IMAGING SYSTEM, IN PARTICULAR FOR A CAMERA

Abstract

An imaging system having multiple imaging devices arranged in succession in the direction of an optical axis, including a first imaging device for generating a real intermediate image of an object on an intermediate image plane, a second imaging device for generating a virtual mirror image of the real intermediate image, the mirror image being laterally offset to the real intermediate image on the intermediate plane, and a third imaging device for imaging the real intermediate image and the virtual mirror image together as a real image on an image receiver surface to be arranged at an axial distance to the intermediate image plane. The imaging system has an optical filtering device for filtering the imaging of the real intermediate image and/or at least one of the virtual mirror images separately from each other. The imaging system includes the image receiver surface and a device for processing a real image captured by the image receiver surface. The processing device uses the image to determine positions in the direction of the optical axis of object region points, which are imaged by at least individual pixels of the pixels of the image.

Claims

1-26. (canceled)

27. A plenoptic imaging system, comprising: multiple imaging devices arranged in succession in a direction of an optical axis, the multiple imaging devices including a first imaging device configured to generate a real intermediate image of an object in an intermediate image plane, a second imaging device configured to generate at least one virtual mirror image of the real intermediate image, which virtual mirror image is arranged offset to the real intermediate image in the intermediate image plane, and a third imaging device for jointly imaging the real intermediate image and the virtual mirror image as a real image on an image receiver surface to be arranged at an axial distance to the intermediate image plane; and an optical filtering device configured to filter the image of the real intermediate image and/or at least one of the virtual mirror images separately from one another.

28. The imaging system according to claim 27, further comprising a processing device for processing a real image recorded by the image receiver surface, the processing device being configured to determine, with respect to the direction of the optical axis, positions of sections of the object, which are imaged by at least individual ones of the pixels of the image, from the image.

29. The imaging system according to claim 28, wherein the processing device is configured to determine the positions and to ascertain how far identical sections of the object are represented arranged offset in relation to one another in the images of the real intermediate image and at least one of the virtual intermediate images and/or in the images of at least two different virtual mirror images.

30. The imaging system according to claim 27, wherein the filtering device is arranged in front of the image receiver surface.

31. The imaging system according to claim 27, wherein the filtering device is arranged in the first imaging device or is part of the first imaging device.

32. The imaging system according to claim 27, wherein the filtering device is arranged directly in front of or behind the intermediate image plane in or in the direction of the optical axis.

33. The imaging system according to claim 27, wherein the filtering device includes at least two optical filters.

34. The imaging system according to claim 33, wherein the filtering device includes a carrier, in which the optical filters are arranged in various filter positions.

35. The imaging system according to claim 27, further comprising a device for holding the filtering device, wherein the holding device includes a device for adjusting a position of the filtering device in the holding device.

36. The imaging system according to claim 33, wherein the filtering device includes N×N filter positions in a matrix arrangement, wherein the matrix arrangement extends in a direction perpendicular to the optical axis.

37. The imaging system according to claim 36, wherein the filtering device includes 3×3, 5×5, or 7×7 filter positions in the matrix arrangement.

38. The imaging system according to claim 36, wherein at least two of the optical filters have the same filter properties, wherein the at least two optical filters, which have the same filter properties, are arranged in outer filter positions of the matrix arrangement.

39. The imaging system according to claim 38, wherein the at least two optical filters, which have the same filter properties, are arranged in outer filter positions of the matrix arrangement opposite to one another diagonally.

40. The imaging system according to claim 27, wherein the second imaging device includes at least one mirror for generating the at least one virtual mirror image, wherein the second imaging device preferably forms a kaleidoscope.

41. The imaging system according to claim 40, wherein the second imaging device forms a kaleidoscope.

42. The imaging system according to claim 33, wherein the filtering device includes an identifier operative to ascertain and/or retrieve properties of the optical filters and/or an arrangement of the optical filters in the filtering device.

43. A method for plenoptic imaging of an object area, comprising the steps of: imaging the object area using multiple imaging devices arranged in succession in a direction of an optical axis, wherein the imaging devices include a first imaging device for generating a real intermediate image of an object in an intermediate image plane, a second imaging device for generating at least one virtual mirror image of the real intermediate image, which is arranged offset to the real intermediate image in the intermediate image plane, and a third imaging device for jointly imaging the real intermediate image and the virtual mirror image as a real image on an image receiver surface to be arranged at an axial distance to the intermediate image plane; and filtering the image of the real intermediate image and/or at least one of the virtual mirror images separately from one another.

44. The method according to claim 43, including determining positions in the direction of the optical axis of object area points, which are imaged by at least individual ones of pixels of the image.

45. The method according to claim 44, wherein the positions are determined by ascertaining how far identical sections of the object are represented arranged offset in relation to one another in the images of the real intermediate image and at least one of the virtual intermediate images and/or in the images of at least two different virtual mirror images.

46. The method according to claim 44, including ascertaining the positions only from images in the real image, which are unfiltered or are filtered using optical filters that have identical filter properties.

47. The method according to claim 44, including ascertaining the positions from images in the real image which are filtered using optical filters that have different filter properties.

48. The method according to claim 43, wherein in the various images, at least individual ones of the pixels are linked to points in the object area which they image and the positions of points in the object area in the direction of the optical axis are ascertained at least in relation to one another based on the linkages.

49. A computer program product comprising commands which, upon execution of the program by a computer, prompt the computer to carry out the method according to claim 43.

50. A computer program product comprising commands which, upon execution of the program by a computer, prompt the computer to determine positions in a direction of an optical axis of object area points which are imaged by at least individual ones of pixels from separately filtered images of a real intermediate image and/or at least one virtual mirror image, which have been generated by the imaging system according to claim 27.

51. The computer program product according to claim 50, comprising commands which, upon the execution of the program by the computer, prompt the computer to process separately filtered images of the real intermediate image and/or at least one of the virtual mirror images in dependence on the respective filtering by the imaging system.

52. The computer program product according to claim 50, wherein the computer program product is a computer program stored on one of the group consisting of: a data carrier; a personal computer; a device having an embedded processor; a computer embedded in a device; a smart phone; a computer of a device for creating an image recording; or a signal sequence representing data suitable for transmission via a computer network.

53. A device for data processing, comprising means for carrying out the method according to claim 43.

54. The device according to claim 53, wherein the device is part of an imaging system and/or is a camera.

55. A data carrier signal, which transmits the computer program product according to claim 49.

Description

[0067] In the figures:

[0068] FIG. 1 shows an imaging system according to the invention,

[0069] FIG. 2 shows a further imaging system according to the invention,

[0070] FIG. 3 shows a beam path of one of the imaging systems according to FIG. 1 or 2,

[0071] FIG. 4 shows further beam paths of one of the imaging systems according to FIG. 1 or 2,

[0072] FIG. 5 shows a filter device of one of the imaging systems according to FIG. 1 or 2,

[0073] FIG. 6 schematically shows a camera provided with the imaging system, and

[0074] FIG. 7 shows an image recorded by means of the imaging system according to the invention.

[0075] FIG. 1 schematically shows how a plenoptic image recording is created using an imaging system 1 in a manner according to the invention. The imaging system 1 includes, in addition to an entry lens group 3 and an exit lens group 5, a mirror box 4 having mirrors 19, which, as shown in FIG. 3, are arranged rectangular in cross section in the mirror box 4. The mirror box 4 forms a kaleidoscope. Light beams 22 which originate from an object area, which images an object 23, enter the entry lens group 3 and are deflected by the entry lens group 3 into the interior of a mirror box 4. Some of the light beams 22 pass through the mirror box 4 up to the exit lens group 5 without striking one of the mirrors 19, other light beams are only reflected a single time on one of the mirrors 19 before they strike the exit lens group 5. Further light beams are in turn reflected multiple times on the mirrors 19 within the mirror box 4, wherein the reflections can take place both on mirrors 19 arranged opposite and also arranged adjacent to one another (cf. FIGS. 3 and 4). The exit lens group 5 is arranged in such a way that the light beams 22 exiting from the mirror box 4 are guided onto a receiver surface 7, which is formed by a sensor, in particular a CCD or CMOS sensor.

[0076] The entry lens group 3, the mirror box 4 and its mirrors 19, and the exit lens group 5 are arranged in such a way that nine images of the object area are formed on the receiver surface 7, which are generated adjacent to one another in a 3×3 grid. The images are generated in such a way that they image the object area originating from the entry lens group 4 from nine different viewing angles.

[0077] The imaging system 1 is provided with a filter device 8 which, as FIGS. 1 and 2 show, can be arranged in the imaging system 1 at various positions. FIG. 1 shows an arrangement of the filter device 8 directly in front of the receiver surface 7. In the arrangement according to FIG. 2, the filter device 8 is arranged in the intermediate image plane.

[0078] The filter device 8 can comprise two glass plates as a carrier, between which filters are arranged. Furthermore, a plastic frame can be provided as a carrier.

[0079] FIG. 5 shows that the filter device 8 has a carrier 18 having nine filter positions 9-17 for accommodating optical filters, which can remain unoccupied or can be occupied with possibly differing optical filters as needed. Each of the filter positions 9-17 is arranged so that in each case those light beams which form a respective one of the various images on the above-explained 3×3 grid pass through them.

[0080] The possibility is thus provided of simultaneously creating unfiltered and filtered and/or differently filtered images of the object area in a real image, which is incident on the receiver surface 7, using a single recording. In addition, it is possible due to the various viewing angles from which the individual images are recorded to determine items of information about positions in the direction of the optical axis of points of the object area which are reproduced by the individual pixels of the image, so that a statement may be made about the positions of the imaged object area points relative to one another with respect to the optical axis. Items of information can thus be obtained about the image depth.

[0081] The items of information about the mentioned positions may be ascertained comparatively easily from images which are filtered in the same manner or are unfiltered. Therefore, in one variant of the invention, for the position ascertainment, at least two of the filter positions 9-17 are occupied with filters of identical optical properties or at least two of the filter positions are left free and the positions are determined on the basis of the images which are identical or are unfiltered.

[0082] The imaging device 1 can comprise a computer 20, which is able to read out the sensor forming the image receiver surface 7 and store the read-out data. The computer 20 can be arranged, for example, on an objective supporting the imaging system 1 or, as schematically shown in FIG. 6, on a camera housing 26, which interacts with the imaging system 1. A computer 20 or another data processing device, to which the stored data are transmitted, possibly by means of the computer 20, is configured by means of a computer program 21 running thereon to process the differently filtered images from the stored image. The computer program 21 is provided for this purpose in such a way that each of the images may be assigned a respective filter property which corresponds to the filter which has filtered the respective image in the filter device. In the computer program 21, various data or data sets which match with filters provided for the filter device 8 can be stored in a retrievable manner in a database 24 for this purpose, so that the computer program 21 can automatically access the respectively matching data or data sets upon suitable setting.

[0083] If the filters may be exchanged, for example manually, on a carrier frame 18 of the filter device 8, the matching data sets for the respective filter positions can be selected by means of the computer program 21 in accordance with the selected arrangement. The computer program 21 can subsequently automatically evaluate the image recording on the basis of the data sets which relate to the optical filters.

[0084] Furthermore, one or more prefabricated filter devices 8 could be provided, in which the different filters are placed fixedly. Such filter devices 8 can be provided with an identifier schematically shown in FIG. 6, on the basis of which it may be read out with which filters the filter positions are occupied. It can be provided that the computer program 21 automatically retrieves a suitable data set from the database on the basis of the identifier in order to process the image recording. The identifier 25 of the filter device 8 could be read out automatically. For example, a code, such as a barcode, could be provided on the carrier frame, which is read out automatically, when an image recording is carried out, by means of a corresponding read device 27, which can be arranged on the camera housing. Alternatively, it would be conceivable to store the code in the image, for example in at least one of the images, so that it is automatically recognized upon analysis of the image recording data by the computer program 21 and computer 20 loads the matching data set on the basis of the recognized identifier.

[0085] Furthermore, it could be provided that during recording of an image recording, the identifier is radiated in an area of the receiver surface 7 which is not used to create the image recording, but is retrievable upon readout of the receiver surface 7.

[0086] In a first example, the filter positions 9, 11, 15, 17 and the central filter position 13 are free of filters in the filter device 8 according to FIG. 5. Neutral density filters of different neutral densities are arranged on the remaining filter positions 10, 12, 14, 16.

[0087] On an image recording, the mentioned positions can be determined on the basis of the images which result from beams which have been recorded by the filter positions in the corners and in the center of the receiver surface 7 to ascertain the image depth and furthermore an increased contrast in the recording can be achieved on the basis of the unfiltered and the differently filtered images. Suitable image processing, which is known per se and in which the increased contrast is ascertained from recordings having different exposure (so-called “exposure series”) can be used for this purpose.

[0088] It is apparent that alternatively, for example, only two of the filter positions 9-17 could remain free of filters and the remaining filter positions could be occupied with filters of different neutral densities, in order to achieve a greater or a broader contrast resolution.

[0089] Furthermore, it could be provided that all of the filter positions 9-17 are provided with neutral density filters, or notwithstanding the preceding examples, two or more filters of the same neutral density are provided and the mentioned positions are ascertained on the basis of the images which have been generated using the filters of the same neutral density.

[0090] Due to the larger parallax which exists when the viewing angles, from which the images are generated, are as far apart from one another as possible, it is advantageous to leave two or more of the filter positions 9, 10, 11, 12, 14, 15, 16, 17 lying on the outside in the filter device 8 free or to provide them with filters of the same neutral density in order to determine the positions. The filter positions 9, 11, 15, 17, which form the corner positions in the filter device 8, are particularly well suited.

[0091] In a further exemplary embodiment, optical filters of another type are provided for the filter device 8 instead of the above-mentioned neutral density filters, for example polarization filters, color filters, complementary color filters, or fluorescence filters. In the filter device 8, such filters having different filter strength or filter effect can then respectively be provided and, as described above for the neutral density filter, increased filter resolutions can be achieved by the differently filtered images and the items of information about the mentioned positions can possibly be obtained.

[0092] In a further exemplary embodiment, optical filters of different types are arranged in the filter device. For example, different neutral density filters could be arranged on the filter positions 9-11, different UV filters could be arranged on the filter positions 12-14, and different color filters could be arranged on the filter positions 15-17. In this way, not only different gradations of the same filter effect, but different filter effects may be accommodated in a single image recording.

[0093] In another variant, the positions are ascertained from at least two images, which are optically filtered differently, or from at least one unfiltered and at least one filtered image. For this purpose, an image analysis of the individual images or at least two of the images is preferably carried out, in order to ascertain the pixels which represent the same points or areas of the imaged object in the object area from the differently filtered images. This information is required, as explained above, to be able to determine an offset in the representation.

[0094] FIG. 7 shows by way of example images of an object area in the form in which they are recorded upon a recording by means of the imaging system 1 on the receiver surface 7, which is equipped with a filter device 8 according to a further embodiment. In the exemplary embodiment, the filter positions 15 and 17 are free of filters and the other filter positions are equipped with neutral density filters of different neutral densities. As explained above, the images are incident in a 3×3 grid on the receiver surface 7.