14.4 Image Processing and Report Generation Software
Key Takeaways
- Emissivity, reflected apparent temperature, distance, atmospheric values and transmittance can all be corrected in post-processing — but only if the image was saved as a radiometric file rather than a screenshot
- Focus, framing, thermal range selection, lens choice and whether the file is radiometric at all cannot be fixed afterwards; these are capture-time decisions
- Infraspection Section 9.1 requires every report to carry the thermographer's name and valid certification level and number, the end user's details, assistant names, and the imager's manufacturer, model and serial number
- Quantitative reports additionally require distance to the exception, rated and measured load, percentage load, and the emittance, reflected temperature and transmittance values used in the calculation
- Report generation software should link findings to history for trending, but a template never substitutes for the thermographer's judgement on severity and recommended action
Infraspection's Level II curriculum ends with Preparing Quantitative Reports, and it names four sub-topics: data to gather, report procedures, image processing software capabilities, and report generation software capabilities. ITC's outline includes an Overview of Inspection Report Creation and a software training block. A Level II thermographer who cannot say what software can and cannot fix is not ready to sign quantitative work.
What Image Processing Software Can Fix
A radiometric image stores the raw detector signal for every pixel plus the parameters in force at capture. Because the raw signal is preserved, the temperature calculation can be re-run later with better inputs.
| Parameter | Correctable after capture? | Note |
|---|---|---|
| Emissivity (ε) | Yes | The most common and most valuable correction |
| Reflected apparent temperature | Yes | Re-enter a properly measured RAT from Chapter 5 |
| Distance to target | Yes | Feeds the atmospheric transmission model |
| Atmospheric temperature and relative humidity | Yes | Same model |
| External optics / IR window transmittance (τ) | Yes | If the software exposes an external-optics field |
| Palette and colour scheme | Yes | Cosmetic |
| Level and span (thermal tuning) | Yes | Re-tune for contrast on a radiometric file |
| Spot, area, line and isotherm measurement tools | Yes | Add or move analysis objects |
| Image fusion / blending with the visual image | Yes | If both were captured |
This is exactly the capability that makes the Chapter 13 QA/QC process possible: when a Level I technician leaves ε at 0.95 on oxidised copper, a Level II reviewer can reprocess the original file with the correct ε and reflected temperature and recalculate the temperature rather than sending a crew back to site.
What Software Cannot Fix
| Not correctable | Why |
|---|---|
| Focus | Defocus averages radiation across pixels; the lost detail is not recoverable, and an out-of-focus radiometric measurement is simply wrong |
| Framing and composition | What was outside the field of view was never recorded |
| Whether the file is radiometric | A screenshot, JPEG export, or photo of a screen contains display colours, not detector data. No parameter can be changed afterwards |
| Measurement range selection | A target above the selected range saturates; saturated pixels carry no recoverable value |
| Spot size / MFOV violations | If the target did not fill the measurement field of view, the pixel averaged target and background, and that mixture cannot be unmixed |
| Lens actually fitted | Optical resolution is set at capture |
| Whether a similar reference component was imaged | You cannot create a comparison that was never captured |
Focus deserves emphasis. It is a genuine radiometric error, not an aesthetic one. Infraspection Section 8.7.1 requires that "every effort shall be made to ensure the thermal image is in sharp focus." An unfocused thermogram cannot be rescued by any amount of post-processing.
The one-line rule: radiometric parameters are soft; optics, focus, framing, range, and geometry are hard.
Required Report Content
Infraspection Section 9 sets out what a report must contain. Treat this as a checklist — items appear directly as exam content.
For every inspection (Section 9.1)
| Item | Clause |
|---|---|
| Name and valid certification level(s) and number(s) of the thermographer | 9.1.1 |
| Name and address of the end user | 9.1.2 |
| Name(s) of the assistant(s) who accompanied the thermographer | 9.1.3 |
| Manufacturer, model and serial number of the infrared equipment used | 9.1.4 |
| List of all equipment inspected, and notation of equipment not inspected | 9.1.5 |
| Date(s) of inspection and date the report was prepared | 9.1.6 |
For each exception, qualitative inspections (Section 9.2)
- Exact location of the exception
- Description including nameplate data, phase or circuit number, rated voltage, amperage rating and/or rotation speed
- Environmental conditions where significant: air temperature, wind speed and direction, sky conditions
- Thermogram and corresponding visible-light image
- Field of view of the imager lens
- Notation of any windows, filters or external optics used
- Optionally, the qualified assistant's or end user's subjective rating of importance
- Any other conditions affecting results, repeatability, or interpretation
Additional for quantitative inspections (Section 9.3)
- Distance from the imager to the exception
- Maximum rated load and measured load at the time of inspection
- Percentage load, calculated as measured ÷ rated
- The emittance, reflected temperature and transmittance values used to calculate the temperature
- When using ΔT criteria: the surface temperature of the exception, of the defined reference, and their difference
- When using absolute criteria: the surface temperature and the standard temperature(s) referenced
- Optionally, a temperature severity evaluation and a repair priority rating
Section 9.3.3 is the clause that makes reports auditable: recording the ε, RAT and τ actually used means a reviewer can reprocess the radiometric file and verify your number. Omit it and no one — including a court — can check your work.
What Report Generation Software Should Do
| Capability | Value |
|---|---|
| Template enforcement | Guarantees the Section 9 fields are present on every finding |
| Metadata auto-population | Pulls camera model, serial, date, lens, ε, RAT and distance straight from the radiometric file, removing transcription errors |
| Paired image layout | Places thermogram and visible image side by side as required |
| Asset linkage and history | Ties each finding to an asset ID so the trending of Chapter 12 is possible across surveys |
| Criteria library | Applies the chosen ΔT or absolute criteria set consistently and records which one was used |
| Batch processing | Handles large route inventories without hand-editing each entry |
| Export to the maintenance system | Turns findings into work orders |
Infraspection publishes its own tools in this category, and every major camera vendor ships an analysis and reporting package. The specific product is not the exam point; the capabilities are.
Where software stops
Software can enforce completeness. It cannot supply judgement. It will not decide whether a reference component was genuinely comparable, whether the survey met loading requirements, whether a pattern is a reflection, or whether an exception warrants immediate action. Infraspection Section 4.2 is blunt about the boundary: providing opinions about causes, system integrity, or corrective actions "requires knowledge and skills beyond those of infrared thermography." A template that auto-generates a recommendation you did not evaluate is a liability, not a feature.
Practical Workflow
- Capture radiometric files, in focus, with adequate MFOV, and shoot the visible-light image at the same time.
- Record on site what software cannot recover: load, ambient, wind, sky, distance, lens, windows and filters.
- Post-process ε, RAT, distance, humidity and τ from measured values, not defaults.
- Apply the chosen criteria set and name it.
- Assemble against the Section 9 checklist.
- Review — ideally a second Level II reads the report before issue.
- Archive the original radiometric files, not just the report PDF, so future surveys can trend against genuine data.
Quick Answer: Radiometric files allow post-capture correction of emissivity, reflected temperature, distance, humidity and transmittance; focus, framing, range, lens and spot-size violations are permanent, and a non-radiometric screenshot allows no correction at all. Reports must carry the thermographer's certification level and number, the imager's make, model and serial, the equipment list, and — for quantitative work — distance, rated and measured load, percentage load, and the ε, RAT and τ values used. Software enforces completeness; the thermographer supplies the judgement.
A Level I technician captured findings as JPEG screenshots exported from the camera display rather than as radiometric files. A Level II reviewer discovers the emissivity was set to 0.95 on bright copper. What can be done?
Which of these can NOT be corrected after the image has been captured, even in a radiometric file?
Under Infraspection Section 9.3, which set of values must a quantitative report state for each exception so that another thermographer can verify the calculation?
What is the appropriate limit on report generation software in a Level II workflow?
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