Variable Effect Filtering Device
The variable effect filtering device with a central and peripheral zone, and an adjustable diaphragm, addresses the limitations of fixed focal length lenses by allowing adaptable image rendering, achieving desired effects like diffusion or polarization.
Patent Information
- Application Number
- JP2025535247
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-12-19
- Filing Date
- 2023-12-18
- Publication Date
- 2025-12-05
AI Technical Summary
The film industry faces limitations in modularity and uniformity of image rendering due to the need for lenses with fixed focal lengths and performance ranges, and existing diffusion filters risk visible texture in image blur or non-uniform rendering across the field.
A variable effect filtering device with a filter having a central and peripheral zone, and an adjustable diaphragm that changes the accessible portion of the filtering zone, allowing adaptable image rendering by altering the diaphragm opening.
Enables simple and fast adaptation of the image, the device allows for the adaptable modification of the image's rendering, and the device can be easily adjusted to achieve desired effects such as diffusion, polarization, or wavefront deformation.
Smart Images
Figure 2025539651000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a variable effect filtering device. The invention also relates to an assembly comprising an imaging objective and such a filtering device. The invention also relates to a method for modifying the rendering of an image using such a filtering device. [Background technology]
[0002] FIELD OF THE INVENTION The present invention relates to the film industry and, in general, to imaging.
[0003] In particular, in the film industry, camera operators select lenses depending on the film being produced and also prefer the lens group that is considered suitable for the lighting method. In fact, some lenses are softer, in other words, have low contrast for mid-frequency patterns (5-50 cy / mm), while others may have good resolution (>150 cy / mm) for S35 to FF (full-frame) sensors. On the other hand, others are considered difficult due to their very good quality (or modulation transfer function) at mid-frequency. Therefore, the selection of a particular contrast is (partly) achieved depending on the choice of lens.
[0004] However, this modularity is limited by the need to have a range of focal lengths that have the same performance for a given sequence.
[0005] Diffusion filters can be used before or after the lens, however there is a risk that the texture of the diffuser will be visible in the blur of the image (background blur).
[0006] It is also possible to move the lens to widen the aberrations and reduce contrast, however the rendering is not as uniform across the field as a diffuser. Summary of the Invention
[0007] Therefore, there is a need for a device that can change the rendering of the image formed by the lens in a simple and adaptable way at any time.
[0008] To this end, the present specification has as its object a variable effect filtering device comprising: a. A filter exhibiting an active surface comprising a central zone and a peripheral zone surrounding the central zone, the filter having predetermined optical properties over a zone referred to as the filtering zone, the filtering zone being either the central zone, or the peripheral zone, or the entire active surface; and b. A diaphragm having an adjustable opening between a fully open and a fully closed state, the full opening of the diaphragm corresponding to the working surface of the filter, and the diaphragm being positioned relative to the filter such that changing the opening of the diaphragm changes the accessible portion of the filtering zone or the accessible portion of another zone of the working surface, thereby allowing a change in the filtering effect to be induced.
[0009] According to particular embodiments, the device comprises one or more of the following features, taken alone or in any technically possible combination: The filtering zone is a central zone or a peripheral zone, and the predetermined optical properties are uniform across the filtering zone. The predetermined optical property exhibits a progressive radial variation over the filtering zone. The total opening of the diaphragm defines the peripheral zone of the filter. The openings formed by the filtering zone and the diaphragm have substantially the same shape, within a range of approximate uniformity. The central zone has a shape selected from one of the following shapes: circular, square, rectangular, parallelepiped, triangular, elliptical and star-shaped. The predetermined optical property is selected from one of the following properties: a diffusion property, a polarization property, a colorimetric property, a wavefront deformation property, a transparency property, and a combination of at least two of the aforementioned properties. The filtering zone is a central zone or a peripheral zone, and the active surface of the filter surrounds the central zone and comprises at least one intermediate zone surrounded by the peripheral zone, the at least one intermediate zone comprising a progressive radial variation of predetermined optical properties between the central zone and the peripheral zone. -The diaphragm is the iris diaphragm.
[0010] The present description also relates to an assembly comprising: a. an imaging objective lens; and b. A filtering device, the device being positioned substantially in the aperture of the imaging objective and allowing modification of the rendering of an image formed by the imaging objective.
[0011] The present invention also relates to a method for modifying the rendering of an image formed by an imaging objective, the method comprising: a. placing a filtering device as described above substantially in the aperture of the imaging objective; and b. Modifying the opening of the diaphragm so as to change the accessible portion of the filtering zone or the accessible portion of another zone of the working surface, e.g. to induce a change in the filtering effect, thereby allowing a change in the rendering of the image formed by the imaging objective.
[0012] Other features and advantages of the invention will become apparent from the following description of embodiments of the invention, given by way of example only and with reference to the drawings in which: [Brief explanation of the drawings]
[0013] [Figure 1] FIG. 1 is a schematic diagram of an assembly comprising an imaging objective and a filtering device. [Figure 2] FIG. 2 is a schematic view of a filtering device according to a first embodiment, in which the diaphragm of the filtering device is fully open. [Figure 3] FIG. 3 is a schematic diagram of the filtering device of FIG. 2, with the diaphragm of the filtering device at the intermediate opening. [Figure 4] FIG. 4 is a schematic diagram of the filtering device of FIG. 2, where the diaphragm of the filtering device is at another intermediate opening. [Figure 5] FIG. 5 is a schematic diagram of a filtering device according to a second embodiment, in which the diaphragm of the filtering device is at the intermediate opening. [Figure 6] FIG. 6 is a schematic diagram of the filtering device of FIG. 5, where the diaphragm of the filtering device is at another intermediate opening. [Figure 7] FIG. 7 is a schematic view of a filtering device according to a third embodiment, in which the filtering zone extends over the entire active surface of the filter. DETAILED DESCRIPTION OF THE INVENTION
[0014] In FIG. 1, an imaging objective 10 and a filtering device 12 are shown.
[0015] The imaging objective 10 is capable of forming an image of a scene on a sensor. The imaging objective 10 is, for example, a camera or movie camera lens or a zoom lens. The imaging objective 10 typically comprises at least one lens, and usually a set of lenses.
[0016] The filtering device 12 is capable of producing a variable filtering effect. The term "variable" means that the filtering varies depending on the configuration (adjustment) of the filtering device 12. The adjustment can easily be made in less than a second.
[0017] The filtering device 12 is intended to be placed substantially at the aperture of the imaging objective 10 (as in FIG. 1 ) in order to modify the rendering of the image formed by the imaging objective 10. The term "substantially" means "close to", or more precisely, at a distance of less than a predetermined distance from the aperture. The predetermined distance is, for example, equal to 2 mm.
[0018] The filtering device 12 includes a filter 20 and a diaphragm 22 .
[0019] The filter 20 is a planar optical filter and is made of a material such as glass or plastic.
[0020] As shown in the examples of FIGS. 2 to 6, the filter 20 has a central zone Z C and Central Zone Z C Surrounding Zone Z P In the examples of Figures 2 to 6, the working surface 23 extends over the entire surface of the filter 20. Alternatively, the working surface 23 may extend over only a portion of the filter 20.
[0021] Preferably, the central zone Z C The surface of the peripheral zone Z P equal to at least 30 percent of the surface.
[0022] Preferably, the central zone Z C has a shape that is chosen depending on the desired rendering. C The shape of the central zone Z is for example selected from one of the following shapes: circular, square, rectangular, parallelepiped, triangular, elliptical and star-shaped. More generally, the shape of the central zone Z C The shape of is any shape achievable by an adjustable aperture diaphragm such as an iris diaphragm.
[0023] In the examples of Figures 2 to 6, the central zone Z C is circular.
[0024] The filter 20 has a central zone Z, called the filtering zone. C and surrounding zone Z P , the other zones exhibit different optical properties.
[0025] For example, in the embodiment of FIGS. 2-4, the filtering zone is a central zone Z C and in the embodiment of Figures 5 and 6, the filtering zone is the peripheral zone Z P is.
[0026] Preferably, the predetermined optical property is selected from one of the following properties: diffusion property (diffuse filtering zones and non-diffuse zones), polarization property (polarizing filtering zones and non-polarizing zones), colorimetric property (colored filtering zones and non-colored zones), wavefront deformation property, transparency property (transparent filtering zones and opaque or partially transparent zones), opacity property (opaque or partially transparent filtering zones and another transparent zone), and a combination of at least two of the above properties. The values of the optical properties are adapted depending on the desired rendering.
[0027] In one exemplary embodiment, the predetermined optical property is uniform across the filtering zone.
[0028] Alternatively, the predetermined optical property may exhibit a radial variation across the filtering zone, such that the variation is gradual and continues radially, e.g., in the case of a diffusive property, the diffusion continues to increase from the center of the filtering zone towards the periphery of the filtering zone, or vice versa.
[0029] In one optional embodiment, the filter 20 has a central zone Z C Surrounding Zone Z P The intermediate zone further comprises a central zone Z C and surrounding zone Z PThis involves a gradual (radial) change in predetermined optical properties between the central zone Z and the central zone Z, particularly when the optical properties are uniform across the filtering zone. C and surrounding zone Z P It is possible to avoid discontinuous fluctuations in the optical characteristics between the
[0030] The diaphragm 22 exhibits an adjustable opening between full opening of the diaphragm 22 and maximum closure of the diaphragm 22 .
[0031] Preferably, the opening is continuously adjustable between a fully open position of the diaphragm 22 and a maximum closure of the diaphragm 22. The adjustment is effected, for example, by an adjustment mechanism. The diaphragm 22 is, for example, an iris diaphragm.
[0032] The diaphragm 22 is positioned relative to the filter 20 as follows: - all openings of the diaphragm correspond to the working surface 23 of the filter 20; and A change in the opening of the diaphragm 22 changes the accessible portion of the filtering zone or of another zone of the active surface 23, inducing a change in the filtering effect. In other words, this changes the accessible proportion of the filtering zone relative to the other zone (i.e. the proportion between the unobstructed portion of the filtering zone and the unobstructed portion of the other zone). The term "accessible" means accessible or "useful" for the luminous flux.
[0033] Preferably, the accessible portion of the filtration zone or the accessible portion of another zone of the working surface 23 is changed radially during the change in the opening of the diaphragm 22. In the example of Figures 2 to 6, both the accessible portion of the filtration zone and the accessible portion of the other zone can be changed radially. The term "radially" refers to the area in the plane of the filter 20 from the central zone Z C, which means perpendicular to an axis that passes substantially through the center of the filter 20 and is substantially perpendicular to the plane of the filter 20. The axis considered is the optical axis of the imaging objective 10 when the filtering device 12 is placed substantially at the aperture of the imaging objective 10. In this case, the filtering device 12 is placed substantially perpendicular to the optical axis of the imaging objective 10 and the central zone Z of the filter 20. C is positioned relative to the imaging objective 10 such that its center is located substantially on the optical axis of the imaging objective 10.
[0034] Preferably, the opening in the diaphragm 22 is in the central zone Z C It is positioned at the center of
[0035] Preferably, the entire opening of the diaphragm 22 is within the peripheral zone Z of the filter 20. P Define the following.
[0036] Preferably, the maximum closure of the diaphragm 22 is in the central zone Z of the filter 20. C and surrounding zone Z P Completely blocks out
[0037] Preferably, the central zone Z C and the openings formed by the diaphragm 22 have substantially the same shape (except within a range of approximate uniformity). In the example of FIGS. 2 to 6, therefore, the central zone Z C and the opening has a circular shape.
[0038] Next, a method for modifying the rendering of the image formed by the imaging objective 10 via the filtering device 12 will be described.
[0039] The filtering device 12 is arranged relative to the imaging objective 10 such that it is located substantially at the aperture of the imaging objective 10. The filtering device 12 is preferably arranged such that the optical axis of the imaging objective 10 is aligned with the central zone Z of the filter 20. C and is positioned so as to pass through the center of the filter 20 and be perpendicular to the plane of the filter 20.
[0040] The opening of the diaphragm 22 is then changed so as to radially change the accessible portion of the filtering zone or of another zone of the active surface 23, allowing a change in the rendering of the image formed by the imaging objective 10. Typically, if the property is a diffusion property, depending on the opening of the diaphragm 22, the image is rendered more or less blurred (a "softening" effect). Thus, by opening or closing the diaphragm 22, for example by a simple rotation of a ring, it is possible to specifically change the properties of the image formed by the objective.
[0041] In the embodiment of FIGS. 2 to 4, the central zone Z C Only the diaphragm 22 exhibits diffusion properties. Such properties allow the contrast of the image to be modified (the more light passes through the diffusion zone, the softer the image). In the case of Figure 2, the diaphragm 22 is fully open, which means that about 14% of the aperture is diffused. In Figure 3, the opening of the diaphragm 22 is intermediate (T3.6), and there is still a peripheral zone Z P 4, the opening of the diaphragm 22 is intermediate (T5.6), and the peripheral zone Z P is completely masked, which means that 100% of the aperture is diffused.
[0042] In the embodiment of FIGS. 5 and 6, the peripheral zone Z P In the case of FIG. 5, the diaphragm 22 still has a peripheral zone Z P 6, the diaphragm 22 is in the peripheral zone Z P is completely masked, which means that the aperture is not diffused.
[0043] The filtering device 12 therefore makes it possible in a simple and fast way to modify the rendering of the image formed by the imaging objective 10. The adjustment is made outside the objective and can be made at any time, for example via rotation of the diaphragm ring 22, which allows it to be opened or closed.
[0044] Such optical filters are also cheap and easy to manufacture: for example, in the case of diffusion, the filter can be constructed from a plastic film glued between two plates (Mitchell filters), or by means of a ground plate of the desired surface, or by means of a holographic diffuser, or by gluing a grille, or by any other diffusion principle.
[0045] Furthermore, the present invention makes it possible to obtain the same filtering effect for the same diaphragm opening 22 and for the same series of objective lenses, but with different dimensions of the filter 20 (in particular the central zone Z C and surrounding zone Z P Note that the focal lengths may be different as long as the focal lengths (accessible parts of the image) are adapted.
[0046] Although the examples herein emphasize diffusion properties, the invention applies to any type of optical property that makes it possible to modify the rendering of the image formed by the objective lens depending on the opening of the diaphragm.
[0047] The filtering device also has a central filtering zone Z C or surrounding zone Z PIt should be noted that the present invention is not limited to the case where the filtering zone extends across only one of the active surfaces 23 of the filter 20. Indeed, in an alternative embodiment shown in FIG. 7, the filtering zone extends across the entire active surface 23 of the filter 20. In this case, modifying the openings in the diaphragm 22 only modifies the accessible portion of the filtering zone (and not other zones of the active surface 23, since the filtering zone occupies the entire active surface 23). Preferably, the predetermined optical property exhibits a continuous gradual change (radially) across the filtering zone. For example, in the case of a diffusion property, the diffusion increases from the center (central zone) of the active surface 23 to the periphery (peripheral zone) of the active surface 23, or vice versa. Other features discussed above, particularly with respect to the embodiment of FIGS. 2-6, also apply to this additional embodiment.
[0048] More generally, those skilled in the art will understand that the above-described embodiments and alternatives can be combined with each other if they are technically compatible.
Claims
1. A variable effect filtering device (12) comprising: - Central Zone (Z Ｃ ) and the central zone (Z Ｃ ) surrounding the peripheral zone (Z Ｐ ), said filter (20) exhibiting a working surface (23) comprising a central zone (Z ), said filter (20) having predetermined optical properties over a zone called a filtering zone, said filtering zone being Ｃ ) or the peripheral zone (Z Ｐ ) or the entire working surface (23), and a diaphragm (22) with an opening that is adjustable between the full opening of the diaphragm (22) and the maximum closing of the diaphragm (22), the full opening of the diaphragm corresponding to the active surface (23) of the filter (20), the diaphragm (22) being positioned relative to the filter (20) in such a way that a change in the opening of the diaphragm (22) changes the accessible portion of the filtering zone or of another zone of the active surface (23), allowing a change in the filtering effect to be induced; A variable effect filtering device (12) comprising:
2. The filtering zone is the central zone (Z Ｃ ) or the peripheral zone (Z Ｐ ) and the predetermined optical characteristic is uniform across the filtering zone.
3. The apparatus (12) of claim 1, wherein the predetermined optical property exhibits a progressive radial variation across the filtering zone.
4. The entire opening of the diaphragm (22) is in the peripheral zone (Z Ｐ The device (12) of any one of claims 1 to 3, defining a
5. The device (12) of any one of claims 1 to 4, wherein the filtering zone and the opening formed by the diaphragm (22) have substantially the same shape, except within a range of approximate uniformity.
6. The central zone (Z Ｃ 6. The device (12) according to any one of claims 1 to 5, wherein the first and second electrodes (12) have a shape selected from one of the following shapes: circular, square, rectangular, parallelepiped, triangular, elliptical, and star-shaped.
7. 7. The device (12) of claim 1, wherein the predetermined optical property is selected from one of the following properties: a diffusion property, a polarization property, a colorimetric property, a wavefront deformation property, a transparency property, and a combination of at least two of the foregoing properties.
8. The filtering zone is the central zone (Z Ｃ ) or the peripheral zone (Z Ｐ ), and the working surface (23) of the filter (20) is Ｃ ) and surrounds the peripheral zone (Z Ｐ ) and the at least one intermediate zone is surrounded by the central zone (Z Ｃ ) and the peripheral zone (Z Ｐ 8. The device (12) of claim 1, comprising a progressive radial variation of the predetermined optical property between
9. The device (12) according to any one of claims 1 to 8, wherein the diaphragm (22) is an iris diaphragm.
10. a. an imaging objective (10), and b. A filtering device (12) according to any one of claims 1 to 9, wherein said device (12) is arranged substantially in the aperture of said imaging objective lens (10) and allows for modification of the rendering of an image formed by said imaging objective lens (10); Including the assembly.
11. A method for modifying the rendering of an image formed by an imaging objective (10), comprising: a. Placing a filtering device (12) according to any one of claims 1 to 10 substantially in the aperture of the imaging objective (10); and b) modifying the opening of the diaphragm (22) to change the accessible portion of a filtering zone or of another zone of the working surface (23) so as to induce a modification of the filtering effect, allowing a modification of the rendering of the image formed by said imaging objective (10); A method comprising: