Image capture device embedded in a vehicle

Abstract

The invention relates to an image capture device (100) for vehicle-mounted acquisition of at least one image inside said vehicle, said device (100) comprising: - a camera (10) sensitive at least in the infrared range, arranged to acquire said at least one image, said camera (10) comprising a principal optical axis (12), - a protective panel (20) comprising a secondary optical axis (21), said protective panel (20) being arranged to mechanically protect said camera (10), characterized in that said camera (10) comprises at least one optical element (11) arranged to introduce barrel optical distortion onto at least a portion of the at least one image, said protective panel (20) being arranged to introduce pincushion optical distortion onto at least a portion of the at least one image. Figure for the abstract: Fig. 1

Description

Title of the invention: Vehicle-mounted image capture device Technical field of the invention

[0001] The present invention relates generally to an image capture device embedded in a vehicle.

[0002] It relates more particularly to an image capture device embedded in a vehicle allowing the acquisition of images of the interior of the vehicle with zero or very low distortion, for example less than or equal to 5%. State of the art

[0003] Infrared cameras designed to acquire images inside vehicles generally have a wide field of view, enabling them to capture all or a large part of the vehicle's interior. However, the wider the camera's field of view, the more its optical performance can be degraded by optical aberrations, which can impact the quality of the images acquired. Among optical aberrations, distortion is an optical aberration that increases as the field of view increases. Therefore, the larger the field of view of these cameras, the greater the distortion.

[0004] Image capture devices are known that include an infrared-sensitive camera and a protective panel to mechanically protect the camera from, for example, people or objects inside the vehicle. When it is necessary to correct optical aberrations of the camera, at least one additional optical element is generally positioned in front of the camera lens. These devices are functional but present various problems, particularly in terms of size and implementation, since these devices require the use of at least one additional optical element, and in terms of costs related to the addition of extra optical components.In addition, the addition of optical components also implies losses in the intensities of the light rays captured by the camera, thus degrading optical criteria related to image contrast such as the modulation transfer function, the point spread function, also known as the English name Point Spread Function (PSF), etc.

[0005] The invention aims to remedy at least one of the aforementioned drawbacks. Presentation of the invention

[0006] In order to overcome the aforementioned drawbacks of the prior art, the present invention proposes an image capture device embedded in a vehicle for to acquire at least one image inside said vehicle, said device comprising: - a camera sensitive at least in the infrared arranged to acquire said at least one image, said camera comprising a principal optical axis, - a protective panel comprising a secondary optical axis, said protective panel being arranged to mechanically protect said camera by covering at least part of the field of view of said camera, characterized in that said camera comprises at least one optical element arranged to introduce on at least a part of at least one image a barrel optical distortion, said protective panel being arranged to introduce on at least a part of at least one image a pincushion optical distortion.

[0007] According to the device as disclosed herein, no additional optical elements are added to compensate for the distortion introduced by the camera. Optical properties have been added to this panel to compensate for the distortion introduced by the camera.

[0008] Thus, thanks to the invention, since no additional optical elements are added to compensate for the distortion introduced by the camera, the device of the present disclosure is less bulky, easier to implement, and less expensive. Furthermore, such a device makes it possible to limit the optical losses induced by the presence of additional optical elements. Consequently, the optical performance related to contrast is improved compared to state-of-the-art systems.

[0009] By distortion, we mean an optical aberration introduced by an optical element. This distortion can, in a known way, be expressed by Seidel polynomials.

[0010] Other advantageous and non-limiting features of the device according to the invention, taken individually or according to all technically possible combinations, are explained below.

[0011] In one embodiment, the protective panel is at least partially transparent in infrared, for example the protective panel has a transparency greater than 85% in the field of view of the camera covered by said protective panel in infrared.

[0012] In one embodiment, said secondary optical axis is angularly offset from the main optical axis by at least one rotation around an axis transverse to the main optical axis.

[0013] Such an arrangement makes it possible to choose specific parts of the image to compensate for the distortion introduced by the camera in those parts, while offering a device that is inexpensive and easy to implement.

[0014] In one embodiment, the secondary optical axis is inclined with respect to the main optical axis at a first angle.

[0015] In one embodiment, the secondary optical axis is inclined with respect to the axis main optics following a second angle.

[0016] In one embodiment, the first angle is between 1 degree and 40 degrees, preferably between 5 and 19 degrees and / or the second angle is between 1 degree and 40 degrees, preferably between 5 and 19 degrees.

[0017] The choice of the inclination of the first and / or second angle allows precise selection of parts of the image.

[0018] In one embodiment, the protective panel comprises an external surface and an internal surface, opposite the external surface and oriented towards said camera - said external surface comprising a portion having an external radius of curvature, and / or - said internal surface comprising a part having an internal radius of curvature.

[0019] In a particular embodiment, the external and internal radii of curvature are distinct.

[0020] In one embodiment, the internal radius of curvature is between 50.0 millimeters and 1990.0 millimeters and / or the external radius of curvature is between 50.0 millimeters and 1990.0 millimeters.

[0021] In another embodiment, the external and internal radii of curvature are similar to within 10%.

[0022] In one embodiment, the camera comprises a total field of view, the internal radius of curvature and / or the external radius of curvature being curved over the entire total field of view of said camera.

[0023] In one embodiment, the part of the external surface has a diameter between 5.0 millimeters and 10.0 centimeters and / or the part of the internal surface has a diameter between 5.0 millimeters and 10.0 centimeters.

[0024] In one embodiment, the camera is spaced from the protective panel by a distance varying between 0.5 millimeters and 10.0 centimeters along the main optical axis.

[0025] In another embodiment, the camera is arranged to introduce barrel optical distortion into at least one peripheral area of ​​said image, said protective panel being arranged to introduce said pad optical distortion into said at least one peripheral area.

[0026] In one embodiment, the protective panel is arranged to introduce a maximum offset of 120.00 micrometers on at least a portion of at least one image compared to a portion of an image undistorted by the protective panel, said offset being defined between an object belonging to both at least one image and said undistorted image, said object of the at least one image having a position spatial in at least one image similar to a spatial position of the object in said undistorted image.

[0027] In one embodiment, the protective panel is arranged to reduce the barrel optical distortion introduced by said camera by at least 10%, preferably by at least 50%.

[0028] In one embodiment, the barrel optical distortion obtained on said image is less than or equal to 5% over the whole image or over at least one area of ​​the image.

[0029] In another embodiment, the camera has a total field of view greater than 30 degrees, preferably between 30.0 and 110.0 degrees.

[0030] In one embodiment, the optical element is arranged to introduce on at least one other part of the at least one image a pincushion optical distortion, said protective panel being arranged to introduce on at least one other part of the at least one image a barrel optical distortion in order to compensate for the pincushion distortion introduced by said camera.

[0031] The invention also proposes a display device installed in a vehicle for acquiring at least one image inside said vehicle, said device comprising: - a camera sensitive at least in the infrared range, arranged to acquire said at least one image, said camera comprising a principal optical axis, - a protective panel comprising a secondary optical axis, said protective panel being arranged to mechanically protect said camera, characterized in that said camera comprises at least one optical element arranged to introduce on at least a part of the at least one image an optical distortion, said protective panel being arranged to introduce on at least a part of the at least one image an optical distortion of opposite sign to said optical distortion introduced by the camera, said secondary optical axis being angularly offset from the main optical axis by at least one rotation around an axis transverse to the main optical axis.

[0032] The other embodiments listed above are also applicable to this embodiment.

[0033] In one embodiment, the optical distortion introduced by the camera's optical element is a barrel distortion, while the optical distortion of opposite sign introduced by the protective panel is a pad distortion.

[0034] Of course, in another embodiment, the optical distortion introduced by the camera's optical element is a pincushion distortion, while the optical distortion of opposite sign introduced by the protective panel is a barrel distortion.

[0035] Of course, the various features, variants, and embodiments of the invention can be combined with one another in various ways, provided they are not incompatible or mutually exclusive. Detailed description of the invention

[0036] The following description, with reference to the attached drawings, given by way of non-limiting examples, will make it clear what the invention consists of and how it can be implemented.

[0037] On the attached drawings:

[0038] [Fig-1] is a schematic representation of an embodiment of a device according to the present invention in a top view plane;

[0039] [Fig.2] is a schematic representation of another embodiment of a device according to the present invention in a top view plane;

[0040] [Fig.3] is a schematic representation of an embodiment of a protective panel used in the device according to the present disclosure in a view plane of the protective panel;

[0041] [Fig.4] is a schematic representation of a second embodiment of a protective panel used in the device following the present disclosure in a view plane of the protective panel;

[0042] [Fig.5] is a schematic representation of an example of an image acquired by a camera without the protective panel of the device according to this disclosure and without additional optical element to compensate for distortion induced by the camera;

[0043] [Fig.6] is a schematic representation of the example image acquired from [Fig.5] by a camera illustrated in [Fig.1] as well as an example image acquired by the device according to this disclosure;

[0044] [Fig.7] is a schematic representation of an image of a target without distortion as well as an example of an image acquired by the device according to this disclosure;

[0045] [Fig.8] is a schematic representation of the embodiment of the device illustrated in [Fig.2] in another viewpoint.

[0046] Device

[0047] An example of an embodiment of a vehicle-mounted image capture device 100 according to the present disclosure will be described with the aid of [Fig.1], [Fig.3] and [Fig.4].

[0048] The device 100 illustrated in [Fig. 1] comprises a camera 10 and a protective panel 20. The camera 10 comprises at least one optical element 11. The optical element 11 is, for example, a lens associated with the camera, such as a lens of the objective lens associated with the camera 10.

[0049] By optical element is meant an element which has at least one of the following characteristics following optical characteristics, such as aperture, focal length, field of view, diameter and radius of curvature.

[0050] The camera 10 of the device 100 is an infrared-sensitive camera. For example, the camera is sensitive to near-infrared wavelengths, for example between 780 nanometers and 1400 nanometers. Of course, the camera 10 can also be sensitive to wavelengths in the visible spectrum, for example between 400 nanometers and 780 nanometers (preferably excluding 780 nanometers).

[0051] In the device 100, the camera 10 is arranged to acquire at least one image, in particular an image inside the vehicle.

[0052] In the example illustrated in [Fig.1], the camera 10 has a principal optical axis 12. The principal optical axis 12 is arranged to pass through an optical center of the optical element 11. The principal optical axis 12 is also coincident with an optical axis of the optical element 11.

[0053] The protective panel 20 illustrated in [Fig. 1] is arranged to mechanically protect the camera 10 by partially covering a field of view of the camera 10, particularly from mechanical shocks. According to this disclosure, the protective panel 20 is arranged to protect the camera from at least 10 mechanical shocks in each spatial direction (x, y, z) equal to or less than an acceleration of 500 m / s².

[0054] A protective panel is defined as an element that has at least one of the following mechanical characteristics, such as a level of hardness, a thickness arranged to provide a level of rigidity and / or protection against moderate impacts. For example, the Shore D hardness level is less than 40. Moderate impacts are defined as impacts of less than 500 m / s².

[0055] In this example, the protective panel 20 is made of polycarbonate and has a transparency greater than at least 85% in the infrared, for example for wavelengths between 700 nanometers and 1400 nanometers, preferably between 780 nanometers and 1400 nanometers. In the example considered, the protective panel 20 has a transparency of 89%.

[0056] In the example of device 100, the optical element 11 of the camera is arranged to introduce distortion on at least a portion of the image, and the protective panel 20 is arranged to induce distortion on at least a portion of the image with the opposite sign to the distortion introduced by the optical element 11 of the camera 20. Thus, thanks to device 100, the distortion introduced by the camera 10 is compensated by the distortion introduced by the protective panel while preserving the mechanical properties of the protective panel. Such a device thus makes it possible to locally, simply, and inexpensively cancel the distortion that would have appeared on the image without a protective panel, according to this disclosure. Furthermore, in device 100, it is not necessary to add another optical element in addition to the camera 10 to compensate for the distortion introduced by the camera 10, which improves the size of the device 100, facilitating easier integration of the camera into the interior of the vehicle and also its price.

[0057] By way of example, the distortion introduced by the optical element 11 in at least a part of the image is barrel distortion, while the distortion introduced by the protective panel 20 is pincushion distortion. Barrel distortion is understood to be negative distortion, and pincushion distortion is understood to be positive distortion. This distortion can be represented by Seidel polynomials of order 3. In another example, this distortion can be decomposed into a 3rd-order and a 5th-order aberration in Seidel polynomials.

[0058] The protective panel 20 illustrated in [Fig.1] includes a secondary optical axis 21. By primary optical axis 12 or secondary 21, we mean the optical axis of a centered system which corresponds to the axis of rotational symmetry of this system.

[0059] In the example illustrated in [Fig.1], the secondary optical axis 21 of the protective panel 20 is angularly offset from the main optical axis 12 by at least one rotation around an axis, for example an axis transverse to the main optical axis (x-axis) 12 and / or another axis transverse to the optical axis (y-axis).

[0060] The angular offset is related to the positions of the distortion that one wants to compensate for in the image. The greater the offset (for example, when it is greater than 19 degrees), the more the device 100 is arranged to compensate for the distortion towards the edges or peripheral areas of the image (i.e., less so in the central area of ​​the image). Conversely, a small offset, for example, less than 10 degrees, allows for greater compensation of the distortion towards the center of the image.

[0061] In the first view illustrated by [Fig. 1] (top view), the secondary optical axis 21 is angularly offset from the principal optical axis 12 by a rotation about an axis transverse to the principal optical axis 12, here oriented along the x-axis of the camera frame. As a result, the secondary optical axis is inclined with respect to the principal optical axis 12 at a first angle 30°. By way of example, the first angle 30° is between 0.001 degrees and 40 degrees, preferably between 5 and 19 degrees.

[0062] Optionally, in the device 100, the protective panel 20 of the device 100 comprises an internal surface 23 and an external surface 22 as explained below in the example of [Fig. 3] and [Fig. 4]. Furthermore, the camera 10 is spaced from the protective panel 20 by a distance d varying between 1.00 millimeters and 10.00 centimeters along the main optical axis 12. This point will also be detailed below following [Fig. 3] and [Fig. 4].

[0063] A second example of device 600 will be described with reference to [Fig. 2], [Fig. 3], [Fig. 4], and [Fig. 8]. Device 600 includes all the elements of device 100 illustrated in [Fig. 1]. Thus, only the differences with [Fig. 1] will be described.

[0064] The device 600 illustrated in [Fig.2] and [Fig.8] includes the camera 10 and the protective panel 20. The camera 10 includes at least the optical element 11. The protective panel 20 illustrated in [Fig.2] and [Fig.8] includes a secondary optical axis 21. In this example, the secondary optical axis is angularly offset from the main optical axis 12 by a rotation about the axis transverse to the main optical axis 12, here oriented along the x-axis of the camera frame 10. Typically, the secondary optical axis 21 is inclined with respect to the main optical axis 12 at the first angle 30, which is here 7 degrees.

[0065] In the embodiment illustrated in [Fig. 2] and [Fig. 8] (schematic illustrations), the secondary optical axis 21 is further angularly offset from the main optical axis 12 by a rotation about an axis transverse to the main optical axis 12, here the y-axis. Thus, in this example, the rotation is decomposed into two rotations using the Euler angles R = Rx„R'b where Rxa is a rotation about the initial transverse x-axis of the camera 10 by angle a, with a as the first angle 30°, and Ryb is a rotation about the initial y-axis of the camera 10 by angle b, with b as the second angle 40°. As a result, the protective panel 20 is also inclined relative to the camera 10 at a second angle 40° with respect to the transverse y-axis of the camera, defining a second axis z' for the protective panel 20.

[0066] By way of example, the second angle 40 is between 0.001 degrees and 40 degrees, preferably between 5 and 19 degrees. Such a shift makes it possible to compensate for the distortion introduced by the camera 10 in different areas of the image, for example in peripheral areas of the image (or the edges of the image) and in areas near the center of the image.

[0067] In the example illustrated in [Fig.2] and [Fig.8], the first angle 30 is equal to 7 degrees and the second angle is equal to 17 degrees.

[0068] Design examples of the protective panel 20 used in devices 100 and 600 will now be described with reference to [Fig. 3] and [Fig. 4]. In the examples shown in [Fig. 1] and [Fig. 2], the protective panel 20 comprises an internal surface 23 and an external surface 22, as shown in [Fig. 3]. The internal surface 23 is oriented towards the camera 10, in particular towards the optical element 11. But in practice, the protective panel 20 is made as described in [Fig. 3] and [Fig. 4].

[0069] In [Fig. 3], the internal surface 23 includes a portion having an internal radius of curvature RI, which in [Fig. 1] and [Fig. 2] is concave (given in the defined direction from the camera 10 towards the protective panel 20). The other portions of the internal surface 23 are preferably flat. Thus, following this example, the secondary optical axis 21 is the optical axis that passes through the center of the internal surface 23. including the radius of curvature RI and which is perpendicular to a plane of the internal surface 23 including said radius of curvature RI.

[0070] By way of example, the internal radius of curvature RI is between 50.00 millimeters and 1990.00 millimeters. In the illustrated example, the internal radius of curvature RI is 55.16 millimeters.

[0071] The curved portion of the internal surface 23 has a diameter between 5.00 and 10 centimeters. In the illustrated example, the diameter of the radius of curvature RI is 10 millimeters.

[0072] Furthermore, in the example of [Fig.1] and [Fig.2], the camera 10 is spaced from the protective panel 20 by a distance d varying between 1.00 millimeter and 10.00 centimeters along the main optical axis 12. In this embodiment, the distance d is defined between the optical center 13 of the optical element 11 and the optical center 24 of the part having the radius of curvature RI.

[0073] By way of example, the camera 10 comprises a total field of view of, for example, 60 degrees. Following this example, the internal radius of curvature RI is curved over the entire total field of view of said camera 10. Such an arrangement makes it possible to correct distortion in all parts of the image. Therefore, the diameter of the curved portion (internal radius RI) of the internal surface 23 is adapted to the total field of view of the camera 10. It is thus chosen with respect to the total field of view of the camera so as to cover it entirely.

[0074] Figure 4 also illustrates another example of a panel embodiment The protective panel 20 in this example has an internal surface 23 with a radius of curvature RI, as shown above in [Fig. 3]. Furthermore, the external surface 22 of the protective panel 20 includes a portion with an external radius of curvature R2. "External" refers to a surface positioned on the side of an object viewed by the camera. The external radius of curvature R2 is arranged to introduce an additional distortion identical to the distortion introduced by the radius of curvature RI of the internal surface 23. This arrangement improves the correction of the distortion introduced by the camera 10. In [Fig. 4], the external radius of curvature R2 is positioned relative to the internal radius of curvature RL. Thus, the optical center of the internal radius of curvature RI and the optical center of the external radius of curvature R2 are aligned on the secondary optical axis 21 of the protective panel 20.

[0075] Preferably, in this embodiment, the internal radius of curvature RI is concave and the external radius of curvature R2 is convex. Of course, in another embodiment, the external radius of curvature R2 may be concave.

[0076] In this embodiment illustrated in [Fig. 4], the internal radius of curvature RI and the external radius R2 are similar to within 10% in absolute value. Preferably, the radius The radius of curvature R2 of the external surface 22 differs by ±10 percent from the radius of curvature RI of the internal surface 23 in absolute value. This characteristic helps maintain the optical quality of the device 100, 600. Typically, no drop in the modulation transfer function, also called MTF, is observed with such an arrangement of the device 100, 600 following the addition of the curvature R2 of the external surface 22. As an example, the internal surface 23 has a radius of curvature RI of 55.17 millimeters and a diameter of 10.00 millimeters, while the external surface 22 has a radius of curvature R2 of 55.00 millimeters and a diameter of 10.00 millimeters.

[0077] In this example, the difference between the radius of curvature RI and the radius of curvature R2 is therefore less than 0.1%. This arrangement thus improves the optical qualities of the device 100, 600 and therefore results in a higher quality image (i.e., less distorted than an image obtained with a protective panel that does not introduce distortion and / or compared to an image obtained with the embodiment illustrated in [Fig. 3]). Thus, in this embodiment, the internal radius RI and the external radius R2 are optimized (i.e., selected) to improve the overall performance of the device 100, 600.

[0078] In another example of this embodiment, the external surface 22 may be specified by the manufacturer (styling constraints in the vehicle). In this case, the internal radius of curvature RI of the internal surface 23 is optimized to maximize an optical function of the device 100, 600. Its optimization may depend on the external radius of curvature R2 of the external surface 22, the inclination of the protective panel 20, and an optical index of the protective panel 20, which, in this example, is the optical index of polycarbonate. Figure 8 illustrates such an example. In this example, the internal radius of curvature RI and the external radius of curvature R2 have a similar optical design, that is, differing by no more than ±10 percent in absolute value, preferably less than ±1 percent.

[0079] Thus, in the two examples illustrated by [Fig. 4] and [Fig. 8], the internal radius of curvature RI is optimized with respect to the external surface 22 and therefore depends on the external radius of curvature R2. Optimizing the internal radius of curvature RI of the internal surface 23 with respect to the external surface 22 will maximize the overall optical function of the device 100 and 600. By overall optical function, we mean a function that allows us to assess the optical quality of the device 100 and 600. For example, the optical function can be based on the optical transfer function (MTF) or on the point spread function (PSF). Such an arrangement makes it possible to obtain a device with a better optical function.

[0080] Figure 5 illustrates an example of an image acquired by a camera having barrel-type optical aberration. For this image, a test pattern is imaged by the camera. The test pattern displays at least one letter and a perfect grid of straight lines. The acquired image illustrated in Figure 5 is not corrected by the distortion introduced by the protective panel.

[0081] In this example, the camera used has a total field of view of 44 degrees x 36 degrees. This camera uses an optical element exhibiting barrel distortion equal to or less than 4 pixels, preferably on the order of 3-4 pixels of shift at the edges of the camera's total field of view. The camera 10 has a sensor with pixels of size 3 micrometers. The image acquired 200 in this example thus has peripheral parts 201, 202, 203, 204 near the corners of the image 200. The peripheral parts 201, 202, 203, 204 exhibit barrel distortion. The peripheral parts 201, 202, 203, 204 each correspond to a square of four pixels positioned at a corner of the image 200.

[0082] Figure 6 compares the image acquired in Figure 5 with an image acquired by device 100 or 600, for example, the one shown in Figure 1, Figure 2, Figure 3, or Figure 4. The camera 10 of device 100 or 600 is identical to the camera used in the example in Figure 5. Thus, images 200 and 300 are the same size. The camera 10 used imaged the same object, here a target representing a grid and a letter (letter F).

[0083] In this example, the protective panel 20 has a radius of curvature RI on its inner surface 23 of 55.17 millimeters and a diameter of approximately 10.00 millimeters. The protective panel 20 has a radius of curvature R2 on its outer surface 22 of 55.00 millimeters and a diameter of approximately 10.00 millimeters. Furthermore, the external surface 22 of the protective panel 20 is located 6.2 millimeters from the surface of the optical element 11 of the camera 10 positioned with respect to the internal surface 23 of the protective panel 20. The protective panel 20 has a thickness of 2.3 millimeters oriented along the main optical axis 12. In this example, the secondary optical axis 21 is angularly offset from the main optical axis 12 by a rotation around the initial transverse axis x of the camera 10 by the first angle 30 equal to 7.0 degrees and by a rotation around the initial transverse axis y of the camera 10 by the second angle 40 equal to 19.0 degrees.

[0084] Similarly, for image 300, the same target is imaged by device 100 or 600. In this example, image 300 has a peripheral part 301. At the level of the peripheral part 301, image 300 is superimposed with image 200 (at the level of the peripheral part 201 of image 200). The peripheral part 301 of image 300 has a spatial position in image 300 identical to the spatial position of the peripheral part 201 of image 200. In this example, the spatial position is defined using the pixels of the image in question, particularly according to the position of the pixels within the image. Thus, the protective panel 20 does not introduce any additional distortion in the peripheral part 301 of the image 300. The peripheral part 301 of the image 300 exhibits a distortion which, for example, is smaller than the size of a pixel, i.e., on the order of a micrometer (less than ten micrometers). For the other parts of the image 200 and 300, a shift between the image 200 and 300 is observed along a first spatial direction 305 and a second spatial direction 306 of the images 200, 300. In this example, the protective panel 20 is arranged to introduce a maximum shift of 120 micrometers (of opposite sign to the shift introduced by the camera 10) in order to compensate for the distortion introduced by the camera 10. This shift may be different depending on the spatial directions of the image 300.For example, the offset between image 200 and image 300 along the first spatial direction is preferably less than 120.0 micrometers, and the offset between image 200 and image 300 along the second spatial direction is preferably less than 50.0 micrometers. Thus, in this example, the protective panel 20 introduces a distortion of opposite sign, here pincushion distortion, which locally cancels the distortion introduced by the camera 10. The barrel distortion introduced by the camera 10 is compensated, in particular, at the peripheral edges of image 300, here by four-pixel squares positioned in three corners of image 300, which have a spatial position that is similar to or corresponds to the spatial position of the peripheral parts 202, 203, and 204 of image 200.In this example, the protective panel 20 reduced the barrel optical distortion introduced by said camera 10 by at least 10% in areas that have a spatial position similar to the spatial position of the peripheral parts 202, 203, 204 of the image 200. Typically, the barrel optical distortion obtained on said image 300 is less than or equal to 5% on at least the areas of the image 300 (here the three edges of the image 300) that have a position similar to the peripheral parts 202, 203, 204 of the image 200.

[0085] Figure 7 compares another image 400 obtained with device 100 or 600 and an image 500 of a target that would be obtained if the camera 10 introduced no distortion, here barrel distortion, onto the image. Images 400 and 500 are the same size. In this example, the protective panel 20 has a radius of curvature RI on its inner surface 23 of 55.17 millimeters and a diameter of 10 millimeters. The protective panel 20 has a radius of curvature R2 on its outer surface 22 of 55.00 millimeters and a diameter of 10 millimeters. The same target is used for the acquisition of images 400 and 500. This target has a grid and a letter (letter F). In this example, image 400 has a portion 405, here approximately 3x8 pixels in size. In this section 405, the imaged target from image 400 is superimposed with The target of image 500. Thus, part 405 of image 400 shows no distortion. The letters of each image 400 and 500 overlap. In this example, the barrel distortion obtained on said image 400 is less than or equal to 5% over the entire image 400.

[0086] Variants

[0087] The present invention is in no way limited to the embodiments described and represented, but a person skilled in the art will be able to make any variation in accordance with the invention.

Claims

Demands

1. A vehicle-mounted image capture device (100, 600) for acquiring at least one image (300, 400) inside said vehicle, said device (100, 600) comprising: - a camera (10) sensitive at least in the infrared arranged to acquire said at least one image (300, 400), said camera (10) comprising a principal optical axis (12), - a protective panel (20) comprising a secondary optical axis (21), said protective panel (20) being arranged to mechanically protect said camera (10) by covering at least part of the field of view of said camera (10), characterized in that said camera (10) comprises at least one optical element (11) arranged to introduce barrel optical distortion onto at least part of the at least one image (300, 400), said protective panel (20) being arranged to introduce on at least a part of at least one image (300, 400) an optical pincushion distortion.

2. Device (100, 600) according to claim 1, characterized in that the secondary optical axis (21) is angularly offset from the main optical axis (12) by at least one rotation about an axis transverse to the main optical axis (12).

3. Device (100, 600) according to any one of claims 1 to 2, characterized in that the secondary optical axis (21) is inclined with respect to the main optical axis (12) at a first angle (30).

4. Device (100, 600) according to any one of claims 1 to 3, characterized in that the secondary optical axis (21) is inclined with respect to the main optical axis (12) at a second angle (40).

5. Device (100, 600) according to any one of claims 1 to 4, characterized in that the first angle (30) is between 1 degree and 40 degrees and / or the second angle (40) is between 1 degree and 40 degrees.

6. Device (100, 600) according to any one of claims 1 to 5, characterized in that the protective panel (20) comprises an external surface (22) and an internal surface (23), opposite the external surface (22) and oriented towards said camera (10): - said external surface (22) comprising a portion having an external radius of curvature, or - said internal surface (23) comprising a part having an internal radius of curvature.

7. Device (100, 600) according to claim 6, characterized in that the internal radius of curvature is between 50.00 millimeters and 1990.00 millimeters and / or the external radius of curvature is between 50.00 millimeters and 1990.00 millimeters.

8. Device (100, 600) according to claim 7 taken in dependence on claim 6, characterized in that the external and internal radii of curvature are similar to within 10%.

9. Device (100, 600) according to any one of claims 6 to 8, characterized in that the camera (10) comprises a total field of view, the internal radius of curvature and / or the external radius of curvature being curved over the entire total field of view of said camera (10).

10. Device (100, 600) according to any one of claims 6 to 9, characterized in that the part of the external surface (22) has a diameter between 5.0 millimeters and 10.0 centimeters and / or the part of the internal surface (23) has a diameter between 5.0 millimeters and 10.0 centimeters.

11. Device (100, 600) according to any one of claims 1 to 10, characterized in that the camera (10) is spaced from the protective panel (20) by a distance varying between 1.0 millimeter and 10.0 centimeters along the main optical axis (23).

12. Device (100, 600) according to any one of claims 1 to 11, characterized in that the camera (10) is arranged to introduce barrel optical distortion into at least one peripheral area of ​​said image (300, 400), said protective panel (20) being arranged to introduce said pad optical distortion into said at least one peripheral area.

13. Device (100, 600) according to any one of claims 1 to 12, characterized in that the protective panel (20) is arranged to introduce a maximum offset of 120.00 micrometers on at least a part of at least one image (300, 400) compared to a part of an image (500) not distorted by the protective panel (20), said offset being defined between an object belonging both to at least one image (300, 400) and to said undistorted image (500), said object of at least one image (300, 400) having a spatial position in at least one image (300, 400) similar to a spatial position of the object in said undistorted image (500).

14. Device (100, 600) according to any one of claims 1 to 13, characterized in that the protective panel (20) is arranged to reduce the barrel optical distortion introduced by said camera (10) by at least 10%.

15. Device (100, 600) according to any one of claims 1 to 14, characterized in that the optical barrel distortion obtained on said image is less than or equal to 5% over the whole image (300, 400) or over at least one area of ​​the image (300, 400).

16. Device (100, 600) according to any one of claims 1 to 15, characterized in that the camera (10) has a total field of view greater than 30 degrees, preferably between 30.00 and 110.00 degrees.

Images