WO2022171413A1 - Lentille pannini et dispositif optique d'imagerie - Google Patents

Lentille pannini et dispositif optique d'imagerie Download PDF

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WO2022171413A1
WO2022171413A1 PCT/EP2022/051182 EP2022051182W WO2022171413A1 WO 2022171413 A1 WO2022171413 A1 WO 2022171413A1 EP 2022051182 W EP2022051182 W EP 2022051182W WO 2022171413 A1 WO2022171413 A1 WO 2022171413A1
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lens
image
pannini
optical device
imaging optical
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PCT/EP2022/051182
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German (de)
English (en)
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Vladan Blahnik
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Carl Zeiss Ag
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Publication of WO2022171413A1 publication Critical patent/WO2022171413A1/fr

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/08—Anamorphotic objectives
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/06—Panoramic objectives; So-called "sky lenses" including panoramic objectives having reflecting surfaces

Definitions

  • the invention relates to a lens, an imaging optical device, a mobile terminal device and a set comprising a lens or an imaging optical device and instructions for use.
  • the ideal mapping is the rectilinear projection onto a plane, also known as gnomonic projection.
  • a rectilinear projection is a central projection where the projection center is at the center of the body to be imaged. It corresponds to the imaging of a pinhole camera, i. H. each point of the 3-dimensional object space is mapped onto a plane called the image plane along a straight line through the hole that forms the perspective center PC of the projection.
  • the normal of the image plane passing through the perspective center PC is defined as the optical axis z.
  • the angle q between the optical axis z and the light ray from the object point Ob through the perspective center PC is called the object angle.
  • the distance between the perspective center PC and the image plane along the optical axis z is denoted by f. If the hole is replaced by a simple, limited lens, then f corresponds to the focal length of the lens if these object points are sharply imaged onto the image plane at an infinitely large distance.
  • the rectilinear projection depicts straight lines as a straight line in the image plane, regardless of their position and orientation in the object space. It leads to the well-known laws of central perspective: parallel lines all meet at the horizon on the line of the eye in a single vanishing point. In a perpendicular to On the plane positioned in the projection axis, all straight lines are mapped identically, in particular horizontal and vertical lines remain horizontal and vertical. Deviations from this projection are referred to as distortion. Camera lenses should generally be distortion-free.
  • a rectilinear perspective is very disadvantageous.
  • people appear fatter at the edges of the image, and their heads are shown as egg-shaped deformed.
  • This distortion of three-dimensional objects is referred to as rectilinear perspective distortion, sometimes referred to as elliptical distortion to match the depiction of eggheads.
  • the reason for the rectilinear perspective distortion is that the rectilinear projection of 3-dimensional objects becomes progressively wider towards the edge of the field in the radial direction.
  • Important painters used perspective as a stylistic device for composition, such as Leonardo da Vinci in “The Last Supper”.
  • Important Italian vedute painters such as Piranesi or Canaletto, deliberately deviated from the central perspective in some paintings.
  • Canaletto used a camera obscura to realistically depict spatial perspective, but deliberately modified the proportions to emphasize central image content.
  • St. Mark's Square in Venice, the side buildings follow separate vanishing points. Perspectively correct, they run towards the same eye line as the vanishing lines (floor slabs) of the central St. Mark's Square, so that the violation of the central perspective remains unnoticeable to the viewer.
  • the side buildings are more pointed towards the vanishing point than St. Mark's Square, so that a greater spatial depth is suggested to the viewer.
  • the long facade of the buildings is rendered compressed and the buildings in the far center, St. Mark's Basilica and St. Mark's Tower, appear relatively enlarged.
  • Pannini depicted survive, Sharpless et al. determine the selected perspective projection via reverse engineering, with the result that Pannini generally chose the rectilinear projection in the vertical direction and another one in the horizontal direction, which compresses the image content towards the edge of the image.
  • the analysis showed that the projection in the horizontal direction was not chosen uniformly in different paintings, in some approximately stereographic, in others more cylindrical.
  • FIG. 1 shows the definition of the coordinates used for this, the coordinates having been adapted to the general conventions of geometric optics, ie the optical axis is denoted by z, the horizontal direction by x and the vertical direction by y.
  • parameters of the optical system can be introduced: If the light comes from infinity, the parameter f ' , the image-side focal length, is sufficient.
  • the object point Ob is located in a y-tangential plane that runs through the y-axis and in the x-z plane encloses an angle f between the y-tangential plane and the z-axis, ie the optical axis. From Ob, a ray, the object ray s, meets the coordinate origin 0 at the angle q to the optical axis. It should be noted that the object-side angle or object angle q of the ray is defined “skew” to the optical axis z and not in the y-tangent plane lies.
  • the three-dimensional space is mapped onto a sphere, the panosphere, along the rays to the perspective center PC.
  • the meeting point of the object ray s with the panosphere is P. Since all object rays run normal to the panosphere through the coordinate origin 0, there is a clear assignment of Ob to P.
  • This panosphere in object space can be thought of as transformed (mirrored, ie with the opposite sign) directly in front of the image surface (x ' ,y ' ), which is usually an image plane.
  • the position of the perspective center PC can be parameterized with d, the distance from the perspective center PC to the coordinate origin 0.
  • the perspective center PC is the center of the entrance pupil, ie the point of intersection of the optical axis z with the entrance pupil.
  • v ' is the vertical image coordinate and h ' is the horizontal image coordinate.
  • the image coordinates are normalized with the focal length G.
  • the horizontal image coordinate h ' is in the value range [-h ' max, +h ' max].
  • the entire image field thus has the "image width 2 * h ' max.
  • Equation IV The parameterization by Sharpless et al. can be generalized.
  • a projection of the object space referred to in the following as “Pannini mapping” or “Pannini perspective”, is characterized by the following features:
  • the center of the image is not distorted.
  • the focal length or image scale are the same in the center of the image.
  • the object space is barrel-shaped in the horizontal direction compared to the rectilinear mapping, i.e. H. the deviation from the gnomonic image location increases monotonically in the horizontal direction.
  • this definition also contains, for example, the cylindrical perspective, according to which x is proportional to q in the horizontal direction (“f-O mapping”) and rectilinear in the vertical direction.
  • anamorphic imaging which is widespread in professional film: with anamorphic imaging, similar to Pannini imaging, an object field of different sizes is used in the horizontal and vertical direction on the image sensor (same geometry). However, this is achieved by choosing different focal lengths or imaging scales in the horizontal and vertical directions. This makes, in contrast to the optical pannini imaging, a two-step process is necessary to compensate for the deformation of the image when it is reproduced.
  • Pannini mapping characterizes the compression of the image information in the horizontal direction (in the case of conformal mapping of straight lines in the vertical direction). This is not the case with anamorphic imaging.
  • the barrel distortion, usually in both horizontal and vertical directions, in some patented and commercially available wide-angle anamorphic lenses is a result of a simple design principle.
  • the anamorphic image does not meet the above mentioned.
  • Features 1st and 3rd of the Pannini illustration Nevertheless, there is a similarity between Pannini imaging and anamorphic imaging, which should be mentioned here because it is very popular in cinematography with anamorphic lenses and is partly the reason for its use, despite the considerable additional costs.
  • Defocused highlights in the image background appear oval in anamorphic imaging. For example, lights have Streetlights, for example, have a “candle-like” shape, which many filmmakers appreciate, as well as the fact that changing the focal plane has the dynamic effect of vertically “pulling” the sharpness.
  • panomorph lenses particularly as an alternative to circular fish-eye lenses that image the entire hemisphere onto the image plane.
  • panomorph lenses particularly as an alternative to circular fish-eye lenses that image the entire hemisphere onto the image plane.
  • image sensors are usually rectangular, they can therefore be better utilized.
  • These lenses use cylindrical or toric lenses.
  • the figure differs fundamentally from the Pannini figure - vertical lines neither remain straight nor is the horizontal figure barrel-shaped. Rather the opposite is the case.
  • the local image scale increases towards the horizontal edge of the image, so that the unfavorable perspective image becomes even stronger. Consequently, the above features 2. and 3. of the Pannini figure are not fulfilled.
  • a basic idea of the invention is to implement the recording and playback in Pannini perspective with purely optical means, ie without the need for digital transformation.
  • a first aspect of the invention relates to an objective.
  • the lens can be used, for example, as a lens for a camera, e.g. B. a film camera or a photo camera, or be designed as a lens for a projection device.
  • the lens has image-forming optical elements with one or more non-rotationally symmetrical curved surfaces, which are arranged along an optical axis.
  • the lens can be designed in particular as a wide-angle lens, z. B. with a diagonal angle of view of 60 ° and larger, preferably 75 ° and larger, more preferably 85 ° and larger.
  • the lens can also be designed as a zoom lens.
  • the image-forming optical elements are designed and arranged in such a way that an image to be formed on an image surface is a Pannini image.
  • a Pannini map is characterized by the following features: equal magnification at image center along every direction in the image plane (feature 1), straight vertical mapping of straight vertical lines across the entire image field (feature 2), and barrel distortion of object space in the horizontal direction (Feature 3).
  • the "centre of the image” means the area on the image surface in the immediate vicinity of the optical axis.
  • Feature 1 requires that the focal length of the lens in the area of the rays that generate the center of the image is also the same in the x and y directions. Due to the same magnification in the center of the image, the center of the image is not distorted. Minor deviations, i. H. Deviations that are imperceptible to the viewer are permissible. Such minor deviations can, for example, amount to a maximum of 15%, i. H. the compression or stretching factor in the center of the image may deviate from the ideal “no distortion” by a maximum of 15%.
  • Feature 2 means that vertical straight lines are imaged as straight vertical lines over the entire field of view. Minor deviations, ie deviations that are imperceptible to the viewer, are also permitted here. Such minor deviations can amount to a maximum of 5%, for example.
  • the deviation of 5% refers to the so-called "TV distortion", which describes the crookedness of a desired straight line.
  • TV distortion is defined as the change in the distance from the center of the picture to the top of the picture divided by the distance from the bottom of the picture to the top of the picture. It will i.e. measured how much the image is bent by a straight line at the edge of the image, especially at the long edge of a rectangular format. This deflection is related to the total image height and expressed as a percentage.
  • Feature 3 means that the image space is barrel-wrapped in the horizontal direction compared to the rectilinear mapping, i. H. the deviation from the gnomonic image location increases monotonically in the horizontal direction. Since the deviation can be expressed as a 3rd order polynomial, this means that the deviations increase towards the vertical edge of the image. In other words, the image information is increasingly squeezed in the direction of the vertical edge of the image, i. H. wide areas are mapped narrower.
  • the Pannini image can be placed on an arbitrarily shaped image surface, for example a flat image surface, e.g. B. on a flat surface of an image sensor in the case of a film or photo camera or a flat projection surface in the case of a projection lens.
  • a flat image surface e.g. B. on a flat surface of an image sensor in the case of a film or photo camera or a flat projection surface in the case of a projection lens.
  • Other forms of the picture surface e.g. B. cylindrical or toric image surfaces can also be used.
  • the design and arrangement of the image-forming optical elements is carried out in such a way that a Pannini image can be generated on the selected image area.
  • the lens according to the invention is characterized in that a Pannini image with features 1 to 3 can be generated directly using exclusively optical means. Such a lens is also referred to below as a Pannini lens. Thus, no digital transformation of the image is required, nor are multiple optical systems required to generate the Pannini image.
  • Pannini lens in a smartphone camera, an action video camera (action cam), as a camera lens for a reflex camera or a mirrorless system camera, as a camera lens in professional cinematography, as a projection lens, etc.
  • action cam action video camera
  • existing lenses with To modify attachment or back adapter optics in such a way that a Pannini lens is obtained, so that consequently the selection and arrangement of the additional image-forming optical elements is dependent on the existing lens.
  • Another field of application includes afocal systems, ie binoculars, spotting scopes, telescopes, etc.
  • afocal systems ie binoculars, spotting scopes, telescopes, etc.
  • a Pannini lens for such an afocal system has a significantly different structure than a Pannini lens for a photo or film camera. Consequently, the specific structure of the Pannini lens is highly dependent on the desired application.
  • one or more non-rotationally symmetrical acting optical elements are necessary in order to be able to influence the beam path differently in different areas and thereby, inter alia, the desired one to achieve distortion.
  • optical elements that act in a rotationally symmetrical manner can also be present.
  • Optical elements that act non-rotationally symmetrical can either actually be non-rotationally symmetrical optical elements that are positioned in such a way along the optical axis, e.g. B. are arranged perpendicular to the optical axis, that the non-rotational symmetry is not z. B. is canceled by tilting, or it can be rotationally symmetrical optical elements that are arranged along the optical axis in such a way that they still do not appear rotationally symmetrical, for example by tilting relative to the optical axis.
  • cylindrically curved, toric surfaces or free-form surfaces can be used as non-rotationally symmetrical curved surfaces.
  • optical elements of the lens can have optically effective surfaces that act as lenses (refraction) or mirrors (reflection).
  • optical elements can also be implemented as diffractive elements (diffraction). The latter also includes optical meta surfaces.
  • Optically active surfaces can preferably be used which are symmetrical to the x-axis and to the y-axis of the lens, e.g. B. cylindrically curved surfaces, toroidal surfaces or correspondingly designed free-form surfaces.
  • the “x-axis” is to be understood as meaning the axis aligned in the horizontal direction at a right angle to the z-axis, which corresponds to the optical axis.
  • the “y-axis” means the axis oriented in the vertical direction at right angles to the z-axis.
  • Cylindrically curved surfaces are characterized by a radius (either rx or ry), which can be positive or negative, convex or concave. The other radius is infinite.
  • a cylindrically curved surface corresponds to a section of a lateral surface of a vertical circular cylinder.
  • a "toric surface” is a surface that has two mutually perpendicular principal sections of different curvature and in which the cross-sections in both principal sections are nominally circular. We are therefore dealing with symmetrical surfaces whose two surface radii can be finitely large and have any sign.
  • the toric surface shape also includes a rotationally symmetrical asphere on the toric surface. This is usually given by a conic constant k and a set of polynomial coefficients a4, a6,...
  • the asphere In the case of free-form surfaces, the asphere is generally not rotationally symmetrical.
  • a “freeform surface” is to be understood in a broader sense as a complex surface that can be represented in particular by means of functions defined in certain areas, in particular functions defined in different areas that can be continuously differentiated twice.
  • suitable region-wise defined functions are (particularly piecewise) polynomial functions (particularly polynomial splines, such as bicubic splines, fourth-degree or higher degree splines, or polynomial non-uniform rational B-splines (NURBS)).
  • Fliervon are to be distinguished from simple surfaces, such as e.g. B. spherical surfaces, aspherical surfaces, cylindrical surfaces, toric surfaces, which are described at least along a main meridian as a circle.
  • a free-form surface does not need to have axial symmetry and point symmetry and can have different values for the mean surface refractive index in different areas of the surface.
  • a free-form surface is usually produced on an optical element by machining the optical element, for example by milling, as part of a CNC process in which the free-form surface is produced under numerical control on the basis of a mathematical description of the surface.
  • the negative press mold must be processed with the appropriate allowances for temperature-dependent shrinkage using CNC processes.
  • the optical system that is to say all of the image-forming optical elements, can be arranged along a single optical axis.
  • the Surface geometry applies in particular to the shape of the surface, i.e. the deformation of the surface, but can also have an advantageous effect if the optical surface has a correspondingly symmetrical boundary.
  • separate field diaphragms with symmetry about the x and y axes can have an advantageous effect. Boundaries of optical surfaces or field stops cut off the light beam of an object point. This is called “vignetting" and reduces optical artifacts.
  • the desired barrel distortion can be achieved, for example, using the lens configuration aperture stop, +", i. H. with a configuration in which the object-side lens part has a negative refractive power and the image-side lens part has a positive refractive power, the object-side and image-side lens parts being separated from one another by the aperture stop.
  • the distortion coefficient is of the 3rd order
  • Equation VI with h object (image) height, n, n ' refractive indices of the media at the interface, i ray incidence angle at the interface, u ray angle to the optical axis, hk ' the refractive index between the last optical surface and the image surface and Uk ' the corresponding ray angle to the optical one Axis between last optical surface and image surface and w ray height at the interface to the optical axis.
  • the index “p” designates the principal ray that runs through the center of the pupil; the corresponding non-indexed quantities, the axial tuft marginal ray (see Warren Smith (1993), Modern Lens Design, McGraw-Hill, pp. 447 and 448). From this expression it follows that a single positive lens (of any shape) behind the aperture will result in barrel distortion, just like a negative lens in front of the aperture. Consequently, a negative lens, then aperture, then positive lens configuration also results in barrel distortion.
  • the focal lengths in x and y are equal, or for finite object distances the image scales,
  • the refractive power of the arrangement in the horizontal direction must be more negative at the front, i.e. close to the object, and more positive at the back, i.e. close to the image.
  • the near-field lenses in front and behind the rectilinear direction become more front-diverging and rear-converging in the barrel deformed direction.
  • a Pannini lens with at least two non-rotationally symmetrical optical components e.g. B. cylindrical or toric lenses required. Otherwise, the focal length at the center of the image would be unequal in the horizontal and vertical directions, because changing a single component power without changing distances between the components (which are the same in both slices x and y) also changes the total power.
  • the total refractive power f 1/G for the entire Lens
  • Equation VII be equal.
  • the distance between the main levels of the two subsystems is denoted by dHE.
  • this distance dHE is the same for the x and y components, so that the following must apply:
  • the distortion is corrected by the quasi-symmetrical structure of the lens, in the horizontal direction, on the other hand, the desired distortion of the near stereographic perspective can be achieved through a retrofocus structure.
  • a spherically curved field of view with the center of curvature facing the lens, can significantly reduce complexity, particularly for the wider aperture lenses mentioned.
  • almost concentric lenses made up of a few spherical elements an image that is as good as that achieved with lenses with more than a dozen lenses or aspheric lenses for imaging on one plane.
  • a comparatively simple lens structure can also be used when using non-flat image areas such.
  • B. cylindrically curved image surfaces can be achieved. It is to be expected that cylindrically curved image surfaces, e.g. B. image sensors, are much easier to implement than spherically curved.
  • a problem with spherically curved image sensors is that the uniform curvature on a square pixel grid causes different shearing forces on the grid elements, since the orientation of the individual pixels to the surface curvature varies. This is different with a cylindrically curved image sensor, since the same forces act homogeneously in each x or y direction.
  • Pannini images on cylindrically curved image surfaces with a very large field of view angle in the order of magnitude of the entire hemisphere, in contrast to rotationally symmetrical fisheye images on rotationally symmetrically curved image surfaces.
  • a Pannini image can already be generated with two toric elements as long as the aperture is not very large (focal ratio f/8 or smaller). It is also possible to realize a Pannini image with only two toric elements if the aperture is relatively large but the field of view angle is not very large.
  • Pannini lenses with three toric elements significantly more degrees of freedom are opened up to Pannini lenses for both large field of view angles and for large to get apertures.
  • the light paths in the lens pass through the lens elements at significantly different heights.
  • this also enables the correction of other image errors, such as e.g. B. the transverse chromatic aberration.
  • the transverse chromatic aberration For example, by choosing an entrance pupil position for the stereographic imaging direction with a strongly curved front lens closer to the objective entrance, the light can pass through the lens at a lower height and produce a transverse chromatic aberration comparable to that in the vertical direction.
  • a general procedure for achieving the desired barrel-shaped distortion in the horizontal direction is based on the knowledge that bundles of rays must be able to be influenced independently of one another. Elements close to the field are primarily influenced here, while elements close to the pupil are of little importance.
  • Optical surfaces that have a subaperture ratio between greater than 0.5 and 1, in particular between 0.7 and 1, are referred to as “near the pupil”.
  • optical surfaces that are “near the field” have a subaperture ratio of between 0 and 0.5, in particular between 0 and 0.3.
  • the subaperture diameter DSA is the maximum diameter of a partial area of the optical element that is illuminated with rays of a beam bundle emanating from a given field point.
  • the optically free diameter DCA is the diameter of the smallest circle around a reference axis of the optical element, the circle enclosing that area of the surface of the optical element that is illuminated by all rays coming from the object field.
  • the geometry and arrangement of elements close to the field in particular can be varied in order to obtain a Pannini image.
  • the effect of free-form surfaces is all the more effective the smaller the associated sub-aperture diameter DSA is.
  • the numerical assignments can be specified using exemplary data for focal length and image length where the object angles are specified in degrees. Since the image coordinates, e.g. B. positions on the image sensor, are given in the calculation, the object angles are required as a function of the image coordinates. For the horizontal coordinate we get
  • Equation XI This results in the vertical component with
  • Equation XIII the explicit angles result as a function of the image coordinates (h', v') after replacing Equation V
  • Equation XIV Equation XIV:
  • Equation XV Equation XV:
  • Tables 1 and 2 below list the resulting angles for various h-values and v-values.
  • Table 1 b Vertical angles in rectilinear projection, rotationally symmetrical,
  • a rectilinear perspective results, i.e. the same allocation of object angle to image height.
  • the same object angle of 38.7° to the optical axis results at the maximum height.
  • the resulting angles can be calculated accordingly for other focal lengths and image widths.
  • object angles and image positions are assigned, but the object position (e.g. beam passage on the plane in front of the lens entrance) is free.
  • object pupil point of intersection
  • a (generally slight) parallax of the principal rays is thus permissible, which means that the entrance pupil is not a point but is spatially distributed. This is particularly common with fisheye lenses.
  • the optimization of the concrete lens design can be carried out with standard optical design programs, such as e.g. B. Code-V, Zemax Optio Studio, OSLO, where the direction cosines as well as other equivalent ray angles can be entered as indicated and set as boundary conditions.
  • standard optical design programs such as e.g. B. Code-V, Zemax Optio Studio, OSLO, where the direction cosines as well as other equivalent ray angles can be entered as indicated and set as boundary conditions.
  • Pannini lens can be used in a variety of applications, e.g. B. in cinematography, DSLR photography (DSLR, English, digital single lens reflex), CSC photography (CSC, English, compact system camera), in action cams, in photography with mobile devices and the corresponding projection applications.
  • DSLR digital single lens reflex
  • CSC compact system camera
  • action cams in photography with mobile devices and the corresponding projection applications.
  • Pannini lens can be combined with a suitable digital transformation, for example for distortion correction, warping, etc., so that specific image quality requirements, e.g. B. in terms of resolution, contrast, chromatic aberrations, etc., can be maintained in the image field.
  • a suitable digital transformation for example for distortion correction, warping, etc.
  • the purely optical implementation of the Pannini perspective in the form of the lens described offers advantages over a digital-optical solution, which become greater the wider the recorded area is.
  • a digital-optical solution which become greater the wider the recorded area is.
  • the initially rectangular image section is distributed over a large star-shaped area, so that when it is cropped rectangularly, e.g. B. for viewing on a monitor, a large part of the recorded image information is lost, the entire image information is retained.
  • a high resolution of object details can also be achieved at the edge of the image, with the contrast being retained. Consequently, an image field with little variation in resolution as well as contrast can be obtained.
  • the lens can have a field stop, the shape of which deviates from a circular shape and a rectangular shape.
  • a field stop the shape of which deviates from a circular shape and a rectangular shape.
  • the use of field stops is essential for photographic lenses, especially for interchangeable lenses for larger image formats, e.g. B. 36 x 24 mm 2 .
  • the beams of rays towards the edge of the field are increasingly cut off by the field stop. This makes it much easier to correct the image errors.
  • field pruning is accompanied by a reduction in irradiance.
  • the irradiance should be checked for each pixel.
  • Typical specifications of permitted variations in irradiance in the image with wide-angle lenses are 2 to 3 f-stops (EV), i.e. a factor of 25% or slightly less compared to the center of the image. If the differences in luminosity are greater, this is often perceived as annoying, especially with evenly bright subjects.
  • the edge light drop is often digitally compensated. But then the noise at the edge of the field is higher than in the middle of the image.
  • FIG. 13 shows footprint distributions of a Pannini lens in different planes. In the area close to the field, the area is angular, but generally not rectangular, whereas in the area close to the pupil it is circular (if a circular pupil is selected). FIG. 13 shows the footprints in specific planes and makes it clear that the field stops would have the shape indicated in each case.
  • Such more complex shapes can be advantageous for minimal design sizes as well as a defined influence on the light fall-off in the image field. They deviate from the rectangular or circular shape.
  • the field stop is not flat but three-dimensional in shape, further advantageous with four sectors of the same shape, i.e. xy-sym metric. This means that the optimal position of the field stop in the z-direction can deviate in the x-direction from the y-direction.
  • a corresponding three-dimensional shape is therefore often advantageous for a uniform irradiance, but not absolutely necessary.
  • the image-forming optical elements can be designed and arranged in such a way that the image to be formed can be formed on a flat image surface, i. H. the Pannini image is generated on a flat image surface.
  • Pannini lens can thus be used advantageously together with already existing components of an imaging optical device.
  • the image-forming optical elements can be designed and arranged in such a way that the image to be formed can be formed on a cylindrically curved image surface, i. H. the Pannini image is generated on a cylindrically curved image surface.
  • the lens can be a camera lens or a projection lens.
  • the camera lens can be used, for example, for a photo camera, ie as a photo lens, or for a film camera, ie as a film lens. Combined use is also possible. Other applications, e.g. B. in the areas of observation, measurement, qualification, quantification are possible.
  • the projection lens can be used accordingly for a projection device.
  • the light path is reversed.
  • the object to be imaged e.g. B. a self-illuminating OLED display, an illuminated slide, etc.
  • the projection surface takes the place of the object plane.
  • the projection surface can be curved towards the viewer, for example, and can therefore have the advantages of a domed cinema.
  • the formation of the lens as a camera or projection lens advantageously enables the recording or reproduction of Pannini images.
  • the lens can be an attachment lens or a back adapter lens.
  • the lens can be designed as an optical system that is used before (attachment lens) or after (back adapter lens) another lens and z. B. changed the focal length or imaging properties of this other lens.
  • the Pannini image is generated by combining both lenses.
  • the specific design and arrangement of the image-forming optical elements depends on the structure and the properties of the further objective.
  • the lens Due to the design of the lens as an attachment lens or back adapter lens, existing lenses can be used flexibly, i. H. with and without an attachment lens or back adapter lens to create Pannini images or other images.
  • a further aspect of the invention relates to an imaging optical device with an objective as described above.
  • the imaging optical device can be used, for example, as a camera, e.g. B. as a photo camera or film camera, be designed, the camera can have, for example, a flat or cylindrically curved image surface.
  • the camera has an image sensor, preferably a full-frame image sensor.
  • the imaging optical device can also be a projection device, a telescope, binoculars, a microscope, etc.
  • a projection device has a light source in addition to the projection objective.
  • a further aspect of the invention relates to a mobile terminal device with an imaging optical device as described above.
  • the mobile end device can be in the form of a smartphone, tablet, smartwatch, data glasses, etc., for example.
  • the mobile terminal device can have an imaging optical device designed as a camera.
  • Imaging optical device and the associated lens can be transferred accordingly to the mobile terminal device.
  • the advantages of the imaging optical device and the associated objective are correspondingly connected to the mobile terminal device. Another advantage is that by implementing the lens in a mobile device, Pannini images can also be generated on the go.
  • a further aspect of the invention relates to a so-called kit-of-parts, namely a set which, firstly, includes a lens as described above or an imaging optical device as described above, and, secondly, an instruction manual with instructions for using the Specify the lens or the imaging optical device with a flat or curved image surface, includes.
  • the instructions for use can be designed, for example, in the form of a pictogram or instructions in text form. It defines the use of the lens or the imaging optical device with either a flat or a curved image surface, e.g. B. a cylindrically curved image surface.
  • lens and the imaging optical device can be transferred to the set accordingly. With the set, the advantages of the lens or the imaging optical device are connected accordingly.
  • FIG. 2a shows a first exemplary lens (X-section);
  • 3a shows a second exemplary lens (X-section).
  • 3b shows the second exemplary lens (Y section);
  • FIG. 4a shows a third exemplary lens (X-section).
  • 5a shows a fourth exemplary lens (X-section).
  • 5b shows the fourth exemplary lens (Y-section).
  • 6a shows a fifth exemplary lens (X-section).
  • FIG. 7a shows a sixth exemplary lens (X-section).
  • FIG. 10 is a schematic representation of an exemplary imaging optical device
  • FIG. 11 shows a schematic representation of an exemplary mobile terminal device
  • Fig. 13 Footprints over the field of view in different lens planes.
  • FIG. 1 serves to illustrate the coordinates for describing the Pannini projection. In this regard, reference is made to the explanations in the introductory description.
  • FIGS. 2a and 2b show the lens 1 of a first exemplary embodiment with a focusing setting at infinity.
  • This first exemplary embodiment is a lens 1 designed as a compact wide-angle lens for mirrorless cameras for forming a rectilinear-stereographic Pannini image in a format of 36 ⁇ 24 mm 2 .
  • the lens 1 is very short with a length of 33.4 mm.
  • the ratio of overall length to sensor diagonal is only 0.77.
  • the objective 1 has five toric lenses (without aspheric orders) as image-forming optical elements 2 .
  • the focal length on the image side is 11.6 mm. This makes it possible to use this lens 1 as an interchangeable lens on certain mirrorless cameras.
  • the basic design data of the lens 1 of the first exemplary embodiment are given in Table 5 below, with the tolerance range of the specified values can be ⁇ 5%.
  • the curved surfaces of the image-forming optical elements 2 of the first embodiment are denoted by A1 to A12.
  • the rows show, from top to bottom, the surface numbers of the lenses corresponding to FIGS. 2a and 2b.
  • Area A1 is a so-called dummy area, which is used for better representation in the layout plots ( Figures 2a and 2b).
  • the columns show, from left to right, the surface number, the surface type (spherical, toroidal, etc.), the apex radius of the surface curvature in the y- and y-direction, the distance to the following surface (the air gap or the lens thickness), the Abbe number Vd, the refractive index nd and half the diameter of the optically used area in the x and y directions.
  • the Abbe number Vd is defined as: where nd, nF etc.
  • FIGS. 3a and 3b show the lens 1 of a second exemplary embodiment with a focusing setting at infinity. It is also a compact wide-angle lens for a mirrorless camera
  • the lens 1 is extremely short with a length of 26.7 mm.
  • the ratio of overall length to sensor diagonal is only 0.62 and thus even smaller than modern smartphone lenses.
  • the objective 1 has six lenses, namely four toric lenses (without aspheric orders) and 2 spherical lenses as image-forming optical elements 2 .
  • One of the toric lenses is a field lens just in front of the image plane to correct specific distortion, field curvature and astigmatism.
  • the diameters of the other lenses are very small at ⁇ 11 mm.
  • the screen is flat.
  • the modulation transfer function or contrast transfer function MTF is consistently >50% at 20 lp/mm.
  • the basic design data of the lens 1 of the second exemplary embodiment are given in Table 6 below, with the tolerance range of the specified values can be ⁇ 5%.
  • the curved surfaces of the image-forming optical elements of the second embodiment are denoted by B1 to B14.
  • B1 to B14 For a more detailed explanation of the basic design data, reference is made to the first exemplary embodiment.
  • FIGS. 4a and 4b show the lens 1 of a third exemplary embodiment with a focusing setting at infinity.
  • This third exemplary embodiment is a lens 1 designed as a wide-angle lens with a front pupil for forming a rectilinear-stereographic Pannini image, which is designed as a 4/28 mm lens 1 for a 35 mm format.
  • the pupil (system diaphragm) is located directly at the system entrance in front of the first lens.
  • the basic construction data of the lens 1 of the third exemplary embodiment are given in Table 7 below, with the tolerance range of the given values being able to be ⁇ 5%.
  • the curved surfaces of the image-forming optical elements of the third embodiment are denoted by C1 to C11.
  • C1 to C11 For a more detailed explanation of the basic design data, reference is made to the first exemplary embodiment.
  • FIGS. 5a and 5b show the lens 1 of a fourth exemplary embodiment with a focusing setting at infinity.
  • This fourth exemplary embodiment is a lens 1 designed as a wide-angle lens with a high aperture for mirrorless cameras for larger image formats, such as a 35 mm format or similar.
  • the objective 1 has two toric lenses directly in front of the flat image surface 3 .
  • the basic design data of the lens 1 of the fourth exemplary embodiment are given in Table 8 below, with the tolerance range of the given values being able to be ⁇ 5%.
  • the curved surfaces of the image-forming optical elements of the fourth embodiment are denoted by D1 to D19.
  • FIGS. 6a and 6b show the lens 1 of a fifth exemplary embodiment with a focusing setting at infinity.
  • This fifth exemplary embodiment is also a lens 1 designed as a wide-angle lens with a high aperture for mirrorless cameras for larger image formats, such as a 35 mm format or similar.
  • the objective 1 has two toric lenses directly in front of the cylindrically curved image surface 3 .
  • the basic construction data of the lens 1 of the fifth exemplary embodiment are given in Table 9 below, with the tolerance range of the given values being able to be ⁇ 5%.
  • the curved surfaces of the image-forming optical elements of the fifth embodiment are denoted by E1 to E19.
  • E1 to E19 For a more detailed explanation of the basic design data, reference is made to the first exemplary embodiment.
  • FIG. 6c shows the distortion grating of the lens 1 of the fifth exemplary embodiment.
  • the ideal grating is shown thin, the grating obtained by means of the lens 1 of the fifth exemplary embodiment is shown highlighted (heavy lines) and has the characteristics of Pannini imaging: vertical lines remain almost vertical, while the spacing of vertical lines decreases monotonically in the horizontal direction ( horizontal barrel distortion).
  • FIG. 6d shows the course of the modulation transfer function of the lens 1 of the fifth exemplary embodiment.
  • the modulation transfer function gives the contrast of structures of a certain period, characterized by the spatial frequency of periodic structures in units of line pairs per millimeter (English: cycles per millimeter).
  • a Nyquist frequency of 100 line pairs/mm results for typical pixel periods of modern image sensors of modern DSLR or system cameras of about 5 microns.
  • Very fine structures that are still reproducibly imaged with such an image sensor are at around the Nyquist frequency/3, i.e. slightly more than 30 Lp/mm.
  • the MTF graph shows the contrast starting from coarse periodic structures to these fine structures in the range 0 to 30 lp/mm for various pixels in the image field (see legend next to the diagram).
  • the image performance is 10 lp/mm for almost that entire image field over 80% (shown in the diagram as a relative value of 0.8) and at 30 lp/mm over 30%, with the contrast in the center of the image being higher than at the edges.
  • This means that the picture performance of this Pannini lens is as high as that of a very good, conventional, rotationally symmetrical lens for a professional full-frame system camera.
  • FIGS. 7a and 7b show the lens 1 of a sixth exemplary embodiment with a focusing setting at infinity.
  • This sixth exemplary embodiment is also a lens 1 designed as a wide-angle lens with a high opening for a mirrorless camera for larger image formats, such as a 35 mm format or similar.
  • the horizontally imaged area is significantly larger than with a purely rectilinear imaging lens (104° compared to 88°) and reduces 3D deformations at the edges of the image.
  • the objective 1 contains four toric lenses (lenses 1, 3, 4 and 5) in the front area of the objective 1, especially in the area nearer the pupil (one of which is aspherical). These are all designed with a spherical basic shape (no higher polynomial coefficients).
  • the basic construction data of the lens 1 of the sixth exemplary embodiment are given in Table 10 below, with the tolerance range of the given values being able to be ⁇ 5%.
  • the curved surfaces of the image-forming optical elements of the sixth embodiment are denoted by F1 to F30.
  • the surfaces F28 and F29 are flat plates in front of the image sensor.
  • this can be protective glass for the image sensor, optionally with an integrated low-pass and/or infrared filter.
  • Tables 11 and 12 show the coefficients of the aspheric surfaces F26 and F27 according to the definition equation of the vertex shape.
  • the vertex shape is described by the equation: J where z is the arrow height, R is the vertex radius of curvature of the lenses, r is the radial distance with jy , the conic constant and A, B, C, D, E, F, G, H, J denote the strain coefficient of the respective order.
  • the coefficients F, G, Fl and J (14th to 20th order) and the conic constant or conic constants are zero for all aspheric surfaces listed.
  • the respective crest radius can be found in Table 10.
  • Table 11 Coefficients of the aspheric surface F26
  • Table 12 Coefficients of the aspheric surface F27
  • FIG. 7c shows the distortion grating of the lens 1 of the sixth exemplary embodiment.
  • the ideal grating is shown thin, the grating obtained by means of the lens 1 of the sixth exemplary embodiment is shown highlighted (heavy lines) and has the characteristics of Pannini imaging: vertical lines remain almost vertical, while the spacing of vertical lines decreases monotonically in the horizontal direction ( horizontal barrel distortion).
  • FIGS. 8a and 8b show the lens 1 of a seventh exemplary embodiment with a focusing setting at infinity.
  • This seventh exemplary embodiment is a lens 1 designed as a wide-angle lens for a single-lens reflex camera for larger image formats, such as a 35 mm format or similar.
  • the image performance, contrast and correction of chromatic aberrations is on a par with a premium ultra-wide-angle lens such as the rectilinear Distagon ZE/ZF 2.8/15 mm from ZEISS.
  • the lenses 1 to 6 are toric, one lens is aspherical (rotationally symmetrical; directly in front of aperture 4), the other lenses are spherical.
  • the basic construction data of the lens 1 of the seventh exemplary embodiment are given in Table 13 below, with the tolerance range of the given values being able to be ⁇ 5%.
  • the curved surfaces of the image-forming optical elements of the seventh embodiment are denoted by G1 to G34.
  • the surfaces G33 and G34 are flat plates in front of the image sensor.
  • this can be protective glass for the image sensor, optionally with an integrated low-pass and/or infrared filter.
  • Tables 14 and 15 show the coefficients of the aspheric surfaces G21 and G22 according to the definition equation of the vertex shape.
  • FIGS. 8c to 8e show transverse aberration diagrams for the lens 1 of the seventh exemplary embodiment.
  • Transverse aberration diagrams are often used to measure the image performance of lenses such as B.
  • photographic lenses The ordinate characterizes the deviation of a ray in the image plane Ay ' from the point of passage of the main ray of the same ray bundle of an object point in the image plane depending on the pupil coordinates YEP (abscissa). The scale of the ordinate is 0.025 mm.
  • FIG. 8f shows the course of the modulation transfer function of the lens 1 of the seventh exemplary embodiment.
  • the image performance at 10 lp/mm for almost the entire image field is over 80% (indicated in the diagram as a relative value of 0.8) and at 30 lp/mm over 30%, with the contrast in the center of the image is higher than at the edge.
  • This means that the picture performance of this Pannini lens is as high as that of a very good, conventional, rotationally symmetrical lens for a professional full-frame system camera.
  • the objective 1 does not contain any toric surfaces, but instead 4 cylindrical lenses (lenses 1 to 4) and, as in the seventh exemplary embodiment, an aspherical and otherwise spherical lens.
  • the image performance is comparable to that of the seventh embodiment.
  • the front lens diameter is larger and the system is heavier. Use in cinematography would be possible here.
  • the basic construction data of the lens 1 of the eighth exemplary embodiment are specified in Table 16 below, with the tolerance range of the specified values being able to be ⁇ 5%.
  • the curved surfaces of the image-forming optical elements of the eighth embodiment are denoted by H1 to H34.
  • H1 to H34 are flat plates in front of the image sensor.
  • this can be protective glass for the image sensor, optionally with an integrated low-pass and/or infrared filter.
  • Tables 17 and 18 show the coefficients of the aspheric surfaces H21 and H22 according to the definition equation of the vertex shape.
  • FIG. 10 shows an exemplary imaging optical device 10 which is designed as a photo camera.
  • the imaging optical device 10 has a lens 1 with a plurality of image-forming optical elements 2 which are arranged along the optical axis z.
  • the image-forming optical elements 2 are shown in stylized form in FIG. 10 in the form of four lenses.
  • the actual structure of the lens 1 can correspond to the first to eighth exemplary embodiments, for example.
  • the imaging optical device 10 has an image surface 12 arranged in a housing 11, which is shown flat in FIG. B. cylindrically curved, can be.
  • the image area corresponds to the image sensor, which can be designed, for example, as a full-frame image sensor 12 (image circle diameter 43.2 mm).
  • FIG. 11 shows a mobile terminal device 100 in a schematic representation.
  • the mobile terminal 100 can be a smartphone, for example.
  • the mobile terminal 100 has a camera as imaging optical device 10, which in turn has a lens 1, which is designed as a Pannini lens.
  • FIG. 12 shows a set 200, which includes a lens 1, for example designed as explained with reference to one of FIGS.
  • the instructions 202 are directed to the use of the lens 1 and specify that the lens 1 is to be used with a flat image surface 3 or, alternatively, with a curved image surface 3 .
  • the set 200 can also include an imaging optical device 10 with such a lens 1.
  • FIG. 13 shows footprints over the field of view in different lens planes. Reference is made to the relevant explanations in the above description.
  • the term "and/or" when used in a series of two or more items means that each of the listed items can be used alone, or any combination of two or more of the listed items can be used.
  • the lens can be A alone, B alone, C alone, A and B in combination, A and C in combination, B and C in combination, or A , B and C in combination.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
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Abstract

L'invention concerne une lentille (1) comprenant des éléments optiques de formation d'image (2) qui présentent des surfaces incurvées à effet non symétrique en rotation et sont disposés le long d'un axe optique z. Les éléments optiques de formation d'image (2) sont configurés et agencés de telle sorte qu'une image à former sur une surface d'image (3) est une projection Pannini ayant les caractéristiques suivantes : une échelle de projection identique dans le centre de l'image le long de chaque direction dans la surface d'image (3), une projection verticale droite de lignes verticales droites sur l'ensemble du champ d'image et de la distorsion de cylindre de l'espace d'objet dans une direction horizontale. Un dispositif optique d'imagerie (10), un terminal mobile (100) et également un ensemble comprenant une lentille (1) ou un dispositif optique d'imagerie (10) et des instructions d'utilisation (201) sont en outre spécifiés.
PCT/EP2022/051182 2021-02-12 2022-01-20 Lentille pannini et dispositif optique d'imagerie WO2022171413A1 (fr)

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DE102021103323.3A DE102021103323A1 (de) 2021-02-12 2021-02-12 Pannini-Objektiv und abbildendes optisches Gerät
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GB2164470A (en) * 1984-09-14 1986-03-19 Michael Rodney Browning Iris device having linearly movable blades
DE102008021341A1 (de) * 2008-04-29 2009-11-05 Carl Zeiss Ag Anamorphotisches Abbildungsobjektiv
US20100149509A1 (en) * 2008-09-18 2010-06-17 Nikon Corporation Optical system, exposure apparatus, and method of manufacturing electronic device
US20130022345A1 (en) 2011-06-14 2013-01-24 Aurelian Dodoc Anamorphic objective
WO2014122477A1 (fr) * 2013-02-07 2014-08-14 Cardiff Metropolitan University Améliorations apportées et relatives à la prise d'image

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ITTO20130683A1 (it) 2013-08-08 2015-02-09 Sisvel Technology Srl Apparato e metodo per la correzione delle deformazioni prospettiche delle immagini
KR20180028782A (ko) 2016-09-09 2018-03-19 삼성전자주식회사 전자 장치 및 그 제어 방법

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GB2164470A (en) * 1984-09-14 1986-03-19 Michael Rodney Browning Iris device having linearly movable blades
DE102008021341A1 (de) * 2008-04-29 2009-11-05 Carl Zeiss Ag Anamorphotisches Abbildungsobjektiv
US20100149509A1 (en) * 2008-09-18 2010-06-17 Nikon Corporation Optical system, exposure apparatus, and method of manufacturing electronic device
US20130022345A1 (en) 2011-06-14 2013-01-24 Aurelian Dodoc Anamorphic objective
WO2014122477A1 (fr) * 2013-02-07 2014-08-14 Cardiff Metropolitan University Améliorations apportées et relatives à la prise d'image

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THOMAS K SHARPLESS ET AL: "Pannini: A New Projection for Rendering Wide Angle Perspective Images", INTERNATIONAL SYMPOSIUM ON COMPUTATIONAL AESTHETICS IN GRAPHICS, VISUALIZATION, AND IMAGING 2010 (CAE 2010), 14 June 2010 (2010-06-14), pages 1 - 8, XP055118304, Retrieved from the Internet <URL:http://tksharpless.net/vedutismo/Pannini/panini.pdf> [retrieved on 20140515] *

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