DE102022203889A1 - Method for adaptive video data compression in a vehicle and corresponding device - Google Patents

Abstract

In a method according to the invention for adaptive video data compression in a vehicle, video data of successive images (B-1, B0) with a predefined color space quality are captured (1) by an image sensor of the vehicle (F). At least one parameter that relates to the vehicle, the driving situation, the environment of the vehicle and/or the connection of the vehicle to an external communication network is determined (2). Depending on the at least one determined parameter, the video data compression is parameterized (3), with the parameterization defining a reduction in the color space quality. The video data is compressed using parameterized video data compression (4), whereby for two consecutive images the color space quality is reduced in accordance with the parameterization (4-1) and a difference image (Bo') is calculated (4-2) over the two successive images with reduced color space quality .

Description

The present invention relates to a method for adaptive video data compression in a vehicle, which can be used in particular when transmitting video data recorded with a vehicle sensor. The present invention further relates to a corresponding device.

A large number of sensors are now used in motor vehicles. For example, various sensors are often used to monitor the vehicle's surroundings, with the generated sensor data being made available to driver assistance systems in order to provide the driver with improved comfort and increased safety when driving the vehicle in traffic. For example, one or more video cameras or ultrasonic, radar or laser-based sensors can be installed in the vehicle.

The captured sensor data can be processed and evaluated locally in the vehicle. Particularly in the case of complex analyzes of high-resolution sensor data, such as image and video data, it can be advantageous due to the limited computing power available locally in the vehicle to transmit the recorded sensor data via a communication network to a central computing unit in order to carry out the analysis there. This also makes it possible for the central processing unit to evaluate sensor data from a larger number of vehicles together, for example in order to use the transmitted data to train neural networks in the perception of the environment for automated driving. Furthermore, for example, for remote-controlled steering of a vehicle by an operator, so-called “teleoperated driving”, it is necessary to transmit comprehensive sensor data from the vehicle to the operator in real time.

This is only possible with mobile networks that offer high and stable data throughput, short latency times and consistent network coverage. In reality, however, the parameters of the mobile phone connection of the respective vehicle vary, for example because the vehicles are moved through areas with different mobile phone coverage while driving. Cities often have good network coverage based on current mobile communications standards, so that the data transmission requirements mentioned can be met. In towns and rural areas, however, coverage based on current mobile communications standards is often incomplete, meaning that older mobile communications standards with lower data rates may have to be used, or data transmission via mobile communications may not be possible at all in the short term.

This is particularly a problem when transmitting high-resolution sensor data, as this involves a high data rate. There are therefore approaches to reducing the amount of sensor data in such cases, for example to enable transmission even in areas with poor mobile communications technology.

The DE 10 2018 215 151 A1 discloses a radar control unit in which the radar data is filtered. Parts of the radar data that do not contain a potential target object are eliminated in order to reduce the amount of radar data. The radar control unit can optionally also carry out further lossless compression. The filtered and, if necessary, loss-free compressed raw radar data is fed to an evaluation unit, which can be located in the vehicle or outside the vehicle. In one embodiment, the raw radar data can be transmitted from the vehicle to a server or to a cloud system, where an optimal driving position of the vehicle is determined based on the transmitted raw radar data and a planned driving maneuver.

The DE 10 2012 206 406 A1 describes a method for generating a data stream for transmitting image data that has been captured with a digital video camera of a vehicle. In this case, intra-coded image data or differential-coded image data are generated and transmitted for image segments of a captured video image in accordance with known compression methods, such as the MPEG-4 standard for video coding.

It is an object of the invention to provide a method for adaptive video data compression and a corresponding device.

This task is solved by the independent claims. Preferred embodiments of the invention are the subject of the dependent claims.

In a method according to the invention for adaptive video data compression in a vehicle, video data from successive images with a predefined color space quality are captured by an image sensor of the vehicle. At least one parameter that relates to the vehicle, the driving situation, the environment of the vehicle and/or the connection of the vehicle to an external communication network is determined. Depending on the at least one determined parameter, the video data compression is parameterized, with the parameterization defining a reduction in the color space quality. The video data is compressed using parameterized video data compression, whereby the color space quality is reduced for two consecutive images in accordance with the parameterization and a difference image is calculated over the two consecutive images with reduced color space quality.

Color space quality is understood to mean any color space features with which the brightness and/or color values of the captured pixels can be specified. In particular, the predefined color space quality can be used to specify how many colors or gray tones the pixels contained in the video data can have.

With the invention, demand-based video compression can be carried out efficiently, which does not require significant computing effort and can therefore be carried out quickly. Therefore, the video data compression according to the invention can be implemented as a real-time application in the vehicle, for example in a control unit of the vehicle. Furthermore, the bandwidth required for transmitting the video data can be significantly reduced in this way. In addition, the video compression according to the invention highlights dynamic areas of the respective video images. This highlighting enables, for example, artificial neural networks and algorithms for autonomous driving to specifically analyze the highlighted areas of the image.

According to one embodiment of the invention, it is checked whether there is a change in the image content for the current image compared to the previous image, with a difference image being further processed and transmitted if there is a change, and no difference image being transmitted if there is no change between two successive images has been determined or it is the first image of a video sequence. By only sending a difference image when there is a change, be it to a previous image or because there is no previous image, the amount of data transmitted is further reduced.

To check a change in the current image, a quantized image is advantageously first calculated and a difference value to the corresponding values of the previous quantized image is calculated for the respective brightness and/or color values of the pixels of the current image.

In particular, the difference value can be compared with an associated threshold value.

Likewise, the strength of the quantization of the images can advantageously be selected depending on the currently determined parameters for the vehicle, the driving situation, the vehicle environment or the vehicle connection to the external communication network.

According to one embodiment, difference values are calculated, compressed and transmitted for all pixels.

According to a further embodiment, difference values are calculated, compressed and transmitted for only a partial area of the captured image, with position information being transmitted for this partial area.

Advantageously, the brightness and/or color values of the pixels are present in a binary representation, with binary shifts being applied to them to reduce the color space quality, and with the parameterization of the video data compression comprising the number of binary shifts.

Likewise, after the difference image has been calculated, a run length coding is advantageously applied to the brightness and/or color values of the pixels, with the run length coding providing information about how often the same brightness and/or color value occurs in successive pixels in the values released by the shifts Bits are stored, and the compressed video data is assigned information about the number of binary shifts applied in each case, which is stored or transmitted together with the compressed video data for a reconstruction of the video data.

Advantageously, after the difference image has been calculated, the difference values for the individual pixels can first be binary classified and the binary classified pixels can be fed to the run length coding.

• - einen Bildsensor, der Videodaten aufeinanderfolgender Bilder mit einer vordefinierten Farbraumgüte erfasst;
• - eine Auswerte- und Steuereinheit zum Ermitteln von mindestens einem Parameter, der sich auf das Fahrzeug, die Fahrsituation, das Umfeld des Fahrzeugs und/oder die Anbindung des Fahrzeugs an ein externes Kommunikationsnetz bezieht, und zur Parametrisierung der Videodatenkompression in Abhängigkeit von dem mindestens einen ermittelten Parameter, wobei durch die Parametrisierung eine Reduktion der Farbraumgüte definiert wird;
• - eine Komprimierungseinheit, in der die Videodaten mittels der parametrisierten Videodatenkompression komprimiert werden, wobei für zwei aufeinanderfolgende Bilder die Farbraumgüte entsprechend der Parametrisierung reduziert wird und über die zwei aufeinanderfolgenden Bilder mit reduzierter Farbraumgüte ein Differenzbild berechnet wird; und
• - eine Kommunikationseinheit zur Übertragung der komprimierten Videodaten.

The device according to the invention for adaptive video data compression in a vehicle comprises

• - an image sensor that captures video data from successive images with a predefined color space quality;
• - an evaluation and control unit for determining at least one parameter that relates to the vehicle, the driving situation, the environment of the vehicle and / or the connection of the vehicle to an external communication network, and for parameterizing the video data compression depending on the at least one determined parameters, whereby the parameterization defines a reduction in the color space quality;
• - a compression unit in which the video data is compressed using the parameterized video data compression, the color space quality being reduced for two consecutive images in accordance with the parameterization and a difference image being calculated over the two successive images with reduced color space quality; and
• - a communication unit for transmitting the compressed video data.

A computer program according to the invention comprises instructions that cause a device to carry out the steps of the method according to the invention.

Finally, the invention also includes a motor vehicle that is set up to carry out a method according to the invention or has a device according to the invention.

• 1 zeigt ein Ablaufdiagramm, das die grundlegenden Schritte des erfindungsgemäßen Verfahrens zur adaptiven Videodatenkompression in einem Fahrzeug wiedergibt;
• 2 zeigt mehrere Teilschritte zur erfindungsgemäßen Kompression der Videodaten;
• 3 zeigt schematisch ein Beispiel für zwei zu aufeinanderfolgenden Zeitpunkten erfasste Videobilder, wobei von dem späteren Bild nur ein Teilbereich mit Bildänderungen übertragen und zur Rekonstruktion des erfassten Bildes verwendet wird; und
• 4 zeigt schematisch ein Fahrzeug mit einer erfindungsgemäßen Vorrichtung und einen zentralen Server, an den komprimierte Videodaten übertragen werden.

Further features of the present invention will become apparent from the following description and the claims in conjunction with the figures.

• 1 shows a flowchart that shows the basic steps of the method according to the invention for adaptive video data compression in a vehicle;
• 2 shows several sub-steps for compressing the video data according to the invention;
• 3 shows schematically an example of two video images captured at successive times, with only a partial area of the later image being transmitted with image changes and used to reconstruct the captured image; and
• 4 shows schematically a vehicle with a device according to the invention and a central server to which compressed video data is transmitted.

For a better understanding of the principles of the present invention, embodiments of the invention are explained in more detail below with reference to the figures. It is understood that the invention is not limited to these embodiments and that the described features can also be combined or modified without departing from the scope of the invention as defined in the claims.

1 shows a flowchart of a method according to the invention. In a first method step 1, video data is captured by one or more image sensors of a vehicle. The image sensors can in particular be external cameras of the vehicle, with which video recordings of two- or three-dimensional images of the vehicle's surroundings are generated. This involves continuous acquisition of video data from successive images, even if the image sensors only capture image data for individual images at a time. The captured video data can first be temporarily stored before further processing, with additional position and/or time data being captured and stored as metadata for the image data.

The brightness and/or color values of the captured image data can be specified by various characteristic color space features. So these can depend on a color space can be specified via the colors, for example RGB or CMYK. Likewise, a specification can be made using luminance plus color, for example with the YCbCr model, which divides the color information into the basic brightness Y and the two color components Cb (Blue-Yellow Chrominance) and Cr (Red-Green Chrominance). There is also a description in the HSL color model, which is based on the characteristics of hue, saturation and lightness. The invention is explained below using the example of an RGB color space, in which the colors of the individual pixels are specified by the additive mixing of three primary colors red, green and blue and the color space quality corresponds to the color depth.

Due to the large number of pixels in an image and the usual refresh rates, large amounts of data arise, especially with a high color depth. For example, an RGB video signal with a color depth of 24 bits in full HD format (1920 x 1080 pixels) and a refresh rate of 30 Hz results in a data volume of 3 x 8 x 1920 x 1080 x 30 = 1492992000 bits per second thus a data rate of approx. 178 MB/s.

The color depth indicates how many colors or gray tones the pixels contained in the image data can have. For example, the color depth can be 24 bits, which, for example, are distributed evenly with 8 bits each across the red, green and blue components when using an RGB color space. A bit value of 0 means that the color component is missing, a bit value of 255 means that the color component is present at maximum intensity. By mixing the three color components, a total of 256x256x256 = 16.77 million colors can be displayed. In the same way, 256 different gray tones can be specified with 8 bits, which are sufficient to display a seamless gradient from black to white.

In a method step 2, at least one parameter that relates to the vehicle, the driving situation, the environment of the vehicle and/or the connection of the vehicle to an external communication network is determined. For example, the current speed of the vehicle can be read by a vehicle control unit when the video data is recorded. Likewise, the vehicle surroundings can be recorded with additional vehicle sensors or information about the vehicle surroundings can be determined from map data in connection with the current position of the vehicle determined with a navigation system. The currently available bandwidth for data transmission can also be queried from a mobile radio unit located in the vehicle. The parameters determined in this way enable the subsequent compression to be adapted to the situation, for example by selecting a lower compression when the reception conditions of the mobile radio unit are good, and thus there is a large available bandwidth for the connection of the vehicle to the external communication network, than when reception conditions are poor. In particular, by determining the available bandwidth, the video data compression can be adjusted so that uninterrupted transmission of the compressed video data can take place via the external communication network.

In a method step 3, the subsequent compression of the video data is then parameterized, with the parameterization defining a reduction in the color depth depending on the at least one determined parameter. The invention takes advantage of the fact that the color or gray gradients of an image do not have to be available in high resolution for image processing and image analysis. Rather, by reducing the color depth, edges of objects within the image are sharpened, which is advantageous for such post-processing.

In a method step 4, the video data is then compressed using the parameterized video data compression before the compressed data is then transmitted to a central server for further image processing and image analysis. The algorithm used for the video data compression according to the invention is described below.

As in 2 shown, several sub-steps are applied for video data compression, some of these steps being optional. In particular, there is no previous image in the first image of a video sequence, so that no comparison can be made with a previous image and no difference image can be generated. For such a first image of a video sequence, only sub-steps 4-1, 4-5 and, if necessary, sub-steps 4-6 and 4-7, which are also optional in this case, are carried out. Sub-steps 4-2, 4-3, on the other hand, are only carried out for images in a video sequence for which a previous image already exists, as is sub-step 4-4, which may optionally be carried out.

In a first sub-step 4-1, the original image captured by the image sensor is first quantized. Here, binary shifts or shift operations are applied to the color values of the pixels in binary representation, whereby the previously carried out parameterization of the video data compression includes the number of binary shifts. Information about the number of binary shifts applied is assigned to the compressed image data and stored or transmitted together with the compressed image data for a later reconstruction of the image data.

A binary shift operation is used for the color components of the pixels, so that the maximum available bit values and thus color values are reduced, so that similar colors are displayed uniformly. If the color depth is significantly reduced, this can result, for example, in a street captured by an image sensor being displayed uniformly gray or the sky captured by the image sensor being uniformly blue. Color gradients become coarser or may no longer be displayed at all; instead, an image with pronounced color contrasts is created.

In particular, it can be provided that the same binary shift operation is applied for each color component and for each pixel, for example that the color value for the red, green and blue components is shifted to the right by one bit or several bits for each pixel. However, it is also possible to select shifts of different magnitudes for the different color components, for example depending on the extent to which the different color components are present in the image signal. Furthermore, it is also possible to select a shift of different magnitudes for different image areas, for example a larger shift at the edge of the image than in the center of the image.

The following two tables show an example of compression using binary shift operations and subsequent optional rounding for five color values 30 to 34 (decimal). For reasons of clarity, only the five bits with the lowest significant bits are shown; in the case of a color space representation with 8 bits per color value, the leading three bit values are not shown in the table. The original values for color values 30 to 34 result in the following values after a shift of 1, 2 or 3 bit positions: Original value Shift operation (1 bit) Shift operation (2bit) Shift operation (3bit) decimal binary binary decimal binary decimal binary decimal 34 100010 10001 17 1000 8th 100 4 33 100001 10000 16 1000 8th 100 4 32 100000 10000 16 1000 8th 100 4 31 011111 01111 15 0111 7 011 3 30 011110 01111 15 0111 7 011 3

As can be seen, with originally five different color values 30 to 34 (decimal), after a shift of 1 bit there is a reduction to three different color values and after a shift of 2 or 3 bits there is a reduction to only two different color values.

Optionally, rounding can also be carried out during compression using the binary shift operations, in which the shifted value is rounded to the next higher quantization level. The rounding information is taken from the bits omitted by the shift operations. This is illustrated in the following table for the above example of the five color values 30 to 34, where again only five binary values are reproduced. The original values for color values 30 to 34 result in the following values after a shift of 1, 2 or 3 bit positions: Original value Shift operation (1 bit) Shift operation (2bit) Shift operation (3bit) decimal binary binary decimal binary decimal binary decimal 34 100010 10001 17 1001 9 100 4 33 100001 10001 17 1000 8th 100 4 32 100000 10000 16 1000 8th 100 4 31 011111 10000 16 1000 8th 100 4 30 011110 01111 15 1000 8th 100 4

Here too, for color values 30 to 34, after a shift of 1 bit with additional rounding there is a reduction to three color values, after a shift of 2 bits with additional rounding there is a reduction to two different color values and after a shift of 3 bits with additional rounding a reduction to just one color value.

In the subsequent sub-step 4-2, the current quantized image is compared with a previous quantized image and, if necessary, a complete or partial difference image is calculated. In particular, the immediately preceding image can be used for the comparison, for example with a refresh rate of 30 Hz the image that was captured 33 ms earlier. But it is also conceivable to go back to an earlier image.

For this purpose, the difference to the color values or the gray value of the pixels of the previous image at time t _-1 is calculated for each pixel of the current image at time to for the color values or the gray value. In this way, a difference image is obtained in which unchanged parts of the image receive the value “0” for each of the color values or the gray value. This can be the case, for example, for a road surface in the front of the vehicle that appears uniformly gray due to the reduction in color depth, as long as there are no noticeable changes in this area, for example due to objects on the road or other road users appearing in the captured image area. If, on the other hand, there are noticeable changes in an area, the pixels there have the values that result from the difference calculation.

The comparison or calculation of the reference image is preferably carried out based on threshold values. A change in the image or image area occurs when the threshold value is exceeded for one of the color values or the gray value after the difference calculation for an image point. The threshold values may have already been defined in advance, for example depending on the subsequent processing of the video data. Likewise, the threshold values can also be selected depending on the vehicle parameters currently determined in method step 2, the driving situation, the vehicle environment or the vehicle connection to the external communication network.

In the following sub-step 4-3 it is then checked whether there is a change in the image content of the current image compared to the previous image. If this is not the case, no difference image is transmitted and the process continues in step 4-1 for the next image of the video sequence. This can be the case if no change has been detected between two consecutive images or if it is the first image of the video sequence, so there can be no change to a previous image.

However, if there are changes between the two images of the video sequence, the compression process is continued in steps 4-4 to 4-7. Two different embodiments come into consideration here. On the one hand, difference images can be further processed and ultimately transmitted with reduced color depth, but still with different color-related gray tones. However, it is also possible to completely dispense with different colors or shades of gray for the difference images. In the second-mentioned case, the difference image is first converted into a binary black-and-white image in sub-step 4-4; in the first-mentioned case, however, this sub-step 4-4 is skipped.

In the following substep 4-5, a run length coding is then applied to the difference values for the difference images, or to the color, gray or black and white values of the image points when a non-difference-coded image is transmitted. For example, if the same difference or color value is repeated four times in succession, this value is not transmitted four times, but rather information that a specific difference or color value follows four times in the image data. On the one hand, the reduction in the color values resulting from the use of the binary shift operations leads to the number of the same difference or color values increasing compared to the original image and thus increasing the effectiveness of the subsequently applied run length coding becomes. On the other hand, for areas of successive images in which there is no change, even without the reduction of the color values that occur, a large number of identical difference values result.

Optionally, in substeps 4-6 for run length coding, information about how often the same difference or color value occurs in successive pixels can be stored in the bits released by the shifts. This so-called “bit packing” will be illustrated in the following example for the transmission of the color value “16” (decimal) or “0001 0000” (binary) with a threefold shift of the binary value. Shifting the binary value “0001 0000” three times to the right results in “0000 0010”, correspondingly a reconstruction by shifting left by 3 bits would again result in the binary value “0001 0000”. The unused (underlined) area of the binary value “0000 0010” after the three-fold shift to the right can now be used to indicate the number of subsequent color value repetitions. For the above example of repeating the same color value four times in succession, this results in “100 | 0 0010” with the format “Number of consecutive values | shifted value”. Alternatively, a reverse arrangement “00010 | 1100" with the format "shifted value | number of consecutive values" possible.

Since no complex calculations need to be carried out to process the data in substeps 4-1 to 4-6, these can be carried out in real time. If real-time processing can be dispensed with, this will allow increased computing effort to be used in the vehicle. In this case, additional, more complex compression methods can be used in the optional sub-steps 4-7 in order to achieve an even higher compression rate.

After the compression of the video data described above, the compressed difference images are then transmitted to a server in method step 5. This can then be used to decompress the difference images and reconstruct the original images from the decompressed data. After reconstruction, the video images transmitted in this way can then be used, for example, to train artificial neural networks for environment recognition in automated driving. With so-called “Corner Case Detection”, dynamic objects can also be detected in training data in unusual situations, which are of great importance in the area of autonomous driving, for example. The video images transmitted in this way can also be used for predictive maintenance procedures, so-called “predictive services”.

For the server-side use of the video data transmitted in this way, it can be provided that a database is provided on the server in which the received difference images are retained even after processing and evaluation.

On the one hand, the transmission of the difference images can take place in such a way that difference values are calculated, compressed and transmitted for all pixels. This is particularly advantageous if there are changes for a significant portion of the captured images.

However, it can also be provided that the difference values are not transmitted and processed for the entire, i.e. for all pixels, but only for a partial area of the captured image. This is particularly advantageous if only small areas of the entire image are changed. In this case, position information for the changed area is then transmitted, for example by indicating the position within the image and the size of the area. For example, difference values can be determined for a rectangular sub-area of the image, whereby the sub-area can then be specified by a position information for the upper left pixel of this sub-area and the number of further pixels in the sub-area in the horizontal and vertical directions.

The transmission of such a partial area for an image captured by the vehicle at time t ₀ is exemplified in 3 shown. Here, image B _-1 is first captured by a vehicle at time t _-1 . In the present example, no previous image should exist for this image B _-1 , so that compressed image data for all pixels is transmitted to a central server in the form of the image B _-1 '. After transmission, the server then decompresses the received image data and reconstructs an image B _-1 ", which corresponds to the original image B _-1 .

At a subsequent time to, the image Bo is then captured by the vehicle. The only change compared to picture B _-1 is that in the left traffic light contained in the picture, the red signal lamp at the top is no longer lit, but the green signal lamp at the bottom is now lit. There the rest of the image content is unchanged compared to the previous time t _-1 , in this case it is sufficient to only transmit image data Bo', which shows the signal lamps of the traffic lights. During the server-side reconstruction of the image, only these pixels in the area of the signal lamps in the previous image B _-1 have to be replaced by the pixels corresponding to the image data B ₀ ' in order to obtain the reconstructed image Bo" at time to.

For the compression of the original image data in the vehicle, but also for the server-side reconstruction of the compressed image data, it can also be provided that, instead of using binary shift operations, tables are used in which pre-calculated values for the various color values and shift operations are stored. In a further embodiment it can also be provided that corresponding tables are generated by the vehicle and transmitted to the server.

The transmission of the compressed image data by the vehicle can take place in the form of a push model, in which the vehicle transmits the image data continuously or, for example, whenever video data is generated for a new section of route. Likewise, the transmission can also take place in the form of a pull model, in which the captured image data is first stored in a memory of the vehicle and is only transmitted by the vehicle when requested by the server.

In 4 A vehicle F with a device according to the invention and a central server S are shown schematically. This server can be provided as a backend server for a large number of vehicles in the cloud and be part of an IT infrastructure not described further here. The vehicle F can in particular be a passenger car or truck.

The vehicle has various units for carrying out the method according to the invention. In particular, an evaluation and control unit AS is provided, which can be designed, for example, as a control device of the vehicle F and can have one or more microcontrollers or microprocessors.

Furthermore, in the example shown, a forward-facing and a rear-facing image sensor BS are provided, with which the vehicle environment in front of and behind the vehicle can be detected. Likewise, the vehicle can also be equipped with just one image sensor or can also have image sensors that record the side surroundings of the vehicle. This can in particular be one or more vehicle cameras that record the vehicle surroundings in the visible or near-infrared spectral range.

The video data generated by the image sensors is fed via a digital data bus DB in the vehicle to the compression unit K, which compresses the video data as described above. For the parameterization of the video data compression, the evaluation and control unit AS evaluates parameters that relate to the vehicle, the driving situation, the environment of the vehicle and/or the connection of the vehicle to an external communication network. Depending on the result of this evaluation, the evaluation and control unit AS then controls the compression unit K to compress the currently available video data. The parameterization can be updated continuously or at regular intervals in order to be able to react quickly to the current parameters at any time.

The vehicle also has a communication unit C with which the compressed video data can be transmitted to the server S. The transmission can take place, for example, using a mobile communications standard such as 4G or 5G, or based on a wireless local network such as WLAN. The compressed video data can also be transmitted to third-party vehicles via Car2Car connections using the communication unit C.

In addition, the vehicle can have further components, not shown. For example, a memory can be provided for storing the video data. The memory can have both volatile and non-volatile memory areas and include a wide variety of storage devices and storage media. Furthermore, instructions for executing a program that implements the method according to the invention can be stored in the memory. Likewise, the vehicle can be localized using a position detection unit that evaluates GPS signals, for example, in order to be able to assign position data to the captured video data. Furthermore, the time at which the video data is captured can be determined using a time unit in order to record the video data with corresponding time frames to provide pelts. These components can be present as separate units and then make the respective information available to the above-mentioned units in the vehicle via the digital data bus DB, or can also be integrated in the evaluation and control unit AS, the compression unit K or another unit.

The invention can be used in any vehicle in which an image-based environment perception takes place, but is not limited to this.

Reference symbol list

1-4

basic procedural steps

4-1 - 4-7

Process steps for video data compression and reconstruction

5

Process step for transmitting the compressed video data

B-1, B-1', B-1"

Image data captured at time t _-1 , transmitted and reconstructed image data based on this

B0, B0', B0"

Image data captured at time t ₀ , transmitted difference image and reconstructed image data

F

vehicle

S

server

B.S

Image sensor

AS

Evaluation and control unit

C

Communication unit

DB

Data bus

K

Compression unit

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102018215151 A1 [0006]
• DE 102012206406 A1 [0007]

Claims (11)

Method for adaptive video data compression in a vehicle, in which - video data of successive images (B _-1 , B ₀ ) with a predefined color space quality are captured (1) by an image sensor of the vehicle (F); - at least one parameter that relates to the vehicle, the driving situation, the environment of the vehicle and/or the connection of the vehicle to an external communication network is determined (2); - the video data compression is parameterized (3) depending on the at least one determined parameter, the parameterization defining a reduction in the color space quality; - the video data is compressed (4) using the parameterized video data compression, the color space quality being reduced (4-1) for two successive images (B _-1 , B ₀ ) in accordance with the parameterization and a difference image (4-1) being created over the two successive images with reduced color space quality ( B ₀ ') is calculated (4-2). Procedure according to Claim 1 , whereby it is checked (4-3) whether there is a change in the image content for the current image (B ₀ ) compared to the previous image (B _-1 ), and a difference image (B ₀ ') is further processed and transmitted if one There is a change, and no difference image is transmitted if no change has been detected between two consecutive images or if it is the first image of a video sequence. Procedure according to Claim 2 , whereby to check a change in the current image (Bo), a quantized image is first calculated and a difference value to the corresponding values of the previous quantized image is calculated for the respective brightness and/or color values of the pixels of the current quantized image. Procedure according to Claim 3 , whereby the difference value is compared with an associated threshold value. Procedure according to Claim 4 , whereby the strength of the quantization of the images is selected depending on the currently determined parameters for the vehicle, the driving situation, the vehicle environment or the vehicle connection to the external communication network. Method according to one of the preceding claims, wherein difference values are calculated, compressed and transmitted for all pixels. Procedure according to one of the Claims 1 until 5 , whereby difference values are calculated, compressed and transmitted for only a partial area of the captured image and a position information is transmitted for this partial area. Method according to one of the preceding claims, wherein the brightness and/or color values of the pixels are present in a binary representation and binary shifts are applied to them to reduce the color space quality, and wherein the parameterization of the video data compression includes the number of binary shifts. Method according to one of the preceding claims, wherein after the calculation of the difference image (Bo '), a run length coding is applied to the brightness and / or color values of the pixels (4-5) and for the run length coding information is provided, how often the same brightness and / or color value occurs in successive pixels, is stored in the bits released by the shifts, and the compressed video data is assigned information about the number of binary shifts applied in each case, which is stored or transmitted together with the compressed video data for a reconstruction of the video data becomes. Method according to one of the preceding claims, wherein after the calculation of the difference image (Bo'), the difference values for the individual pixels are first binary classified (4-4) and the binary classified pixels are fed to the run length coding. Device for adaptive video data compression in a vehicle, with - an image sensor (S) which captures video data of successive images (B _-1 , B ₀ ) with a predefined color space quality; - an evaluation and control unit (AS) for determining at least one parameter that relates to the vehicle, the driving situation, the environment of the vehicle and / or the connection of the vehicle to an external communication network, and for parameterization of the video data compression depending on the at least one determined parameter, a reduction in the color space quality being defined by the parameterization; - a compression unit (K), in which the video data is compressed using the parameterized video data compression, the color space quality being reduced in accordance with the parameterization for two consecutive images (B _-1 , B ₀ ) and a difference image (Bo ') is calculated; and - a communication unit (C) for transmitting the compressed video data.

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