DE102021208659A1 - Apparatus for providing a graphical representation of sonar data - Google Patents

Abstract

An apparatus (20) for providing a graphical representation of sonar data (22) is disclosed. The device includes a monitor interface (24) and a graphics processor (26). The graphics processor is configured to send a sequence of images (28) graphically representing the sonar data (22) to the monitor interface (24). The graphics processor (26) is also designed to generate further sequences of images (28) at update times that correspond to the current sonar data (22) and to send the images of the further sequences to the monitor interface (24). The graphics processor is further designed to manipulate a first image of a sequence of the further sequences of images and to send the sequence with the manipulated image to the monitor interface (24) in order to prevent flickering of a monitor (30) connected to the monitor interface (24). to reduce the transition from an image of a current sequence to a subsequent image of a subsequent sequence.

Description

The invention relates to the reduction of flickering (also referred to as flickering) of monitors, in particular liquid crystal monitors (LCD - Liquid Crystal Display). Screen or display are synonyms for a monitor.

Flickering of monitors and especially liquid crystal monitors occurs when picture elements (pixels) that are close together are switched from light to dark at the same time. The more pixels are involved in this switching, the more noticeable is the area-wide “flickering”, which can become very uncomfortable for the viewer in the long run. Current monitors, such as liquid crystal monitors or monitors made from organic light emitting diodes (OLED monitors), are more or less affected by the flicker phenomenon depending on the technology or panel used. Liquid crystal monitors are currently probably the most widespread monitors. In particular, liquid crystal monitors with IPS panels (in-plane switching panels) are well suited for use in consoles, which are used, for example, in a control station of a watercraft, e.g. a ship or a submarine, due to their viewing angle independence. With liquid crystal monitors, flickering occurs to varying degrees depending on the panel used. Flickering is very pronounced on IPS panels. In the days of tube monitors, the effect was even less noticeable, since the individual pixels had a greater inertia and each pixel therefore already had a kind of low-pass filter.

When displaying sonar data, the flickering effect caused by the image information can be seen very clearly. For example, sonar data mainly shows noise, so that neighboring pixels of the monitor are not deterministic and can assume any brightness values. Only in the area of the image where a target is detected is there a larger area with pixels that are in a similar brightness range. If a new image is displayed, the pixels that represent noise can assume any other brightness value. Jumps in brightness occur over a large area of the monitor when the image changes. The flickering is clearly perceptible to the human eye.

The flickering of today's monitors is caused by the asymmetry of the switch-on and switch-off characteristics of the individual pixels of a monitor panel. If a bright pixel shifts to the next line, the pixel that is still switching off has a certain sluggishness. The same applies to the pixel that is just turning on, which also has a finite turn-on time. An exemplary representation of a characteristic curve for a pixel is in 1a shown. The ideal switch-on and switch-off process is shown in dashed lines, while an exemplary real switch-on and switch-off process is shown with the solid line.

As can be seen, the fall time of the pixel is slower as the brightness decreases, while the pixel turning on shows a relatively steep brightness curve. Since the brightness curves are not linear, the average brightness does not balance out at the time of switching in such a way that it corresponds to the brightness of an individual pixel. In other words, in extreme cases, the switch-on and switch-off edges of two pixels overlap in such a way that at the moment of switching the residual brightness is added in such a way that there is either a brief drop in brightness or an increase in brightness, depending on whether the rising edges overlap at the extreme point in such a way that the total brightness of the pixel turning off and on is less than or greater than the brightness of the individual pixel. Depending on the display technology, ambient temperature, control electronics and color tone, the average brightness can add up in different ways.

The brightnesses add up visually during the switching times in such a way that the perceived brightness is either lower or higher. These overshoots and undershoots are accordingly perceived as "flickering". In 1b such a brightness curve of a monitor is shown schematically. Looking at the representation in 1b you can see the short-term drop in average brightness three times in the period of the image change. In relation to the average brightness, the measurable reduction is small, but this decrease is clearly perceived by the human eye.

It should be noted that 1a represents only an exemplary schematic representation of the brightness curve of a pixel. The curve has a parabola-like shape when rising and falling. This means that the characteristic curve is similar to charging or discharging a capacitor. However, depending on the technology used in the monitor, the increase can also be more linear or have a greater or different curvature. It is also possible that the rise in the characteristic curve takes longer than the fall. However, it is common for the switch-on and switch-off processes not to have the same duration.

Likewise shows 1b only an exemplary schematic representation of the brightness curve of a monitor.

Although monitor manufacturers offer solutions for flickering, these are expensive and/or inflexible. Monitor manufacturers, for example, offer to artificially slow down the response time of monitor pixels. However, this is cost-intensive, since an individual production and one is bound to these manufacturers and therefore inflexible when choosing the monitors. Furthermore, the monitor also becomes sluggish for applications in which flickering is not visible or disturbing.

There is also the option of arranging a compensation box between the monitor interface and the monitor. Again, this approach is expensive and inflexible, since the compensation boxes are only appropriate for a specific monitor (i.e. monitors of one type from one manufacturer). If new interfaces are developed, the compensation box must be adapted to the new interface. There are also separate license costs for encryption (e.g. HDCP - High-bandwidth Digital Content Protection).

The object of the present invention is therefore to create an improved concept for displaying sonar data.

The object is solved by the subject matter of the independent patent claims. Further advantageous embodiments are the subject matter of the dependent patent claims.

Example embodiments show an apparatus for providing a graphical representation of sonar data with a monitor interface and a graphics processing unit (GPU). The device is, for example, a personal computer (PC) or an embedded computer that includes the graphics processor. The graphics processor is configured to send a sequence of images graphically representing the sonar data to the monitor interface. The images of the sequence of images can be provided at a refresh rate by the graphics processor at the monitor interface. At update times, the graphics processor generates further sequences of images that correspond to current sonar data. That is, the sequence of images can be generated at an update rate.

The refresh rate is typically lower than the refresh rate. For example, the refresh rate is between half a second and three refreshes per second, while the refresh rate is between 20 and 100 Hertz (Hz), typically 50 or 60 Hz. That is, the (same) images are provided at the monitor interface more often than new sequences of images with different content are generated. The current sonar data may correspond to the data obtained at the last sampling time. The sonar data can be provided by hydrophones. The sensor data can be obtained from the hydrophones by sampling at sampling times.

The graphic interface sends the images of the further sequences to the monitor interface. That is, the graphics interface provides the images of the other sequences using the monitor interface. The sending of the images or the provision of the images can in turn take place at the frame rate.

The graphics processor is now designed to manipulate a first image of a sequence of the further sequences of images and to send the sequence with the manipulated image to the monitor interface in order to prevent flickering of a monitor connected to the monitor interface due to the transition from an image of a current sequence to reduce a subsequent image of a subsequent sequence.

This means that the graphics processor generates a sequence of images, for example with the refresh rate. The images correspond to the sonar data to be displayed. Since the sonar data is typically updated less frequently than the image on the monitor, several identical images are generated. However, the first image of a new sequence, i.e. the first image in which new sonar data is presented, is manipulated. The aim of the manipulation is to reduce or prevent the flickering of the monitor. This is achieved by the fact that the manipulation keeps the average brightness as constant as possible during the period in which the picture content is switched. The more constant the average brightness of the monitor while switching from one sequence of images to the next sequence of images, the lower the perception of flickering by the viewer.

The monitor connected to the monitor interface flickers when there is a transition from a (last) image in a current sequence to a (first) subsequent image in an (immediately) subsequent sequence. The idea is now to reduce the flickering by manipulating the first image of the subsequent sequence. This can be carried out not only for one sequence but by manipulating the respective first images of the further sequences of images by the graphics processor for each sequence that follows the first sequence. If it is subsequently said that the image of a sequence is manipulated, it is of course also possible to manipulate the respective first images of the subsequent sequences.

In exemplary embodiments, the graphics processor is designed to send a waterfall display to the monitor interface as a graphic display. The waterfall display is the most common way to display sonar data. However, this is also very susceptible to flickering. In the case of the waterfall display, the current sampling of the waterborne transducers is typically displayed in the top line of the monitor. When the sonar data of the next scan arrives, the previous scans are shifted down one row so that the current data can be displayed on the top row again. The pixels of a line correspond to the direction from which the sonar data was obtained. The direction can be determined from the data of the waterborne sound transducer by means of direction formation, the so-called beamforming.

By updating the image line by line, for example with the update rate, the noise, which typically makes up the majority of an image line, is also shifted down one line with each update. However, the line being overwritten is uncorrelated to the new line in the areas where the noise is present. Jumps in brightness of the individual pixels can and will therefore predominantly occur. The waterfall display therefore reveals a high susceptibility to flickering.

In further exemplary embodiments, the graphics processor is designed to manipulate the first image of the sequence depending on the connected monitor. The property can include any selection of the following characteristics of the connected monitor: the brand or the manufacturer, the model, an (operating) temperature, an age or an operating time, an average brightness, a panel type (e.g. IPS, TN, VA , MVA, etc.). The data can be entered manually or sent automatically from the monitor or a sensor to the graphics processor. In this way, the manipulation of the first image in the sequence can be adapted to the current situation and thus optimized in order to further reduce flickering. In this exemplary embodiment, the monitor can also be part of the device.

Exemplary embodiments show that the graphics processor has a shading unit that is designed to manipulate the first image. Since the rise/fall time of a pixel is in the range of approx. 5-10 ms and is therefore less than the time that an image is displayed on the monitor (60 Hz corresponds to a duration of 16.6ms that an image is displayed ) it is advantageous that the compensation for flickering intervenes at the exact clock rate of the display refresh rate without slowing down the display. The use of the shaders of the graphics processor (both onboard and dedicated) is particularly suitable for this reason, since they know exactly when the monitor can display the new image through the use of V-Sync (vertical synchronization).

In exemplary embodiments, the graphics processor is designed to provide pixels of the first image of the further sequence with a bias or to multiply them by a factor in order to manipulate the first image. This means that the first image in a sequence is manipulated in such a way that it becomes lighter or darker. This can be done by means of a bias (also referred to as an offset), which is subtracted from or added to the brightness value of the pixel. Alternatively, this can also be done using a factor that is multiplied by the brightness value of the pixel. In this way, each pixel of the image can be manipulated, i.e. changed, with the same value (bias or factor). But it is also possible to manipulate just a part of the image, i.e. a selection of pixels. For example, it is possible to detect the track of a target on the monitor and to exclude the corresponding pixels, which typically have a similar brightness value over several lines and several pixels next to one another, from being manipulated. Because these pixels have a similar brightness value, they are less or not at all susceptible to flickering.

In exemplary embodiments, the device includes a monitor that is connected to the monitor interface. The graphics processor is now designed to manipulate the first image as a function of a current temperature of the monitor. The device or the graphics processor can have an interface in order to obtain a value from a temperature sensor. For example, the monitor can have a temperature sensor. This can transmit the current temperature of the monitor to the graphics processor.

The temperature can also be determined indirectly via the current or voltage consumption of the monitor over time. This is possible because the (internal) resistance of the monitor depends on the current temperature of the monitor. This means that the current temperature of the monitor can be determined (indirectly) based on the current or voltage consumption and thus based on the change in resistance of the monitor. The graphics processor can have an interface for a current meter and, additionally or alternatively, a voltage meter. So the graphics processor can record a current or voltage characteristic or receive a current or voltage characteristic from the current or voltage measuring device. Based on the current current or voltage consumption or the change in current or voltage consumption over time, the graphics processor can determine a current temperature of the monitor, for example using the current or voltage characteristic. Without a sensor interface, for example with an interface to read out properties of the monitor, it is possible for the graphics processor to receive current current and voltage consumption from the monitor. The graphics processor can then also determine the current temperature based on the current and voltage consumption of the monitor.

As an alternative or in addition to determining the temperature of the monitor, the device can have a temperature measuring unit that can determine an ambient temperature of the device and transfer it to the graphics processor. Again, the graphics processor can have an interface to get the ambient temperature. The graphics processor can then carry out the manipulation of the first image depending on a current ambient temperature of the monitor. For example, the temperature of the monitor can be estimated based on the ambient temperature.

In further exemplary embodiments, the device also has the monitor, which is connected to the monitor interface. The device also includes a brightness sensor that is designed to determine an average brightness of the monitor. The brightness sensor includes a photodiode, for example. The graphics processor is configured to perform the manipulation of the first image of a third sequence based on an average brightness of the monitor during a first and a second sequence. In other words, the change in the average brightness in two consecutive sequences of images is measured using the brightness sensor. Typically, the first image of the second sequence has already been manipulated. Depending on the change in brightness, the manipulation for the first image of the third sequence can then be adjusted. For example, the first image of the third sequence can be set lighter or darker than the first image of the second sequence. The principle can be continued iteratively so that the optimal manipulation is gradually achieved. Furthermore, a change in the response behavior of the pixels, for example due to a changed temperature of the monitor, can also be compensated for by a changed manipulation.

If the device includes a monitor, this is advantageously a liquid crystal monitor, in particular a liquid crystal monitor with an IPS panel. For technical reasons, these monitors have a great tendency to flicker.

Similarly, a method of graphing sonar data is disclosed, comprising the steps of: sending a sequence of images graphing the sonar data from a graphics processor to a monitor interface; generating, at update times, respective further sequences of images corresponding to current sonar data; manipulating by the graphics processor a first image of a sequence of the further sequences of images; sending the sequence with the manipulated image to the monitor interface to reduce flickering of a monitor connected to the monitor interface due to the transition from an image of a current sequence to a subsequent image of a subsequent sequence.

• 1 a: eine schematische Darstellung eines beispielhaften Helligkeitsverlaufs eines Pixels über der Zeit im Vergleich zu dem idealen Verlauf;
• 1 b: eine schematische Darstellung eines beispielhaften durchschnittlichen Helligkeitsverlaufs eines Monitors über der Zeit; und
• 2: eine schematische Blockdarstellung einer Vorrichtung zur Bereitstellung einer grafischen Darstellung von Sonardaten.

Preferred embodiments of the present invention are explained below with reference to the accompanying drawings. Show it:

• 1 a : a schematic representation of an exemplary brightness profile of a pixel over time in comparison to the ideal profile;
• 1 b : a schematic representation of an exemplary average brightness profile of a monitor over time; and
• 2 1 is a schematic block diagram of an apparatus for providing a graphical representation of sonar data.

Before exemplary embodiments of the present invention are explained in more detail below with reference to the drawings, it is pointed out that identical elements, objects and/or structures that have the same function or have the same effect are provided with the same reference symbols in the different figures, so that the elements shown in different exemplary embodiments Description of these elements is interchangeable or can be applied to each other.

1a and 1b has already been described in the introduction to the description.

2 FIG. 12 is a schematic block diagram of an apparatus 20 for providing a graphical representation of sonar data 22. The graphical representation is provided at a monitor interface 24. FIG. Furthermore, the device 20 comprises a graphics processor 26. The graphics processor 26 constructs sequences of images 28 in response to the sonar data. Graphics processor 26 may also manipulate a first image of the sequence of images 28 to reduce flicker at the transition of a last image of a sequence of images into a first image of a subsequent sequence of images .

In some embodiments, device 20 further includes a monitor 30 that displays the images generated by graphics processor 30 . That is, when the device 20 includes the monitor, not only can the sonar data be provided for graphing, but the graphing is also performed.

The (water) sound transducers disclosed are designed for use under water, in particular in the sea. The sound converters are designed to convert waterborne sound into an electrical signal (e.g. voltage or current) corresponding to the sound pressure, the waterborne sound signal. In addition, the sound converters are designed to convert an applied electrical voltage into waterborne sound. Accordingly, the sound converters can be used as waterborne sound receivers and/or as waterborne sound transmitters. The sound transducers have a piezoelectric material, for example a piezoceramic, as the sensory material. The transducers can be used for (active and/or passive) sonar (sound navigation and ranging). The transducers are not suitable for medical applications.

Although some aspects have been described in the context of a device, it is understood that these aspects also represent a description of the corresponding method, so that a block or a component of a device is also to be understood as a corresponding method step or as a feature of a method step. Similarly, aspects described in connection with or as a method step also constitute a description of a corresponding block or detail or feature of a corresponding device.

The embodiments described above are merely illustrative of the principles of the present invention. It is understood that modifications and variations to the arrangements and details described herein will occur to those skilled in the art. Therefore, it is intended that the invention be limited only by the scope of the following claims and not by the specific details presented in the description and explanation of the embodiments herein.

Reference List

20

contraption

22

sonar data

24

monitor interface

26

GPU

28

Pictures

30

monitor

Claims (12)

Apparatus (20) for providing a graphical representation of sonar data (22), having the following features: a monitor interface (24); a graphics processor (26) configured to send a sequence of images (28) graphically representing the sonar data (22) to the monitor interface (24); wherein the graphics processor (26) is designed to generate further sequences of images (28) at update times, which correspond to the current sonar data (22) and to send the images of the further sequences to the monitor interface (24); wherein the graphics processor (26) is designed to manipulate a first image of a sequence of the further sequences of images and to send the sequence with the manipulated image to the monitor interface (24) in order to prevent flickering of a monitor ( 30) by transitioning from an image of a current sequence to a subsequent image of a subsequent sequence. Device (20) according to claim 1 , wherein the graphics processor (26) is designed to send a waterfall display to the monitor interface (24) as a graphic display. Device (20) according to one of the preceding claims, wherein the graphics processor (26) is designed to manipulate the first image of the sequence depending on a property of the connected monitor (30). Device (20) according to one of the preceding claims, wherein the graphics processor (26) is designed to manipulate the respective first images of the further sequences of images. Device (20) according to one of the preceding claims, wherein the graphics processor (26) has a shading unit which is designed to carry out the manipulation of the first image. Device (20) according to any one of the preceding claims, wherein the graphics processor (26) out forms is to provide pixels of the first image of the further sequence with a bias or to multiply by a factor in order to manipulate the first image. Device (20) according to any one of the preceding claims, with a monitor (30) which is connected to the monitor interface (24), wherein the graphics processor (26) is designed to manipulate the first image as a function of a current temperature of the monitor (30). Device (20) according to claim 7 , The monitor (30) having a temperature sensor which is designed to transmit the current temperature of the monitor (30) to the graphics processor (26). Device (20) according to claim 7 or 8th , The graphics processor (26) receiving a current current and voltage consumption of the monitor (30) and being designed to determine the current temperature based on the current and voltage consumption of the monitor (30). Device (20) according to any one of the preceding claims, with a temperature measuring unit which is designed to determine an ambient temperature of the device (20) and to transfer it to the graphics processor (26); wherein the graphics processor (26) is designed to manipulate the first image as a function of a current ambient temperature of the monitor (30). Device (20) according to any one of the preceding claims, with a monitor connected to the monitor interface (24), and a brightness sensor which is designed to determine an average brightness of the monitor (30); wherein the graphics processor (26) is configured to perform the manipulation of the first image of a third sequence based on an average brightness of the monitor (30) during a first and a second sequence. Method of graphing sonar data (22), comprising the following steps: - sending a sequence of images graphically representing the sonar data (22) from a graphics processor (26) to a monitor interface; - generating, at update times, respective further sequences of images which correspond to current sonar data (22) by the graphics processor; - manipulating a first image of a sequence of the further sequences of images by the graphics processor; - Sending the sequence with the manipulated image to the monitor interface (24) in order to reduce flickering of a monitor (30) connected to the monitor interface (24) due to the transition from an image of a current sequence to a subsequent image of a subsequent sequence.

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