Underwater camera for taking underwater pictures

Abstract

The invention relates to an underwater camera (1) for taking underwater images, comprising a camera (2) which is designed to take images in one viewing direction, a nozzle unit and a water supply (5) for supplying the nozzle unit (3) with clear water, wherein the nozzle unit comprises a plurality of nozzles (3), each having a water inlet (E) and a water outlet (A) and arranged such that water guided through the nozzles (3) flows out of the nozzles (3) essentially in the viewing direction, wherein an inflow region (B) of the nozzles (3) at the water inlet (E) narrows towards the water outlet (A).

Description

The invention relates to an underwater camera for recording underwater images.Subsea cameras are needed for many different applications. An underwater camera is understood to mean a camera which is encapsulated in a watertight manner. This can be done by inserting a (normal) camera into a watertight housing or by watertight production of the camera housing.In addition to the recording of motifs in clear waters, underwater inspection is an important field of application of an underwater camera in particular. In the course of such an underwater inspection, for example, underwater images of hull vessels or structures such as sheetpiles, quay walls or lock ports are produced with the underwater camera and evaluated on land.In underwater recordings, the problem of a limited visibility frequently occurs, since suspended matter in the water clearly limits the visibility. If the visibility in clear seawater is normally up to 30 meters, the visibility can drop to a few centimeters in the case of a high level of suspended matter.A great problem with underwater inspection is that they often have to be carried out where a high density of suspended matter is present, e.g. at lock entrances or in port basins. It is sometimes impossible to achieve evaluable images, since these do not allow any usable results due to the limited visibility conditions. Also, the use of headlights often does not aid, since the suspended particles reflect the light and diffusely direct it into the camera.Thus, in soiled environments, often only the possibility remains of carrying out examinations haptically with diving persons or by means of sonar. Investigations by diving are both subjective assessment and imperfect, since some damage that could be easily visually recognized cannot be detected haptically or clearly recognized. An examination by means of sonar has very low resolution and no damage can be detected which does not manifest itself by deformations, e.g. corrosion.It is an object of the present invention to specify an underwater camera for recording underwater images in a viewing direction, with which the above-described disadvantages are avoided.This object is achieved by an underwater camera according to the claims.An underwater camera according to the invention serves for recording underwater images. It comprises a camera which is designed to record images in a viewing direction, a nozzle unit and a water supply for supplying the nozzle unit with clear water. The nozzle unit comprises a plurality of nozzles, each having a water inlet and a water outlet and arranged such that water conducted through the nozzles flows out of the nozzles substantially in the direction of view, wherein an inflow region of the nozzles at the water inlet narrows towards the water outlet.The camera of the underwater camera records images which lie in their viewing direction. It is arranged in the underwater camera such that its water-sensitive elements are encapsulated in a watertight manner. In particular, it is mounted in the interior of a housing of the underwater camera such that only its objective protrudes outwards. However, it can also be arranged completely behind a transparent window in the housing wall.The nozzle unit includes a plurality of nozzles. These can be formed, for example, in a wall of a housing of the underwater camera, for example as holes. They must be arranged in such a way that water conducted through the nozzles flows out of the nozzles essentially in the viewing direction, preferably in a laminar manner (compliance with the Reynolds number is preferably sought). This means that the main jet direction of a water jet emerging from a nozzle is substantially parallel to the viewing direction. The term "substantially" here means at most 20° inclined to the viewing direction, preferably at most 10°, in particular at most 5° or even at most 1°. Assuming that the nozzles are said holes in one side of the underwater camera and the camera looks out of this side in the direction of the surface normal, the holes are preferably oriented perpendicular to this side.Preferably, the nozzles surround the camera and are arranged in the form of a group on a circle or polygon around the camera. It is particularly preferred that the nozzles are arranged in a plurality of groups on a plurality of concentric circles or polygons (in particular offset with respect to one another in the case of adjacent circles / polygons). The nozzle arrangements do not necessarily have to be close to the camera or homogeneously cover the entire area around the camera. It is quite possible for the distance between the innermost and the outermost group to be smaller than half the diameter of the arrangement of the innermost group. Thus, in the preferred case that the groups are arranged on (concentric) circles, the radius of the innermost circle would be greater than the distance of the innermost circle from the outermost. This has the advantage that the area in front of the camera can be optimally clarified with clear water without degrading the view with the breast being agitated.However, the nozzles (e.g., the holes) are not monotonously cylindrical, but have a part that narrows (the inflow region). Each of these nozzles has a water inlet and a water outlet. This means the sides of the nozzle into which the water flows in or out. The nozzle channel is located between the water inlet and the water outlet. That part of the nozzle channel which lies at the water inlet is the inflow region. The inflow region narrows towards the water outlet. This means that the inflow region can be understood to mean that part of a nozzle channel which narrows. By "narrowed" is meant the decrease in the diameter of the nozzle channel in the intended direction of flow of water.The water supply can be a simple pipe or a hose. It must be designed so that water can be guided through it to the nozzle unit. In the example described above, the water supply can be a pipe leading into the annular volume. The supplied clear water can be distributed therein and reach the nozzle units. The water supply can have a flange at its end facing away from the camera, with which it can be connected to a water source.Even if the camera can be supplied with energy by a rechargeable battery and can store its recordings on an internal storage medium, it is nevertheless advantageous to perform the energy supply from the outside and also to store the recordings externally. For this purpose, a cable can be led through the water supply or along the water supply, through which cable the camera can be supplied with energy and its recording data can be led. A cable is preferably guided out of the housing of the underwater camera on the side facing away from the viewing direction or out of the lateral surface thereof.The camera can preferably also transmit its image data by radio transmission, e.g. via a WLAN or a mobile radio network. In this respect, the known frequency ranges can be used for underwater radio. For this purpose, it is preferred that the camera is supplied with energy by means of a rechargeable battery, so that any cable connection can be dispensed with.Such an underwater camera can provide usable recording, in particular in the case of turbid visibility conditions. This is of great advantage in particular in the underwater inspection of ships or structures, for example of sheetpiles, quay walls or lock ports.Further, particularly advantageous embodiments and developments of the invention are evident from the dependent claims and the following description, wherein the claims of one claim category can also be developed analogously to the claims and description parts to another claim category and in particular individual features of different exemplary embodiments or variants can also be combined to new exemplary embodiments or variants.As already indicated above, a preferred underwater camera is characterized in that the nozzles are arranged annularly around the camera, preferably on a plurality of concentric rings (circular or polygonal).Regardless of a specific nozzle arrangement, the nozzle unit has an annular space around the camera, into which the water feed opens and in the wall of which the nozzles are arranged. This space serves for supplying clear water to the individual nozzles. The camera is arranged here in the center of the space and enclosed by walls, and the space surrounds the camera at least in a region orthogonal to the viewing direction around the camera. For example, if the underwater camera comprises a cylindrical housing, the camera is surrounded by inner walls at the centre of this cylinder and the space around it between the inner walls and outer walls of the housing is said space.A preferred underwater camera is characterized in that it additionally has nozzles counter to the viewing direction. By means of these (second) nozzles, which expel water in the opposite direction to the aforementioned (first) nozzles, the repulsion forces of the first nozzles can be canceled out and the underwater camera can be held stable in the water more easily. This second arrangement of the nozzles preferably has the same number of nozzles as the first arrangement and is in particular designed identically to the first arrangement of the nozzles.For simple guidance in the water, the underwater camera can also have an electric motor which drives a ship's screw and is mounted on the camera housing. The ship's propeller can be positioned in particular in such a way that it generates a thrust in the viewing direction in order to counteract the counterpressure of the nozzles. This represents a water-saving alternative to the nozzles counter to the viewing direction. However, it is also preferred that the ship's propeller is steerable. The underwater camera is preferably configured with a control unit which is designed to control the steering and in particular also the thrust of the ship's propeller or of a plurality of such ship's propellers with electric motors. This control unit is furthermore preferably designed to be remotely controlled by cable or radio or to approach and hold a position autonomously. The drive and the control can be supplied with energy from an accumulator or by means of a cable.Preferably, the water supply comprises a pump which pumps water with pressure to the nozzles. The pump can be supplied with energy from the outside by a cable or via an accumulator of the underwater camera.In this embodiment with a pump, it is particularly preferred that the water supply additionally comprises a filter system, in particular an electrical filter system, which is configured to filter the water moved by the pump. This makes it possible to clarify surrounding, contaminated water to such an extent that it can be used as clear water for the underwater camera. The filter system can be cleaned after use of the underwater camera or by a brief switching over of the pump.The underwater camera can well have a plurality of water feeds which lead water into different spaces within the housing of the underwater camera, wherein the housing has nozzles for each of these spaces. Preferably, the first nozzles can issue from a first space and the second nozzles from a second space. By applying different water pressures to the two spaces, a force can then be exerted on the camera in a targeted manner. In this regard, it is also preferred that the camera has nozzles in the lateral surface of its housing (the sides in the viewing direction and opposite are referred to as "end faces", the lateral wall as "lateral surface"), which nozzles are connected to its own space and to its own water feed. By applying water pressure to these nozzles, the camera can be moved laterally or held stable against a flow.A preferred underwater camera is characterized in that the constriction of the inflow region is regular or the change in the constriction decreases towards the water outlet. The constriction is preferably funnel-shaped with straight walls or with curved walls, wherein the curvature becomes steeper towards the water outlet when considering the cross section along the longitudinal axis. If, for example, the nozzle channel has parallel walls at the water outlet, the walls of the inflow region are bent in the shape of a trumpet.Preferably, the cross section (orthogonal to the longitudinal axis) is round and the inflow region is conical. The diameter of the inflow region can, however, also become smaller with a decreasing gradient in the direction of the water outlet (first the cross section narrows sharply, then narrows less sharply).A preferred underwater camera is characterized in that the nozzle channel behind the inflow region has a constant cross section or a cross section which increases continuously from the water inlet over its length. This serves to improve laminar flow.Preferably, the cross section of the nozzle channel is cylindrical or prism-shaped.A preferred underwater camera is characterized in that a nozzle diameter d of the nozzles which is present at least at the end of the inflow region (facing the water outlet) is at least 1 / 10 mm, preferably at least 1 mm, in particular at least 2 mm and / or at most 8 mm, preferably at most 5 mm, in particular at most 4 mm. For this purpose, the Reynolds number should be taken into account at a predetermined water pressure so that a laminar flow takes place. A nozzle diameter of 3 mm or at least in the range of 1 mm around this value is particularly advantageous.A preferred underwater camera is characterized in that the nozzle channel has at least a length of d (i.e. corresponds at least to the nozzle diameter). The length is preferably at least 2 d, in particular at least 3 d. The length is preferably a maximum of 6 d, preferably a maximum of 4 d. A length between 3d and 4d is particularly advantageous for laminar flow.The inflow region preferably has a length of at least d / 10, preferably at least d / 3, in particular at least d / 2. the length thereof is preferably a maximum of 2 d, in particular a maximum of d. A length between d and d / 2 is particularly advantageous for a laminar flow.According to a preferred embodiment, nozzles (in particular all nozzles) are designed as elongated holes. This means that they are longer in the direction of their width orthogonal to the longitudinal direction of the nozzle channel than in the direction of their height. Straight slots (a rectangle bounded by semicircles) or slots whose shape follows an arc, in particular an arc on which the nozzles are arranged, are preferred. Preferably, the width of an elongated hole is longer than its height, in particular at least twice the height. Preferably, however, an elongated hole is not wider than 10 times its height, in particular not wider than 7 times its height, or even less than 4 times its height. A nozzle in the form of an elongated hole with a preferred height of 3 cm is preferably at least 5 mm wide and at most 1.5 mm wide.A preferred underwater camera is characterized in that the inflow region of a nozzle corresponds to a volume bounded by a torus, e.g. the upper half of an inner region surrounded by the torus. In this case, the circular cross section of the toroidal volume (i.e. a straight section through the annular volume) preferably has a radius of at most d, particularly preferably at most 2 / 3d, in particular at least d / 2 and / or preferably a radius of at least d / 5, in particular at least d / 3.A preferred underwater camera is characterized in that the minimum distance between two adjacent nozzles is 5 mm, preferably 8 mm, and / or that the maximum distance between two nozzles is 50 mm, preferably 30 mm. This means the distance from the closest nozzle.The underwater camera can additionally have illumination elements, e.g. light-emitting diodes. These are preferably arranged around the camera, in particular between the nozzles and the camera and / or between the nozzles. They are preferably arranged in the form of a number of rings around the camera.The underwater camera can have a rod, on which it can be fastened or held, which in particular is attached or can be attached to the lateral surface of the housing of the underwater camera. However, it is also possible to hold the underwater camera on the water supply or to fasten it to an object, e.g. to an underwater robot, by means of a flange on the water supply. It is not excluded to guide the camera system with a diving robot.In particular, in the case that the camera is held by divers, it is preferable that the image of the camera is displayed in the dive glasses. For this purpose, a screen and a display optics are preferably installed on or in the diving glasses, said display optics displaying the image of the camera, preferably reflected on the spectacle lens, to a diving apparatus. It is preferred that a measurement of the position and viewing direction of the diving apparatus takes place relative to the position and viewing direction of the underwater camera and the images transmitted to the diving apparatus from the underwater camera are displayed based on this measurement. The technique for this is known from augmented and virtual reality. In combination with the underwater camera, the diving apparatus thus receives an image as it would prevail in a clear environment.The invention is explained in more detail below with reference to the attached figures on the basis of exemplary embodiments. In this case, identical components are provided with identical reference numerals in the different figures. The figures are generally not to scale. The following are shown: FIG. 1 is a perspective view of an underwater camera according to the invention. FIG. 2 shows the underwater camera in a plan view from the front. FIG. 3 shows an example of a subsea camera as a cross-sectional view from the side. FIG. 4 shows a preferred nozzle shape, FIG. 5 shows a further preferred nozzle shape, FIG. 6 shows a preferred nozzle shape with size ratios. FIG. 7 is a perspective view of an underwater camera according to the invention, FIG. 8 shows nozzles in the form of an elongated hole.Fig. 1 shows in perspective an example of an underwater camera according to the invention. It comprises a camera 2 which is designed to record images in a viewing direction (the objective is seen here), a nozzle unit and a water feed 5 for supplying the nozzle unit with clear water. The nozzle unit is formed by the nozzles and the inner space behind the nozzles.The nozzle unit includes a plurality of nozzles 3 arranged in the form of three groups annularly on three concentric circles around the camera 2. A hose can be connected to the flange 6 of the water supply 5 and supply clear water to the underwater camera. The underwater camera 1 can, however, also be fastened to an object by means of the flange 6, e.g. to a ship or a diving robot.FIG. 2 shows an underwater camera as shown, for example, in FIG. 1, in a front view. The arrangement of the three groups of nozzles 3 on the three concentric circles can be seen very well here. The innermost circle may have a diameter of, for example, 130 mm, the middle one 145 mm and the outermost one 160 mm. On each circle there are 18 nozzles, which can have a nozzle channel diameter of 3 mm, for example (and a distance on the respective circle of approximately 24 mm on the inside and 30 mm on the outside from one another). The middle of the three groups of nozzles is offset from the inner and outer. The distances between the nozzles are in the range between 8 mm and 20 mm. A circle is indicated on the left in dotted lines, which is intended to represent the minimum distance r between two adjacent nozzles 3.FIG. 3 shows a preferred underwater camera as a sectional view from the side. In the middle, the camera 2 is arranged in an interior space enclosed by walls W. This space is in the form of a cylinder. The housing 4 of the underwater camera 1 is also cylindrical, so that the space between the interior and the housing wall W is annular. Clear water flowing in in the direction of the lower arrow through the water supply 5 can be distributed in the entire annular space and emerge uniformly from the nozzles 3 (arrows). Here, only two groups of nozzles 3 are shown, which are arranged annularly around the camera 2 as holes in the wall W. As a special feature, the underwater camera 1 additionally has nozzles 3 counter to the viewing direction.Figure 4 shows a preferred nozzle shape. The illustration can be regarded as an enlargement of the nozzles 3 in the wall W of FIG. 3 and shows a possible variant for a nozzle 3. the nozzle 3 has a water inlet E and a water outlet A, wherein an inflow region B at the water inlet E narrows conically towards the water outlet A.Fig. 5 shows another preferred nozzle shape. This illustration can also be regarded as an enlargement of the nozzles 3 in the wall W of FIG. 3 and shows a further possible variant for a nozzle 3. The diameter thus decreases in the direction of the water outlet A with a decreasing gradient.FIG. 6 shows a preferred nozzle shape with size relationships. The nozzle channel K behind the inflow region B has a constant cross section here over its length and is preferably cylindrical. The diameter d of the nozzle channel K is here, for example, 3 mm. A diameter between 2 mm and 4 mm is particularly advantageous for laminar flow. The length a of the nozzle channel K is 3.5 d in this example. Since the nozzle 3 is a hole in the wall W of the housing 4 of the underwater camera, the wall thickness should therefore be 10.5 mm for a 3 mm nozzle diameter.The length b of the inflow region B is here, for example, 1.5 mm, that is to say half the diameter of the nozzle. The shape of the inflow region B corresponds to a volume bounded by a torus (the upper half of the interior space thereof). The circular cross section of the toroidal volume in this example has a radius r which corresponds to half the diameter d of the nozzle 3.Fig. 7 shows in perspective an example of an underwater camera according to the invention as it could be used in practice. It is similar to the underwater camera of FIG. 1 with a camera 2, three rings of nozzles 3 and a water supply 5, but with a handle G, to which it can be held by a diving person or attached to a sheet pile and a holding rod H, with which it can be mounted on an object, e.g. a submarine, a ship or also a sheet pile, has more details than FIG. 1.FIG. 8 shows nozzles 3 in the form of an elongated hole in plan view. The nozzles 3 are not circular here, as shown in the preceding figures, but have the shape of an elongated hole. This slot may be straight, as shown on the left, or it may have a slightly curved shape to conform to the shape of a circle on which a plurality of such nozzles 3 lie. The longitudinal section of such a nozzle 3 is preferably as shown in FIGS. 4 to 6. The width of the slot (from right to left) is three times its height (from top to bottom).Finally, it is pointed out once again that the invention described in detail above is merely exemplary embodiments which can be modified in a wide variety of ways by the person skilled in the art without departing from the scope of the invention. Furthermore, the use of the indefinite article "a" or "an" does not exclude that the features in question can also be present multiple times. Likewise, terms such as "unit" do not exclude that the relevant components consist of a plurality of interacting sub-components, which may optionally also be spatially distributed. The term "a number" is to be read as "at least one(s)".List of reference characters1 Underwater camera 2 Camera 3 Nozzle 4 Housing 5 Water supply 6 Flange A Water outlet B Inflow region E Water inlet G Handle H Holding rod K Nozzle channel W Wall

Claims

Underwater camera (1) for recording underwater images, comprising a camera (2) which is designed for recording images in a viewing direction, a nozzle unit and a water feed (5) for supplying the nozzle unit with clear water, wherein the nozzle unit comprises a plurality of nozzles (3) which each have a water inlet (E) and a water outlet (A) and are arranged such that water conducted through the nozzles (3) flows out of the nozzles (3) substantially in the viewing direction, wherein an inflow region (B) of the nozzles (3) narrows towards the water outlet (A) at the water inlet (E).Underwater camera (1) according to claim 1, characterised in that the nozzles (3) are arranged annularly around the camera (2), preferably on a plurality of concentric rings, preferably wherein the nozzle unit has an annular space around the camera (2), into which the water feed (5) opens and in the wall (W) of which the nozzles (3) are arranged.Underwater camera (1) according to one of the preceding claims, characterized in that it additionally has nozzles (3) counter to the viewing direction.Underwater camera (1) according to one of the preceding claims, characterized in that the constriction of the inflow region (B) is regular or the change in the constriction decreases towards the water outlet (A), preferably wherein the cross section is round and the inflow region (B) is conical or the diameter decreases with a decreasing gradient in the direction of the water outlet (A), wherein the inflow region (B) is preferably in the form of a trumpet.Underwater camera (1) according to one of the preceding claims, characterized in that a nozzle channel (K) behind the inflow region (B) has a cross section which is constant or increases continuously over its length from the water inlet (E), preferably wherein the cross section is cylindrical or prismatic.Underwater camera (1) according to one of the preceding claims, characterized in that a diameter d of the nozzles (3) which is present at least at the end of the inflow region (B) is at least 1 / 10 mm, preferably at least 1 mm, in particular at least 2 mm and / or at most 8 mm, preferably at most 5 mm, in particular at most 4 mm.Underwater camera (1) according to claim 6, characterised in that the length of the nozzle channel (K) corresponds at least to the diameter d, preferably to at least 2d, in particular to at least 3d and / or to a maximum of 6d, preferably to a maximum of 4d and / or that the length of the inflow region (B) with respect to the diameter d corresponds to at least d / 10, preferably to at least d / 3, in particular to at least d / 2 and / or to a maximum of 2d, preferably to a maximum of d.Underwater camera (1) according to claim 6 or 7, characterised in that the nozzles 3 are designed as elongated holes, preferably as straight elongated holes or as elongated holes, the shape of which follows an arc, in particular an arc on which the nozzles 3 are arranged, preferably wherein the width is at least twice the height and / or is not more than 10 times the height, in particular not more than 7 times.Underwater camera (1) according to one of the preceding claims, characterized in that the inflow region (B) of a nozzle (3) corresponds to a volume bounded by a torus, preferably wherein the circular cross section of the torus volume corresponds to a radius of at most the diameter d of the nozzle (3), preferably at most 2 / 3d, in particular at most d / 2 and / or at least d / 5, preferably at least d / 3.Underwater camera (1) according to one of the preceding claims, characterized in that the minimum distance r between two adjacent nozzles (3) is 5 mm, preferably 8 mm, and / or in that the maximum distance between two nozzles (3) is 50 mm, preferably 30 mm.

Images