Cycles across target
Detection (D)
1.5 cycles
An object is present in the field of view, distinguishable from the background.
Johnson Criteria · NATO STANAG 4347 · 64 thermal models
Johnson Criteria Calculator (2026): NATO STANAG 4347 Detection / Recognition / Identification
Defensible DRI sizing for thermal CCTV — in the browser, with the same cycles-on-target framework cited by perimeter-detection tenders, NATO procurement, and every thermal manufacturer worth taking seriously. 64 verified thermal models. Datasheet DRI tables. No spreadsheets.
What the criteria actually says
Cycles on target, not pixels per metre.
John Johnson's 1958 work at the U.S. Army Night Vision Laboratory took a pragmatic question — "how good does the imager need to be for the operator to do the job?" — and converted it into a measurable threshold. The answer: cycles of resolution across the minimum target dimension. 1.5 cycles to confirm something is there. 6.4 cycles to recognise its class. 12.8 cycles to identify which member of that class it is. These numbers were validated against thousands of operator trials and have survived seven decades of sensor evolution.
NATO STANAG 4347 took the Johnson framework and codified the reference targets: a NATO-class human (~0.75 m × 1.8 m projected dimension) and a NATO-class vehicle (~2.3 m × 2.3 m). Manufacturers' DRI tables are then computed against these references using the imager's pixel pitch, focal length, and modulation transfer function. The DRI distance the datasheet quotes is the maximum range at which a stated number of cycles still falls across the minimum target dimension under defined contrast and atmospheric conditions.
Two consequences for the integrator. First — Johnson DRI is a thermal-imaging metric. Applying it to a visible-light CCTV camera is a category error; for visible cameras use EN 62676-4 DORI instead. Second — the cycles-on-target framework already accounts for the geometry of the target. You do not need to re-derive pixel density. The DRI radius the datasheet quotes is the answer.
Johnson Criteria thresholds
Cycles across target
Recognition (R)
6.4 cycles
Object class can be discerned: human vs. animal vs. vehicle. No identity claim.
Cycles across target
Identification (I)
12.8 cycles
Specific class member can be identified: armed vs. unarmed, vehicle make / model, individual.
Cycles per the Johnson 1958 paper, retained by NATO STANAG 4347. Reference targets: NATO-class human (0.75 m minimum dimension) and NATO-class vehicle (2.3 m minimum dimension). Datasheet DRI distances are computed against these references.
Worked example: long-range perimeter intrusion detection
Brief. Critical-infrastructure outer fence at 600 m from the thermal mast. Tender requires Recognition (operator can confirm a human-class intruder rather than wildlife) at the fence line. Atmospheric conditions: clear, 70% relative humidity baseline.
Target. NATO-class human, 0.75 m minimum projected dimension. Required cycles for Recognition: 6.4 across that 0.75 m.
Camera selection. A 640 × 480 microbolometer with a 75 mm thermal lens, manufacturer DRI table: Detection 1700 m, Recognition 600 m, Identification 320 m on a NATO-class human. The 600 m Recognition distance matches the fence line — exactly the design intent.
Atmospheric correction. Datasheet DRI assumes clear-air conditions. Persistent fog, heavy rain, or above-95% humidity will reduce effective DRI by up to 50%. Tender response should specify the assumed atmospheric class and recommend a denser sensor layout (or an additional radar layer) for sites where degraded conditions are routine.
Result. Camera passes Johnson Recognition at the fence line on a NATO-class human under clear-air conditions. The CCTVplanner export documents the DRI radii on the canvas, the source datasheet, and the assumed target class — three lines an auditor can verify in minutes.
How CCTVplanner makes Johnson Criteria designs trivial
64 thermal models, datasheet DRI tables
Every thermal camera in the catalog ships with the manufacturer's DRI table loaded as data. No interpolation, no "approximately" — the radii drawn on the canvas come straight from the datasheet that the auditor will pull up on their phone.
Dual-spectrum FOV cone for thermal+visible
Dual-sensor cameras render two FOV layers — Johnson DRI for the thermal sensor, EN 62676-4 DORI for the visible sensor — so the integrator has both compliance paths visible at once.
STANAG 4347-style report in the PDF export
The exported PDF includes per-camera DRI radii, target class assumed, source datasheet, and atmospheric conditions assumed — the four lines a NATO procurement auditor expects to find.
Mixed thermal + visible projects
A single project can carry both Johnson DRI (thermal long-range) and EN 62676-4 DORI (visible inner-perimeter PTZ) on the same drawing. One submission. Two compliance paths. No spreadsheet.
Johnson Criteria / STANAG 4347 checklist
- Define the operational task per thermal camera (Detection, Recognition, or Identification of a NATO-class target).
- Use the DRI table from the manufacturer's datasheet — these are the only DRI numbers an auditor will accept.
- Verify the target dimension assumed by the manufacturer (typically 0.75 m × 0.75 m human, or 2.3 m × 2.3 m NATO vehicle).
- Account for atmospheric attenuation in long-range thermal — fog, humidity, and rain reduce effective DRI.
- For dual-spectrum (thermal + visible) cameras, document both Johnson DRI (thermal) and EN 62676-4 DORI (visible) — they are separate compliance paths.
- Include the DRI table in the design submission and reference NATO STANAG 4347 (or its national equivalent) where the tender requires it.
Frequently asked questions
What is the Johnson Criteria and where does it come from?
The Johnson Criteria is the framework John Johnson published in 1958 at the U.S. Army Night Vision Lab for sizing electro-optical sensors against tactical targets. It expresses required image quality in cycles of resolution across the minimum target dimension: 1.5 cycles for Detection, 6.4 for Recognition, and 12.8 for Identification. Although the original work was for image-intensifier and FLIR systems, the same maths is the de-facto standard for modern thermal CCTV — every reputable thermal manufacturer publishes a DRI table on the datasheet, and those tables are derived from Johnson.
How does NATO STANAG 4347 fit in?
NATO STANAG 4347 is the alliance-level standardisation agreement that fixes the Johnson Criteria as the reference method for thermal-imager performance characterisation. It defines target dimensions (NATO-class human, NATO-class vehicle), reference contrast levels, and reporting format. For perimeter and critical-infrastructure projects in NATO member states, the tender will typically cite STANAG 4347 directly. The DRI numbers in CCTVplanner are sourced from datasheets that follow this convention.
Is Johnson Criteria the same as EN 62676-4 DORI?
No — and treating them as the same is a common design error. EN 62676-4 DORI uses pixel density on the target plane (px/m), valid for visible-light cameras with a defined sensor pitch and lens. Johnson DRI uses cycles-on-target across the minimum target dimension, valid for thermal imagers where contrast and atmospheric MTF matter as much as raw resolution. A thermal camera with 384 × 288 microbolometer pixels can absolutely deliver Johnson Identification at 600 m on a NATO-vehicle target — yet by the EN 62676-4 px/m yardstick that same camera looks underspec. Different physics, different metric.
How does CCTVplanner integrate Johnson Criteria for the 64 thermal models?
Each of the 64 thermal cameras in the catalog has the manufacturer's DRI table loaded as data — not estimated, not interpolated. When you place a thermal camera, the DRI radii (Detection / Recognition / Identification) are drawn directly on the canvas. Dual-spectrum models (thermal + visible) show a stacked FOV cone — Johnson DRI for the thermal sensor, EN 62676-4 DORI for the visible sensor — so the integrator has both compliance paths visible at once.
Can the same project mix thermal and visible cameras with both standards documented?
Yes — and this is the realistic case for perimeter installations. A typical site uses long-range thermal cameras to detect intrusion at 300–800 m (Johnson Recognition or Identification on the NATO-class human target), backed up by visible-spectrum PTZ cameras to identify the intruder once they are inside the inner perimeter (EN 62676-4 Identification at 250 px/m). The PDF export documents both, side by side, so a single submission satisfies both standards.
Run a Johnson Criteria thermal design in your browser
Free to start. 64 thermal models with datasheet DRI. Dual-spectrum aware. STANAG 4347-style PDF export. EU-hosted. Used by integrators from all over the world.
Also explore: EN 62676-4 calculator · DORI calculator · Lens selector · NDAA §889 compliance
DEFENSAR · 100% Engineered and Hosted in the EU