De La Rue Systems Ltd.

De La Rue International Limited

Michael Potter

John Alan Skinner

Peter Dilwyn Evans

Peter Alan Pullan

Barry Clifford Scowen

John Buttifant

David C Reeves

Victor B Chapman

Anthony R Burge

Paul D Lloyd

Derek A Melleney

A method of detecting a coded magnetic thread is provided that includes sensing the response of a magnetic field detector as a thread passes the detector, the response varying from an initial magnitude in first and second senses to exhibit a first peak, and then in the first sense to exhibit a second peak; comparing the response with first and second thresholds disposed about the initial magnitude in the first and second senses respectively; and indicating the passage of a code element of the thread when the response passes the second threshold and then the first threshold in a predetermined manner characterized in that the first threshold is adjusted in accordance with a first predetermined algorithm based on the magnitude of the first peak. The first predetermined algorithm adjusts the first threshold so that the magnitude of the first threshold is the average of a predetermined number of preceding first peaks.

Apparatus for and method of detecting a coded magnetic thread

Systems and methods for identifying a coded magnetic thread comprise generating a digital representation of the thread and comparing the digital representation with one or more known digital representations; scanning the digital representation to locate a predetermined code sequence; and rotating the digital representation to locate the predetermined code sequence in a predetermined position corresponding to the position of the predetermined code sequence in a stored version of the or each known digital representation prior to carrying out the comparison.

Magnetic thread reader

A method of detecting a magnetic thread comprises causing relative movement between the thread and an array of magnetic heads, each head generates a signal upon detecting a portion of the thread. The arrival of a thread at one of the heads is detected, that head being denoted a primary head, and the head on each side a secondary head. Output signals from the primary and secondary heads are monitored to generate a representation of the thread, and the magnitude of the signals from the primary and secondary heads are compared such that if the magnitude of the output signal from a secondary head exceeds that from the primary head, the primary and secondary heads are reallocated accordingly.

A method and apparatus for detecting radiation in a relatively narrow wavelength band within radiation having a wide range of wavelengths. The method comprises detecting radiation in a first wavelength band including the narrow wavelength band and other wavelengths; detecting radiation in a second wavelength band which comprises substantially only the other wavelengths; and comparing the levels of detected radiation to determine the presence of radiation in the narrow wavelength band.

Detector methods and apparatus

A conductive strip detector comprises a capacitor defined by an elongate, electrically conductive element (5) and a laterally spaced, electrically conductive member (1). Monitoring circuitry (15,16) monitors changes in the capacitance of the capacitor when an electrically conductive strip substantially parallel with the element is passed by the capacitor and indicates when a change in capacitance is due to the presence of an electrically conductive strip.

Conductive strip detector

Apparatus for feeding articles, such as banknotes, along a feed path comprises first and second separately driven feed systems the second feed system being operated at a substantially constant speed. The first feed system feeds articles to the second feed system. A sensing system includes a sensor for sensing the passage of articles. The sensor is connected to a motor control system which controls the feed rate of the first feed system by controlling a motor of the first feed system so that the separation between successive articles passing through the second feed system satisfies at least one predetermined condition.

Method and apparatus for feeding articles

A thread detector assembly for detecting an activated, elongate thread which is integral with a sheet comprises an elongate detector or set of detectors. A conveyor is provided to cause relative movement between a sheet and a detector. The detector or detectors extend at an acute angle to the thread in use whereby the thread is presented successively to different parts of the detector or detectors.

Thread detector assembly

Holes, tears and missing portions in a sheet, such as a banknote, are detected. The sheet is irradiated with radiation so that the radiation passes through the sheet with a relatively low degree of attenuation in areas where holes, tears and missing portions do not exist and with a relatively high degree of attenuation in areas where holes, tears and missing portions exist. The attenuated radiation is retroreflective back through the sheet and is then received by appropriate photodetectors. Since the sheet is relatively opaque and the radiation passes through the same points in the sheet twice, the contrast between the received radiation having passed through the holes, tears and missing portions and the received radiation passing through the relatively opaque sheet is very high making it simple to differentiate between those areas and thereby to positively detect holes, tears and missing portions in the sheet.

Sheet inspection method and apparatus having retroreflecting means

Methods are apparatus for monitoring the diffuse reflectivity of a

Luminescent security features in or on documents are detected using a detector comprising a fibre optic light guide arranged to transmit an interrogation beam originating from a source onto a document to be tested; and a housing in which a photo-diode array is mounted to receive luminescence emitted from the document. The photo-diode array is connected to electronic circuitry for discriminating between luminescence due to a security feature and other luminescence emitted by the document and for determining that a security feature has been detected.

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Hampshire, United Kingdom

Michael Potter