EOS DYNAMICS || EOS Learning Center || D.O.R.I. RANGE CALCULATORS

EOS Dynamics Engineering Tools

D.O.R.I. & EO/IR Range Calculators

Atmospheric Screening Module

D.O.R.I. and Johnson DRI are geometric range estimates. Atmosphere does not change the pixel count on target, but it reduces contrast, signal strength and practical detectability.

Use atmospheric screening

Spectral Band

Design Wavelength (µm)

Atmosphere / Weather

Visibility (km)

Known Atmospheric Transmission at 1 km - Optional

If this value is entered, the calculator uses it directly as T(1 km) and estimates transmission as T(range) = T(1 km)^{range km}. If left empty, a visibility-based screening model is used. For formal EO/IR range prediction, use MODTRAN / LOWTRAN / HITRAN-based atmospheric modelling.

CCTV / IEC DORI Pixel Density Calculator

Estimate Detection, Observation, Recognition and Identification ranges using pixel density in the scene. This mode is based on pixels per meter (px/m), commonly used in CCTV and video surveillance planning.

CCTV / IEC DORI thresholds used here

Detection: 25 px/m, Observation: 63 px/m, Recognition: 125 px/m, Identification: 250 px/m.

Horizontal Pixels Vertical Pixels Pixel Pitch (µm) Focal Length (mm)

Target Preset Target Width (m) Target Height (m)

Target size is not required for DORI range itself, because CCTV DORI is based on px/m. It is used here to show approximately how many pixels the selected target occupies. Preset dimensions are practical approximations and can be edited.

Result will appear here.

EO/IR Johnson DRI Calculator

Estimate Detection, Orientation / Observation, Recognition and Identification ranges using Johnson-style cycles or line pairs across the target critical dimension.

Johnson DRI concept

Johnson DRI does not use px/m. It uses cycles, also called line pairs, across the target critical dimension. In digital imaging, 1 cycle is approximately 2 pixels.

Horizontal Pixels Vertical Pixels Pixel Pitch (µm) Focal Length (mm)

Target Preset Target Width (m) Target Height (m) Critical Dimension (m)

DRI Model Probability Level

Probability scaling is an engineering approximation. For formal military qualification, project-specific target acquisition models, atmospheric effects, MRTD/MRT, contrast, noise and customer requirements should be used.

Result will appear here.

Custom Target Criterion Calculator

Use this mode when you have your own required pixel density or cycle criterion.

Horizontal Pixels Vertical Pixels Pixel Pitch (µm) Focal Length (mm)

Criterion Type Required Criterion Value Target Critical Dimension / Width (m)

If you choose px/m, the calculator uses scene pixel density. If you choose cycles, it assumes 1 cycle ≈ 2 pixels and calculates range based on target critical dimension.

Result will appear here.