Aerial camera with electronic global and external shutters

Abstract

An aerial camera with an electronic global shutter and an external shutter. The invention relates to an aerial camera instrument configured to acquire high resolution aerial images from a target area. The aerial camera instrument includes (i) an imaging sensor having an electronic global shutter function, (ii) an external shutter assembly, and (iii) a coupling function configured to synchronize the electronic global shutter function and the external shutter assembly.

Description

Technical Field

[0001] The present invention relates to the structure and operation of an aerial camera instrument configured to acquire high resolution aerial images from a target area. The aerial camera instrument includes an imaging sensor having an electronic global shutter and an external shutter assembly. Background Art

[0002] Aerial cameras are used to survey swaths of land by capturing photographs of the Earth's surface directly below and / or at oblique angles to the aircraft. Some of the key challenges of high-resolution aerial photography are small ground sampling distances, high flight speeds, and the need to survey under varying ambient light conditions.

[0003] Due to the high flight speeds, many methods or technical solutions common in standard photography are undesirable or even simply unsuitable for aerial photography. For example, the commonly applied rolling shutter method (wherein frames are captured not by taking a snapshot of the entire scene at a single moment in time but by rapidly scanning the scene) will lead to a "rolling shutter effect", i.e. a perspective shift during exposure. The rolling shutter effect will lead to complications for software algorithms, which assume that each image is taken at the same moment in time. Therefore, the preferred solution for aerial photography is a global shutter.

[0004] For mechanical shutters, a central leaf shutter is usually used, optionally combined with an adjustable aperture. For large apertures, the shutter speed is the limiting factor, for example, a mechanical leaf shutter is not fast enough to avoid overexposure in strong sunlight.

[0005] The aperture is rarely adjusted during a single flight, so it has almost no wear. On the other hand, the shutter needs to be actuated back and forth for each image. With frame rates up to, for example, 5fps, hour-long flights and multi-camera systems, this can add up to hundreds of thousands of actuations per flight. Therefore, the wear of the shutter cannot be ignored, usually resulting in designs with replaceable shutter mechanisms - increasing size and cost. When the shutter fails during a flight, the flight must be canceled, the shutter replaced and a new flight planned. Therefore, it is desirable to reduce the number of shutter actuations or to get rid of mechanical shutters altogether.

[0006] The availability of very good / sensitive imaging sensors (e.g., back-illuminated CMOS imaging sensors) with electronic global shutters allows the design and construction of compact camera systems that can operate with short integration times. With no moving parts, the switching speed is several orders of magnitude faster than a mechanical shutter, e.g., 1 μs for an electronic shutter compared to 1 ms for a mechanical shutter. Thus, overexposure can be avoided even in the brightest conditions and with large apertures. Contemporary imaging sensors are generally insensitive to light arriving before integration begins because a pixel reset can be performed before then. These properties are also advantageous because sensitivity to blur-causing motion decreases with shorter, more defined illumination times. An electronic global shutter also avoids rolling shutter effects while providing shutter speeds that are practically unachievable with a mechanical global shutter. Additionally, the electronic shutter is extremely precise and repeatable, making it possible to precisely synchronize the exposure of all cameras in a multi-camera setup, which can simplify or speed up the aerotriangulation process because intra-camera exposure delay variations can be ignored.

[0007] Due to the sequential readout of current pixel-based imaging sensors, the readout phase is typically several orders of magnitude longer than the integration phase. Unlike a mechanical shutter, an electronic shutter does not actually block light from reaching the sensor, but blocks charge from moving to a storage node that is protected from incident light but still very close to the photosensitive area. Due to unwanted effects such as reflection and scattering, some photons may unfortunately end up in the storage node. In other words, the imaging sensor is still photosensitive to some extent not only during the integration phase but also at other times including the readout phase via direct or indirect light. This parasitic light signal (PLS) causes imaging artifacts that reduce image quality, especially when the photographic scene includes a high reflectivity surface (such as water, polished metal or glass surface, solar panel) that reflects direct sunlight to the camera. PLS also depends on the wavelength of the light and the type of sensor exposed to the light. The effect is most significant in the near-infrared state, especially 750nm-950nm.

[0008] Typically, due to the relative motion of the camera to the target area, PLS results in long degraded (especially oversaturated) areas on the image data, which are called PLS streaks. There are some post-processing solutions to remove PLS artifacts, such as by interpolation. However, it is desirable to limit the spatial extent, i.e., the length of the PLS streak or its intensity, i.e., to attenuate it from full oversaturation to brightness and color errors.

[0009] Alternatively or additionally, mechanical image stabilization as a function of the current flight speed and the ground sampling distance can also be used by a so-called forward motion compensation (FMC) mount, for example, as disclosed in EP4008995A2. The FMC mount mechanically moves the camera or a part thereof substantially parallel to the flight direction during the integration phase in order to provide image data without forward motion blur. Typically, these types of camera systems operate with additional gyroscopic stabilization mounts to compensate for the aircraft drift angle and blur caused by aircraft vibration and angular motion. Alternatively, a two-axis or three-axis motion compensation (MC) mount that compensates for the aircraft angular motion can be used. The MC mount operates similarly to the FMC mount. Unless otherwise provided, from here on, MC mounts are used as a general term covering both single-axis compensation mounts and multi-axis compensation mounts. Such a system can also be used to mitigate the PLS effect. The disadvantage of the available mechanical solutions is the large construction that results in a large camera body. Furthermore, longer stabilization times (eg, extension to the readout phase) require longer strokes of the MC mounts, which results in an even more complex mechanism. It is therefore desirable to reduce the required stabilization time. Summary of the invention

[0010] Purpose of the invention

[0011] In view of the above, it is an object of the present invention to achieve an improved compact aerial camera instrument providing a high image quality.

[0012] Another object of the invention is to improve the wear behavior and service life of components of aerial camera instruments.

[0013] Another object of the present invention is to reduce the complexity and / or performance requirements of the mechanical components of an aerial camera instrument while maintaining or improving image quality.

[0014] Another object of the present invention is to provide an aerial camera instrument in which the influence of parasitic light is at least reduced, preferably eliminated.

[0015] Summary of the Invention

[0016] The present invention relates to an aerial camera instrument configured to acquire high-resolution aerial images from a target area. A camera instrument in the sense of the present invention means that the instrument may include further components, in particular a support configured to mount the camera instrument to an aerial vehicle. Unless otherwise specified, a camera is to be understood as a separate component that may or may not be mounted on board the airborne vehicle.

[0017] As an example, the target area is a ground target area, in particular a ground target area at least 100 meters from the camera. The airborne vehicle may be a fixed-wing aircraft, a helicopter or a heavy drone. During the acquisition of the aerial photograph, the airborne vehicle (and therefore the camera instrument itself) may take more than 50 ms. -1 or 100 knots relative to the target area.A camera instrument in the sense of the present invention is configured to acquire high resolution aerial photographs with similar specifications.

[0018] The camera instrument of the present invention is particularly suitable for aerial mapping and surveying. Such aerial mapping and surveying systems are foreseen to include one or more camera instruments of the present invention and a scanning LIDAR. LIDAR is designed to scan an extended area, and it is required that the camera system including one or more cameras of the present invention also covers this area, so that the point cloud from the LIDAR can be colored using the image data. In order to make it easier to distinguish vegetation from man-made objects, for example, one or more cameras can acquire aerial photographs in the near infrared spectrum.

[0019] The aerial camera instrument comprises an imaging sensor. The imaging sensor comprises an electronic global shutter function that provides for each pixel a simultaneous start and stop of an integration phase. The integration phase corresponds to capturing light and converting the captured light into a pixel-resolved electronic signal. In other words, for the camera instrument of the invention, the integration phase is only activated by the electronic global shutter function. Depending on the ambient light, the integration phase may be less than 1 ms long, in particular as low as 300 μs long. In other words, a shutter speed of up to 1 / 1000 s, preferably up to 1 / 3000 s, is required.

[0020] The imaging sensor also presents a readout phase. The readout phase corresponds to the transformation of the pixel-resolved electronic signal into digital image data. The readout of the pixels is usually performed sequentially. As a result, the readout phase requires a longer period than the integration phase, in particular its length exceeds 10 ms. Although it is possible in principle, the case of activating the integration phase and the readout phase simultaneously will not be discussed in detail. The specific characteristics of this case can be applied accordingly.

[0021] A variety of sequential readout methods are known to those skilled in the art. A non-exclusive list includes (i) row-by-row readout, where rows of pixels are read out sequentially, (ii) interleaved readout, where, for example, a group of even rows are read out first, followed by a group of odd rows, (iii) random readout, etc. A person skilled in the art will appreciate that while some readout methods will provide synergistic effects to the claimed invention in terms of reducing PLS effects, the claimed invention is not limited to any particular readout technique.

[0022] The aerial camera instrument comprises an external shutter assembly. The external shutter assembly is configured to provide an open state and a closed state. The open state provides light transmission toward the imaging sensor. Compared with the open state, the closed state provides a reduced, in particular at least partially reduced light transmission toward the imaging sensor. The open state and the closed state in the sense of the present invention will be explained by the image data obtained. In particular, the imaging sensor comprises a global electronic shutter, that is, the closed state in the sense of the present invention is a state of a functional part of the global electronic shutter that improves. Or in other words, the amount of light reaching at least the most exposed and / or oversaturated pixels is reduced. This can be achieved by blocking or deflecting the light, or by defocusing / blurring the light, so that the same light intensity is divided by multiple pixels. In other words, the closed state represents a reduced imaging contrast with respect to the open state. External in the sense of the present invention means that the shutter assembly does not play a role in setting the integration phase. In other words, despite the presence of certain artifacts, the aerial camera instrument can obtain high-resolution aerial images from the target area without operating the external shutter assembly. The external shutter assembly can be implemented as a detachable additional assembly or as an integral part of the aerial camera instrument.

[0023] Preferably, the external shutter component is implemented as a dispersive component. A dispersive component in the sense of the present invention is configured to manipulate light and can be based on diffraction or refraction. A non-exclusive list of such dispersive components includes a diffraction grating, in particular a switchable grating, a liquid lens, a liquid crystal shutter, a polymer dispersed liquid crystal or a fourth generation optical component, such as a liquid crystal cell. From here on, unless explicitly stated otherwise (e.g. by referring to a mechanical shutter component), external shutter and external dispersive component are used as equivalents.

[0024] The aerial camera instrument includes a coupling function. The coupling function is configured to provide a configurable coupling of the electronic shutter function with an external shutter assembly. The configurable coupling provides different activation settings of the electronic shutter function and the external shutter assembly relative to each other. Among other options, the coupling function can be implemented by hardware components as part of a computer program product that controls other aspects of the aerial camera instrument, or as a dedicated computer program product for this aspect, and combinations of these embodiments.

[0025] In some embodiments, the connection function is configured to provide different connection settings, i.e., different connection modes, according to different ambient light conditions and / or different reflection conditions associated with the target area. In particular, the connection function can provide that for conditions where the PLS effect is negligible (i.e., cloudy days), the external shutter is not activated. The ambient light conditions can be provided by measurements. The ambient light and / or reflection conditions can be provided manually by operator input. Alternatively, the operator can provide or select certain input data, e.g., clear sky, image acquisition time 3 p.m., and the connection function provides the appropriate mode. Alternatively, the connection function can automatically access the required input data.

[0026] In some embodiments, the aerial camera instrument is configured to access navigation data. Navigation data in the sense of the present invention corresponds to a planned route including a plurality of target areas. The aerial camera instrument is configured to derive different reflection conditions based on the navigation data. The navigation data may in particular provide high reflectivity targets of water surfaces, solar fields, urban areas and similar. In some specific embodiments, the coupling function is configured to provide automatic setting of different activation settings based on the navigation data. Alternatively or additionally, the coupling function may provide a warning signal to the operator about the presence of a high reflectivity object in the target area.

[0027] In some embodiments, the aerial camera instrument, in particular the imaging sensor, provides for measuring the ambient light intensity. For an array comprising a plurality of cameras, another camera may provide ambient light intensity data, and / or the camera instrument of the invention may provide ambient light intensity data for another camera. Alternatively or additionally, the aerial camera instrument provides for determining an expected intensity within an image of the imaging sensor, in particular based on previous digital image data. The coupling function is configured to provide automatic setting of different activation settings depending on the measured ambient light intensity and / or the expected intensity within the image of the imaging sensor.

[0028] In some embodiments, the coupling function is configured to provide automatic setting of different activation settings depending on meteorological information, in particular solar radiation information and / or cloud cover information.

[0029] In some embodiments, the different activation settings include a setting that activates only the electronic shutter function, and a setting that activates both the electronic shutter function and the external shutter assembly. Activating the external shutter assembly only when it is expected to provide a benefit to image quality will reduce the number of activations, i.e., wear and tear on the external shutter assembly. In other words, the service life of the external shutter assembly can be increased.

[0030] In some specific embodiments, the different activation settings include settings in which: (i) an open state of the external shutter assembly is set for the integration phase, and (ii) a closed state of the external shutter assembly is set for at least a portion of the readout phase, in particular for a majority of the readout phase. In other words, the external shutter protects the imaging sensor from artifacts, in particular PLC-related artifacts during the readout phase. One advantage of this setting is that the range of the portion affected by PLC is smaller, which enables more accurate corrections, for example based on interpolation. A randomized and / or structured readout of the pixel-resolved electronic signal can be beneficially combined with such an embodiment. As a further advantage, shorter PLS stripes also make it more feasible to keep the image still with MC.

[0031] In some embodiments, the different activation settings include settings that provide different invocations of the closed state of the external shutter assembly relative to the time interval provided by the readout phase of the imaging sensor. In particular, the closing of the external shutter assembly can be timed so that the highest proportion of the readout phase can be performed in the closed state of the external shutter assembly. Since the integration phase has a negligible length compared to the shuttering of the external shutter assembly, the pixel reset and integration phase of the imaging sensor can be performed when the command to close the external shutter assembly has been provided.

[0032] In some embodiments, the aerial camera instrument further comprises a (forward) motion compensation - (F) MC - unit. Such a MC unit is typically used to reduce motion blur. The MC is configured to (i) derive motion data corresponding to the relative motion of the camera instrument to a target area projected onto a stable plane, and (ii) provide start and stop signals for compensating movement of the camera instrument based on the derived motion data. The coupling function is configured to provide the MC unit with a settable activation setting regarding the coupling to either of the electronic shutter function and the external shutter assembly.

[0033] In some specific embodiments, the coupling function is configured to provide a stop signal for compensating movement of the camera instrument, the stop signal: (i) in a first MC coupling mode, in response to a shutter closed notification, indicating a closed state of the external shutter assembly, (ii) in a second MC coupling mode, in response to a readout start notification, indicating a readout phase of the imaging sensor, and (iii) in a third MC coupling mode, in response to a readout stop notification, indicating readout completion. The first MC coupling mode and the second MC coupling mode correspond to settings regarding activation of the external shutter assembly.

[0034] In the first MC mode, providing a compensating movement until the external shutter assembly is closed and artifact-free is expected improves image quality. The advantage of such an embodiment is that the MC stroke must be extended to cover only the shutter cycle of the external shutter assembly rather than the entire readout phase. Such an embodiment of the invention is advantageously suitable for refurbishment of existing systems, because instead of replacing the complete MC mechanism, installing an ultimately simple and relatively inexpensive external shutter assembly can provide a similar performance increment.

[0035] The second MC coupling mode refers to prior art practice where the compensating movement is suspended when the integration phase is stopped. This mode can be advantageously utilized when the ambient light conditions and / or reflective conditions associated with the target area do not require the use of extended compensating movement and / or the use of external shutter components.

[0036] The third MC coupling mode corresponds to the case where motion compensation is active for the entire acquisition of the image. The disadvantage of this mode is that longer MC strokes are required. However, advantageously, there is usually a PLS effect with high levels of ambient light. Therefore, almost no MC motion is required during the integration time, so all strokes can be used for PLS compensation. For low ambient light conditions, long strokes are required during the integration phase, but not during readout.

[0037] As an example, the MC unit is described by a single-axis FMC unit. The invention is not limited to such a system and is equally applicable to multi-axis MC units having a second stabilization plane and / or configured to provide rotation compensation. Furthermore, in particular for multi-axis MC units, alternative compensating movements can also be performed during shutter closure of the external shutter assembly. In particular, the MC unit can provide a movement orthogonal to the direction of movement so that the PLS stripes become wider and therefore less bright. Alternatively, the MC can provide a compensating movement so that continuous PLS stripes become a series of bright spots covering a much smaller image area.

[0038] In some embodiments, the imaging sensor is specifically implemented as a back-illuminated CMOS imaging sensor including at least 4000×4000 pixels and is configured to provide a refresh rate of at least 1 image / second. In some specific embodiments, the imaging sensor is specifically implemented as an RGB sensor, and / or a full-color sensor, and / or a sensor configured to provide near-infrared images. The photosensitive area of ​​the imaging sensor is smaller than the area of ​​a full-frame imaging sensor, in particular, the diagonal of the photosensitive area is 19.3 mm.

[0039] In some embodiments, the external shutter assembly is embodied as a mechanical shutter, in particular a central leaf shutter, which is configured to completely block light transmission toward the imaging sensor in a closed state.

[0040] In some specific embodiments, the mechanical shutter is configured to provide a mechanical shutter speed of at least 1 / 50 s. In other words, the shutter closure of the mechanical shutter is independent of the integration time. The shutter closure of the mechanical shutter is configured to ensure a minimum amount of additional pixel oversaturation.

[0041] In some embodiments, the electronic global shutter is configured to provide an electronic shutter speed of at least 1 / 2000 s and a shutter efficiency exceeding 1000, wherein the shutter efficiency corresponds to the sensitivity difference during the integration phase and the readout phase.

[0042] In some embodiments, the external shutter assembly is specifically implemented as a liquid crystal (LC) shutter. The LC shutter is configured to provide a contrast ratio of more than 100. The electronic global shutter is configured to provide an electronic shutter speed of at least 1 / 2000s. Although LC shutters themselves cannot suppress artifacts like PLS, according to the present invention, they are not used as independent components, but as auxiliary components to improve the shutter efficiency of the electronic shutter function. LC shutters are advantageous because they do not exhibit mechanical components, so their shutter speeds are not limited to mechanical movement and do not experience mechanical wear. In particular, shutter speeds of up to 1 / 5000s can be achieved using contemporary designs.

[0043] In some embodiments, the external shutter is specifically implemented as a dispersive element with a variable scattering state. In particular, the dispersive element (i) includes an element with a polymer dispersed liquid crystal (PDLC), and / or (ii) is configured to provide a shutter speed of at least 1 / 50 s. In PDLC, liquid crystals are dispersed in the form of small droplets within a solid polymer substrate. When no voltage is applied, the crystals are randomly aligned in each droplet. Since the liquid is strongly birefringent, this change in orientation leads to a change in the refractive index. The change in refractive index in turn diffuses the light because the light is refracted in different directions at each polymer-LC interface. When a voltage is applied, all LC molecules in all droplets align with the electric field, thereby eliminating the change in refractive index and making the device clearly visible. A disadvantage of contemporary PDLC is the slow transparent to diffuse switching because it is based on passive release. Typical switching times are in the range of tens to hundreds of milliseconds.

[0044] In some embodiments, the aerial camera instrument includes a support element configured to provide a releasable fit between an external shutter assembly and a housing of the camera instrument. These embodiments are advantageous because they allow the external shutter assembly to be retrofitted to an existing aerial camera system. In addition, such a system allows for easy replacement of a worn shutter. The support element can be implemented by (i) a bayonet mount, (ii) a groove or rail mount, (iii) a threaded mount, and (iv) a quick release unit. Those skilled in the art will appreciate that the above list is non-exhaustive and may include any other suitable alternatives.

[0045] Alternatively, an external shutter assembly (particularly when it is implemented as a dispersive assembly) can be placed between the imaging optics and the imaging sensor. Unlike a mechanical shutter, such a dispersive element typically contains no moving parts, so ease of replacement is not particularly important. By placing the dispersive element close to the imaging sensor, the size can be reduced, and thereby the cost and environmental impact can be reduced.

[0046] In some embodiments, the external shutter component is embodied as a dispersive component.

[0047] In some embodiments, the dispersive element comprises a switchable diffuser. In some specific embodiments, the diffuser comprises (a) a first transparent solid component, in particular a first glass plate, (b) a second transparent solid component, in particular a second glass plate, and (c) a liquid component, in particular a liquid crystal, arranged between the first solid component and the second solid component, and (d) an electro-actuated element electrically coupled to the liquid component and configured to provide an open state and a closed state by applying a first electrical signal and a second electrical signal to the liquid component, respectively, in particular wherein the first electrical signal and the second electrical signal are provided by square wave signals. In some specific embodiments, the peak-to-peak voltage exceeds 50V, in particular exceeds 100V.

[0048] Switching from the closed state to the open state and from the open state to the closed state is possible in the millisecond range, in particular 1-3 ms or better. The liquid component is preferably implemented as a thin liquid film, in particular with a thickness of 1-15 μm, in particular 2-10 μm, more in particular about 5 μm. Such a low thickness is advantageous because it allows a high transmission rate of more than 90% in the open state. In addition, a low thickness also allows lower voltages, because the field strength is the voltage divided by the thickness.

[0049] Such components are based on switching the homogeneity of the refractive index of a liquid crystal material. In the transparent or open state, the material is homogeneous and therefore does not scatter. In the diffuse or closed state, the refractive index varies randomly, so the material becomes opaque. Liquid crystals are very suitable for this because they offer strong birefringence, i.e. the difference in refractive index depends on the orientation. By orienting all molecules in the same direction, the material becomes transparent, by randomizing the orientation, the material becomes opaque. The difference lies in how the orientation is modulated.

[0050] In some embodiments, the external dispersive component includes a liquid lens. The liquid lens contains a transparent liquid formed into the shape of a lens by a thin, flexible transparent membrane. By pumping more or less liquid into the lens cavity, the power of the lens can be changed. Typically, the pump is implemented using a voice coil actuator that pushes onto another part of the membrane and can achieve switching speeds of 1 ms. To compensate for temperature-induced effects, the lens usually has a built-in temperature sensor and a controller that adjusts the voice coil current.

[0051] In some embodiments, the external dispersive component comprises a diffraction grating. In particular, the diffraction grating can be embodied as a switchable grating comprising a structured alignment layer formed by liquid crystal. The camera instrument of the present invention collects light over a large area and angular spectrum at the same time, so the switchable grating will need to provide a very large steering angle to move the steered image enough to completely separate it from the main image. It also needs to have good diffraction efficiency (low zeroth order) over a large bandwidth. However, in order to suppress PLS and similar broadband artifacts, a wavelength dependence of the steering angle is advantageous due to the reduced intensity of the higher order parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] By way of example only, specific embodiments of the present invention will be described more fully hereinafter with reference to the accompanying drawings, in which:

[0053] Figure 1 An aircraft is shown performing aerial photography over an area including objects having different reflectivities.

[0054] Figure 2a A schematic diagram of a CMOS imaging sensor is shown.

[0055] Figure 2b Schematic diagram showing the appearance of parasitic light signals in a CMOS imaging sensor.

[0056] Figure 3a A schematic effect of a mechanical global shutter is shown.

[0057] Figure 3b A schematic effect of an LC-based external shutter is shown.

[0058] Figure 3cSchematic effects of an element with polymer dispersed liquid crystal are shown.

[0059] Figure 3d and Figure 3e A schematic diagram of a switchable diffuser based on fourth-generation optics is shown.

[0060] Figures 4a to 4c Some embodiments of the coupling function are schematically shown.

[0061] Figure 5 An embodiment of a coupling function providing a first MC coupling mode is schematically shown.

[0062] Figure 6 Input data and output data related to the coupling function are schematically shown.

[0063] Figures 7a to 7d Schematically shows the switched-on state and some options for reducing the light intensity by various dispersive elements. DETAILED DESCRIPTION

[0064] Figure 1 An aerial camera instrument 1 is shown carried by an aircraft 4 for acquiring high-resolution aerial images from a target area 2 when the aircraft 4 moves relative to the target area 2 in a flight direction 40. The camera instrument 1 is usually mounted together with further survey elements and cameras aligned in a known manner relative to the general flight direction 40. The depicted camera faces the nadir ("vertically downward"). Alternative mountings (e.g. the camera may be pointed obliquely to one side or forward or backward with respect to the flight direction 40) are also within the meaning of the invention. Relative movements of the field of view 20 (in particular the projection of said movements into a stable plane 400 corresponding to the flight direction 40) can be compensated by a fine mounting.

[0065] The depicted target area 2 includes areas with different reflectivities, such as a forest 22 or a river 21. The latter are considered to be partially mirror-like surfaces. In other words, a non-negligible portion of the light 290 from the sun 29 is reflected by the mirror surface. Since the sun disk appears to be ~50,000 times brighter than a diffuse white surface, the light 230 of the mirror reflection 23 can be several orders of magnitude brighter than light from other sources. Contemporary mechanical shutters are not fast enough to avoid overexposure of large aperture lenses, so electronic shutters are used. The disadvantage of electronic shutters is that they cannot completely prevent light from entering the sensor, especially causing an electronic response. This prevents modern electronic shutters from completely blocking the reflected light 230.

[0066] Figure 2aA general back-illuminated CMOS imaging sensor 10 is shown having a plurality of pixels 100. Although many features of the present invention will be described in conjunction with a back-illuminated CMOS imaging sensor 10, the present invention is not limited to this particular type of imaging sensor 10. Specific features of different types of imaging sensors 10 may be applied accordingly.

[0067] The pixels 100 of the depicted imaging sensor 10 each comprise a photosensitive domain 11 (ie comprising an active cell such as a photodiode), a storage domain 12, a blocking shield 13, corresponding electronic wiring 14 and an optional microlens 15. The microlens 15 improves the light collection efficiency.

[0068] The photosensitive domain 11 converts the captured light 110 into electrical charges 119. The electrical charges 119 are then accumulated 120 in the storage domain 12, for example via a drift mechanism, providing pixel-resolved electrical signals 121. In a readout phase, the pixel-resolved electrical signals 121 are accessed 140 via the electronic wiring 14 to provide electronic image data 141.

[0069] Although Figure 2a shows the normal operating mode of the CMOS sensor 10 during the integration phase, but Figure 2b The generation of an electrical signal 121 caused by parasitic light 111-114 in a light-insensitive state of the sensor 10 is shown. In the light-insensitive state, charge generation in the photosensitive domain 11 and / or charge transfer from the photosensitive domain to the storage domain 12 is minimal. However, due to the parasitic light 111-114 reaching the storage domain 12 directly, an electrical signal 121 may be generated or modified. The light may pass through 113 an incompletely blocking shield 13, may reach the storage domain directly at an oblique incident angle 112, or the incident light 111 may be reflected / scattered 114 by the metal wiring 14 towards the storage domain 12. Since the readout corresponding to the light-insensitive state is typically several orders of magnitude longer than the actual integration, the bright incident light 111-113 may result in a sizable electrical signal 121.

[0070] Figure 3aThe effect of a mechanical shutter 30 (particularly a central leaf shutter) transitioning 309 to a closed state is shown. For reasons of clarity, the shutter 30 and the sensor 10 are not to scale. Since the mechanical shutter 30 is an external shutter component, it can provide complete coverage and can be made thick enough to completely block incident light 113, unlike the blocking shield 13. In other words, in the closed state of the mechanical shutter 30, no light is emitted toward the imaging sensor 10. However, it is important to note that the integration phase is provided solely by the imaging sensor 10, i.e., the global electronic shutter prevents charge transfer between the photosensitive domain 11 and the storage domain 12. The mechanical shutter 30 is only used to block parasitic light. Therefore, the shutter speed requirements of the mechanical shutter 30 are relaxed. Therefore, a slower (i.e., cheap and / or robust) mechanical shutter 30 is able to perform the required function.

[0071] Figure 3b The LC shutter 31 is shown during a transition, wherein a portion is transformed into a closed state 311 and another portion remains in an open state 310. Since the transition is rapid, this does not represent a typical situation. Those skilled in the art will appreciate that the electronic global shutter provides a primary shutter effect for the camera apparatus of the present invention. The purpose of the LC shutter 31 is to sufficiently suppress incident light 113 so that light transmitted 118 toward the imaging sensor 10 in the closed state does not provide significant artifacts, particularly artifacts associated with the PLC. As a result, the shutter speed and contrast requirements of the LC shutter 31 are relaxed. That is, a slower and less performing (i.e., cheaper and / or more transparent) LC shutter 31 (which cannot be applied as a stand-alone shutter) can perform the desired function.

[0072] Figure 3c An external shutter assembly is shown including an element having a polymer dispersed liquid crystal 32 in a closed state. This design is similar to Figure 3b The LC shutter of 110 operates similarly, with the added effect that the incident light 113 is dispersed, i.e., the transmitted light 118 affects multiple pixels of the imaging sensor 10, each with a reduced intensity. In other words, the contrast of the resulting digital image is reduced. While high contrast is generally beneficial, the reduction in contrast reduces the intensity of the PLS artifacts, ideally to a level comparable to the background noise. Even for situations when PLS affects the resulting image, avoiding oversaturation is beneficial for correction through post-processing.

[0073] Figure 3dAn example of a switchable diffuser 35 is shown. The depicted diffuser 35 comprises a first glass plate as a first transparent solid component 358 and a second glass plate as a second transparent solid component 359. Respective transparent electrodes 356, 357 are arranged on the outside of the transparent solid components 358, 359. The electrodes 356, 357 may comprise indium tin oxide, graphene or a suitable alternative conductive material. Alternatively, the respective transparent solids 358, 359 may be made of such a conductive material or include a conductive region.

[0074] Electrodes 356, 357 are connected to respective poles of an electro-actuated element 391 (depicted as a signal generator). The electro-actuated element 391 is configured to provide a first electrical signal and a second electrical signal to electrodes 356, 357. Electrical signals in the sense of the present invention may be specific electrostatic states provided by electrodes 356, 357. The first electrical signal may be a charged state that generates an electric field between electrodes 356, 357, and the second electrical signal may be the absence of the electric field. The first electrical signal may correspond to a first polarity of the electric field between electrodes 356, 357, and the second electrical signal may correspond to a second polarity that is the opposite polarity of the first polarity. Alternatively, electrical signals in the sense of the present invention may relate to dynamic states of the electric field. In particular, the first electrical signal may be an electrical waveform of a higher frequency than the second electrical signal. Alternatively or additionally, the first electrical signal has a higher amplitude than the second electrical signal. Those skilled in the art will appreciate that all of the listed options may also be implemented in a mirrored manner, i.e., exchanging the roles of the first electrical signal and the second electrical signal.

[0075] The depicted diffuser 35 also includes a liquid component disposed between a first solid component 358 and a second solid component 359. The left hand panel shows an open state 350 of the liquid component when an electric field is provided by an electro-actuated element 391. The right hand panel shows a closed state 351 in the absence of a field. The liquid is transparent to light in the open state 350, but is opaque in the closed state 351. Opaque in the sense of the present invention may also include a hazy translucent or "milky" state.

[0076] For applications requiring a rapid transition toward the closed state 351, an electrically activated closed state 351 is preferred, such as Figure 3e As shown. It is known that reverse mode polymer dispersed liquid crystal or dynamic scattering based diffusers provide this effect. However, the present invention is not limited to the above-mentioned embodiments.

[0077] Figure 4aA first embodiment of the coupling function 7 is shown using a timeline depicting the states 600-602 of the imaging sensor 10, the commands 603, 604, 606, 608 provided by the electronic global shutter 6, the states 300, 301, 307, 309 of the external shutter assembly 3, the commands 306, 308 provided by its controller 39, and the activation commands 706, 708 provided by the coupling function 7 in the category axis (n). Figures 4a to 5 In the diagram, a bar represents a specific phase or state, wherein transition phases are marked with a dotted pattern, a triangle represents a command to transition to a specific phase or state, and a circle represents a notification indicating the presence or arrival of a state. For the sake of clarity, only the command sequence for a single camera is shown. In a multi-camera system, it is also necessary to synchronize multiple cameras. Therefore, a single camera will receive a trigger from an external source, which starts the sequence. The present invention is applicable to both cases.

[0078] In the depicted embodiment, the starting state is such that the imaging sensor 10 is in a dark phase 601, i.e., neither light integration nor pixel-resolved electronic signal readout. The external shutter assembly 3, in particular a mechanical shutter, is in a closed state 301. In order to take into account the variable delay of the mechanical shutter, an external shutter open command 306 is first generated, which causes the external shutter assembly 3 to transition 307 from the closed state 301 to the open state 300. The coupling function 7 provides 706 an integration start 606 command to the electronic global shutter 6 with a delay corresponding to the transition phase 307 of the external shutter assembly 3. In response to the integration start command, the imaging sensor 10 changes to the integration phase 600. The electronic global shutter 6 and the imaging sensor 10 can provide the integration phase 600 without any significant transition. The imaging sensor 10 is also provided with a pixel reset 603, which results in discarding any pixel-resolved signal corresponding to the previous phase, in particular the dark phase 601. Then, the electronic global shutter 6 provides an integration stop 608 command, for which the imaging sensor 10 terminates the integration phase 600. In parallel, a readout start 604 command is also provided, which sets the imaging sensor 10 to the readout phase 602. In response, the coupling function 7 also provides 708 an external shutter close command 308. A delay is provided 708 to the command, which is not strictly necessary. In response, the external shutter assembly 3 transitions 309 from the open state 300 to the closed state 301.

[0079] Although Figure 4ais a diagrammatic representation of the concept and is not drawn to scale for the purposes of this description, but it is generally clear that the readout phase 602 is much longer than the integration phase 600. The transitions 307, 309 of the external shutter assembly 3 are of comparable length at being no longer than the integration phase 600. Ideally, the major part of the readout phase 602 is associated with the closed state 301 of the external shutter assembly 3, and only the closing of an insignificant part of the readout phase 602 is performed in the open state 300 of the external shutter assembly 3.

[0080] Figure 4b An alternative embodiment of the coupling function 7 is provided. In the depicted case, the command 306 to transition 307 the external shutter assembly 3 from the closed state 301 to the open state 300 is provided well in advance, but independently of the integration start command 606. Since the imaging sensor performs a pixel reset 603, it is expected that opening the external shutter assembly significantly earlier than the integration start 606 will not cause adverse effects. The integration stop command 608 not only stops the integration phase 600 of the imaging sensor 10, but also causes 708 the generation of the external shutter closing command 308 without delay. In response, the external shutter assembly 3 transitions 309 from the open state 300 to the closed state 301.

[0081] Figure 4c An embodiment of the coupling function 7 is shown, wherein the external shutter assembly 3 is permanently in an open state 300. The coupling function 7 receives 707 a notification 304 about the open state 300 of the external shutter assembly 3, whereas the global electronic shutter function 6 provides commands to start 606 and stop 608 an integration phase 600 of the imaging sensor 10, which is essentially disconnected from the controller 39 of the external shutter assembly 3.

[0082] Those skilled in the art will understand that Figures 4a to 4c Some notable features of some possible embodiments of the connection function are shown. The connection function may include further features, in particular accessing and processing further data. Furthermore, the depicted embodiments are non-exclusive and alternative implementations of the connection function are within the meaning of the claimed invention.

[0083] Figure 5An embodiment of a coupling function 7 is shown for performing coupling of the MC 8 with the external shutter assembly 3 according to a first MC coupling mode. The MC 8 comprises a corresponding controller 89. The MC 8 provides a compensating movement 80 in a movement compensation phase 800, which phase can be separated from a non-compensating phase 802 of the MC 8 by a transition phase 803. The corresponding start signals 306, 606, 806 are asynchronous. Due to the different time scales involved, the controllers 39, 89 of the external shutter assembly 3 and the MC 8 can perform corresponding actions independently of each other and independently of the electronic global shutter 6. Furthermore, the imaging sensor 10 can perform as Figure 4a The pixel reset depicted in , therefore, can largely ignore any events that occur before the integration phase 600. These embodiments and other similar embodiments are also within the meaning of the present invention.

[0084] In the depicted embodiment, the coupling function 7 provides 708 a command 308 to transition 309 to the closed state 301 of the external shutter assembly 3 based on the signal to stop 608 the integration phase 600 and start 604 the readout phase 602. According to the first MC coupling mode, the coupling function 7 provides 782 a stop signal 808 for compensating the movement in response to the shutter closed notification 305, indicating the closed state 301 of the external shutter assembly 3. Further MC coupling options, in particular a second MC coupling mode and a third MC coupling mode, may be similarly provided.

[0085] Figure 6 Some possible options for the connection function 7 are schematically depicted, shown by data flows. The data flows are represented by dashed lines. By way of example, the connection function 7 receives as input data operator input data 700, ambient light sensor data 710, weather data 720, navigation data 730, and previous image data 142. A person skilled in the art will appreciate that further embodiments of the connection function 7 of the present invention may receive as input data only a portion of the mentioned data, or may receive further input data.

[0086] Operator input data 700 may include, in particular, preferred or mandatory settings, such as aperture size, image refresh rate, disconnecting an external shutter assembly. Operator input data 700 may include manual settings, such as sensor resolution, time of day, weather preparation settings, whether day or night photography is performed, or mission-related data.

[0087] The ambient light sensor data 710 may be provided by an external sensor or by the camera instrument itself, in particular, the ambient light sensor data 710 may be derived from processing previous image data 142. In the sense of the present invention, the meteorological data 720 include in particular data about current ambient light conditions and forecasts about future ambient light conditions, i.e. solar radiation data 721 or cloud cover data 722.

[0088] In one aspect, navigation data 730 may include the travel speed of the aircraft, which is associated with MC control commands 890 and MC activation settings 78. Of particular importance is target area reflectivity data 731, which provides information about shiny surfaces that are associated with PLC problems.

[0089] The connection function 7 can process the ambient light sensor data 710 and / or the meteorological data 720 and / or the navigation data 730 and / or the previous image data 142 to calculate the expected intensity data 143 about the possible pixel oversaturation. The activation setting 73 of the external shutter component, the activation setting 76 of the electronic global shutter 6 and the activation setting 78 of the MC can be selected based on the expected intensity data 143 and the constraints between the settings 73, 76, 78. Alternatively or additionally, a part of the input data can be directly processed. The external shutter control command 390 and the MC control command 890 are provided based on the corresponding settings 73, 76, 78 about the state of the electronic global shutter function 6 and the command provided to the electronic global shutter function 6.

[0090] The coupling function 7 may also provide output data 799 , in particular regarding the selected activation settings 73 , 76 , 78 of the operator.

[0091] Figures 7a to 7d The open state 350 is schematically shown, as well as some options for reducing the light intensity by various switchable dispersive elements 33-35. For clarity in the depicted embodiment, the dispersive elements 33-35 are arranged in front of the imaging sensor 10. While these embodiments allow the size of the dispersive elements 33-35 to be reduced, which results in reduced cost, power consumption and environmental impact of manufacturing, other embodiments of the invention are also possible. In particular, the switchable dispersive elements 33-35 can be placed in front of a camera instrument (not shown) as a reproducible add-on component.

[0092] Figure 7a350 represents an open state of the switchable diffuser. In particular, in the depicted case, the open state 350 corresponds to a high transmission state, wherein the incident light 113 is transmitted toward the imaging sensor 10 with substantially no losses, and in particular, the intensity of the transmitted light 118 is at least 90% of the incident light 113. Those skilled in the art will appreciate that, while high transmission is preferred, the present invention may also be implemented with a dispersive element having a lower transmittance. In particular, some states of the liquid crystal shutter may provide less than 60% transmission in the open state. Figure 7a In the illustrated embodiment, the open state 350 of the diffuser provides no imaging, ie, the transmitted light rays 118 substantially follow the beam path of the incident light 113. Other embodiments of the external dispersive component may have additional imaging functionality and provide focusing in the open state 350.

[0093] Figure 7b The switchable diffuser is shown in a closed state 351. The switch is controlled by a signal generator 391 ( Figure 7a In the transparent or on state of the diffuser, the material is homogeneous and therefore does not scatter (e.g. Figure 7a ). In the diffuse or closed state 351, the refractive index varies randomly, making the material opaque. That is, the transmitted light 118 is scrambled and does not represent the incident light 113. The diffuser 351 may absorb or reflect a portion of the incident light 113.

[0094] Figure 7c An alternative embodiment of an external dispersive component, a switchable diffraction grating 34 in a closed state is shown. The switching is driven by a generator 391. For clarity, only one ray of the incident light 113 is shown. The zeroth order 117 or undeflected portion of the transmitted light 118 is transmitted with reduced intensity. The higher order portions 116 have a sufficiently large steering angle so that they are completely separated from the main image. In the depicted embodiment, the higher order portions 116 do not reach the imaging sensor 10, but are deflected to the beam dump 340. To suppress PLS and similar broadband artifacts, the wavelength dependence of the steering angle is advantageous because the intensity of the higher order portions 116 is reduced.

[0095] Figure 7d Another alternative embodiment of the external dispersive component is shown, with the liquid lens 33 in a closed state. The shape of the liquid lens 33 causes the incident light 113 to be defocused, i.e., a portion of the transmitted light 118 does not reach the imaging sensor 10. A person skilled in the art will appreciate that in addition to this global defocus, the defocus has local effects, such as Figure 3c As shown, the image will be blurred. Due to the blurring, strong PLS signals or similar artifacts are imaged to multiple pixels with reduced intensity. Preferably, the intensity is reduced to a level that does not generate parasitic signals above the background noise level during the readout phase.

[0096] The depicted liquid lens contains a transparent liquid formed into a lens shape by a thin flexible transparent membrane. By pumping more or less liquid into the lens cavity, the optical power of the lens can be changed. The depicted pump is implemented by a permanent magnet 331 and an electromagnetic element 332 driven by a signal generator 391. The pump pushes the liquid to another part of the membrane and a 1ms switching speed can be achieved.

[0097] Although the present invention has been described in the foregoing with reference to some specific embodiments, it must be understood that many modifications and combinations of different features of the embodiments are possible. All these modifications are within the scope of the appended claims.

Claims

1. An aerial camera instrument (1), the aerial camera instrument being configured to acquire a high-resolution aerial image (141) from a target area (2), the aerial camera instrument (1) comprising Imaging sensor (10), the imaging sensor (10) An electronic global shutter function (6) is included, wherein each pixel (100) providing simultaneous starting (606) and stopping (608) of an integration phase (600) corresponding to capturing light (110) and converting (120) the captured light into a pixel-resolved electronic signal (121), and presenting a readout phase (602) corresponding to transforming (140) the pixel-resolved electronic signal (121) into digital image data (141), An external shutter assembly (3, 30, 31, 32) configured to provide an open state (300, 310) and a closed state (301, 311), wherein The open state (300, 310) provides light transmission toward the imaging sensor (10), The closed state (301, 311) provides reduced light transmission (118) toward the imaging sensor (10) compared to the open state (300, 310), A coupling function (7) configured to provide a configurable coupling between the electronic shutter function (6) and the external shutter assembly (3, 30, 31, 32), wherein: The configurable coupling provides different activation settings (73, 76) of the electronic shutter function (6) and the external shutter assembly (3, 30, 31, 32) relative to each other.

2. The aerial camera apparatus (1) according to claim 1, wherein: The coupling function (7) is configured to provide different coupling settings depending on different ambient light conditions and / or different reflection conditions (731) associated with the target area (2).

3. The aerial camera instrument (1) according to claim 2, wherein the aerial camera instrument (1) is configured to access navigation data (730) corresponding to a planned route including a plurality of target areas (2), and is configured to derive the different reflection conditions (731) based on the navigation data (730), in particular wherein: The coupling function (7) is configured to provide automatic setting of the different activation settings (73, 76) based on the navigation data (730).

4. An aerial camera instrument (1) according to any one of claims 2 to 3, wherein The aerial camera instrument (1), in particular the imaging sensor (10), provides for measuring the ambient light intensity and / or for determining an expected intensity (143) within an image (141) of the imaging sensor (10), and The coupling function (7) is configured to provide automatic setting of the different activation settings (73, 76) depending on the measured ambient light intensity (710) and / or the expected intensity (143) within the image (141) of the imaging sensor (10).

5. Aerial camera instrument (1) according to any one of the preceding claims, wherein: The coupling function (7) is configured to provide automatic setting of the different activation settings (73, 76) based on meteorological information (720), in particular solar radiation information (721) and / or cloud cover information (722).

6. Aerial camera instrument (1) according to any one of the preceding claims, wherein: The different activation settings (73, 76) include settings in which only the electronic shutter function (6) is activated and settings in which both the electronic shutter function (6) and the external shutter assembly (3, 30, 31, 32) are activated, in particular, the different activation settings (73, 76) include the following settings, wherein: The open state (300, 310) of the external shutter assembly (3, 30, 31, 32) is provided for the integration phase (600), The closed state (301, 311) of the external shutter assembly (3, 30, 31, 32) is provided for at least a portion of the readout phase (602).

7. Aerial camera instrument (1) according to any one of the preceding claims, wherein: The different activation settings (73, 76) include settings that provide different invocations of the closed state (301, 311) of the external shutter assembly (3, 30, 31, 32) relative to a time interval provided by the readout phase (602) of the imaging sensor (10).

8. Aerial camera instrument (1) according to any one of the preceding claims, further comprising a motion compensation unit (8), wherein The motion compensation unit (8) is configured to derive motion data corresponding to a relative motion (40) of the aerial camera instrument (1) to a target area (2) projected onto a stabilization plane (400), and providing a start (806) and a stop signal (808) for a compensating movement (80) of the aerial camera instrument (1) based on the derived motion data, The coupling function (7) is configured to provide the motion compensation unit (8) with a settable activation setting (78) regarding coupling with any one of the electronic shutter function (6) and the external shutter assembly (3, 30, 31, 32).

9. The aerial camera apparatus (1) according to claim 8, wherein: The coupling function (7) is configured to provide a stop signal (808) for the compensating movement (80) of the aerial camera instrument (1), the stop signal: In the first MC connection mode, in response to (782) a shutter closure notification (305), indicating a closed state (301, 311) of the external shutter assembly (3, 30, 31, 32), In a second MC connection mode, in response to a readout start notification, indicating a readout phase (602) of the imaging sensor (10), and In the third MC connection mode, in response to the read stop notification, the read completion is indicated.

10. Aerial camera instrument (1) according to any one of the preceding claims, wherein: The imaging sensor (10) is embodied as a back-illuminated CMOS imaging sensor comprising at least 4000×4000 pixels (100), and is configured to provide a refresh rate of at least 1 image / second, Especially among them The imaging sensor (10) is embodied as an RGB sensor, and / or a full-color sensor, and / or a sensor configured to provide a near-infrared image, and The photosensitive area of ​​the imaging sensor (10) is smaller than that of a full-frame imaging sensor, in particular, the diagonal of the photosensitive area is 19.3 mm.

11. Aerial camera instrument (1) according to any one of the preceding claims, wherein: The external shutter assembly (3, 30, 31, 32) is embodied as a mechanical shutter (30), in particular a central leaf shutter, and the mechanical shutter (30) is configured to completely block light transmission toward the imaging sensor (10) in the closed state (301, 311).

12. Aerial camera instrument (1) according to claim 11, wherein The mechanical shutter (30) is configured to provide a mechanical shutter speed of at least 1 / 50 s, The electronic shutter function (6) is configured to provide an electronic shutter speed of at least 1 / 2000 s, and The electronic shutter function (6) is configured to provide a shutter efficiency exceeding 1000.

13. The aerial camera apparatus (1) according to any one of claims 1 to 10, wherein: The external shutter assembly (3, 30, 31, 32) is specifically implemented as a liquid crystal shutter (31), wherein The liquid crystal shutter (31) is configured to provide a contrast ratio exceeding 100, The electronic shutter function (6) is configured to provide an electronic shutter speed of at least 1 / 2000 s, and The electronic shutter function (6) is configured to provide a shutter efficiency exceeding 1000.

14. An aerial camera instrument (1) according to any one of claims 1 to 10, wherein: The external shutter (3, 30, 31, 32) is embodied as a dispersive element with a variable scattering state, In particular, the dispersion element A component comprising a polymer dispersed liquid crystal (32), and / or Configured to provide a shutter speed of at least 1 / 50s.

15. An aerial camera instrument (1) according to any one of the preceding claims, comprising a support element configured to provide a releasable fit between the external shutter assembly (3, 30, 31, 32) and a housing of the aerial camera instrument (1), In particular, the support element comprises one of the following: Bayonet mounting, Groove or track mounting, Threaded mounting, Quick release unit.

16. An aerial camera instrument (1), the aerial camera instrument being configured to acquire a high-resolution aerial image (141) from a target area (2), the aerial camera instrument (1) comprising An imaging sensor (10), wherein The imaging sensor (10) An electronic global shutter function (6) is included, wherein each pixel (100) providing simultaneous starting (606) and stopping (608) of an integration phase (600) corresponding to capturing light (110) and converting (120) the captured light into a pixel-resolved electronic signal (121), and presenting a readout phase (602) corresponding to transforming (140) the pixel-resolved electronic signal (121) into digital image data (141), An external dispersive component (3, 31-35) configured to provide an open state (300, 310, 350) and a closed state (301, 311, 351), wherein The open state (300, 310, 350) provides light transmission (118) toward the imaging sensor (10), and The closed state (301, 311, 351) provides a reduced, in particular at least partially reduced, light transmission (118) towards the imaging sensor (10) compared to the open state (300, 310, 350), a coupling function (7), the coupling function being configured to provide a configurable connection of the electronic shutter function (6) and the external dispersive component (3, 31-35), wherein the configurable connection provides different activation settings (73, 76) of the electronic shutter function (6) and the external dispersive component (3, 31-35) relative to each other.

17. The aerial camera apparatus according to claim 16, wherein: The dispersive element comprises (3, 31-35) a switchable diffuser (35), in particular wherein the diffuser (35) comprises a first transparent solid component (358), in particular a first glass plate, a second transparent solid component (359), in particular a second glass plate, a liquid component, in particular a liquid crystal, which is arranged between the first transparent solid component (358) and the second transparent solid component (359), and An electric actuator (391) electrically connected to the liquid component and configured to provide the open state (350) and the closed state (351) by applying a first electric signal and a second electric signal to the liquid component, respectively, wherein the first electric signal and the second electric signal are provided by square wave signals having a peak-to-peak voltage exceeding 50V.

18. Aerial camera instrument (1) according to any one of claims 16 to 17, wherein: The external dispersion component (3, 31-35) comprises an element having polymer dispersed liquid crystal (32).

19. Aerial camera instrument (1) according to any one of claims 16 to 18, wherein: The external dispersive component (3, 31-35) comprises a liquid lens (33).

20. Aerial camera instrument (1) according to any one of claims 16 to 19, wherein: The external dispersive component (3, 31-35) comprises a diffraction grating, in particular wherein the diffraction grating is embodied as a switchable grating (34) comprising a structured alignment layer formed by liquid crystal.

21. An aerial camera apparatus according to any one of claims 16 to 20, wherein: The external dispersive components (3, 31-35) are configured to provide a variable scattering state, wherein a first scattering state, the first scattering state corresponding to the open state (300, 310, 350), the first scattering state providing a low-loss transmission of the incident light (113), in particular providing a transmission higher than 90%, a second scattering state, the second scattering state corresponding to the closed state (301, 311, 351), the closed state providing at least one of the following: deflecting a portion of the incident light (113) so that the deflected portion is not imaged on the imaging sensor (10), diffuse a portion of the incident light (113) so that the transmitted light rays imaged to a plurality of pixels (100) of the imaging sensor (10) each have a reduced intensity, absorbing a portion of the incident light (113), and reflecting a portion of the incident light (113), In particular, The imaging contrast is reduced to at least 1 / 2, in particular at least 1 / 10.

22. An aerial camera apparatus according to any one of claims 16 to 21, wherein: The electronic shutter function (6) is configured to provide an electronic shutter speed of at least 1 / 2000 s, and The electronic shutter function (6) is configured to provide a shutter efficiency exceeding 1000.

23. Aerial camera instrument (1) according to any one of claims 16 to 22, wherein: The coupling function (7) is configured to provide different coupling settings according to different ambient light conditions and / or different reflection conditions (731) associated with the target area (2), Especially among them The camera device (1), in particular the imaging sensor (10), provides for measuring the ambient light intensity and / or for determining an expected intensity (143) within an image (141) of the imaging sensor (10), and The coupling function (7) is configured to provide automatic setting of the different activation settings (73, 76) depending on the measured ambient light intensity (710) and / or the expected intensity (143) within the image (141) of the imaging sensor (10).

24. Aerial camera instrument (1) according to any one of claims 16 to 23, wherein: The coupling function (7) is configured to provide automatic setting of the different activation settings (73, 76) based on meteorological information (720), in particular solar radiation information (721) and / or cloud cover information (722).

25. Aerial camera instrument (1) according to any one of claims 16 to 24, wherein: The different activation settings (73, 76) include settings in which only the electronic shutter function (6) is activated and settings in which both the electronic shutter function (6) and the external dispersion components (3, 31-35) are activated, in particular, the different activation settings (73, 76) include settings in which: setting the open state (300, 310, 350) of the external dispersive component (3, 31-35) for the integration stage (600), The closed state (301, 311, 351) of the external dispersive component (3, 31-35) is set for at least a part of the readout phase (602).

26. Aerial camera instrument (1) according to any one of claims 16 to 25, wherein: The different activation settings (73, 76) include settings that provide different invocations of the closed state (301, 311, 351) of the external dispersive component (3, 31-35) relative to a time interval provided by the readout phase (602) of the imaging sensor (10).

27. Aerial camera instrument (1) according to any one of claims 16 to 26, further comprising a motion compensation unit (8), wherein The motion compensation unit (8) is configured as deriving motion data corresponding to the relative motion (40) of the aerial camera instrument (1) to the target area (2) projected onto a stabilization plane (400), and providing a start (806) and a stop signal (808) for a compensating movement (80) of the aerial camera instrument (1) based on the derived motion data, The coupling function (7) is configured to provide a settable activation setting (78) for the motion compensation unit (8) regarding coupling with any one of the electronic shutter function (6) and the external dispersive component (3, 31-35).

28. The aerial camera apparatus (1) according to claim 17, wherein: The coupling function (7) is configured to provide a stop signal (808) for the compensating movement (80) of the aerial camera instrument (1), the stop signal: In the first MC connection mode, in response to (782) a shutter closure notification (305), indicating a closure state (301, 311, 351) of the external dispersion component (3, 31-35), In a second MC connection mode, in response to a readout start notification, indicating a readout phase (602) of the imaging sensor (10), and In the third MC connection mode, in response to the read stop notification, the read completion is indicated.

29. Aerial camera instrument (1) according to any one of claims 16 to 28, wherein: The imaging sensor (10) is embodied as a back-illuminated CMOS imaging sensor comprising at least 4000×4000 pixels (100), and is configured to provide a refresh rate of at least 1 image / second, Especially among them The imaging sensor (10) is embodied as an RGB sensor, and / or a full-color sensor, and / or a sensor configured to provide a near-infrared image, and The photosensitive area of ​​the imaging sensor (10) is smaller than that of a full-frame imaging sensor, in particular, the diagonal of the photosensitive area is 19.3 mm.

30. An aerial camera instrument (1) according to any one of claims 16 to 29, comprising a support element configured to provide a releasable fit between the external dispersive component (3, 31-35) and a housing of the aerial camera instrument (1), In particular, the support element comprises one of the following: Bayonet mounting, Groove or track mounting, Threaded mounting, Quick release unit.

Images