30 GND29 MIPI CLK P28 MIPI CLK N27 GND26 MASTER CLKPinout Diagram (viewed from back of camera module)25 GNDFigure 324 RESET L1 GND23 PWR DWN L2 GPIO322 SDA3 GPIO221 SCL4 GPIO120 GND5 GPIO019 VDD6 GND18 GND7 VDDC8 GND8Proprietary to FLIR Systems, Inc9 GND10 GND11 SPI MOSI12 SPI MISO13 SPI CLK14 SPI CS L15 GND16 VDDIO17 NCVersion 1.2.1, September 23, 2014

LEPTON Long Wave Infrared (LWIR) Camera ModulePin Descriptions5.0 Pin DescriptionsThe Lepton camera module pin descriptions are shown in Table 2.Table 2 Lepton Camera Module Pin DescriptionsPin #Pin NameSignalTypeSignal LevelDescription1, 6, 8,9, 10,15, 18,20, 25,27, 30GNDPowerGNDCommon Ground2GPIO3IN/OUTVDDIO3GPIO2IN/OUTVDDIOThe GPIO multiplexed functions are optionaland configurable. The GPIO pins are unusedin the current er1.2VSupply for MIPI Core, PLL, ASIC Core (1.2V /- 5%)11SPI MOSIINVDDIOVideo Over SPI Slave Data In (see VoSPIChannel, page 25)12SPI MISOOUTVDDIOVideo Over SPI Slave Data Out (see VoSPIChannel, page 25)13SPI CLKINVDDIOVideo Over SPI Slave Clock (see VoSPIChannel, page 25)14SPI CS LINVDDIOVideo Over SPI Slave Chip Select, active low(see VoSPI Channel, page 25)16VDDIOPower2.5 V — 3.1 VSupply used for System IO17No connection———19VDDPower2.8VSupply for Sensor (2.8V /- 3%).21SCLINVDDIOCamera Control Interface Clock, I2Ccompatible22SDAIN/OUTVDDIOCamera Control Interface Data, I2Ccompatible23PWR DWN LINVDDIOThis active low signal shuts down the camera24RESET LINVDDIOThis active low signal resets the camera26MASTER CLKINVDDIOASIC Master Clock Input (see OperatingStates and Modes, page 13)28MIPI CLK NOUTDiff PairMIPI Digital Video Clock Negative1Version 1.2.1, September 23, 2014Proprietary to FLIR Systems, Inc9

Pin DescriptionsLEPTON Long Wave Infrared (LWIR) Camera ModuleTable 2 Lepton Camera Module Pin Descriptions (continued)Pin #Pin NameSignalTypeSignal LevelDescription29MIPI CLK POUTDiff PairMIPI Digital Video Clock Positive131MIPI DATA NOUTDiff PairMIPI Digital Video Data Negative132MIPI DATA POUTDiff PairMIPI Digital Video Data Positive1Note(s)1. MIPI is not currently supported. Let the MIPI pins float.10Proprietary to FLIR Systems, IncVersion 1.2.1, September 23, 2014

LEPTON Long Wave Infrared (LWIR) Camera ModuleSystem Architecture6.0 System ArchitectureA simplified architectural diagram of the Lepton camera module is shown in Figure 4.Figure 4Lepton ArchitectureHousingLensAssy.FocusedIR FPA)SoCI2C( comm)GPIO(optional)Discrete controlsDigitaldatastreamImagePipelineClkVDD, VDDC, VDDIOThermistorThe lens assembly focuses infrared radiation from the scene onto an 80x60 array of thermal detectors with17-micron pitch. Each detector element is a vanadium-oxide (VOx) microbolometer whose temperaturefluctuates in response to incident flux. The change in temperature causes a proportional change in eachmicrobolometer’s resistance. VOx provides a high temperature coefficient of resistance (TCR) and low 1/fnoise, resulting in excellent thermal sensitivity and stable uniformity. The microbolometer array is grownmonolithically on top of a readout integrated circuit (ROIC) to comprise the complete focal plane array (FPA).Once per frame, the ROIC senses the resistance of each detector by applying a bias voltage and integratingthe resulting current for a finite period of time called the integration period.The serial stream from the FPA is received by a system on a chip (SoC) device, which provides signalprocessing and output formatting. The image pipeline is defined in Video Pipeline, page 12.Version 1.2.1, September 23, 2014Proprietary to FLIR Systems, Inc11

Video PipelineLEPTON Long Wave Infrared (LWIR) Camera Module7.0 Video PipelineA block diagram of the video pipeline is shown in Figure 5.Figure 5Lepton Video Pipeline Block DiagramImage Pipelineraw data inNon-uniformitycorrection (NUC)DefectReplacementSpatial / TemporalFilteringAGC disabledAGC enabledAGCColorizeAGC / Colorization enabledThe video pipeline includes non-uniformity correction (NUC), defect replacement, spatial and temporalfiltering, automatic gain correction (AGC), and colorization.7.1NUCThe non-uniformity correction (NUC) block applies correction terms to ensure that the camera produces auniform output for each pixel when imaging a uniform thermal scene. Factory-calibrated terms are applied tocompensate for temperature effects, pixel response variations, and lens-illumination roll-off. To compensatefor temporal drift, the NUC block also applies an offset term that can be periodically updated at runtime via aprocess called flat-field correction (FFC). The FFC process is further described in FFC States, page 15.7.2Defect ReplacementThe defect-replacement block substitutes for any pixels identified as defective during factory calibration orduring runtime. The replacement algorithm assesses the values of neighboring pixels and calculates anoptimum replacement value. The typical number of defective pixels is 1.7.3Spatial / Temporal FilteringThe image pipeline includes a number of sophisticated image filters designed to enhance signal-to-noise ratio(SNR) by eliminating temporal noise and residual non-uniformity. The filtering suite includes a scene-basednon-uniformity correction (SBNUC) algorithm which relies on motion within the scene to isolate fixed patternnoise (FPN) from image content.7.4AGCThe AGC algorithm for converting the full-resolution (14-bit) thermal image into a contrast-enhanced imagesuitable for display is a histogram-based non-linear mapping function. See AGC Modes, page 22.7.5ColorizeThe colorize block takes the contrast-enhanced thermal image as input and generates a 24-bit RGB coloroutput. This feature is anticipated in a future release and is not currently accessible.12Proprietary to FLIR Systems, IncVersion 1.2.1, September 23, 2014

LEPTON Long Wave Infrared (LWIR) Camera ModuleOperating States and Modes8.0 Operating States and ModesLepton provides a number of operating states and modes, more completely defined in the sections that follow: 8.1Power States, page 13FFC States, page 15Telemetry Modes, page 17Radiometry Modes, page 20AGC Modes, page 22Interface Descriptions, page 24Power StatesLepton currently provides five power states. As depicted in the state diagram shown in Figure 6, most of thetransitions among the power states are the result of explicit action from the host. The automatic transition toand from the overtemp state is an exception. In the figure, transitions that require specific host-side action areshown in bold. Automatic transitions are not bolded.Figure 6State Diagram Showing Transitions among the Five Power StatesNote: Transition to “off” from every otherstate occurs by removing VDD, VDDC, andVDDIO. For simplicity, these transitions arenot shown below.OffApply VDD, VDDC, andVDDIOStandby10-sec countertimes nceLepton 80COvertempOnStart-up sequenceLepton 80CVersion 1.2.1, September 23, 2014Proprietary to FLIR Systems, Inc13

Operating States and ModesLEPTON Long Wave Infrared (LWIR) Camera ModuleThe power states are listed here: Off: When no voltage is applied, Lepton is in the off state. In the off state, no camera functions areavailable.Uninitialized: In the uninitialized state, all voltage forms are applied, but Lepton has not yet beenbooted and is in an indeterminate state. It is not recommended to leave Lepton in this state as power isnot optimized; it should instead be booted to the on-state (and then transitioned back to standby ifimaging is not required).On: In the on state, all functions and interfaces are fully available.Standby: In the standby state, all voltage forms are applied, but power consumption is approximately 4mW. In the standby state, no functions are available, but it is possible to transition to the on state viathe start-up sequence defined in Figure 7 on page 14. The shutdown sequence shown in Figure 7 onpage 14 is the recommended transition back to the standby state. It is also possible to transitionbetween standby and on states via software commands, as further defined in the software IDD.Overtemp: The overtemp state is automatically entered when the Lepton senses that its temperaturehas exceeded approximately 80 C. Upon entering the overtemp state, Lepton enables a “shutdownimminent” status bit in the telemetry line and starts a 10-second counter. If the temperature of theLepton falls below 80 C before the counter times out, the “shutdown imminent” bit is cleared and thesystem transitions back to the on state. If the counter does time out, Lepton automatically transitions tothe standby state.Power sequencing is as shown in Figure 6.Figure 7Power SequencingStart-up Sequence(from uninitialized to onand standby to on)De-assertPWR DWN L(should be high)Shutdown Sequence(from on to standby)Assert PWR DWN LAssert RESET L(should be low)Enable MASTER CLKWait 100 msecWait 5000 clkperiodsDe-assert RESET L14Proprietary to FLIR Systems, IncDisable MASTER CLKVersion 1.2.1, September 23, 2014

LEPTON Long Wave Infrared (LWIR) Camera Module8.2Operating States and ModesFFC StatesLepton is factory calibrated to produce an output image that is highly uniform, such as shown in Figure 8 (a),when viewing a uniform-temperature scene. However, drift effects over long periods of time degradeuniformity, resulting in imagery which appears more grainy (Figure 8 (b)) and/or blotchy (Figure 8 (c)).Operation over a wide temperature range (for example, powering on at -10 C and heating to 65 C) will alsohave a detrimental effect on image quality.For scenarios in which there is ample scene movement, such as most handheld applications, Lepton iscapable of automatically compensating for drift effects using an internal algorithm called scene-basednon-uniformity correction (scene-based NUC or SBNUC). However, for use cases in which the scene isessentially stationary, such as fixed-mount applications, scene-based NUC is less effective. In thoseapplications, it is recommended to periodically perform a flat-field correction (FFC). FFC is a process wherebythe NUC terms applied by the camera's signal processing engine are automatically recalibrated to produce themost optimal image quality. The sensor is briefly exposed to a uniform thermal scene, and the camera updatesthe NUC terms to ensure uniform output. The entire FFC process takes less than a second.Figure 8Examples of Good Uniformity, Graininess, and Blotchiness(a) Highly uniform image(b) Grainy image(high-spatial frequency noise)(c) Blotchy image(low-spatial frequency noise)The current FFC state is provided through the telemetry line. There are three FFC states, as illustrated inFigure 9 on page 16:1. FFC not commanded (default): In this state, Lepton applies by default a set of factory-generatedFFC terms.2. FFC in progress: Lepton enters this state when FFC is commanded. The default FFC duration isnominally 23 frames.3. FFC complete: Lepton automatically enters this state whenever FFC is completed.Lepton also provides an “FFC desired” flag in the telemetry line. The “FFC desired” flag is asserted atstart-up, when a specified period (default 3 minutes) has elapsed since the last FFC, or when thesensor temperature has changed by a specified value (default 3 Celsius degrees) since the last FFC.The “FFC desired” flag is intended to indicate to the host to command an FFC at the next possibleopportunity.Version 1.2.1, September 23, 2014Proprietary to FLIR Systems, Inc15

Operating States and ModesFigure 9LEPTON Long Wave Infrared (LWIR) Camera ModuleFFC StatesLepton powered onFFCCommandedFFC NotCommandedFFC InProgressFFC CompleteFFCComplete16Proprietary to FLIR Systems, IncFFCCommandedVersion 1.2.1, September 23, 2014

LEPTON Long Wave Infrared (LWIR) Camera Module8.3Operating States and ModesTelemetry ModesThere are three telemetry modes that affect the video output signal:Telemetry disabled (default)Telemetry as headerTelemetry as footer Explicit commands over the CCI select each mode. The contents and encoding of the telemetry data areshown in Table 3. Note that the second and third lines (line B and line C) are reserved for future growth andcontain no information at this time.Table 3 Telemetry Data Content and EncodingTelemetryRowWordstartWordEndNumberof 16-bitWordsNameA001TelemetryRevisionA122Time CounterA342Status BitsA5128Module serial #A13164Software revisionA17194ReservedA20212Frame CounterA22221Frame MeanA23231FPA TempIn counts (prior to conversion to Kelvin)A24241FPA TempIn Kelvin x 100A25251Housing TempIn counts (prior to conversion to Kelvin)A26261Housing TempIn Kelvin x 100A27282ReservedA29291FPA Temp at lastFFCVersion 1.2.1, September 23, 2014NotesFormat major (byte 1), minor rev (byte0).32 bit counter in units of msec elapsedsince boot-upSee Table 4 on page 1932-bit counter of output framesUpdated every FFC. Units are Kelvin x100Proprietary to FLIR Systems, Inc17

Operating States and ModesLEPTON Long Wave Infrared (LWIR) Camera ModuleTable 3 Telemetry Data Content and Encoding (continued)TelemetryRowWordstartWordEndNumberof 16-bitWordsNameA30312Time Counter atlast FFCUpdated every FFC. Units are msecA32321Housing temp atlast FFCUpdated every FFC. Units are Kelvin x100A33331ReservedA34374AGC ROIA38381AGC Clip-LimitHigh18A39391AGC Clip-LimitLowA407334ReservedA74741Log2 of dProprietary to FLIR Systems, IncNotes(top, left, bottom, right)See AGC, page 12See FFC States, page 15Version 1.2.1, September 23, 2014

LEPTON Long Wave Infrared (LWIR) Camera ModuleOperating States and ModesTable 4 shows the encoding of the status bits (Telemetry Row A, Words 3 and 4).Table 4 Status Bit Encoding (Telemetry Row A, words 3 and 4)Bit startBit endNumber ofBits0NameNotesReserved331FFC Desired10 FFC not desired1 FFC desired452FFC State1Telemetry Revision 8:00 FFC never commanded01 FFC in progress10 FFC complete11 undefinedTelemetry Revision 9:00 FFC never commanded01 Reserved10 FFC in progress11 FFC complete6116Reserved12121AGC State13197Reserved20201Overtemp shut downimminent213111Reserved0 Disabled1 EnabledGoes true 10 seconds beforeshutdown (see Power States,page 13)Note(s)1. See FFC States, page 15.Version 1.2.1, September 23, 2014Proprietary to FLIR Systems, Inc19

Operating States and Modes8.4LEPTON Long Wave Infrared (LWIR) Camera ModuleRadiometry ModesThere are two radiometry modes that affect the video output signal: Radiometry disabled (default)Radiometry enabledThe radiometric modes affect the transfer function between incident flux (scene temperature) and pixel output.From an image-quality standpoint, both radiometry modes produce nearly identical performance (no change inNEDT), and either mode is appropriate for strict imaging applications. However, for applications in which it isintended to convert the Lepton output signal to one proportional to scene temperature, the radiometry-enabledmode is preferred because the conversion is constant over the full operating temperature range of thecamera. Note that the following discussion assumes AGC is disabled (see AGC Modes, page 22). If AGC isenabled, the differences between the two radiometry modes are completely obscured by the AGC algorithm.In other words, with AGC enabled, any differences in signal output between radiometry-disabled andradiometry-enabled modes are negligible.8.4.1Radiometry DisabledWith radiometry disabled, the output of a given pixel is intended to be near the middle of the 14-bit range( 8192) when viewing a scene with a temperature equal to the temperature of the camera. Furthermore, theresponsivity, which is defined as the change in pixel output value for a change in scene temperature, variesover the camera's operating temperature range. The resulting output for three different scene temperatures isillustrated hypothetically in Figure 10 (note that the figure is for illustration purposes and not perfectlyrepresentative).Figure 1020Hypothetical Illustration of Camera Output vs. Camera Temperature in Radiometry-disabled ModeProprietary to FLIR Systems, IncVersion 1.2.1, September 23, 2014

LEPTON Long Wave Infrared (LWIR) Camera Module8.4.2Operating States and ModesRadiometry EnabledWith radiometry enabled, Lepton performs internal adjustments to the signal level such that in principle theoutput is independent of the camera's own temperature. The resulting output for three different scenetemperatures is illustrated hypothetically in Figure 11. Notice in Figure 11 that the output is only a function ofscene temperature, not camera temperature (again, the figure is for illustration purposes only and notperfectly representative. In practice, there is slight output variation as camera temperature changes,particularly when the temperature change is rapid). Also notice that responsivity is also independent ofcamera temperature; that is, the difference in output between two different scene temperatures is a constant,as opposed to in Figure 10 on page 20, where it decreases with increasing camera temperature.Figure 11Hypothetical Illustration of Camera Output vs. Camera Temperature in Radiometry-enabled ModeVersion 1.2.1, September 23, 2014Proprietary to FLIR Systems, Inc21

Operating States and Modes8.5LEPTON Long Wave Infrared (LWIR) Camera ModuleAGC ModesThere are two AGC modes: AGC disabled (default)AGC enabledAGC is a process whereby the large dynamic range of the infrared sensor

8 Proprietary to FLIR Systems, Inc Version 1.2.1, September 23, 2014 Lepton Camera Module Pinout Diagram LEPTON Long Wave Infrared (LWIR) Camera Module 4.0 Lepton Camera Module Pinout Diagram Figure 3 Pinout Diagram (viewed from back of camera module) 24 RESET L 23 PWR DWN L 2