METHOD FOR ADJUSTING THE FOCUS OF A MOVIE CAMERA

Description

[0001] The present invention relates to a method for adjusting the focus of a film camera, in which distance information is obtained with a measuring device arranged in the area of ​​the film camera, which is used to adjust the focus of the film camera.

[0002] To improve the focus adjustment of a film camera, measuring devices are sometimes used that assign distance data to different image areas. This allows an operator, for example, to select an image area to focus on.

[0003] It is known from AT 511 312 B1 that a depth image can be generated using a stereoscopic camera arrangement to control the focus of a camera. The real image of the measuring camera and the depth image of the measuring camera are displayed on a touchscreen PC or monitor. By manually selecting an image area or through automated tracking, the distance can be measured in this area, and the focus of the film or television camera is subsequently adjusted accordingly.

[0004] US 2016 / 088212 A1 describes a method in which depth information is recorded by a measuring device and directly incorporated into the real image of the film camera. This is computationally intensive and slow and requires precise knowledge of the position of the measuring device relative to the film camera.

[0005] EP 2 947 510 A1 and WO 2012 / 126868 A1 describe various ways in which measuring devices for distance measurement can be connected to a film camera and their depth information can be incorporated into the real image of the film camera, similar to US 2016 / 088212 A1.

[0006] Disadvantages of the known solution are: The cameraman cannot use a touchscreen PC or other monitor to independently adjust the focus while performing his work (operating the camera, adjusting the image area). The video image from the measuring device has a different perspective and different image area than the image from the film camera. The cameraman or focus assistant cannot see exactly which subjects are in the scene because the image areas (perspectives) of the auxiliary camera and the film camera are different. The image from the real camera cannot be viewed on the touchscreen PC, i.e. the result of the focusing process is not visible. The focus assistant therefore needs a second auxiliary monitor (the Video Assist 3a) to also view the image from the real camera.

[0007] It should also be noted that if a 3D sensor, e.g. a stereoscopic measuring device, is placed next to film camera 1, the actual image from the measuring device always shows a different section of the image than the image from film camera 1. Since the image from the measuring device is often wider-angled than the image from film camera 1, this has the advantage that an operator can measure objects before they come into the image from film camera 1. However, there is the fundamental disadvantage that the operator cannot see how the film material is being recorded. To do this, they would need a second monitor next to the measuring device, which displays the image from film camera 1, and they would have to constantly look back and forth between the monitor on the measuring device and the so-called video assist (or viewfinder).

[0008] On the other hand, the following disadvantages arise if the image from film camera 1 is used to track (automatically track) an image area: Film lenses have a narrow depth of field. They also blur the desired areas of the image. However, if image areas are blurred, tracking in these areas is not possible because objects in the video image cannot be detected and analyzed. If the focus plane needs to be shifted from area A to area B, this may not be possible because area B is not detected. Often, the images from a film camera 1 are exposed in such a way that only certain subjects are illuminated, while other areas of the image are kept in the dark and are difficult or not visible at all in the real image.

[0009] Due to this disadvantage, the image from a film camera is not suitable for a tracking algorithm. Therefore, the image from a film camera cannot be used for video tracking.

[0010] The object of the present invention is to avoid these disadvantages and to provide a method with which the focusing of a film camera can be improved .

[0011] According to the invention, this object is achieved by the method and a device according to the independent claims.

[0012] This makes it possible for a cameraman or focus assistant to see the actual image from the film camera in the viewfinder, video assistant, or other monitor. A video tracking algorithm can run in this image, tracking and following any subject. Each image area of ​​this actual image should be assigned a distance value. Image areas should be selectable or automatically tracked, and the focus of the film camera is controlled by the distance values.

[0013] The key feature of the method according to the invention is that the real image from the measuring device has a high resolution and a large depth of field. This makes it possible to compare it with the image from the film camera and to assign the image elements so that the individual pixels in one image are assigned corresponding pixels in the other image. This compensates for the unavoidable parallax that results from the different positions of the film camera and the measuring device. Ultimately, this is an image transformation in which the image from the film camera could be reconstructed from the real image from the measuring device if it were not present. The only pixels excluded from this transformation are those that are obscured in an image by an object in front of it. However, if the distance between the film camera and the measuring device is not too great, the proportion of such pixels is relatively small.Since the real image of the measuring device is previously enriched with distance information from the depth image, this depth information can also be transferred to the image of the film camera.

[0014] A key feature of the present invention is that the transformation ensures a perspective-accurate match between the view of the film camera and the view of the measuring device, thus assigning depth information to each (or at least a sufficient number) pixels of the real image of the film camera. This method yields a depth image of the film camera.

[0015] This enables particularly efficient automatic focusing procedures, but also enables displays that were previously unavailable in this way, which can make manual or semi-automatic focusing much easier.

[0016] It is particularly preferred that the real image of the measuring device has a large depth of field, preferably covering the entire distance range expected for the recording. This allows for efficient focusing even when the focus of the film camera at the relevant moment differs significantly from the distance of the object on which the focus is ultimately to be achieved. This also applies when the aperture of the film camera is fully open and the depth of field is accordingly shallow.

[0017] Particularly advantageous user support is provided when the real image of the measuring device, onto which distance information is superimposed, is displayed on a first display device. This exploits the property of the real image that typically the entire image area can be displayed in focus. However, such a display will generally only be provided in addition to the image from the film camera, since it is usually desirable to see exactly what the film camera records, including the blur of objects outside the depth of field.

[0018] Alternatively, or in addition, it is possible to display the film camera image on another display device, with distance information superimposed on it. This way, the exact section of the image is always displayed without any parallax distortion.

[0019] However, the display can also be done by overlay, which is made possible in a sensible way by the correct position and perspective assignment.

[0020] According to a particularly preferred embodiment of the present invention, the distance information is related to the focus setting of the film camera. This means, for example, that objects in front of the focal plane are displayed in one color and objects behind the focal plane are displayed in a different color, whereby the color intensity and / or shading can vary depending on the distance from the focal plane.

[0021] Automatic focusing can be achieved particularly advantageously by tracking objects in the real image of the film camera. Tracking objects outside the depth of field is usually considerably difficult or impossible due to blurriness. Due to the perspective correspondence between the film camera image and the real image of the measuring device, tracking can be performed easily even in blurred areas, since the image recognition processes or similar are performed on the real image of the measuring device, and the results are then transferred to the film camera image.

[0022] Image transformation is preferably performed using image recognition and feature detection algorithms with translation, rotation, distortion correction, and scaling of the views. The advantage of this is that no calibration is required when configuration changes occur.

[0023] Alternatively, the image transformation can be performed by specifying the geometric and optical parameters of the film camera and the measuring device and their relative arrangement. This can reduce the required computing power.

[0024] A particularly advantageous embodiment of the invention provides that, based on the depth information, regions of the film camera image are combined into elements of groups, each of which can be selected separately. The three-dimensional detection allows the pixels belonging to specific real objects, such as a person, to be grouped particularly efficiently.

[0025] The formation of groups is possible not only because of the depth information, but also because of the real image, e.g. a group of "eyes" (as elements of the groups).

[0026] Using the measuring device's real-image and depth data, image areas can be divided into groups and marked in the image. These groups, or elements of the groups, are calculated and displayed as an overlay in the film camera image with precise perspective. A control device can select a group or switch between groups. A tracking algorithm can be started based on this selection. The stored depth data determines the distances of the group elements to the film camera, which can then be used to adjust the focus.

[0027] In addition, the markings, labels and distance information determined in the measuring device can be calculated and displayed as layers in the film camera image with precise perspective.

[0028] Efficient data processing can be achieved by linking image data and depth data from the film camera with a timecode signal and storing them together.

[0029] The present invention also relates to a device for adjusting the focus of a film camera, wherein a measuring device is arranged in the area of ​​the film camera in order to obtain distance information which can be used for adjusting the focus of the film camera.

[0030] According to the invention, this device is characterized in that the measuring device consists of a real image camera and a depth camera, which are fixedly arranged on a common carrier.

[0031] A special variability and flexibility can be achieved by detachably attaching the carrier to the film camera. Because image recognition techniques can be used to ensure that the real image from the measuring device and the image from the film camera match, it is not essential to precisely adjust the position of the carrier relative to the film camera and to recheck it whenever a change occurs, for example, in the optics.

[0032] A processing unit is located in the measuring device or as a separate device, which creates the real image of the measuring device (7) enriched with depth information. This processing unit has the ability to run image processing algorithms.

[0033] The device according to the invention can also provide that markings and the corresponding distance values ​​can be selected by an operating device and further processed on the operating device.

[0034] To achieve the greatest possible depth of field and uniform illumination of the real image, the real image camera preferably has an image sensor with HDR (High Dynamic Range Image) functionality. Known methods compensate for large brightness differences. It is important for the processing according to the invention that the depth of field in the real image from the measuring device is sufficiently large. It is advantageous if the real image sensor has an HDR function to reproduce the real image from the measuring device with reasonably uniform illumination, so as not to lose any information.

[0035] The real-image camera may also be designed with a small sensor and / or small aperture. The aperture and focus settings are optimally selected so that the entire area of ​​interest can be captured in sharp focus. For filming, for example, this could be an area in front of the camera between 40 cm and 1 / 100 fps.

[0036] A video overlay unit is provided to incorporate the real image from the measuring device into the image from the film camera. The video overlay unit has an input for data from the measuring device, the control devices, and the film camera. The data can be output to the display device. The video overlay unit is integrated into the measuring device, the film camera, or the display device, or mounted as a separate device next to the film camera.

[0037] Preferably, the measuring device can be arranged on a lens hood of the film camera. A lens hood is a device that is usually located on the lens of the film camera. It serves to reduce or prevent stray light, such as sunlight or light from light sources diagonally behind or next to the camera, from entering the lens. Such lens hoods, sometimes also called compendiums or matte boxes, often have adjustable flaps (French flags).

[0038] The measuring device can thus be positioned very close to the film camera, where it does not interfere and forms a compact unit with it. This enables a space-saving design with a simple structure. The measuring device can be integrated into the lens hood. Particularly preferably, the lens hood has a square outer frame, with the measuring device arranged in the area of ​​at least one corner of the outer frame. The outer frame is arranged along the axis of the film camera lens at the end of the lens hood facing away from the film camera.

[0039] The present invention will now be explained in more detail with reference to the exemplary embodiments illustrated in the figures. They show: Fig. 1 is a schematic representation of the device according to the invention; Fig. 2 is a diagram explaining the configuration of the device.

[0040] The device of Fig. 1consists of a film camera 1 with a lens 2 and a viewfinder 3. A support 4 is detachably attached to the film camera 1, which supports a real-image camera 5 and a depth camera 6. These are arranged vertically one above the other in the operating position. The operating position is the usual position of the film camera 1, in which the long side of the rectangular image is horizontal. Thus, the connecting line between the real-image camera 5 and the depth camera 6 is perpendicular to the long side of the rectangular image and thus to the sensor of the film camera 1.

[0041] The carrier 4, including the real-image camera 5 and the depth camera 6, is a measuring device 7 that enables image information to be enriched with distance information. Distance information is assigned to each pixel (or a sufficient number of pixels) of the real image.

[0042] A touchscreen PC 8 serves as a display device, enabling the display of various representations that facilitate automatic or, in particular, manual focus control. Another control device 9 with a rotary knob can also be used for control.

[0043] Fig. 2 shows the logical interconnection of the individual components. The film camera 1 is connected to a video overlay unit 10 to transmit the image to it. The video overlay unit 10 also receives image and distance information from the measuring device 7 in order to be able to correctly align the image from the film camera 1 with the real image from the real image camera 5 and the depth image from the depth camera 6 of the measuring device 7.

[0044] At the same time, a servo motor 11 on the film camera 1 can be controlled via the measuring device 7 in order to control the focus setting.

[0045] 8, 9 and 12 designate various control devices, namely a touch PC 8, another control device 9 with a rotary control and a control device 12 with a joystick.

[0046] The viewfinder 3 can optionally be provided with the desired displays. Alternatively or in addition to the viewfinder 3, a screen can be provided as a video assist 3a.

[0047] In the following, typical properties and characteristics of the individual components are briefly explained. Measuring device 7:

[0048] It generates a matrix of distance values ​​using a 3D sensor, commonly referred to here as a depth camera. The 3D sensor consists of a stereoscopic camera array, a TOF camera, a laser scanner, a lidar sensor, a radar sensor, or a combination of different 3D sensors to improve measurement quality, measurement range, and resolution.

[0049] The measuring device 7 has a video camera that generates a real image and is therefore referred to here as real image camera 5. The 3D sensor and the real image camera 5 are mechanically fixed and calibrated to each other. The display perspectives are identical. Thus, a distance value can be assigned to each recognizable pixel of the video camera. This assignment is called a depth image. This real image camera 5 preferably has an infinite depth of field in order to be able to depict all objects in the image sharply. This video camera preferably has a wide exposure range (e.g., through an HDR mode) in order to be able to depict subjects of varying brightness evenly.

[0050] The measuring device 7 consists of the depth camera 6 (3D sensor) and the real-image camera 5 as the measuring unit, and a computing unit for processing the measurement results. The measuring unit and computing unit are preferably located in the same housing. However, they can also exist as separate units.

[0051] The measuring device 7 is arranged on a film or television camera (here film camera 1) in such a way that it can be aligned with the image of the film camera 1, namely that the image of the film camera 1 is contained in a partial area of ​​the real image camera 5.

[0052] The field of view of the measuring device 7 is very wide-angle and usually larger than the field of view of the film camera 1.

[0053] The measuring device 7 is detachably arranged on or near the film camera 1.

[0054] Preferably, the optical axes of the real image camera 5 of the measuring device 7 and the film camera 1 are parallel.

[0055] A control device is preferably implemented in the measuring device and / or an interface for the focus motor or all three lens motors (focus, iris, zoom) of the film camera 1 is provided.

[0056] The measuring device 7 may contain an IMU (Inertial Measurement Unit), which is used to calculate the spatial position of the measuring device 7.

[0057] In measuring device 7, tracking algorithms for automatically tracking objects in the video image are executed by analyzing video images. The closest point to the film camera 1 can also be calculated.

[0058] In measuring device 7, image areas can be divided into groups using the available real image and depth data.

[0059] Using the available real-image information, image recognition algorithms can extract features from images. Such features can be eyes, human faces, entire people, or a wide variety of predefined objects. For example, all faces can be divided into elements of the "face" group and marked with a frame in the real image.

[0060] Using the available depth information, contiguous image areas can be defined into elements of a group based on their distance and color-coded. For example, areas of 1-2 m are displayed in red, areas of 2-3 m in blue, etc.

[0061] Due to the available depth information, contiguous image areas with a regular depth gradient can form a group element. For example, a floor exhibits a regular depth gradient as long as it is sufficiently flat and there are no objects lying on the floor. Therefore, the group element "floor" can be created in the image and summarized as a single image object and marked in the real image. Video Overlay Unit 10:

[0062] The video overlay unit 10 has interface input and output for the video image of the film camera 1. This allows a video image to be read in and output again.

[0063] The video overlay unit 10 has an interface input for the real image and the depth image of the measuring device 7.

[0064] The real image of the measuring device 7 is converted into the perspective of the image of the film camera 1. The transformation can be performed in the following ways: Automatically through image recognition / feature detection. This transformation is based on feature detection, where matches are searched for in both images. The transformation of the image from the measuring device into the image from the film camera is carried out by: ▪ Translation, ▪ Rotation, ▪ Rectification, and ▪ Scaling of the two video images based on image features found in both images. Theoretically, three identical image features are sufficient, although preferably there are several features distributed across the image that are detected in both images. This type of transformation has the advantage that when the lens of the film camera is changed, the image perspectives are automatically compared without manual interaction. Semi-automatically by entering the geometric and optical parameters.

[0065] The image transformation between the real image of the film camera and the images of the measuring device can also be done by a purely mathematical shift if ▪ the distances and ▪ the alignment of the optical center, ▪ the distances of the image sensors, and ▪ the image sections of the optics A simple image transformation, and thus an incorrect matching of the perspective, can also be achieved with just two or three of the listed parameters. Manually by overlapping the representations of the real image of the film camera with the real image or depth image of the measuring device on a monitor.

[0066] The transformation can also be calculated if the two real images are displayed graphically and are moved over each other by manual graphic manipulation on the screen (moving, rotating, tilting, scaling).

[0067] Since there is a direct correlation between the depth image and the real image of the measuring device 7, this transformation of the real images also establishes a relationship between the pixels of the image from the film camera 1 and their distance. Thus, a depth image is created from the image from the film camera 1.

[0068] The image of the film camera 1, the real image of the measuring device 7 and the depth image of the measuring device 7 can be displayed together as an overlay, or only individual layers of the overlay are displayed.

[0069] Additional information can be placed over the image from film camera 1 as an additional overlay layer.

[0070] Markings, designated image areas, and the position of tracking points or tracking areas, cursors, etc. are also calculated as an overlay into the video image of the main camera with precise perspective through the transformation, making them displayable and controllable. Even if the image from film camera 1 is blurry or too dark, these markings, labels, and tracking functions can run correctly because they are calculated in the background using the real image from the measuring device.

[0071] Groups or elements of a group and their marking can be incorporated into the real image of the film camera with precise perspective through image transformation.

[0072] These image groups are displayed in the real image in color, by shading, as a pattern or framed as an overlay.

[0073] By coloring the pixels, a color overlay can be placed over the image from the film camera. The image from film camera 1 is ideally represented as a grayscale image in such representations.

[0074] Each pixel or image area is assigned its own color coding. This provides depth information for the image from film camera 1.

[0075] The depth of field is calculated as an overlay in the video image of film camera 1 and can be displayed. The pixels / image points of film camera 1 that are in focus are highlighted in color. This corresponds to a conventional focus peaking function for video cameras.

[0076] Each pixel or image area of ​​the image from film camera 1 can be given its own color representation depending on its distance from the focal plane. This color marking can be displayed as an overlay. This makes it clear at a glance which areas are in the focal plane and what distance image areas are from the focal plane. This function is called visual focus peaking. It is based on the focus peaking function in traditional video cameras or still cameras, where only the pixels that are in the focal plane are marked. In contrast, here the distance to all other pixels can also be displayed in color.

[0077] The distance of an image area can also be represented using various intersection lines. A horizontal or vertical line is placed in the video image. Depending on the distance of the corresponding pixel on this intersection line, a bar is used to display how far the corresponding pixel is from the focal plane. Pixels in front of the focal plane are shown with a bar above the intersection line, while pixels behind the focal plane are shown with a bar below the intersection line. This creates a histogram that shows the distance of the pixels from the focal plane.

[0078] The video image from film camera 1 can be tilted in the display perspective by linking it to the depth information. In this display, the focal plane can be displayed, making it easy to see how the image areas are spatially related to the focal plane.

[0079] General settings and information of the measuring device are calculated as an overlay in the video image of the film camera 1 and can be displayed.

[0080] The thus processed and expanded image of the film camera 1 is displayed on a video assist monitor 3a or in the video viewfinder 3 of the film camera 1.

[0081] The thus processed image of the film camera, the real image of the measuring device 7 and the depth image can also be output to a touch PC, on which image areas are manually or automatically selected, saved and retrieved.

[0082] The processed image from film camera 1 can be linked to a time code signal and saved. Thus, the real image and depth information from film camera 1 are available at any defined point in time.

[0083] This video overlay unit is preferably located in the measuring device 7 or the Video Assist 3a and is part of it. Video Assist 3a and / or Viewfinder 3:

[0084] The Video Assist 3a or the viewfinder 3 are display elements for the image from the film camera 1.

[0085] Video Assist 3a or viewfinder 3 can have a touchscreen and / or control buttons on which the measuring device 7 can be directly controlled. This also allows the selection of an image area to focus on. Control unit 9, 12:

[0086] The control unit 9, 12 has a control element for adjusting the focus. Rotating / moving it causes a spatial shift of the focal plane.

[0087] The control unit 9, 12 has a control element for adjusting a focus ramp.

[0088] These two control options can be one element or two elements.

[0089] The control element, preferably a haptic control element (e.g., slider, rotary knob), has an adjustment range and two stops. The two stops are designated as the initial value and the final value.

[0090] Focus planes (distances) can be assigned to the control element. For example, the initial value is assigned to focus plane A and the final value is assigned to focus plane E.

[0091] Focal plane A and focal plane E can be distances, tracking areas, image areas, etc.

[0092] Different focus levels (A1, A2, A3,..., E1, E2, ...) can be assigned to the initial or final value of the control element. This can be done by pressing a button or by other means.

[0093] The initial and final values ​​are therefore not fixed distance values, but rather variable distance planes in space. Thus, planes A and E can be derived from the tracking algorithm.

[0094] For example, level A can be the set value of the manual control element, level E can be derived from the tracking algorithm.

[0095] The control unit has switches or buttons for switching between automatic focusing and manual focusing.

[0096] In automatic mode, the initial value is assigned a focal plane A, and the final value is assigned a focal plane B. Moving / rotating the control element causes the focal plane to shift. The speed of rotation / movement determines how quickly the focus should move from the initial value to the final value, i.e., from plane A to plane E. Therefore, the control element does not manually change the distance, but rather controls the time at which the focus should move in space (= controlling a focus ramp).

[0097] In conventional controllers, control elements (usually a rotary knob for adjusting the focus plane) have two fixed distances at the start and end of the rotation range. For example, the focus can be shifted from 1 m to 10 m in space. In contrast, here, variable focus planes are assigned to the start and end values. These variable planes can, for example, be two tracking points of two different subjects. The subjects can, of course, move in space and therefore constantly change their distance from the camera. This means that the operator no longer actually adjusts the focus in distance, but rather only controls the timing—how long and when the focus should be at the new end point. This relieves them of the difficult task of constantly "knowing" (or estimating) the correct distance to the final subject. They can devote themselves exclusively to the temporal progression of the focus ramp, which leads to more artistically interesting results.

[0098] In manual mode, the focal planes are fixed. The adjustment range corresponds to a corresponding distance. A rotation or shift causes the focal plane to shift in space.

[0099] The control unit has controls or switches for setting, retrieving and deleting tracking points or markers or for moving a cursor on the video image.

[0100] Control elements or switches and control elements can be distributed in one device or in several devices.

[0101] Control element can be designed as a slider, joystick, sensor surface, touchscreen or other actuator instead of a rotary knob

[0102] The control element can be used to position a cursor in the video image. This control element can be a switch, joystick, touchpad, user eye tracking, gyroscope, or other element for controlling x / y coordinates.

[0103] If the cursor is moved over the real image of the film camera, the corresponding distance value can be output or the focus position on the optics can be moved.

[0104] The control unit is connected directly to the measuring device via cable or radio connection

[0105] The control unit can also be connected to a lens control system, which in turn has a connection to the measuring device 7.

[0106] The control device can also control the iris and / or zoom of the film camera 1.

[0107] The rotary knob is motorized. This allows the knob to automatically rotate to the corresponding distance position on the measuring device. The rotary knob is therefore always in the position that corresponds to the current distance value on the measuring device.

[0108] The control element allows you to select subjects or groups of images from the video image / depth image in a variety of ways: The cursor is used to move to tracking points on the Video Assist 3a and set them at the touch of a button. Distance measurement can then run automatically.

[0109] The distance to a specific object is measured. This object is preferably located in the optical center of the main camera. At the push of a button on the control unit, this distance is saved and a tracking point is started. Using the set tracking point, the object can then be automatically tracked and focused on using image recognition in the real image. This eliminates the need for the operator to look at a monitor to set a tracking point and save or start automatic focusing.

[0110] Image feature recognition can be initiated via the control device. These image features include eyes, faces, or people. These features are displayed as an overlay on the video image from the main camera. By toggling, a feature can be selected and saved as a tracking point, or tracking can be started. Using depth data that is perspectively correct for the film camera image, the area of ​​the focal plane (Depth of Field, DoF) can be displayed in color or as a pattern in the film camera image as an overlay. Only those pixels that are in the DoF are marked; the other pixels remain in the real image.

[0111] Image feature recognition can be initiated via the control unit. These image features include eyes, faces, or people. By turning the rotary knob, the features corresponding to the corresponding distance are highlighted. This feature is then selected and can be saved as a tracking point.

[0112] By turning the rotary knob, the corresponding distances in the video image are highlighted in color. If only one area of ​​the video image is highlighted, it can be saved as a tracking point. If multiple areas are highlighted, a specific area can be selected and saved as a tracking point by toggling the knob.

[0113] The elements of a group can be selected using the control unit. This allows all elements to be marked sequentially. When an element is selected at the touch of a button, the corresponding distance value can be displayed or the focus position can be determined. It is also possible to save this element as a tracking point or start tracking based on this element.

[0114] It is particularly advantageous if the distance of a first group from a focal plane is assigned to a first stop of a control device, and a further distance of a further group from the focal plane is assigned to a further stop of the control device. The adjustment range of the control device is dynamically adjusted to the distance between the two groups, allowing the focal plane to be continuously adjusted between the groups. However, it is also possible to link only one stop to the distance of a group.

Claims

1. Method for setting the focus of a film camera (1), in which a measuring device arranged in the region of the film camera (1) is used to obtain distance information that is used for setting the focus of the film camera (1), wherein - the measuring device (7) produces on the one hand a real image and on the other hand a depth image; - the measuring device (7) produces a real image augmented with depth information from this real image of the measuring device and this depth image of the measuring device; characterised in that - this real image augmented with depth information is calculated into the image of the film camera (1) by means of an image transformation.

2. Method according to claim 1, characterised in that the real image of the measuring device (7) has a large depth of field, which preferably covers the entire distance range to be expected for the recording.

3. Method according to one of claims 1 or 2, characterised in that the real image of the measuring device (7) is displayed on a display device, in which distance information is optionally superimposed.

4. Method according to one of claims 1 to 3, characterised in that the image of the film camera (1), into which distance information is optionally superimposed, is displayed on a display device.

5. Method according to claims 3 and 4, characterised in that the real image of the measuring device (7) and the image of the film camera (1) can be displayed in a switchable manner or superimposed with perspective accuracy.

6. Method according to one of claims 3 to 5, characterised in that the distance information is related to the focus setting of the film camera (1).

7. Method according to claim 6, characterised in that the distance from each pixel or from contiguous image areas to the focal plane is superimposed in color, or represented as patterns, as an overlay.

8. Method according to one of claims 1 to 7, characterised in that objects are tracked in the image of the film camera (1).

9. Method according to claim 8, characterised in that the tracking is performed on the real image of the measuring device (7) and thereafter the results are transferred to the image of the film camera (1).

10. Method according to one of claims 1 to 9, characterised in that the image transformation is carried out by image recognition and feature recognition algorithms with translation, rotation, distortion correction and scaling of the views.

11. Method according to one of claims 1 to 9, characterised in that the image transformation is carried out by presetting the geometrical and optical parameters of the film camera (1) and of the measuring device and arranging them relative to one another.

12. Method according to one of claims 1 to 9, characterised in that the image transformation is carried out by manually nesting the display of the image of the film camera and the real image or the depth image of the measuring device on a display device.

13. Method according to one of claims 1 to 12, characterised in that, on the basis of the depth information, contiguous areas of the real image are combined to form elements of groups which are transferred into the image of the film camera (1) and which can each be selected separately.

14. Method according to claim 13, characterised in that individual elements are selectable.

15. Method according to one of claims 12 or 14, characterised in that the distance of a first group from a focal plane is assigned to a first stop of a control unit, and in that a further distance of a further group from the focal plane is assigned to a further stop of the control unit.

16. Method according to one of claims 13 to 15, characterised in that individual elements or groups can optionally be tracked.

17. Method according to one of claims 1 to 16, characterised in that image data and depth data of the film camera (1) are linked with a time code signal and stored together.

18. Device for adjusting the focus of a film camera (1), in which a measuring device (7) is arranged in the region of the film camera (1) in order to obtain distance information which can be used for adjusting the focus of the film camera (1), wherein the measuring device (7) consists of a real image camera (5) and a 3D sensor (6) which are arranged fixedly on a common carrier (4), and that the device comprises a computing unit that is adapted to produce a real image augmented with depth information, characterised in that the device is adapted to calculate this real image augmented with depth information into the image of the film camera (1) by means of an image transformation.

19. Device according to claim 18, characterised in that the carrier (4) is detachably attached to the film camera (1).

20. Device according to one of claims 18 or 19, characterised in that the real image camera (5) of the measuring device (7) comprises an image sensor with HDR function (High Dynamic Range Image).

21. Device according to one of claims 18 to 20, characterised in that a first display device is provided to display the real image of the measuring device (7) into which distance information is superimposed.

22. Device according to one of claims 18 to 21, characterised in that a further display device is provided to display the image of the film camera (1) in which distance information is superimposed.

23. Device according to one of claims 18 to 22, characterised in that a video overlay unit is provided to calculate the real image of the measuring device (7) into the image of the film camera (1).

24. Device according to one of claims 18 to 23, characterised in that the measuring device (7) is arranged on a lens hood of the film camera.

25. Device according to one of claims 18 to 24, characterised in that an operating element for setting the focus is provided which has at least one stop associated with one distance of a group of picture elements.