Methods for the photographic recording of freeform surfaces by targeted surface illumination and long exposure

Abstract

Method for the photographic recording of objects with freeform surfaces, in particular motor vehicles, by targeted object illumination and long exposure, comprising the following steps: - Setting up the object or moving it to a completely darkened room or a suitable environment free of residual light; - Determining the line of sight and the desired shooting perspective; - Stable and shake-free positioning of the image recording device according to the defined line of sight and recording perspective at the greatest possible distance between the object and the image recording device; - Activating a remote release setting with pre-release time on the image capture device; - manual or mechanically assisted continuous slow movement of an elongated rod light over the contour and along the object, which, in conjunction with the triggered long exposure, lays a carpet of light over the object; - Repeating the long exposure step with different guidance of the light bar along all freeform surfaces of the object, taking into account the currently selected shooting perspective, whereby the remote release of the image recording device is activated and the object contour is quasi traced by means of movement of the light bar; - repeating a long exposure, wherein the rod light is pivoted or rotated about at least one imaginary fixed point by a predetermined angle and the pivot axis is oriented essentially parallel to a freeform surface of the object; and - Saving the images of the separately illuminated, different areas of the object in a storage device, importing the images into an image processing program and precisely superimposing the individual images to complete the image, as well as optionally isolating the object from the background.

Description

[0001] The invention relates to a method for the photographic recording of freeform surfaces by targeted object illumination and long exposure according to the teaching of claim 1 and a rod lamp for such a method according to the combination of features according to claim 12, wherein the dependent claims include expedient embodiments and further developments.

[0002] In many cases, the ambient lighting in a room is insufficient to illuminate objects or people. To achieve better-exposed photographs, artificial light sources are used. Common examples include continuous lighting and studio flash units, which differ in light output and color temperature.

[0003] Artificial light sources have the advantage that the lighting effect and the formation of light and shadows can be controlled.

[0004] Continuous light sources are designed to illuminate a subject over an extended period. They have become established in studio photography because the lighting effect can be easily assessed. With flash lighting, the modeling light performs this function.

[0005] Shadows and reflections can be assessed. The effect of changing the position of the light is also easily noticeable.

[0006] Continuous light lamps are offered according to the known state of the art as ring lamps, area lights or the like, possibly with so-called light shapers.

[0007] Halogen spotlights as well as LED light sources are used.

[0008] The combined use of continuous light and flash is also well-known, as it allows for better utilization of the strengths of both light sources. In this case, the continuous light acts as a modeling light, as described above, for the preliminary monitoring of the flash unit built into the same light.

[0009] To produce high-quality photographs of objects with various freeform surfaces, such as motor vehicles, especially passenger cars but also motorcycles, it has previously been necessary to bring the object to be photographed into a specially equipped photo studio or to set up the necessary studio lighting equipment in a vehicle hall. For such photographs, light / shadow optimization is often used to particularly emphasize vehicle contours, especially the vehicle body.

[0010] In addition to the aforementioned studio panel lights, a photographic light with a rod-shaped form is known, for example, from US Patent 8,905,562 B1. The housing contains a multitude of LEDs to emit light in one direction towards the housing opening. Furthermore, the known rod-shaped light has a semi-cylindrical diffusion plate. This diffusion plate also serves to close a corresponding housing opening. Additionally, a semi-cylindrical opaque plate is present, which can be positioned on the housing.

[0011] With a light like this, which is relatively compact, shadow effects can be reduced in outdoor or studio shots, thus improving the quality of the resulting image. The light is portable thanks to a handle system with an integrated power supply, but can also be mounted on a tripod.

[0012] Another mobile lighting device is disclosed in US patent 2016 / 0209727 A1. This lighting device is intended for use in document scanning or video recording of one- and three-dimensional objects. The lighting device can be operated in conjunction with smartphones or video cameras, as well as still cameras.

[0013] The light for film or video cameras according to DE 20 2004 007 573 U1 is positioned on or in front of the camera lens or on the camera itself, or can be used as a standalone light. Depending on the embodiment, the light itself has one or more fluorescent tubes.

[0014] US Patent 2014 / 0126835 A1 discloses a technology for illuminating an object with a linear light source at various angles and combining the individual image files into a single finished image. The initial exposures are taken using conventional ambient light. Once these exposures are complete, a second exposure occurs. This second exposure utilizes a relatively short light bar that is moved in an arc over the object. The purpose of this technology, as described in US Patent 2014 / 0126835 A1, is to create an object image with less noise, more balanced shading, and improved appearance without the need for multiple lighting devices.

[0015] CA 2261376 A1 uses flash illumination. However, this type of illumination has many disadvantages. Among other things, it leads to unwanted reflections or overexposure, especially with metallic or highly glossy objects.

[0016] Based on the foregoing, the object of the invention is to provide a further developed method for the photographic recording of freeform surface structures by targeted object illumination and long exposure, which makes it possible to photograph the object in question directly on site without the need to transport it to a suitably equipped photo or film studio. The method according to the invention is intended to eliminate the need for complex and energy-intensive lighting technology analogous to that used in a studio. Furthermore, the method is designed in such a way that previously unknown structures, reflections, and optical impressions can be obtained, regardless of the specific type of surface and its color, such as a painted surface of a motor vehicle or a surface-finished, for example, chrome-plated, add-on part on an exemplary vehicle.

[0017] Furthermore, it is an object of the invention to provide a further developed rod lamp for the inventive method, which is lightweight and optimized for the method. The rod lamp to be created should not focus on optimal light output, but rather on suitable handling with regard to the inventive method steps.

[0018] The problem of the invention is solved methodologically by the teaching according to claim 1 and with regard to the rod lamp according to the invention with the features of claim 12, wherein the dependent claims include expedient embodiments and further developments.

[0019] It is therefore assumed that a method for the photographic recording of free-form surface structures is used by targeted object illumination and long exposure.

[0020] The objects with freeform surfaces are in particular objects such as motor vehicles, especially passenger cars or motorcycles.

[0021] In contrast to conventional methods using quasi-daylight illumination with additional light sources, according to the invention the object to be captured is set up or moved into a darkened room or a corresponding environment free of residual light.

[0022] This could be, for example, the usual vehicle depot or the location where the vehicle in question is parked. This location does not need to be specially prepared with elaborate lighting or other equipment for the recordings.

[0023] Once the object is set up, the line of sight and the desired shooting perspective are determined. Necessary adjustments by changing the setup location or the position of the vehicle on site can then be made step by step.

[0024] Preferably, the greatest possible distance between the object and the image capture device is chosen.

[0025] The image capture device, for example a camera, is then positioned stably and without shaking, according to the desired definition of the viewing axis and shooting perspective.

[0026] It is essential to ensure that the camera remains in the same position throughout the recording sequence and that no mechanical adjustments are made.

[0027] After these procedural steps have been completed, a remote release setting with pre-release time is activated on the image capture device.

[0028] Once this has been done, a long, rod-shaped light is moved manually or mechanically over the contour and along the object, which, in conjunction with the triggered long exposure, creates a carpet of light over the object.

[0029] This is followed by a single or multiple repetition of the long exposure step described above, using different directions for the light source along all freeform surfaces of the object, taking into account the currently selected shooting perspective.

[0030] For this purpose, the remote triggering of the image recording device is activated via a corresponding remote control, and the object contour is virtually traced by moving the rod light.

[0031] Exposure times, for example, range between 5 and 15 seconds.

[0032] Furthermore, a long exposure is repeated, whereby the light source is swiveled around at least one imaginary fixed point by a predetermined angle. The plane of swiveling lies essentially parallel to a suitably selected freeform surface of the object.

[0033] The captured images are saved. They are then imported into an image processing program and precisely overlaid. If desired, the subject can be isolated from the background using image editing software.

[0034] In a further development of the invention, after changing the position of the object to create another perspective, the image illumination and recording steps can be repeated.

[0035] For example, a vehicle can first be photographed at an angle from the front, then at an angle from the rear, or additionally from the front and rear.

[0036] It is essential that the movement of the stick lamp during exposure or illumination is continuous and uniform.

[0037] When moving the stick light over or along the object, the distance to the object should be kept essentially constant.

[0038] Additionally, at least one extra long exposure photograph can be taken with a moving point light source.

[0039] Furthermore, it is possible to take an additional long-exposure photograph of the interior of a suitable object, for example, a vehicle. These photographs are then also included in the set of individual images that are later layered and processed to create a final image.

[0040] When photographing a vehicle, the flashlight is moved over, for example, the hood, roof and rear of the vehicle during the respective long exposure.

[0041] Additionally, the vehicle's side surfaces as well as the front and rear apron areas can be illuminated and recorded by swiveling the light bar around fixed points.

[0042] Furthermore, the stick light can also be moved parallel to the surface and moved by raising and lowering it during long exposures.

[0043] In a further development of the invention, the long-exposure photographs are displayed during their creation or after completion and transferred to a mobile device for review. This allows the quality of the photographs to be assessed on-site and any erroneous shots to be corrected, thus reducing the overall exposure time.

[0044] It is also possible to record and save the size, location and distance of the object from the image recording device to create a virtual spatial model of the object.

[0045] Standard software programs are readily available for image post-processing and image editing. A qualified professional will select these programs according to their needs and expertise, making further detailed explanations unnecessary.

[0046] The rod lamp according to the invention for the method described above is a lightweight lamp with a length in the range of essentially 2 - 3 m, i.e. adapted to the objects to be illuminated.

[0047] The stick lamp features an arrangement of light-emitting diodes, which are equipped with a light-diffusing cover.

[0048] The elongated lamp, which is only a few centimeters in diameter, can have an integrated forearm support for easier manual guidance of the lamp over the object.

[0049] Furthermore, it is possible to connect the light to a suspension or movable mounting device, especially when larger or taller objects are to be photographed.

[0050] According to the invention, the rod lamp is coupled to a buoyancy body, the buoyancy body compensating at least partially for the weight of the lamp.

[0051] A suitably gas-filled balloon could be used as a buoyancy aid.

[0052] To improve photographic effects and optimize visible reflections, the rod light can be designed to be bendable around a fixed point or to be completely flexible. In its flexible version, the rod light could be shaped into a curve that corresponds to or approximates a partial contour of the object, for example, a vehicle, in the form of an envelope.

[0053] The invention will be explained below using an exemplary embodiment.

[0054] The example involves creating photographic images of classic vehicles that have very different body shapes, different colors, and often voluminous chrome-plated add-on parts, such as bumpers, radiator grilles, or the like.

[0055] The photographic recordings are made on site in the large garage, vehicle hall or similar facility, i.e. at the usual parking or storage location of the vehicles.

[0056] First, an optical line of sight is established. It is important to maintain as much distance as possible from the vehicle in order to avoid distortions in the recordings and, in particular, to optimize the recording quality.

[0057] Distances of 5-15 m, depending on the spatial conditions, are advantageous here.

[0058] Depending on the desired view of the vehicle, it is positioned and the image recording device, i.e. the camera on a fixed tripod, is aligned.

[0059] The camera's remote trigger is then activated. It is advantageous to select a pre-trigger time to ensure that the operator is in the starting position with the light bar, ready to illuminate the object.

[0060] In a completely darkened room, the light bar is moved across the freeform surface of the object being photographed—in this example, a vehicle. This movement is timed to the exposure time, which is typically between 5 and 20 seconds. This time is sufficient to perform a continuous, slow movement of the light bar across the vehicle. As a result of this long exposure combined with the movement of the light bar, a light carpet is optically formed.

[0061] The lighting process, involving movement of the pole light, is repeated several times. Additionally, the pole light can be swiveled around a fixed point or moved parallel to the floor of the vehicle hall, raised, and lowered again.

[0062] Additionally, the vehicle is repeatedly exposed to a point light source. Here too, a long exposure is used.

[0063] Additionally, the vehicle interior is illuminated and this image is also saved for later overlay with other images.

[0064] For all recordings, it is essential to ensure that the image recording device remains stable in the selected location and is stored without vibration.

[0065] The corresponding shots or shooting cycles are repeated after the vehicle's positioning has been changed, for example from a diagonal front view to a diagonal rear view, or in some other way.

[0066] The 2-meter-long pole light used is capable of replacing the standard panel lights up to 3 meters wide and 15 meters long typically used in automotive photography. Moving the light over the vehicle during a long exposure creates a correspondingly long band of light. The pole light is preferably powered by rechargeable secondary batteries.

[0067] The different lighting scenarios that arise during a session are subsequently combined in several steps using a suitable image editing program to create a finished image.

[0068] Exposure times, for example between 5 and 15 seconds, depend on the paint finish and color of the object, as well as the distance to the light source. An aperture of at least f / 11 is chosen to ensure sufficient depth of field and to achieve long exposure times.

[0069] During the actual filming, the operator is positioned near the object with the flashlight.

[0070] The remote trigger makes it possible to start the lighting and the formation of the light carpet directly at the start of the exposure from a specific position.

[0071] The pre-release time allows you to get into the necessary positions before and between exposures.

[0072] As already indicated, in the darkened room, after pressing the camera shutter release, the activated flashlight is moved along and / or over the vehicle in a smooth and steady motion during the long exposure.

[0073] The distance covered during the exposure time corresponds to the later length of the resulting light carpet.

[0074] Shape and position are controlled by the posture, distance, and movement of the stick lamp.

[0075] If, as in the exemplary embodiment, the stick light is moved approximately straight across the vehicle roof, a correspondingly straight light reflection is created on the vehicle. This then corresponds to the lighting effect of a comparable panel light, such as those used in photo studios.

[0076] If the light bar is moved along a vehicle contour, for example along a roofline, the resulting reflection can be adjusted to this contour.

[0077] A rotating or swiveling movement of the light around the rod axis produces a circular reflection. A wave-like movement would project a correspondingly curved reflective surface onto the vehicle.

[0078] Using the described steps for moving the light bar, it is possible to essentially model the object. Therefore, by moving the light bar while walking along the area, it is possible to trace the vehicle's design with light.

[0079] When placed in a suitably averted, i.e., non-reflective, position, the stick lamp has an indirect effect and enhances the natural color of the materials.

[0080] According to the above procedure, different areas of the vehicle are illuminated separately. In the subsequent image processing, the final image is created from a multitude of individual shots. Each individual area can be illuminated separately depending on the material (e.g., chrome, paint, plastic, or glass) and its color, which is very difficult to achieve with a single shot using a panel light.

[0081] Post-production is carried out using specialized image editing software. Selected images are adjusted using development settings such as cropping, tonal value, contrast, camera profile, etc. The images are then precisely layered on top of each other. Using a masking technique, only the areas that were illuminated during the shot are then made visible on each layer.

[0082] If desired, the object can be separated from the background using a selection tool. This allows the subject and background to be edited separately.

[0083] The work light is an LED work light with a lightweight housing and diffuser. The work light weighs approximately 1000 g. This low weight allows the light to be moved smoothly and evenly over the object, even throughout a long workday.

[0084] For complex shots, support structures are conceivable. Here, the movement of the light bar can be achieved similarly to a Steadicam. Suspension with a boom arm is also possible, with the boom arm fixed to the operator. Mobile tripod booms can also be used. However, it must be possible to move the light source smoothly in a vertical direction during the lighting process.

Claims

[1] Method for photographic recording of objects with freeform surfaces, in particular motor vehicles, by targeted object illumination and long exposure, comprising the following steps: - Setting up the object or moving it to a completely darkened room or a suitable environment free of residual light; - Determining the line of sight and the desired shooting perspective; - Stable and shake-free positioning of the image recording device according to the defined line of sight and recording perspective at the greatest possible distance between the object and the image recording device; - Activating a remote release setting with pre-release time on the image capture device; - manual or mechanically assisted continuous slow movement of an elongated rod light over the contour and along the object, which, in conjunction with the triggered long exposure, creates a carpet of light over the object; - Repeating the long exposure step with different guidance of the light bar along all freeform surfaces of the object, taking into account the currently selected shooting perspective, whereby the remote release of the image recording device is activated and the object contour is quasi traced by moving the light bar; - repeating a long exposure, wherein the rod light is pivoted or rotated about at least one imaginary fixed point by a predetermined angle and the pivot axis is oriented essentially parallel to a freeform surface of the object; and - Saving the images of the separately illuminated, different areas of the object in a storage device, importing the images into an image processing program and precisely superimposing the individual images for completion, as well as optionally isolating the object from the background. [2] Method according to claim 1, characterized by , that after changing the position of the object to create another perspective, the image lighting and shooting steps are repeated. [3] Method according to claim 1 or 2, characterized by that the movement of the stick light during exposure is continuous and uniform. [4] Method according to claim 3, characterized by that when the stick light is moved over or along the object, the distance to the object is chosen to be essentially uniform. [5] Method according to any of the preceding claims, characterized bythat at least one additional long exposure photograph is taken with a moving point light source. [6] Method according to any of the preceding claims, characterized by that at least one additional long exposure photograph of the interior of a corresponding object, in particular a motor vehicle, is taken. [7] Method according to any of the preceding claims, characterized by , that during a motor vehicle photograph the flashlight is moved over the hood, roof and rear of the vehicle during the respective long exposure. [8] Method according to claim 7, characterized by , that additionally the vehicle side surfaces as well as the front and rear apron areas are illuminated by swiveling the light bar around fixed points. [9] Method according to claim 7 or claim 8, characterized by , that in addition the stick light is moved parallel by raising and lowering during the long exposure. [10] Method according to any of the preceding claims, characterized by , that the long exposure images are displayed during their creation and transferred to a mobile device for review. [11] Method according to any of the preceding claims, characterized by , that the size, location and distance of the object from the image recording device are captured and stored to generate a virtual spatial model of the object. [12] Stick light for a method according to one of the preceding claims, which has a length of essentially 2-3 m and features an arrangement of light-emitting diodes equipped with a light-diffusing cover, where A lightweight housing is used, and an integrated forearm support is designed for easier manual guidance of the stick light over an object. or this is connected to a suspension or movable holding device, characterized by , that The lamp is coupled to a buoyancy body, the buoyancy body compensating at least partially for the weight of the lamp. [13] Stick lamp according to claim 12, characterized by that the buoyancy body is designed as a gas-filled balloon. [14] Stick lamp according to claim 12 or 13, characterized by that the stick light is designed to be bendable around a fixed point or to be bendable overall.