Indirect vision system and method for adjusting a refresh rate

Abstract

Indirect vision system for a vehicle, comprising: at least one image recording device (2) with an image sensor for continuously recording images at a first frame rate; an image memory (4) which temporarily stores images for processing after the images have been taken; an image processing device (6) adapted to continuously calculate at least one new image from at least two consecutively acquired images, the newly calculated images having a second frame rate different from the first frame rate; and an image output device (5) for outputting the continuously recalculated images at the second frame rate, wherein the at least one newly calculated image is formed by summing at least two consecutive images, each multiplied by a percentage factor, wherein the percentage factor corresponds to the temporal position of the newly calculated image in relation to the temporal position of the at least two consecutively recorded images and the sum of the percentage factors is 100%, or greater than 100% in the case of image brightening, or less than 100% in the case of image darkening of the newly generated image.

Description

[0001] The present invention relates to an indirect vision system which can be used in particular as a mirror replacement system according to UN / ECE-R46 for a vehicle, and to a method for adjusting a frame rate of images recorded by an image sensor of an image recording device of the vision system.

[0002] For camera systems or mirror replacement systems (according to UN / ECE-R46), vehicle manufacturers require a refresh rate of 60 Hz or frames per second (fps). LCD panels installed in monitors are already available with more than 60 fps as standard. However, one problem is that the camera used in the mirror replacement system uses standard image sensors that can only output their full resolution and full dynamic range at less than 60 fps. However, to meet the legal requirements for a mirror replacement system according to UN / ECE-R46, high resolution and a higher dynamic range are required.

[0003] When using an LCD panel with, for example, 60 fps as standard and simultaneously using a standard image sensor that does not match in terms of their refresh rate as described above, the problem arises that these two components cannot be operated together without further technical measures.

[0004] According to the state of the art, the above problem is solved by using special, high-priced image sensors that enable high resolution with full dynamic range and a frame rate of, for example, 60 fps.

[0005] Alternatively, according to the prior art, a standard image sensor with a frame rate of less than 60 fps is used, and the frame rate is computationally increased from, for example, 30 fps to 60 fps by a processing unit of the camera system by outputting each image twice in succession to the monitor. A computational increase in the frame rate from, for example, 40 fps to 60 fps can be achieved according to the prior art by outputting every second image twice in succession to the monitor.

[0006] A disadvantage of the above-mentioned techniques for adapting the refresh rate of the image sensor to the refresh rate of the LCD panel is that the image impression for the driver corresponds to that of a 30 fps or 40 fps camera system, and thus appears less "smooth" or "stuttering," making it more difficult to estimate high relative speeds between the driver's own vehicle and other road users. However, the relative speeds are lower for mirror replacement systems according to UN / ECE-R46 of Groups I-IV than for mirror replacement systems of Groups V and VI, rear-view cameras, or surround-view (bird's-eye) systems, due to the image perspective of the image content when using these systems.

[0007] US 2015 / 0 294 479 A1 relates to a method for generating an interpolated image from two consecutive images by averaging pixel values between the consecutive images in order to output images with a higher frame rate.

[0008] EP 2 377 725 A1 relates to an exterior mirror simulation with image data acquisition and a display of the acquired and improved data for the driver of a motor vehicle.

[0009] US 2008 / 0 170 161 A1 relates to an image processing apparatus and an image display apparatus, wherein a frame rate of an input image signal is converted by inserting a plurality of interpolated images between two images in an input signal.

[0010] US 2018 / 0 091 768 A1 concerns image processing to interpolate video images.

[0011] The object of the invention is to provide a camera system for a vehicle and a method which adapt the refresh rate of an image sensor to the refresh rate of a display panel (LCD panel, OLED panel, LED panel, etc.) and at the same time give the driver the impression of a smooth, non-stuttering image sequence.

[0012] The above-mentioned object is achieved by an indirect vision system for a vehicle having the features of claim 1 and by a method according to the features of claim 9. Preferred embodiments are specified in the dependent claims.

[0013] The indirect vision system for a vehicle according to the invention comprises at least one image recording device with an image sensor for continuously recording images at a first frame rate corresponding to the frame rate of the image sensor. Standard image sensors used in the automotive sector typically have a frame rate of less than 60 fps. This low frame rate allows for less data to be transmitted within the system, allowing for the use of more cost-effective components.

[0014] According to the invention, the images captured by the image recording device are temporarily stored in an image buffer in order to further process the images after they have been captured. According to the present invention, this further processing is carried out in such a way that the frame rate of the image sensor is adjusted to a desired frame rate of 60 fps, in this case specified by the vehicle manufacturer, in order to be able to display a smooth motion sequence on an image output device with a frame rate of 60 fps, despite the low frame rate of the image sensor for the human eye.

[0015] According to the invention, the images temporarily stored in the image buffer are processed by an image processing device that continuously calculates at least one new image from at least two consecutively acquired images. As a result of the calculation, the newly calculated images have a second refresh rate that is higher than the first refresh rate at which the images were acquired. For example, the first refresh rate is 40 fps, and the second refresh rate is 60 fps. However, according to the invention, any arbitrary refresh rate can be adapted to any higher or lower refresh rate. This makes it possible to combine more different image sensors with different LCD panels, thereby increasing the number of technical solutions and creating cost advantages.

[0016] Finally, according to the present invention, the indirect vision system comprises an image output device capable of outputting images at the second high frame rate (60 fps). Specifically, the image output device outputs the images continuously recalculated by the image processing device at the adjusted frame rate of the image sensor.

[0017] The continuous calculation of new images in the image processing device, as described above, is specifically achieved by summing two consecutive images, each multiplied by a percentage factor, to generate a newly calculated image. The percentage factor corresponds to a temporal position of the newly calculated image relative to the temporal position of the underlying at least two consecutively acquired images.

[0018] According to the invention, the above-mentioned percentage factors depend in particular on the frame rate of the image capture device or image sensor and the frame rate of the image output device. These percentage factors can be predefined and stored in a memory or calculated by the image processing device during system runtime.

[0019] According to the present invention, when generating a new image, specifically brightness information and / or color information of each pixel in a recorded image is multiplied by a corresponding percentage factor, and to generate the new image, locally corresponding pixels in the at least two consecutively recorded images are summed. In contrast to the generally known frame rate interpolation, no sequence of consecutive images is analyzed and an attempt is made to identify identical or related image parts in order to determine motion vectors from them, with the aid of which the position of an object at the desired time between two consecutive images can then be reconstructed. By using only the brightness information and / or only the color information without taking motion vectors into account, the computational effort required to generate a new image is reduced in particular.The creation of so-called “ghost images” is accepted because these do not impair the impression of a fluid movement for the human eye.

[0020] Alternatively, according to the present invention, when calculating a new image, not the brightness information and / or color information of each pixel of captured images can be used, but the brightness information and / or color information of the raw data of the image sensor itself.

[0021] As mentioned above, to generate a new image, at least two consecutively acquired images are multiplied by a corresponding percentage factor, and the resulting images are summed. The percentage factor corresponds to the temporal position of the newly calculated image relative to the temporal position of the at least two consecutively acquired images. According to the invention, the percentage factors can preferably be stored as constants in the image processing device. In particular, a grid for factor determination (determination of the percentage factors) can be stored in a memory, wherein the grid for factor determination depends on the frame rate of the image acquisition device and the frame rate of the image output device, i.e., on a (first) frame rate of the image sensor, which is to be adapted to the (second) frame rate of the image output device.

[0022] According to the present invention, the aforementioned predetermined grid for factor determination can have a so-called initial phase shift between the first and second frame rates, so that the percentage factors depend not only on the frame rate of the image capture device and the frame rate of the image output device, but also on this initial phase shift between the first and second frame rates. By additionally using the initial phase shift, as many new images as possible can be calculated, of which as few as possible correspond to the originally recorded images.

[0023] According to the present invention, for example, the sum of the percentage factors by which two consecutive images are multiplied can be equal to 100%. If the sum is greater than 100%, the image is brightened; if the sum is less than 100%, the image is darkened in the new image generated from these two consecutive images.

[0024] According to the present invention, the frame rate of the image capture device is lower than the frame rate of the image output device, whereby both frame rates can be static, so that they do not change during operation of the system. Alternatively, it is possible for the frame rate of the image capture device to change dynamically depending on vehicle conditions, for example, speed, forward and reverse travel, standstill, parking, maneuvering, turning, etc., depending on vehicle signals, for example, turn signals, reverse gear, brightness sensors, acceleration sensors, etc., depending on manual input by a user, for example, pressing a button, etc., and / or depending on signals from the indirect vision system itself, for example a brightness detected by the image recording device via the image sensor, by a brightness sensor in the image output device, etc. By dynamically changing the frame rate, in particular by reducing the frame rate in dark surroundings, the exposure time of the image sensor can be extended, whereby higher sensitivity and thus better visibility can be achieved in dark surroundings.

[0025] According to the present invention, for example, the image processing device is integrated in the image pickup device or the image output device, and the intermediate image memory is integrated in the image processing device.

[0026] It should also be mentioned that according to the invention, no more than 200 ms should pass from the time of taking the first of the at least two consecutive images to the display of the newly calculated image for the driver.

[0027] The method for adjusting a frame rate according to the invention comprises continuously capturing images at the frame rate of the image sensor of the image capturing device, temporarily storing the captured images for processing after the images have been captured, continuously calculating at least one new image from at least two consecutively captured images, the newly calculated images having the frame rate of the image output device; and outputting the continuously recalculated images at the frame rate of the image output device.

[0028] Specifically, in the method according to the invention, the at least one new image is calculated by forming a sum of at least two consecutive images, each multiplied by a percentage factor, wherein the percentage factor corresponds to the temporal position of the newly calculated image with respect to the temporal position of the at least two consecutively recorded images.

[0029] According to the method of the present invention, brightness information and / or color information of each pixel in a captured image is further multiplied separately or combined by a corresponding percentage factor, and then corresponding pixels in the at least two consecutively captured images are summed to generate the new image. Alternatively, according to the method of the invention, brightness information and / or color information of the raw data of the image sensor can be multiplied separately or combined by a corresponding percentage factor, and then the respective results in the at least two consecutively captured images can be summed to generate the new image. In the method according to the invention, the percentage factors depend in particular on the frame rate of the image capture device and the frame rate of the image output device.Similar to the system according to the invention, in the method according to the invention the percentage factors may depend not only on the frame rates of the image capture device and the image output device, but additionally on an initial phase offset between the frame rates.

[0030] According to the method of the invention, the percentage factors can be stored as constants in the image processing device or calculated at runtime by the image processing device.

[0031] According to the method of the invention, the sum of the percentage factors by which at least two consecutive images are multiplied may be equal to 100%, or greater than 100% in the case of image brightening or less than 100% in the case of image darkening of the newly generated image.

[0032] In the method according to the invention, the frame rate of the image capture device and the frame rate of the image output device can be static and not change during operation. Alternatively, the frame rate of the image capture device can change dynamically depending on vehicle conditions, vehicle signals, a manual input by the user, and / or signals from a brightness sensor of the image capture device and / or signals from a brightness sensor of the image output device, similar to the above-mentioned system of the invention.

[0033] Furthermore, in the method according to the invention, the image processing device may be integrated in the image recording device or the image output device, and / or the image memory may be integrated in the image processing device, similar to the system according to the present invention described above. Brief description of the drawings

[0034] Preferred embodiments of the invention are described below with reference to the accompanying figures. Like reference numerals denote like components. They show: Fig. 1 is a schematic view of an indirect vision system according to the present invention; Fig. Fig. 2 is a schematic block diagram for explaining the calculation of a new image according to the present invention; Fig. 3 shows a first example of a frame rate increase according to the prior art; Fig. 4 shows a first embodiment of a frame rate increase according to the invention; Fig. 5 shows a second embodiment of a frame rate increase according to the invention; Fig. 6 shows a second example of a frame rate increase according to the prior art; Fig. 7 shows a third embodiment of a frame rate increase according to the present invention; Fig. 8 shows a fourth embodiment of a frame rate increase according to the invention; Fig. 9 a flowchart according to an embodiment of the method according to the invention; and Fig. 10 is a flowchart illustrating the calculation of a new image according to the invention.

[0035] Fig. 1 shows a schematic block diagram of an indirect vision system for a vehicle according to a preferred embodiment of the invention.

[0036] The indirect vision system 1 has two image capture devices 2, each having an image sensor 3 for continuously capturing images at a first frame rate corresponding to the frame rate of the respective image sensor. Only one or multiple image output devices may be present. Only the image output device 2 shown on the left in the figure will be described below. In the preferred embodiment, the frame rate of the image sensor 3 is, for example, 45 frames per second (fps) or 50 fps.

[0037] As in Fig. As shown in Figure 1, the image recording device 2 is connected to an image memory 4, which temporarily stores the images recorded by the image recording devices 2. The images recorded by the image recording devices 2 are continuously recorded images that are displayed to a driver of the vehicle in near real time on an image output device 5. The images recorded by the image recording device 2 can also be permanently stored in the image memory 4 for later use in accident analysis, in the investigation of property damage, etc.

[0038] The vision system 1 further comprises an image processing device 6, which is connected to the image memory 4 and uses the recorded images stored in the image memory 4 for a continuous calculation of at least one new image from at least two consecutively recorded images stored in the image memory 4. The image processing device 6 is in Fig. 1 as a separate component, but can also be integrated in the image memory 4, or the image memory 4 can be integrated in the image processing device 6.

[0039] As in Fig. 1, the image processing device 6 is further connected to the image output device 5 in order to display the images newly calculated in the image processing device 6 on the image output device 5, specifically at a higher frame rate than the image sensor 3 of the image recording device 2 can record. The calculation process performed in the image processing device 6 for calculating a new image from at least two consecutively recorded images will be described in more detail later.

[0040] Fig. 1 further shows a first sensor 7 and a second sensor 8, each connected to the image memory 4. The first sensor 7 and the second sensor 8 can alternatively also be connected to the image processing device 6 and / or the image recording device 2. The first sensor 7 detects, for example, vehicle states such as speed, forward and reverse travel, standstill, parking, maneuvering, turning, etc., and the second sensor 8 detects, for example, vehicle signals such as turn signals, reverse gear, brightness sensor, acceleration sensor. The first and second sensors 7, 8 can also additionally or alternatively detect a manual input from a driver or a brightness detected via the image sensor 3 of the image recording device 2 in order to dynamically adjust the frame rate of the image recording device 2 depending on the signals detected by the first and second sensors 7, 8.For example, by reducing the frame rate of the image sensor 3 in dark environments, the exposure time of the image sensor 3 can be extended and thus higher sensitivity and thus better visibility in dark environments can be achieved.

[0041] Fig. Figure 2 shows a schematic representation to illustrate the calculation of a new image according to the invention.

[0042] The Fig. 2 shown images 9, 10 are taken from the Fig. 1 and stored in the image memory 4 as subsequently recorded images. The image processing device 6 of Fig. 1 takes over these images 9, 10 stored in the image memory 4 and multiplies the image 9 by a percentage factor 1. Furthermore, the image processing device 6 multiplies the image 10 by a percentage factor 2. The calculation or determination of the percentage factors will be described in more detail later.

[0043] Specifically, brightness information and / or color information of each pixel in the image 9 is multiplied by the corresponding percentage factor 1, and each pixel in the image 10 is multiplied by the percentage factor 2. Depending on the frame rate of the image capture device 2 and the image output device 5, the percentage factors 1, 2 may differ from each other. For example, the sum of percentage factor 1 and percentage factor 2 equals 100% and 1, respectively, as described in more detail later.

[0044] As in Fig. As shown in Figure 2, images 9, 10 are summed after multiplying each pixel by a corresponding percentage factor to generate a new image 11. Specifically, pixel 12 in image 9, whose brightness and / or color information has been multiplied by a percentage factor of 1, and pixel 13 in image 10, which has been multiplied by a percentage factor of 2, are summed. In particular, those pixels in image 9 that are located at the same location are added to those in image 10. As shown in Fig. 2, for example, pixel 12 in image 9 is added to pixel 13, although pixel 12 is closer to pixel 14 in Fig. 10. The above process is performed for each individual pixel in images 9 and 10 to calculate the new image 11, which is displayed on the image output device 5.

[0045] Fig. Figure 3 shows a first example of increasing the frame rate from 50 fps to 60 fps according to the state of the art.

[0046] In the top row in Fig. 3 shows ten images taken by the image recording device 2 at a frame rate of 50 fps at 0, 20, ..., 180 ms. The lower row in Fig. Figure 3 shows eleven images output at a frame rate of 60 fps. To increase the frame rate from 50 fps to 60 fps according to the prior art, the image captured at 0 ms is reproduced twice in succession at 0 ms and 16.6 ms. Likewise, the image captured by the image capture device at 100 ms is reproduced twice in succession at 100 ms and 116.6 ms. The images captured by the image capture device at 20 ms, 40 ms, 60 ms, 80 ms, 120 ms, 140 ms, 160 ms, and 180 ms are each output once, but with a time delay, to the image output device, as shown in Fig. 3 to achieve a frame rate of 60 fps.

[0047] In contrast to the present invention, in Fig. 3 no images are recalculated from at least two consecutive images captured by the image capture device, as described below with reference to Fig. 4 described.

[0048] Fig. Figure 4 shows a first embodiment of the invention for a frame rate increase from 50 fps to 60 fps.

[0049] Fig. 4 shows in the middle row, similar to Fig. 3, ten images captured by the image pickup device at a frame rate of 50 fps. According to the first embodiment, the image at 0 ms and the image at 20 ms are captured according to the Fig. 2 described process to a new image 1 in the upper row in Fig. 4 is calculated by multiplying the image taken at 0 ms by the percentage factor 1.0, multiplying the image taken at 20 ms by the percentage factor 0.0, and summing the resulting images to form the new image 1. Due to the percentage factors of 0.0 and 1.0, the newly calculated image 1 in this case is identical to the image taken at 0 ms.

[0050] As in Fig. 4, the new image 1 is output at 20 ms on the image output device 5. As shown in Fig. 4 further shows that the two images taken at 0 ms and 20 ms are further processed to a new image 2, as shown in the upper line of Fig. 4. To do this, the image taken at 0 ms is multiplied by a percentage factor of 0.17, and the image taken at 20 ms is multiplied by a percentage factor of 0.83. As shown in Fig. 2, the resulting images are summed to form the new image 2. The newly calculated image 2 is output at 36.6 ms. Similarly, from the image captured by the image capture device at 20 ms and the subsequent image captured at 40 ms, image 3 is calculated, as shown in Fig. 4 in the row above by multiplying the image taken at 20 ms by the percentage factor 0.33, multiplying the image taken at 40 ms by the percentage factor 0.67, and summing the resulting images to form the new image 3.

[0051] The top line in Fig. 4 corresponds to a grid for determining the percentage factors for converting a frame rate of 50 fps to 60 fps. The grid is predefined, for example, in a memory as described above or is calculated at runtime. The grid changes depending on the frame rate of the image capture device and the frame rate of the image output device, as described later with reference to Fig. 7 becomes clear.

[0052] The Fig. The percentage factors shown in Figure 4 correspond to the temporal position of the newly calculated image in relation to the temporal position of at least two consecutively recorded images. This means that the percentage factors correspond to a type of weighting of the recorded images, which is based on temporal criteria, i.e., on the temporal relationship or distance between the time of the output image and the time of the recorded image. For example, the newly generated image 2 is located in the upper row of Fig. 4 at 36.6 ms, i.e. between the image taken at 20 ms and the image taken at 40 ms in the middle row of Fig. 4. Accordingly, the percentage factor by which the image captured at 20 ms is multiplied is calculated by the time interval (36.6 ms - 20 ms) divided by the time interval between two consecutive images at 50 fps (20 ms). The percentage factor by which the image captured at 0 ms is multiplied to generate the new image 2 is calculated by the time interval between the image captured at 40 ms and the newly generated image 2 (40 ms - 36.6 ms) divided by the time interval between two consecutive images at 50 fps (20 ms).

[0053] As in Fig. As shown in Figure 4, in the same way as described above, the percentage factors are determined from the grid for the remaining captured images and used to generate the new images 3 to 11.

[0054] As in Fig. 4, the newly generated image 1 is output at 20 ms and is calculated from the images captured at 0 ms and 20 ms with the percentage factors 1 and 0 as described above. The newly generated image 2 is output at 36.6 ms and is generated from the images captured at 0 ms and 20 ms with the percentage factors 0.17 and 0.83. The newly generated image 3 is output at 53.3 ms and is generated from the images captured at 20 ms and 40 ms with the percentage factors 0.33 and 0.67. Similarly, the newly generated images 4 to 11 are output on the image output device at a frame rate of 60 fps.

[0055] Fig. 5 shows a second embodiment for a frame rate increase from 50 fps to 60 fps.

[0056] The second embodiment differs from the first embodiment in that the grid for the factor determination additionally has an initial phase offset, as in Fig. 5. An initial phase shift means that the signal in Fig. 4 is shifted in time. According to the Fig. In the second embodiment shown in Figure 5, the grid of Fig. 4 is shifted to the right such that the first newly generated image is created at 8.3 ms. The temporal position of 8.3 ms with respect to the temporal position of the images acquired at 0 ms and 20 ms results in the percentage factors 0.58 and 0.42, which are calculated as described above. Similar to Fig. 4, the sum of the percentage factors for calculating the new image 1 equals 100%. The second embodiment with the initial phase shift has the advantage that as few newly calculated images as possible match the recorded images. Again referring to Fig. 4, for example, the newly computed images 1 and 7, which are output at times 20 ms and 120 ms, are identical to the images acquired at 20 ms and 100 ms. As in Fig. As shown in Figure 5, due to the phase shift, none of the newly generated images 1 to 11 is identical to any of the recorded images.

[0057] As in Fig. 5 shows the output new image 1 calculated from the images taken at 0 ms and 20 ms with the percentage factors 0.58 and 0.42, the newly output new image 2 is calculated from the images taken at 20 ms and 40 ms with the percentage factors 0, 75 and 0.25, the newly output image 3 is calculated from the images taken at 40 ms and 60 ms with the percentage factors 0.92 and 0.08, the newly output image 4 is calculated from the images taken at 40 ms and 60 ms with the percentage factors 0.08 and 0.92, the new image 5 is calculated from the images taken at 60 ms and 80 ms with the percentage factors 0.25 and 0.75, etc.

[0058] Fig. Figure 6 shows a second example of a frame rate increase from 45 fps to 60 fps according to the prior art.

[0059] Fig. 6 shows in the top row nine images taken by the image capture device at 45 fps. The bottom row in Fig. Figure 6 shows the output on the image output device at 60 fps. According to the second prior art example, an increase from 45 fps to 60 fps is achieved by replaying the images captured at 0 ms, 66.6 ms, and 133.3 ms twice in succession. For example, the image captured at 0 ms is replayed twice at 0 ms and 16.6 ms, the image captured at 66.6 ms is replayed at 66.6 ms and 83.3 ms, and the image captured at 133.3 ms is replayed at 133.3 ms and 150 ms to achieve a frame rate increase from 45 fps to 60 fps.

[0060] In contrast, Fig. 7 shows a third embodiment for increasing the frame rate from 45 fps to 60 fps according to the invention. Similar to the first embodiment of Fig. 4, no phase shift is used when increasing the frame rate from 45 fps to 60 fps. As in Fig. As shown in Figure 7, the grid in the top row differs from Fig. 7 from the grid for factor determination in Fig. 4 in that the time intervals between the newly generated images are different. This results from the fact that, according to the third embodiment, the frame rate increases from 45 fps to 60 fps, instead of from 50 fps to 60 fps.

[0061] The calculation of the percentage factors, the generation of the new images using the percentage factors, and the corresponding output of the newly generated images are carried out in a similar manner as described above for the first embodiment and will not be repeated.

[0062] Fig. Figure 8 shows a fourth embodiment of a frame rate increase from 45 fps to 60 fps according to the invention. The fourth embodiment differs from the third embodiment in that, similar to the second embodiment, an initial phase offset is used.

[0063] As described above and from the Fig. 4, Fig. 5 and Fig. 7, Fig. As can be clearly seen in Figure 8, the sum of the percentage factors for calculating a new image is 100% and 1, respectively. If image brightening is desired, the percentage factors can be increased so that the sum is greater than 100%. If image darkening is desired, the sum can be less than 100%.

[0064] Fig. 9 shows a flowchart according to the invention for adapting a frame rate of an image sensor of an image recording device to the frame rate of an image output device.

[0065] In step S1, images are continuously captured at a first frame rate (frame rate of the image sensor). In step S2, the captured images are stored in a buffer. In step S3, at least one new image is calculated from two consecutively captured images stored in the buffer. Step S3 will be described in more detail with reference to Fig. 10. In step S4, each newly calculated image is output at a frame rate that is adapted to the frame rate of the image output device.

[0066] Fig. 10 shows a flowchart illustrating the Fig. Step S3 shown in Figure 9 is explained in more detail.

[0067] In step S31, each recorded image is multiplied by a predetermined percentage factor, which is determined as described above, to generate a new image. In step S32, at least two consecutive images obtained by the multiplication are summed. In this regard, reference is also made to the above description of the Fig. 2.

[0068] It is explicitly emphasized that all features disclosed in the description and / or the claims are to be considered separate and independent of each other for the purpose of the original disclosure as well as for the purpose of limiting the claimed invention, regardless of the feature combinations in the embodiments and / or the claims. It is explicitly stated that all range specifications or specifications of groups of units disclose every possible intermediate value or subgroup of units for the purpose of the original disclosure as well as for the purpose of limiting the claimed invention, in particular also as a limit of a range specification. LIST OF REFERENCE SYMBOLS: 1 vision system 2 Image recording device 3 image sensor 4 image memories 5 Image output device 6 Image processing device 7 first sensor 8 second sensor 9 Image 10 images 11 new picture 12 pixel image 9 13 pixels image 10 14 pixels in image 10

Claims

[1] Indirect vision system for a vehicle, comprising: at least one image recording device (2) with an image sensor for continuously recording images at a first frame rate; an image memory (4) which temporarily stores images for processing after the images have been taken; an image processing device (6) adapted to continuously calculate at least one new image from at least two consecutively acquired images, the newly calculated images having a second frame rate different from the first frame rate; and an image output device (5) for outputting the continuously recalculated images at the second frame rate, wherein the at least one newly calculated image is formed by summing at least two consecutive images, each multiplied by a percentage factor, wherein the percentage factor corresponds to the temporal position of the newly calculated image in relation to the temporal position of the at least two consecutively recorded images and the sum of the percentage factors is 100%, or greater than 100% in the case of image brightening, or less than 100% in the case of image darkening of the newly generated image. [2] A system according to claim 1, wherein brightness information and color information of each pixel in a captured image are multiplied separately or combined by the corresponding percentage factor, and corresponding pixels in the at least two consecutively captured images are summed to generate the new image. [3] System according to claim 1, wherein brightness information and color information of the raw data of the image sensor are multiplied separately or combined by the corresponding percentage factor and summed in the at least two consecutively recorded images to generate the new image. [4] A system according to any one of claims 1 to 3, wherein the percentage factors depend on the frame rate of the image capture device and the frame rate of the image output device. [5] The system of claim 4, wherein the percentage factors additionally depend on an initial phase offset between the first and second refresh rates. [6] System according to one of claims 1 to 5, wherein the percentage factors are stored as constants in the image processing device (6) or are calculated by the image processing device (6) at runtime. [7] System according to one of claims 1 to 6, wherein the frame rate of the image recording device (2) and the frame rate of the image output device (5) are static and do not change during operation of the system, or the frame rate of the image recording device (2) changes dynamically depending on vehicle conditions, vehicle signals, a manual input by a user, and / or signals from a brightness sensor of the image recording device and / or signals from a brightness sensor of the image output device (5). [8] System according to one of claims 1 to 7, wherein the image processing device (6) is integrated in the image recording device (2) or image output device (5) and / or the image memory is integrated in the image processing device (6). [9] A method for increasing a refresh rate, comprising the steps of: continuously recording images at the frame rate of the image sensor (3) of the image recording device (2); Caching the captured images for processing after the images have been captured; continuously calculating at least one new image from at least two consecutively recorded images, wherein the newly calculated images have the frame rate of the image output device (5); and Outputting the continuously recalculated images at the frame rate of the image output device (5), wherein calculating the at least one new image comprises forming a sum of at least two consecutive images, each multiplied by a percentage factor, wherein the percentage factor corresponds to the temporal position of the newly calculated image in relation to the temporal position of the at least two consecutively recorded images and the sum of the percentage factors is 100%, or greater than 100% in the case of image brightening, or less than 100% in the case of image darkening of the newly generated image. [10] The method of claim 9, further comprising: multiplying brightness information and color information of each pixel in a captured image separately or combined by the corresponding percentage factor, and then summing corresponding pixels in the at least two consecutively captured images to generate the new image. [11] The method of claim 9, further comprising: multiplying brightness information and color information of the raw data of the image sensor (3) separately or combined by the corresponding percentage factor, and then summing the respective corresponding results in the at least two consecutively recorded images to generate the new image. [12] Method according to one of claims 9 to 11, wherein the percentage factors depend on the frame rate of the image recording device (2) and the frame rate of the image output device (5). [13] A method according to claim 12, wherein the percentage factors additionally depend on an initial phase offset between the first and second refresh rates. [14] A method according to any one of claims 9 to 13, further comprising: Storing the percentage factors as constants in the image processing device (6), or Calculating the percentage factors at runtime by the image processing device (6). [15] Method according to one of claims 9 to 14, wherein the frame rate of the image recording device (2) and the frame rate of the image output device (5) are static and do not change during operation of the system, or the frame rate of the image recording device (2) changes dynamically depending on vehicle conditions, vehicle signals, a manual input by a user, and / or signals from a brightness sensor of the image recording device and / or signals from a brightness sensor of the image output device (5). [16] Method according to one of claims 9 to 15, wherein the image processing device (6) is integrated in the image recording device (2) or image output device (5), and / or the image memory is integrated in the image processing device (6).

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