Depth camera has no IR projector: passive stereo and laser class

Your safety review has struck out laser products, and the stereo depth camera you shortlisted is listed as a Class 1 laser device. The way out is often documentation rather than substitution: a model sold without an infrared projector contains no laser at all. Two ordinary image sensors watch the scene from slightly offset positions, and depth comes from matching those two images — ambient light does the illuminating. This guide is for integrators whose projects exclude lasers. It shows how to prove a camera is emitter-free from the data sheet and the label, what Class 1 actually certifies, which 3D camera families always carry an emitter, what passive stereo costs in depth quality, and which LED-lit systems work when the ban stays firm.

Does a stereo depth camera without an IR projector emit a laser?

A stereo depth camera that ships without an infrared projector emits no laser at all: two image sensors view the scene from slightly offset positions, depth comes from matching the two images pixel by pixel, and ambient light does all the illuminating.

Stereo without a projector is called passive stereo. The camera measures disparity — the shift of each surface feature between the left and right image — and converts it to distance through the lens and baseline geometry. Nothing in that chain needs a source, so there is no emission to classify and no laser clause in the review to satisfy.

Projector stereo is the active variant: a Class 1 infrared projector paints a dot or speckle pattern onto the scene, giving even blank parts synthetic texture to match. That projector is the laser, and the data sheet's laser-safety section attaches to the models that carry it. The active-IR versus stereo comparison for people counting shows the same split from a different application.

One boundary matters for the wording of your rule: passive means no emitter of any kind, not merely no laser. A camera that floods the scene with infrared from an LED or a laser diode is active either way, and the governing standard changes with the source type.

How do you prove a model has no projector before you buy?

Three documents close this question before any purchase order: the family data sheet's projector table, the certification label on the housing and the optical drawing of the camera apertures.

Start with the data sheet. Short-range stereo families print a comparison table with one row per model and columns for the projector types — usually a standard pattern projector and a wide-field variant. Your model's row showing neither type is the primary evidence. The absence of a laser sentence elsewhere in the document is not: emission details tend to sit in a safety section at the back, so go to the table.

The label is the second check. IEC 60825-1 obliges every laser product to carry classification labelling — class, emitting aperture, wavelength. A housing with no laser label anywhere is consistent with an emitter-free design, and read together with the projector row it becomes proof.

Last, name the emitter type in writing. Some active depth cameras illuminate with LEDs, which appear in no laser table and carry no laser label. If the project rule bans laser sources only, an LED illuminator can still pass; if it bans all emission, only a passive model passes. The rule text decides, so read it first.

What does Class 1 laser actually certify?

Class 1 under IEC 60825-1 certifies that a laser product is safe during normal operation without protective equipment, not that it suits a project that excludes lasers; excluding Class 1 devices is a policy choice, usually inherited from blanket site or customer rules that bar every laser class at once.

IEC 60825-1 sorts laser products by accessible emission. Class 1: safe in normal operation, because the source is enclosed or too weak to harm. Class 2: visible beams below 1 mW, protected by the blink reflex. Class 3R and 3B: higher powers that demand engineering controls and, for 3B, a controlled area. Where a projector lands is set by its wavelength and output, and the maker states the class on the label.

For your review the logic is short. A Class 1 label certifies that a laser exists inside the housing. You are not negotiating power levels; you are removing the source. A passive stereo camera has nothing inside to classify: no source, no class, no clause of the rule to argue.

Which 3D camera types always contain an emitter?

Projector stereo, projected structured light, speckle logistics cameras, laser profilers and most time-of-flight sensors emit their own light by design, while only passive stereo and LED-lit 2.5D systems can be emitter-free; the table below shows what each type emits and which safety standard governs it.

A time-of-flight model such as the MV-DT01WMU measures the return time of its own infrared flood, so an emitter is part of the measurement itself. Speckle-projected structured light and laser galvanometer stereo models also carry their emitters inside the housing; when a review does allow one, these are the emitter-equipped options in the range:

One integration trap belongs here: infrared. An IR-cut filter that helps a colour 2D camera will also swallow a projector's dot pattern, so depth quality collapses when the two share an optical path — the IR-cut filter versus projector conflict walks through that failure.

What does passive stereo cost you in depth quality?

Expect depth noise that grows with the square of distance: an illustrative stereo pair with a 50 mm baseline reads about 1.6 mm of depth noise at a 500 mm working distance and 6.3 mm at 1000 mm, and matching degrades further wherever the part has no texture.

Stereo turns matching error into distance error through the geometry of the pair:

Here d is disparity in pixels, f_px the focal length in pixels, b the baseline, z the working distance, and σd the sub-pixel matching error.

Worked example for an illustrative pair, not a catalog model: image width 1280 px, horizontal field of view 90°, so f_px = (1280 / 2) / tan(45°) = 640 px. Baseline b = 50 mm. At z = 500 mm, disparity d = 640 × 50 / 500 = 64 px. With σd = 0.2 px — the middle of the 0.1–0.3 px range that sub-pixel matching holds on a well-textured part — depth noise is σz = 500² × 0.2 / (640 × 50) = 250,000 × 0.2 / 32,000 = 1.56 mm. Move the part to z = 1000 mm: disparity halves to d = 640 × 50 / 1000 = 32 px, and σz = 1,000,000 × 0.2 / 32,000 = 6.25 mm. Double the distance, four times the noise.

What moves those numbers: doubling the baseline to 100 mm halves σz at both distances, and doubling the resolution at the same field of view does the same through f_px. The term a projector exists for is σd. On a blank moulded face or a glossy bin wall the matcher misses by whole pixels or drops out, leaving holes and flicker in the cloud; a corrugated carton, by contrast, matches well. When noise does show up, start with the noisy stereo point cloud fixes, then the stereo depth jitter and IMU drift troubleshooting guide; the accuracy vocabulary your data sheet uses is unpacked in precision, trueness and spatial resolution, and the baseline lever at longer range in wide-baseline stereo accuracy.

What do you install when the laser ban is firm?

For close-range surface and height inspection, an LED-lit 2.5D system does the shape job with no laser on board: the MV-PSA-12UM-C4D30-WDM pairs a 12 MP camera with a 300 mm white-light dome, reading shape and gloss from shading instead of a projected pattern.

A dome surrounds the part with diffuse light from every direction, so bumps, dents and embossed characters read as shading gradients instead of matched texture — there is no matcher to starve. Height, gloss and print defects on shiny housings, caps and closures are the natural workload.

Here is the system type that closes that gap:

White LED light is still optical radiation, so IEC 62471 replaces the laser standard in the review; the close-range IR LED limits under IEC 62471 work the exposure arithmetic for domes and spot lights.

The decision, case by case:

• Textured part, picking or millimetre-class accuracy, no emitter allowed: passive stereo, sized with the formula above. The 50 mm baseline illustration holds 1.56 mm of noise at a 500 mm working distance, so a ±2 mm pick tolerance sits comfortably inside it; a ±0.5 mm gauging task at that range does not — lengthen the baseline or raise the resolution first.
• Blank, shiny or curved part at close range: LED dome-light 2.5D, where shading carries the shape that matching cannot find.
• Dense cloud on blank parts, or long range: an emitter is the honest answer. Take a Class 1 projector through review with the documents below, or a profiler once its label clears the rule text.
• Conveyor picking with camera count and mounting still open: the 2D or 3D chooser for pick and place settles those before the emitter question.

What do you hand the safety reviewer?

Four items close the review: the projector table with your model's row highlighted, a photo of the housing label, the drawing showing camera apertures only, and a one-paragraph statement that the product contains no laser source and falls outside IEC 60825-1.

1. Projector table. The family data sheet row for your exact model, both projector columns empty — the primary evidence.
2. Label photo. The housing as delivered, with no laser classification label anywhere, since IEC 60825-1 requires one on any laser product.
3. Optical drawing. Camera apertures only: no emitter window on the front face and no emitter on the mechanical interface.
4. The statement. Depth source: passive stereo. No laser source inside the housing; IEC 60825-1 does not apply; illumination is ambient. Map the conclusion onto the rule's own wording — "no laser product of any class" and "no Class 1 device" close with the same sentence.
5. Cross-reference. Where the bill of materials still holds emitter-equipped devices — profilers, time-of-flight, projector stereo — list each with the class printed on its label, so the reviewer sees the split is deliberate.

To assemble the set-up, browse the 3D sensors category, filter the 3D camera finder by depth type, or start at the camera step of the configurator. The 3D vision guides cover the integration side, and contact us when a review needs a data sheet read against the rule text.