Abstract:
A single method and apparatus for producing many of the most common types of hologram from digital data is disclosed. The data are generated entirely by a computer as a 3-D (animated) model or from multiple 2-D camera images taken of a real 3-D(moving) object or scene from a plurality of different camera positions. The data are digitally processed and displayed on a small high resolution spatial light modulator (SLM). A compact low energy pulsed laser is used to record composite holograms. The present invention permits the creation of restricted or full parallax master transmission or reflection type composite holograms, known as H1 holograms, that can be copied using traditional methods. Alternatively the same invention and apparatus permits the direct writing of holograms without the need to pass through the intermediate stage of the H1 transmission hologram.
Abstract:
When a master hologram is formed, a diffusing screen image is made an object light beam and outputted onto a first recording surface (12) through a lens (8'). When a slave hologram is formed, a second recording surface (12'') is placed in a position where the object light beam is focused by the lens (8'). The distance between the diffusing screen (7') and the first recording surface (12) of when the master hologram (12') is formed can be different from the distance between the master hologram (12') and the second recording surface (12'') of when the slave hologram (12'') is formed. Therefore, as necessary, the distances are made different from each other, and thereby a hologram can be formed by means of a small optical system.
Abstract:
We describe a method of fabricating a stereoscopic hologram of an object, the method comprising: capturing a sequence of two-dimensional images of the object by replaying said captured sequence of images one at a time using coherent light to reproduce said sequence of captured images on a diffusing screen; recording a first volume hologram during said replaying of said captured sequence of images; replaying said first volume hologram to replay together said images recorded in said different spatial locations on said surface of said first volume hologram and recording a second, volume reflection hologram of said replayed stereoscopic image of said object replayed by said first volume hologram to provide said stereoscopic hologram of said object.
Abstract:
A hologram duplicating device (10) comprising a first optical system (30) for fabricating an original (H1) by recording a holographic stereogram image on a recording medium for hologram by exposure, a second optical system (60) for fabricating an intermediate hologram (H2) by recording the image recorded on the original (H1) on a recording medium for hologram disposed at a predetermined distance from the original (H1) by exposure by using a diffracted light produced by illuminating the original (H1), and a third optical system (70) for fabricating an edge-lit hologram by recording the image recorded in the intermediate hologram (H2) on a recording medium for hologram disposed at a predetermined distance from the intermediate hologram (H2) by exposure by using a diffracted light produced by illuminating the intermediate hologram (H2).
Abstract:
A direct write holographic printer for producing RGB colour reflection holograms is disclosed. A Nd:YLF crystal (1) in a laser cavity is excited to produce an emission at 1313 nm which is frequency converted by doubling to 656.5 nm and by tripling to 437.7 nm. In a separate cavity a similar Nd:YLF crystal (1a) is synchronously or asynchronously excited to produce an emission at 1047.1 nm (or at the related line of 1053 nm) which is frequency converted by doubling to 523.6 nm (or 526.5 nm). The emissions at 437.7 nm and 656.5 nm are combined co-linearly with the emission at 523.6 nm (or 526.5 nm) to produce a single RGB pulsed laser beam.
Abstract:
A composite hologram comprises a plurality of hologram tiles (48, 50) arranged for display, each of said hologram tiles formed by exposing each of a plurality of different unexposed photographic plates simultaneously to light scattered by an intermediate hologram (H1) using a conjugate complex (R*1) of a first reference wave from a coherent light source and to a second reference wave (R2) from said coherent light source.
Abstract:
L'invention concerne un procédé de génération numérique d'un hologramme dans un plan, dit plan de l'hologramme, à partir d'une scène tridimensionnelle, comprenant une étape de découpage de ladite scène en une pluralité de plans parallèles au plan de l'hologramme. Leprocédé comprend les étapes suivantes, mises en œuvre pour un plan de la pluralité de plans, dit plan courant, les plans étant parcourus du plus éloigné au plus proche du plan de l'hologramme: -comptage d'un nombre de points de la scène d'amplitude non nulle dans le plan courant; -choix d'une première ou d'une deuxième technique de propagation d'une onde lumineuse émise par le plan courant en fonction d'un nombre de points d'amplitude non nulle de la portion de scène comprise dans le plan courant et d'une valeur de seuil prédéterminée, la première technique, dite basée points, destinées à calculer la propagation d'une somme d'ondes lumineuses émises par des sources ponctuelles constituées par les points de la portion de scène d'amplitude non nulle du plan courant sur un plan suivant, la deuxième technique, dite basée champ, destinée à calculer globalement la propagation d'un champ lumineux émis par la portion de scène comprise dans le plan courant sur un plan suivant; -traitement du plan courant en fonction de la technique de propagation choisie, destiné à calculer une onde lumineuse émise par le plan courant; lesdites étapes étant répétées pour la pluralité de plans, et leprocédé comprend en outre une étape d'obtention de l'hologramme à partir des ondes lumineuses calculées pour la pluralité de plans.
Abstract:
A pulsed multiple colour laser system is disclosed having particular application for incorporation into a digital holographic printer for producing RGB colour reflection holograms. A Nd:YLF crystal (1) in a laser cavity is excited to produce an emission at (1313) nm which is frequency converted by doubling to 656.3 nm and by tripling to 437.7 nm. In a separate cavity a similar Nd:YLF crystal (1a) is synchronously or asynchronously excited to produce an emission at 1047.1 nm (or at the related line of 1053 nm) which is frequency converted by doubling to 523.6 nm (or 526.5 m). The emissions at 437.7 nm and 656.5 nm are combined co-linearly with the emission at 523.6 nm (or 526.5 nm) to produce a single RGB pulsed laser beam.
Abstract:
A single method and apparatus for producing many of the most common types of hologram from digital data is disclosed. In one embodiment the data are generated entirely by a computer as a 3-D (animated) model. In another embodiment the data are generated from multiple 2-D camera images taken of a real 3-D (moving) object or scene from a plurality of different camera positions. The data are digitally processed and displayed on a small high resolution spatial light modulator (SLM). A compact low energy pulsed laser, which avoids the usual vibration problems encountered at high rates of production and the installation in normal working environments, is used to record composite holograms on an holographic emulsion using a special optical design. The present invention permits the creation of restricted or full parallax master transmission or reflection type composite holograms, known as H1 holograms, that can be copied using traditional methods to produce full or single colour rainbow white-light transmission holograms, achromatic white-light transmission holograms or single or full-colour white-light reflection holograms. Alternatively the same invention and apparatus permits the direct writing of full or single colour rainbow white-light transmission composite holograms, achromatic white-light transmission composite holograms or single or full-colour white-light reflection composite holograms without the need to pass through the intermediate stage of the H1 transmission hologram. The present invention allows the creation of a compact rugged machine that is capable of producing holograms covering a large size range. In addition the invention produces holograms that can be tiled together to form composite holograms much larger than the component panels.