Information & Digital Age (1950–Present)Machine Vision & Industrial Automation

Lemelson Machine Vision & Automated Video Inspection

US 3,081,379

Television Raster Scanning, Sliced Video Pulse Gauging, and Automated Defect Ejection

Inventor(s)Jerome H. Lemelson

Grant DateMarch 12, 1963

Filing DateDecember 4, 1956

LocationMetuchen, New Jersey

Jerome H. Lemelson's landmark 1963 patent established the foundational architecture for industrial machine vision and automated optical inspection. By sweeping an electron beam across an optical image plane to generate time-varying video signals, synchronizing electronic gating networks to isolate specific target inspection zones, and measuring sliced pulse durations or comparing waveforms against reference templates, the system enabled automated dimensional measurement, character recognition, and high-speed defect rejection on factory production lines.

USPTO PDF

Engineering Analysis & Physical Principles

How It Works: Step-by-Step Mechanical & Physical Breakdown

Before Jerome Lemelson's 1954–1956 invention, factory quality inspection was performed almost entirely by human workers peering through magnifying lenses or by simple fixed photocells that could only sense bulk presence or absence. Lemelson realized that television camera tubes (such as the vidicon and image orthicon) could be repurposed as ultra-fast dimensional metrology instruments: by sweeping a focused electron beam in a precise geometric raster across a moving manufactured part, optical dimensions in space are transformed into pulse durations in time. Electronic gating circuits isolate specific inspection zones, and high-speed threshold comparators measure workpiece dimensions and detect microscopic surface defects to actuate automated pneumatic or solenoid sorting diverters.

The Core Breakthrough Mechanism

A television camera focused on a conveyor belt raster-scans each passing manufactured article with an electron beam deflected at a calibrated horizontal line frequency $f_H = N_L \cdot f_F$ (~15.75 kHz in standard television). The camera's photosensitive target generates a continuous analog voltage waveform $V(t)$ directly proportional to the light reflected from the article's surface. As the beam crosses the boundary between the dark conveyor background and the reflective workpiece, the voltage jumps, creating an electrical pulse. A synchronized electronic gate passes only the scan lines corresponding to the critical inspection zone into an amplitude-slicing comparator. The comparator measures the pulse duration $\tau_{\text{pulse}}$ , and calculates the physical dimension via $L = v_{\text{scan}} \cdot \tau_{\text{pulse}}$ . If the pulse duration deviates from pre-set tolerance limits (indicating an undersized, oversized, or flawed part), a trigger pulse energizes a high-speed electromagnetic solenoid gate $F_{\text{mag}} = \frac{(NI)^2 \mu_0 A}{2 g^2}$ to instantly kick the defective part off the conveyor into a reject bin.

Interactive Real-Time Physical Simulation

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INITIALIZING THREE.JS WEBGL SIMULATION...

Host-Model Telemetry/Computed Readout

Television Raster Scanning & Machine Vision

Horizontal Scan Freq (f_H)

Modern Model

15750Hz[1/T]

Line Duration (T_H)

Modern Model

63.49µs[1]

Beam Scan Velocity (v_scan)

Modern Model

3750.0m/s[L/T]

Detected Pulse Width (τ)

Modern Model

21.87µs[1]

Measured Width (L_meas)

Modern Model

82.0mm[L]

Dimensional Deviation (ΔL)

Modern Model

2.00mm[L]

Reject Solenoid Force (F_mag)

Modern Model

4.97N[ML/T²]

Gate Trip Response (t_act)

Modern Model

33.6ms[T]

Raster scan lines525 lines

Frame rate30 Hz

Field of view width0.2 m

Illumination level1500 lux

Threshold comparator level0.45 V

Nominal part width0.08 m

Actual part width0.082 m

Conveyor speed0.25 m/s

Solenoid coil current2.5 A

Detailed Component Architecture

1Cathode Ray Vidicon Video Camera

An optical scanning camera tube that sweeps an electron beam across a photoconductive target to convert light patterns into analog electrical waveforms.

The camera employs magnetic deflection coils driven by sawtooth horizontal and vertical sweep generators to deflect the electron beam at a calibrated scan velocity $v_{\text{scan}} = W_{\text{target}} / T_{\text{active}}$ . The photoconductive target (e.g. antimony trisulfide) exhibits localized resistivity drops proportional to incident photons, generating an instantaneous current $I(t)$ and output video voltage $V(t) \in [0, 1.2]\text{ V}$ .

19th-C. Term: Electron beam scanning apparatus / television camera pickup tubeModern: CCD / CMOS line-scan and area-scan industrial machine vision camera

2Synchronized Video Gating Network

Electronic gating and commutation circuits that isolate specific regions of interest within the video frame.

Driven by master synchronization pulses and variable delay lines, the gating circuit unblanks the video signal path only during predetermined horizontal scan lines and time intervals corresponding to the critical inspection zone, preventing false triggers from background clutter or conveyor seams.

19th-C. Term: Gating means controlled by variable programming meansModern: Region of Interest (ROI) hardware windowing & FPGA frame grabber gating

3Waveform Amplitude & Pulse Duration Slicer

High-speed voltage comparator and differentiator networks that detect edges and measure workpiece dimensions in microseconds.

A clipper circuit slices the video waveform at an adjustable reference threshold $V_{\text{threshold}}$ . The resulting rectangular pulse has steep edges corresponding to physical part boundaries; pulse width $\tau_{\text{pulse}}$ is measured by high-speed counter clock cycles or analog RC integrators to calculate physical width $L = v_{\text{scan}} \cdot \tau_{\text{pulse}}$ .

19th-C. Term: Clipping circuit, differential analyzer, and pulse width measurement meansModern: Sub-pixel edge detection & 1D/2D dimensional gauging algorithm

4Solenoid Rejection & Defect Ejection Diverter

An electromechanical solenoid actuator that diverts flawed or out-of-tolerance parts off the conveyor belt.

Upon detection of a dimensional error $\Delta L > \Delta L_{\text{tol}}$ , a thyratron or relay circuit discharges a high-current pulse through a multi-turn solenoid coil ( $N=450$ turns, $I=2.5\text{ A}$ ), developing tractive force $F_{\text{mag}} = \frac{(NI)^2 \mu_0 A}{2 g^2} \approx 5\text{ N}$ to extend a diverter paddle across the conveyor within 15 ms.

19th-C. Term: Electromechanical sorting means / solenoid diverter gateModern: High-speed pneumatic blow-off nozzle & servo diverter sortation gate

5Reference Signal Waveform Store

A multi-track magnetic drum or disc that stores golden standard reference waveforms for differential comparison.

A revolving magnetic drum synchronized with the conveyor drive reproduces a recorded golden waveform $V_{\text{ref}}(t)$ . A differential subtraction amplifier computes the instantaneous error $\Delta V(t) = |V_{\text{scan}}(t) - V_{\text{ref}}(t)|$ , flagging surface flaws, scratches, or missing component features.

19th-C. Term: Magnetic drum storage device and differential playback pickupModern: Golden template matching & normalized cross-correlation (NCC) memory buffer

Engineering Principles & Equations

Governing Equations & Engineering Principles

Authored explanation paired with its stated mathematical relation

Television Raster Scan & Dimensional Pulse Slicing

Optical Electronics & Signal ProcessingClaim 1

Mathematical Governing Law

\htmlClass{eq-term eq-term-meas_dim eq-term-emerald}{\htmlData{var=meas_dim}{\textcolor{#059669}{L_{\text{meas}}}}} = \htmlClass{eq-term eq-term-scan_vel eq-term-sapphire}{\htmlData{var=scan_vel}{\textcolor{#2563eb}{v_{\text{scan}}}}} \cdot \htmlClass{eq-term eq-term-pulse_width eq-term-amber}{\htmlData{var=pulse_width}{\textcolor{#d97706}{\tau_{\text{pulse}}}}} = \frac{\htmlClass{eq-term eq-term-field_width eq-term-cyan}{\htmlData{var=field_width}{\textcolor{#0891b2}{W_{\text{target}}}}}}{\htmlClass{eq-term eq-term-active_sweep eq-term-amethyst}{\htmlData{var=active_sweep}{\textcolor{#9333ea}{T_{\text{active}}}}}} \cdot \htmlClass{eq-term eq-term-pulse_width eq-term-amber}{\htmlData{var=pulse_width}{\textcolor{#d97706}{\tau_{\text{pulse}}}}}

Terms:

Plain English DecoderHover or tap any highlighted phrase

The equals the multiplied by the , where scan velocity is the ratio of to .

L_{\text{meas}}

Measured Physical Dimension

Calculated geometric width of the inspected manufactured article

metres (m)[L]

The linear size of the workpiece derived electronically by counting clock cycles or integrating video voltage during beam transit across the part.

Physical Principle & Engineering Insight

Lemelson's breakthrough was converting spatial dimensions on a factory conveyor into temporal durations in a video waveform, allowing microsecond electronic circuits to perform precision metrology.

Historical Context: Claim 1 defines the synchronization between electron beam sweeping, gating circuits, and waveform analyzing circuits.

Electromagnetic Defect Ejection Solenoid Force

Electromagnetics & Actuator DynamicsClaim 1

Mathematical Governing Law

\htmlClass{eq-term eq-term-mag_force eq-term-emerald}{\htmlData{var=mag_force}{\textcolor{#059669}{F_{\text{mag}}}}} = \frac{(\htmlClass{eq-term eq-term-coil_turns eq-term-sapphire}{\htmlData{var=coil_turns}{\textcolor{#2563eb}{N}}} \cdot \htmlClass{eq-term eq-term-coil_current eq-term-amber}{\htmlData{var=coil_current}{\textcolor{#d97706}{I}}})^2 \htmlClass{eq-term eq-term-permeability eq-term-cyan}{\htmlData{var=permeability}{\textcolor{#0891b2}{\mu_0}}} \htmlClass{eq-term eq-term-pole_area eq-term-amethyst}{\htmlData{var=pole_area}{\textcolor{#9333ea}{A_p}}}}{2 \textcolor{#dc2626}{\htmlClass{eq-term eq-term-air_gap eq-term-rose}{\htmlData{var=air_gap}{\textcolor{#e11d48}{g}}}^2}}

Terms:

Plain English DecoderHover or tap any highlighted phrase

The driving the rejection diverter gate scales with , , , , and the inverse square of the .

F_{\text{mag}}

Magnetic Solenoid Actuation Force

Tractive force accelerating the diverter gate across the conveyor

Newtons (N)[M L T^-2]

The mechanical force developed in the solenoid plunger to deflect defective parts into a rejection bin within milliseconds.

Physical Principle & Engineering Insight

Rapid defect rejection requires high peak tractive forces to overcome mechanical gate inertia before the moving conveyor carries the part past the diverter station.

Historical Context: Lemelson described automated sorting gates actuated by video analysis signals to eliminate human sorting labor.

Horizontal Line Raster Scan DynamicsAuthored Principle 1

Stated relation

f_H = N_L \cdot f_F, \quad T_H = \frac{1}{f_H}

The relationship between the number of horizontal scan lines per frame

N_L

, the frame rate

f_F

, and the horizontal line duration

T_H

. In standard 525-line, 30 fps video,

f_H = 15,750\text{ Hz}

and

T_H = 63.49\ \mu\text{s}

, establishing the microsecond timebase for all dimensional measurements.

Optical Beam Deflection & Scan VelocityAuthored Principle 2

Stated relation

v_{\text{scan}} = \frac{W_{\text{target}}}{T_{\text{active}}}

The linear velocity of the electron beam spot sweeping across the target inspection field. For a 200 mm field of view and 53.33 µs active sweep time,

v_{\text{scan}} \approx 3,750\text{ m/s}

, enabling high-speed optical coverage of the conveyor.

Photometric Video Signal GenerationAuthored Principle 3

Stated relation

V(t) = V_{\text{dark}} + S_V \cdot E_{\text{illum}} \cdot R(x(t))

The instantaneous video voltage produced by the photoconductive camera target as a function of target illuminance

E_{\text{illum}}

, local surface reflectivity

R(x(t))

, and tube responsivity

S_V

Sliced Pulse Duration Dimensional GaugingAuthored Principle 4

Stated relation

L_{\text{meas}} = v_{\text{scan}} \cdot \tau_{\text{pulse}}, \quad \Delta L = |L_{\text{meas}} - L_{\text{nominal}}|

The fundamental equation transforming the temporal duration of a threshold-sliced video pulse

\tau_{\text{pulse}}

into a calibrated physical spatial dimension

L_{\text{meas}}

Electromagnetic Solenoid Tractive ForceAuthored Principle 5

Stated relation

F_{\text{mag}} = \frac{(N \cdot I)^2 \mu_0 A_p}{2 g^2}

The magnetic tractive force generated by the rejection actuator coil as a function of ampere-turns

(N I)

, free-space permeability

\mu_0

, pole face area

A_p

, and stroke air gap

g

Interactive Schematic Sheet (Figure 1A)

Overall block diagram showing the scanning camera, synchronization generator, clipping amplifier, gating circuit, and workpiece conveyor belt.

1.00x

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Why It Still Matters

US 3,081,379 is the historic genesis of automated optical inspection and machine vision. Lemelson's insight—that video cameras are non-contact measurement tools that translate spatial geometry into electronic time waveforms—underpins every automated assembly line, semiconductor wafer inspection tool, bar code reader, and high-speed sorting facility in the modern industrial world. Modern machine vision systems (produced by companies like Cognex, Keyence, Basler, and Teledyne DALSA) use CMOS matrix sensors, telecentric lenses, and FPGA edge detection rather than vacuum vidicon tubes, but the fundamental architecture—synchronized image capture, region-of-interest gating, edge thresholding, template subtraction, and automated rejection feedback—remains identical to the system Lemelson patented in 1963.

Legal Claims Decoder (1 Numbered Claims)

Compare dense legalistic claims directly with decoded plain-English functional specifications.

Claim #1Independent Master Claim

1/1

Verbatim Historical Legal Text

“1. Automatic scanning and control apparatus comprising in combination with an electron beam scanning apparatus including means for causing an electron beam to scan an area of an image field in a single frame sweep along a predetermined path in said field and to produce a video picture signal of said scanning on an output of said apparatus, an analyzing means for inspecting a predetermined area of said image field by the analysis of that portion of the picture signal generated during the scanning by said electron beam of said predetermined area of said image field, said analyzing means including an analyzing circuit connected to a gating means in the output of a circuit in which said picture signal is generated, a variable programming means for controlling said gating means whereby to prevent the passage of said picture signal to said analyzing circuit, said programming means being synchronized in its operation for automatically operating said gating means in predetermined time relation to the generation of said picture signal whereby to switch in a manner to pass to said analyzing circuit only that portion of said picture signal which is generated during the scanning of said predetermined area of said image field.”

Plain English Engineering Translation

Claim 1 defines the complete combination of an electron beam scanning camera that sweeps across an image field to produce an analog video picture signal, an analyzing circuit that inspects a specific zone of that field, a gating circuit placed in the video signal path, and a synchronized programming device that automatically triggers the gate to pass only the specific portion of the video signal generated while the electron beam is scanning that predetermined inspection zone.

Key Protected Innovations:

Electron beam video raster scanning of physical workpieces on production conveyorsSynchronized electronic gating networks isolating predetermined inspection zonesThreshold and waveform analyzing circuits executing automatic quality inspectionDirect conversion of optical image scan waveforms into machine control trigger signals

Historical Legal Impact:

Claim 1 was the primary independent claim asserted across decades of high-stakes patent licensing and litigation in the bar-coding and machine vision industries, ultimately culminating in the landmark Federal Circuit case Symbol Technologies v. Lemelson (2004-2005) on the doctrine of patent prosecution laches.

The Historical Bottleneck

Mid-20th century manufacturing lines moved at high speeds, but quality control and dimensional inspection were bottlenecked by human visual fatigue or crude fixed photocells incapable of measuring complex geometry, identifying printed markings, or detecting localized surface flaws.

Why Prior Art Failed

•Human inspectors could not reliably inspect hundreds of components per minute and suffered from eye strain and inconsistency.
•Fixed photocells and mechanical limit switches could only detect bulk physical presence or gross binary blocking of a single light beam.
•Early optical comparators were static benchtop optical projection instruments requiring manual alignment and manual reticle reading.
•There was no electronic system capable of converting optical image scenes into real-time waveform voltages for synchronous automated sorting.

The Breakthrough Insight

“Lemelson realized that a television camera tube could act as a high-speed non-contact dimensional gauge: by raster-sweeping a focused electron beam at a calibrated velocity across a moving workpiece, optical dimensions in space are transformed into pulse durations in time, allowing microsecond electronic gating circuits and threshold comparators to execute automated metrology and trigger rejection gates.”

Patent Wars & Legal Litigations

Vs. Symbol Technologies, Cognex Corp., and the Machine Vision / Barcode IndustryInfringement Challenge

Rival Claim & Defense:

Industrial barcode scanners and CCD machine vision systems developed in the 1980s and 1990s were independent solid-state inventions that should not be subject to patent infringement claims stemming from 1954/1956 vacuum-tube television camera disclosures.

Litigation Conflict:

Starting in the late 1980s, Jerome Lemelson and his licensing foundation aggressively asserted his 1954/1956 patent continuation portfolio against hundreds of major automotive, electronics, and semiconductor manufacturers, collecting over $1.5 billion in licensing royalties. Symbol Technologies and Cognex filed a landmark declaratory judgment action in federal court challenging the validity and enforceability of the asserted claims.

Final Resolution & Judicial Outcome:

In Symbol Technologies, Inc. v. Lemelson Medical, Education & Research Foundation (2004–2005), the U.S. Court of Appeals for the Federal Circuit ruled that the doctrine of prosecution laches is a valid equitable defense against patent enforceability when an applicant engages in an unreasonable and unexplained delay in prosecuting patent claims.

After the Grant

Lemelson used his patent licensing royalties to fund major educational and philanthropic initiatives, creating the Lemelson-MIT Program, establishing the prestigious Lemelson-MIT Prize for American inventors, and donating millions to the Smithsonian Institution's National Museum of American History.

Civilizational Impact

Lemelson's vision of automated optical inspection laid the technical and conceptual foundations for modern machine vision, industrial robotics quality control, automated barcode sortation, and semiconductor wafer metrology across global manufacturing.