Industry // Building materials

Machine vision inspection for building materials

Camera checks for tiles, boards, bricks, blocks, roofing sheets and pipes.

Technical review: Frank GuoReviewed 24 September 2026

// Short answer

On building materials lines, vision checks visible surface defects such as cracks, chips, blisters and glaze faults, measures length, width and squareness, and can sort units into grades or shade classes. Continuous or large products such as board, sheet and pipe are usually imaged with line-scan cameras. Dust, heat and vibration decide how the station is built. Strength, density and internal cracks are not visible to a camera.

// Where it fits

Inspection points from forming to stacking

A generic sequence; each product skips or adds steps.

[Schematic]Process flow · not to scale

Swipe sideways to see the whole drawing →

[1] Continuous surface: board, sheet or pipe imaged by line-scan before cutting.

[2] Dimensions: length, width and squareness of cut units.

[3] Cracks & chips: after drying, firing or curing.

[4] Surface & shade: finish and colour, combined into a grade for sorting.

// Defect risks

What goes wrong at each step

Visible faults by step, and the application that checks for them.

Building materials production steps, visible faults and matching inspections
Production step	Typical visible faults	Inspection
Forming, pressing, extruding	Blisters, paper tears and streaks on board; marks on sheet and pipe	Web & line-scan inspection Surface defect detection
Cutting	Wrong length or width, out-of-square corners, chipped edges	Dimensional measurement
Drying, firing, curing	Cracks, chipped corners and colour change between kiln or dryer zones	Surface defect detection
Glazing, printing, coating	Pinholes, glaze drips, missing or smeared print, coating scratches	Surface defect detection
Sorting and stacking	Grades or shades mixed in one box or pallet	Grading (below)

// Inspections

Checks that apply to building materials

Surface and dimension checks can often share one station.

Surface defect detection

Cracks, chips, blisters, pinholes and glaze faults.

At: after firing, curing or finishing

Surface defect detection

Dimensional measurement

Length, width, squareness and edge straightness of cut units.

At: after cutting

Dimensional measurement

Web & line-scan inspection

Continuous board, sheet or pipe imaged line by line as it moves.

At: after forming, before cutting

Web & line-scan inspection

// Grading

Sorting units into classes

Several checks combine into one decision per unit.

Define the classes on samples

Each grade or shade class is set by physical reference units agreed with your quality team.

Hold the image stable

Shade needs constant lighting and colour settings, checked regularly against a reference.

Combine and signal

Surface, dimension and shade results form one grade, sent to the sorter or stacker.

// Application map

Building materials inspection scenarios by product

Typical products from South African building materials plants, what a camera checks on each, and the application page with the detail. The method in each row is a starting point, confirmed on your own product. Strength, water absorption, density and internal cracks remain laboratory tests.

Building materials inspection scenarios: product and line position, what is inspected, typical fault, inspection method and related application
Product / line position	What is inspected	Typical fault caught	Inspection method	Related application
Ceramic floor tilesafter the kiln, before the sorting line	Glazed face, edges, size and shade	Cracks, chipped corners, pinholes, glaze drops, a shade outside the batch	Diffuse and low-angle light; colour camera for shade	Surface defect detection
Inkjet-printed wall tilesafter the digital printer or kiln	Printed decor across the face	Streaks from blocked print-head nozzles, missing decor, smudges	Colour line-scan or area camera with even light	Surface defect detection
Gypsum board (plasterboard)on the board line after the dryer	Paper face and bound edges	Paper tears, blisters, stains and damaged edges	Line-scan across the width with a line light and encoder	Web & line-scan inspection
Fibre-cement sheets and ceiling boardsafter curing and trimming	Face, edges, length, width and squareness	Cracked or broken corners, edge delamination visible at the cut, out-of-square sheets	Overhead cameras or line-scan with the sheet presented flat	Dimensional measurement
Concrete blocks and paverson the production board after the block machine	Top face and edges of each unit on the board	Broken corners, cracks, missing or incomplete units	Overhead camera triggered once per board, low-angle light	Surface defect detection
Clay face bricksafter the kiln or at the setting machine	Face colour, texture and arrises	Chipped arrises, cracks, colour outside the agreed range	Colour camera with low-angle light	Surface defect detection
Concrete roof tilesafter curing and colour coating	Nibs, interlocks and coating cover	Broken nib, cracked interlock, bare patches in the coating	Camera over the tile with diffuse and low-angle light	Surface defect detection
IBR and corrugated roof sheetingafter the roll former	Coated surface along the moving sheet	Coating scratches, dents, roll marks and colour change. Profile height needs a laser profile sensor	Line-scan camera paced by an encoder	Web & line-scan inspection
PVC pipesafter the extruder, at the marking printer and saw	Printed marking along the pipe, outer surface, cut end	Missing or unreadable marking, streaks, a ragged cut	Cameras around the pipe; OCR/OCV on the marking	OCR/OCV & code inspection
Melamine-faced boardsafter the short-cycle press	Decor surface	Scratches, press marks, dry spots, the wrong decor	Colour line-scan with even light across the board	Web & line-scan inspection
Insulation rollsafter roll wrapping	Wrap intact and the right label for the product	Torn wrap, missing or wrong label	Camera beside the conveyor with diffuse light	Label & print inspection
Cement bagsat the rotary packer discharge	Printed cement class and date code on the valve bag	The wrong class printed after a silo change, missing code, burst bag	Camera over the bag face; OCR/OCV on the code	OCR/OCV & code inspection
Strapped cubes of bricks or blocksat the stacker and strapping station	Cube label present and matching the product; layers complete	Missing or wrong cube label, a gap in a layer	Camera or code reader at the strapping station	Carton & pallet verification

// Environment

Conditions specific to building materials plants

Dust, heat and vibration are designed for from the start.

Dust

Clay, cement and gypsum dust

Dust coats optics and can look like a defect on product. Sealed housings, air purge and cleaning keep the image usable.

We askDust sources near the line

Heat

Kilns and dryers

Radiant heat affects electronics. The check sits after cooling, or the housing is cooled.

We askProduct temperature at the check

Vibration

Presses, saws and conveyors

Vibration blurs images and shifts measurements. Cameras mount on rigid, isolated frames.

We askWhere the station could be mounted

Size

Large and continuous product

Board and sheet are imaged by line-scan cameras paced by an encoder; wide product may need several.

We askProduct width and how speed is measured

Texture

Rough faces and patterns

Textured and printed surfaces vary naturally. Samples show where texture ends and a defect starts.

We askDesigns and finishes that run

// Limits

What a camera cannot tell you about building materials

We agree these boundaries before a project starts.

Needs another method

Internal cracks and laminations. Need methods such as acoustic or ultrasonic testing.
Strength and absorption. Strength, water absorption and density are laboratory tests.
Hidden faces. The underside needs another view; the inside of a pipe may not be visible.
Height. Flatness, warp and thickness need 3D or profile measurement.

Works reliably when

Product is presented consistently. Flat, spaced, with an encoder on continuous lines.
Optics are protected. Housings, air purge and cleaning are part of the design.
Classes are defined on samples. Physical reference units for every grade and shade.

// Samples & acceptance

What to send for a sample test

We test your own products before proposing a station. The same samples later define acceptance.

Sample preparation guide

Good product

Units from normal production, for each size, colour and finish.

Defect samples

Cracks, chips, blisters and out-of-size units, each marked.

Grade references

Units that mark the boundary between grades or shades.

Acceptance

False rejects, missed defects and grading agreement with your inspectors; levels agreed per project.

// FAQ

Building materials inspection questions

Can machine vision find cracks and chips on tiles or bricks?

Usually, when lighting makes the crack or chip stand out; low-angle light shows relief. Fine cracks on rough or patterned faces are harder, so we test your products first.

Can a camera grade tiles by shade?

It can sort units into shade groups when lighting and camera colour are stable and classes are defined on physical reference tiles. Random patterns are harder.

How are boards or roofing sheets inspected while they move?

With line-scan cameras that build the image line by line as the product passes, paced by an encoder. Defect positions can be passed on so the right piece is rejected after cutting.

Can vision check length, width, squareness and flatness?

Length, width and squareness can be measured from a top view when the product is presented consistently. Flatness, warp and thickness need height information, usually from a 3D or laser-profile method.

Will dust and heat stop a camera working?

Not if they are designed for. Sealed housings, filtered air and regular cleaning keep dust off the optics. Near kilns, the station sits where the product has cooled, or the housing is cooled.

Can vision replace strength or water absorption testing?

No. A camera sees surface and shape. Strength, water absorption, density and internal cracks need laboratory or other test methods.

Can concrete blocks and pavers be checked on the production board?

Yes, for visible faults. An overhead camera triggered by the block machine images each board and flags broken corners, cracks and missing or incomplete units. Compressive strength, density and faults below the top face need sampling and laboratory tests.

Surface defect detection →Dimensional measurement →Web & line-scan inspection →Machine vision lighting guide →How we deliver a project →Support & changes →

// Building materials

Request an assessment for your line

Tell us the products, finishes, grades and conditions around the line. We will say which checks apply and what a sample test needs.

Request a Vision Assessment