Method for projecting dynamic illumination beam using illumination system of motor vehicle

Abstract

The invention relates to a method for projecting a dynamic illumination beam using a motor vehicle illumination system (3) on the basis of a compressed video (1.1), characterized in that it comprises the following steps: step (1): reading each image from the compressed video (1.1); for each read image, step (2): decompressing the image using a dictionary-based decompression algorithm, each data sequence being decompressed in a first mode, or a second mode, or a third mode, adding a copy of the sequence to the decompressed image in the first mode, adding a copy of the sequence to the decompressed image in the second mode, or adding a copy of the sequence to the decompressed image in the third mode; the second mode comprises adding a data sequence of the previously read image added to the decompressed image, and the third mode comprises adding a data sequence of a previously decompressed image; step (3): projecting a light beam (6) on the basis of each decompressed image.

Description

[0001] The present invention relates to the field of motor vehicle lighting and projecting a dynamic light beam using a lighting device of a motor vehicle. More specifically, the present invention relates to a method for projecting a dynamic lighting beam using a lighting system of a motor vehicle.

[0002] Lighting systems in modern motor vehicles include an increasing number of light sources that must be controlled in order to provide adaptive lighting functions.

[0003] Due to the miniaturization of electronic lighting components and the wide range of luminous colors and intensities that such systems are able to produce, it is now possible to use vehicle lighting systems as headlights in order to project a series of one or more images onto the road, which thus serves as a projection surface. The series of images can thus form an "adaptive lighting" function, a "driving assistance" function, a transition function between two independent photometric functions, or a "welcome or farewell scene" function. The projected images can thus meet, for example, safety information communication, comfort or aesthetic needs, in particular for the vehicle driver or drivers of nearby vehicles.

[0004] Typically, the lighting system is controlled by a control unit called PCM ("Pixel Controller Module"), which is able to command the lighting modules of the lighting system. A series of digital images pre-stored in the vehicle's memory are provided to the control unit to be projected by the lighting modules in the form of dynamic beams.

[0005] The CAN protocol is usually used - in some of its variants (CAN-FD being the most commonly used one) - to transfer data between the memory and the control unit. However, some motor vehicle manufacturers have decided to limit the bandwidth of the CAN protocol, which affects management operations, which usually require around 5Mbps. Therefore, in order to comply with these restrictions, videos and digital images are usually stored in the form of compressed videos and images. The vehicle's control unit is then responsible for decompressing these images in order to be able to control the lighting modules.

[0006] However, in such lighting systems, the projection speed and the component cost of the system are two key parameters of the system. In fact, in order to maximize the projection speed of the dynamic light beam, the compressed image needs to be decompressed as quickly as possible.

[0007] Therefore, there is a need for a method of projecting a dynamic light beam based on a compressed image sequence that reacts faster than currently known methods.

[0008] The present invention falls into this background and is intended to meet this need.

[0009] For these purposes, a subject of the invention is a method for projecting a dynamic lighting beam using a lighting system of a motor vehicle, the lighting system comprising a memory storing a compressed video comprising a plurality of consecutive images, each image consisting of a plurality of data sequences, a control unit and a lighting module, characterized in that the method comprises the following steps:

[0010] a. reading each image from the compressed video stored in the memory;

[0011] b. for each read image, the control unit decompresses the image using a dictionary-based decompression algorithm to obtain a decompressed image, each data sequence of the read image is decompressed in a first mode, a second mode, or a third mode, in which a copy of the sequence is added to the decompressed image, in which a data sequence of the previously read image added to the decompressed image is added to the decompressed image, and in which a data sequence of the previously decompressed image is added to the decompressed image in the third mode;

[0012] c. The illumination module projects a pixelated light beam determined based on each decompressed image.

[0013] The present invention proposes to use a dictionary-based compression family, such as in particular LZx compression, also known as Lempel-Ziv compression. It will therefore be understood that with the present invention, each image is decompressed based on a compression sequence from a dictionary formed by the compressed image currently being read and the previous compressed image. The previously added image may be the last image decompressed before the image being read, or another image previously decompressed before the image being read.

[0014] As is well known, one of the main drawbacks of dictionary-based compression algorithms is the fact that if the proportion of similar data in the image to be compressed is low, the algorithm can only achieve a poor compression ratio. The significant feature of the present invention is that it uses the fact that two consecutive images in a video are highly similar to improve the compression ratio of the video, thereby improving the decompression speed of the corresponding compressed video. In fact, the image generated by the difference between any two consecutive images in the video will include a large amount of similar data, in particular empty data. It will therefore be understood that the compressed video obtained by doing so will include significantly less data than if each image of the video were compressed directly; thereby improving the decompression speed.

[0015] In the context of the present invention, i.e. the projection of a dynamic light beam using a motor vehicle lighting device, the main limiting factor is the decompression speed of the video to be projected. In fact, too slow a decompression speed of the compressed video can have a negative impact on the visual quality of the projected light beam; on the other hand, it should be understood that the compression time of the video is not a limiting factor, considering the problem solved by the present invention.

[0016] In the present invention, a "data sequence" is understood to mean a finite and ordered set of information units, in particular information bits, or bytes, or even hexadecimal data.

[0017] In the present invention, a "dynamic lighting beam" is understood to mean a light beam whose photometric properties, in particular its illuminance distribution, vary in a predetermined manner over time. For example, such a dynamic lighting beam may represent a visual animation, such as a change in a logo, an image or a pattern. The visual animation may in particular comprise a series of at least 100 images, which appear one after the other at a frequency of at least 20 Hz. For another example, the dynamic lighting beam may be projected onto a road or displayed on a screen.

[0018] In the present invention, a "control unit" is understood to mean a computing module capable of manipulating digital data, in particular a processor of a computer, and capable of communicating with memory storage devices and / or electronic devices (such as headlights of a motor vehicle), in particular via a cable or wireless link.

[0019] In the present invention, "data sequence comparison" is understood to mean determining the degree of similarity between two data sequences, which degree of similarity may specifically be a numerical value determined using a mathematical method related to the information units of the sequences. In the present invention, "similarity function" is understood to mean a mathematical method for implementing data sequence comparison, the program receiving as input two data sequences of the same length and returning a numerical value corresponding to the degree of similarity between the sequences.

[0020] The similarity function may specifically determine the degree of similarity between two data sequences by performing a strict comparison between pairs of information units of these sequences, or by comparing the norms of pairs of information units of these sequences about a given maximum difference, wherein the difference may be the same for each data pair or specific to each data pair. Where applicable, the similarity function may take into account the length of the data sequence.

[0021] Advantageously, the similarity d between a sequence σ and a reference sequence S of the same length as sequence σ S It can be calculated using the following formula:

[0022] [Formula 1]

[0023]

[0024] Among them, corresponds to the length of the sequence σ; σ i corresponds to the i-th element of the sequence σ; the coefficient w is the penalty parameter for the sequence length; and ε max is the maximum difference given. Then it will be understood that, given two data sequences s1 and s2 of the same length, the similarity function associated with the degree of similarity in equation [Formula 1] is given by the following formula:

[0025] [Formula 2]

[0026]

[0027] In the present invention, two compared data sequences are considered "similar" when the degree of similarity between them as determined by a given similarity function is greater than a predetermined tolerance threshold, whereby the threshold is a numerical value representing a range according to which two separate sequences may be considered similar or dissimilar.

[0028] In the present invention, the reading, decompression and projection steps can be implemented sequentially, i.e., image by image. As a variant, a plurality of images can be read successively and stored in a buffer memory, and then the decompression and projection steps are implemented on the images stored in the buffer memory. As another variant, the reading and decompression steps can be implemented sequentially, i.e., image by image, and then the decompressed images are stored in the buffer memory, and then the projection step is implemented on the decompressed images stored in the buffer memory.

[0029] In the present invention, a "lighting module" is understood to mean a module capable of emitting a pixelated light beam, in particular arranged in a headlight of a motor vehicle and arranged such that the pixelated light beam is a light beam comprising a plurality of pixels, for example at least 2500 pixels of a size between 0.05 and 0.3 pixels distributed in a plurality of rows and columns (for example 50 rows and 50 columns). As a variant, the lighting module may be a screen, in particular arranged in a headlight or taillight of a vehicle and capable of displaying an image of at least 2500 pixels of a size between 0.05 and 0.3 pixels distributed in a plurality of rows and columns (for example 50 rows and 50 columns).

[0030] For example, the lighting module may comprise a plurality of elementary light sources. Where applicable, the controller may be arranged to selectively control each of the elementary light sources of the lighting module such that the light source emits an elementary light beam forming one of the pixels of a pixelated light beam or image.

[0031] A light source is understood to mean any light source, possibly associated with an electro-optical element, which can be selectively activated and controlled to emit a primary light beam with a controllable light intensity. This can be, in particular, a light-emitting semiconductor chip, a light-emitting element of a monolithic pixelated light-emitting diode, a part of a light-converting element that can be stimulated by a light source, or a light source associated with a liquid crystal or a micromirror.

[0032] In the present invention, each data sequence of the read image includes a header containing a decompression code, and in the decompression step, each data sequence of the read image is decompressed in the first mode, the second mode or the third mode depending on the decompression code contained in the header of the sequence.

[0033] Each data sequence of the read image is decompressed individually by the decompression code, depending on whether the compressed data sequence needs to be copied verbatim to the decompression stack; or depending on whether the data sequence to be copied to the decompression stack corresponds to the data sequence of the image currently being decompressed and is located before the data sequence currently being decompressed; or depending on whether the data sequence to be copied to the decompression stack corresponds to the data sequence of a previously decompressed image (in particular, an image before the currently decompressed image).

[0034] In a first mode, the copying of a sequence may be a partial copying, in particular a copying of the sequence except for a header of the sequence.

[0035] Advantageously, when the header of the data sequence of the read image includes a decompression code indicating the first mode, the sequence includes a number N1 of codes, and in the decompression step, the data sequence of the read image is decompressed in the first mode by adding N1 data blocks following the number N1 of codes to the decompressed image.

[0036] By means of the code of number N1, an exact amount of information can be decompressed on the image decompression stack while minimizing the amount of data required to reconstruct the decompressed image. Advantageously, the header can consist of a data sequence, in particular a bit sequence, consisting of two complementary subsequences, each subsequence encoding a decompression code and a code of number N1, respectively.

[0037] Advantageously, the decompression code may consist of a 4-bit sequence, in particular all having the value zero.

[0038] In an alternative or additional embodiment of the present invention, when the header of the data sequence of the read image includes a decompression code indicating the second mode or the third mode, the sequence includes an original position code O and a code of length L. Advantageously, in the decompression step, the data sequence of the read image is decompressed in the second mode or the third mode by adding L data added to the decompressed image or a previous decompressed image starting from or until the original position to the decompressed image.

[0039] By means of the original position and the length code, the exact address of the data sequence can be indicated, in particular the starting position indicates the beginning of the sequence to be copied sequentially until the amount of copied data corresponds to the length indicated by the length code L.

[0040] The decompression code may correspond, for example, to four data, in particular four bits having a zero value.

[0041] If necessary, when the header of the data sequence of the read image contains a decompression code indicating the second mode or the third mode, the header and the original position code of the sequence together form a predetermined number N2 of data blocks. Advantageously, in the decompression step, the original position is obtained from all the remaining data starting from the header in the N2 data blocks, the remaining data forming the original position code O.

[0042] With this configuration, the encoding of the header ensures the continuity of the data sequence and minimizes the occupied memory space.

[0043] In an alternative or additional embodiment of the present invention, when the header of the data sequence of the read image includes a decompression code indicating the second mode or the third mode, the length L is obtained from the value of the decompression code constituting the length L or constituting a part thereof.

[0044] With this configuration, the encoding of the header ensures the continuity of the data sequence and minimizes the occupied memory space.

[0045] Advantageously, when the header of the data sequence of the read image includes a decompression code indicating the second mode or the third mode, in the decompression step, the length L is obtained in the following manner: the value of the decompression code is added to the value of each data block after the original position code O until one of these blocks contains data equal to a predetermined value, the set of blocks forming a code of length L.

[0046] By this iterative process, arbitrary length can be encoded in a data sequence, wherein the elements (e.g. bytes) forming the sequence can each contain only a limited amount of information; it will then be understood that the present invention takes advantage of encoding to overcome the information storage capacity limitations of the elements.

[0047] In an alternative or additional embodiment of the present invention, when the header of the data sequence of the read image includes a decompression code indicating the second mode or the third mode, the header includes a text copy code indicating whether there is a last block in the sequence, and in the decompression step, if the text copy code indicates that there is a last block in the sequence, the last block of the sequence is added to the decompressed image at the end of the L added data.

[0048] Thanks to this configuration, the encoding of the header ensures correct decompression of the information contained in all compressed data blocks, while ensuring the continuity of the data sequence. Advantageously, the data blocks may correspond to bytes of information.

[0049] In one embodiment of the present invention, when the header of the data sequence of the read image includes a decompression code indicating the second mode or the third mode, the header includes a target code indicating the second mode or the third mode. Advantageously, in the decompression step, if the target code has a first value, the data sequence of the read image is decompressed in the second mode by adding L data added to the decompressed image starting from the original position to the decompressed image, or if the target code has a second value, the data sequence of the read image is decompressed in the third mode by adding L data added to the previous decompressed image starting from the original position or until the original position to the decompressed image.

[0050] Thanks to this configuration, the encoding of the header ensures correct decompression of the information contained in all compressed data blocks, while preserving the continuity of the data sequence. Advantageously, the data blocks may correspond to bytes of information.

[0051] According to an exemplary embodiment of the present invention, when the header of the data sequence of the read image includes a target code indicating the third mode, the header includes a reading direction code indicating the reading direction of the data to be added to the decompressed image, and in the decompression step, if the reading direction code has a first value, the data sequence of the read image is decompressed in the third mode by adding L data added to the previous decompressed image starting from the original position to the decompressed image, and if the reading direction code has another value, the data sequence of the read image is decompressed in the third mode by adding L data added to the previous decompressed image until the original position to the decompressed image.

[0052] With this feature, it is possible to distinguish the copy direction in which the decompressed data should be added to the decompression stack by reading the direction code.

[0053] Advantageously, for each decompressed image, said pixelated beam is determined based on the sum of this decompressed image and all previous decompressed images.

[0054] By this feature, the video can be completely reconstructed as an additive superposition of a series of decompressed images, and in addition, the digital decoding of the images allows the lighting module to project said video onto any surface, especially the ground.

[0055] Advantageously, each decompressed image may be formed by a matrix of grayscale pixels. Where applicable, the lighting system may comprise a lighting module controller capable of controlling each elementary light source of said lighting module, and the projecting step may comprise a step of the controller transforming the grayscale of each pixel of the decompressed image into an emission set point (in particular a duty cycle), and a step of the controller controlling each elementary light source, the position of which corresponds to the position of a pixel of the decompressed image, so as to emit an elementary light beam according to an emission set point established based on the corresponding pixel. In other words, a set of elementary light beams will form a representation of the decompressed image. It is conceivable that the compressed video comprises three channels, red, green and blue, so that the reading, decompression and projecting steps are implemented for each channel.

[0056] Another subject of the invention is a method for compressing an initial video, implemented by a computing system, characterized in that the method comprises the following steps:

[0057] a. Read each image from the initial video;

[0058] b. compressing each read image to obtain a compressed image, for each read data from the read image, referred to as current data, the compressing step comprises the following steps:

[0059] c. reading data from the read image, referred to as current data;

[0060] d. selecting a first data sequence of the read image from a data sequence set of the read image starting from the current data, and selecting a second data sequence from a previous data sequence set of the read image and a data sequence set of the previous image, wherein the two data sequence sets together maximize a data sequence similarity function;

[0061] e. depending on the length of the selected first data sequence, adding a third data sequence to the compressed image, the third data sequence including the current data or a compressed sequence determined based on the original position and length of the selected second data sequence;

[0062] f. Each read data from the read image is the first data of the read image, and then each first data of the read image is located after the last data of the selected first data sequence;

[0063] g. Storing each compressed image in a memory of the computing system to form a compressed video.

[0064] In other words, the present invention proposes compressing a video by compressing each image of the video in sequence, based on a dictionary dynamically created from a data sequence extracted from the image currently being compressed or from a previous image (in particular, the last image read). In addition, since the maximum similarity features between sequences are used when gradually creating the compression dictionary, the final compression rate of the initial video can be improved. As a variant, the method can use a buffer memory that stores multiple images simultaneously, and these images are read from the buffer memory and then decompressed and projected in sequence. As another variant, the method can sequentially read and decompress the images of the compressed video, then store them in the buffer memory, and then project them directly from the buffer memory.

[0065] Advantageously, for two data sequences, the similarity function of these data sequences is determined based on: the length of the data sequences; the difference between two corresponding data in the data sequences; and a predetermined tolerance threshold of the difference.

[0066] Thus, when calculating the degree of similarity between two data sequences by means of a similarity function, the quantitative characteristics of the sequences are taken into account, in particular the length of the sequences and the numerical difference between the data forming the sequences and a reference threshold. It should then be understood that the present invention seeks to improve the overall compression rate of the initial video by maximizing the multi-criteria data sequence similarity function, while allowing for differences between the two sequences, provided that the differences are less than a predetermined tolerance threshold.

[0067] In an alternative or additional embodiment of the present invention, the set of previous data sequences of the read image in which the second data sequence is sought consists of all data sequences of the read image starting from previous data of the image, and the distance between the position of the previous data of the image and the position of the current data is at most a first predetermined distance. Advantageously, the set of data sequences of the previous image in which the second data sequence is sought consists of all data sequences of the previous image starting from a certain data, and the distance between the position of the data and the position of the current data is at most a second predetermined distance, which is specifically equal to half of the first predetermined distance.

[0068] In other words, by searching the second data sequence through a sliding window, the computational cost of searching for similar data sequences can be reduced, thereby reducing the compression time of the initial video.

[0069] In an alternative or additional embodiment of the present invention, for each current data, the third data sequence includes a header, and the header includes a decompression code indicating whether the third data sequence includes the current data or the compressed sequence.

[0070] In other words, the decompression code of the header specifies the type of compressed information found at the end of the code, thereby determining how the decompression should proceed.

[0071] Advantageously, if said decompression code indicates that said third data sequence comprises said compressed sequence, said third data sequence comprises a code of the original position of said selected second data sequence and a code of the length L of said selected second data sequence.

[0072] By doing so, the code of the original position and length L can precisely point to the data sequence to be copied during decompression of the compressed video in order to partially reconstruct the compressed video.

[0073] Advantageously, if the decompression code indicates the third mode, the structure of the data sequence of the image is organized in the following order:

[0074] a. Indicates a decompression code of the first or second / third mode, wherein the decompression code may be specifically encoded in the form of four bits, all zeros in the case of the first mode, and at least one non-zero bit in the case of the second mode or the third mode;

[0075] b. a literal copy code, specifically encoded in one bit and, depending on the value of said code, indicating whether there is a last block in the data sequence to be added at the last position of the decompressed data sequence;

[0076] c. a target code, specifically encoded in one bit, indicating, depending on the value of the code, whether the sequence should be decompressed in the second mode or in the third mode, corresponding to whether the decompression is based on the current picture or the previous picture;

[0077] d. a reading direction code, specifically encoded in one bit, indicating the reading direction of the data to be added to the decompressed image, depending on the value of the code;

[0078] e. An origin position code, specifically encoded in 9 or 10 bits, depending on whether the sequence needs to be decompressed in the second or third mode, indicating the starting point of the data to be copied during the decompression step.

[0079] Advantageously, if the decompression code indicates the second mode, the structure of the data sequence of the image is organized in the same way as in the case of the third mode, except that the reading direction code is not required. In fact, the second mode means that what is currently being decompressed is the data present in the image, and the reading direction cannot be bidirectional, so the presence of the reading direction code is redundant.

[0080] According to an alternative or additional exemplary embodiment of the present invention, for each current data, the compressing step comprises depending on the length of the selected first data sequence:

[0081] a. adding a third data sequence including the current data to the compressed image, or

[0082] b. adding a third data sequence comprising a compressed sequence determined based on the original position and length of the selected second data sequence to the compressed image, or

[0083] c. Adding the current data to the third data sequence previously added to the compressed image.

[0084] By doing so, the compression method constructs the compressed video as a concatenation of compressed data sequences, such that each of the sequences is compressed in one (and only one) of the three modes described above.

[0085] The present invention will now be described using examples, which are for illustration purposes only and in no way limit the scope of the invention, and with reference to the accompanying drawings, in which the various figures show:

[0086] [ Figure 1 ] schematically and partially illustrates a method for compressing video according to an embodiment of the present invention;

[0087] [ Figure 2a ]and[ Figure 2b ] schematically and partially illustrates searching a current data sequence and another data sequence for a data sequence that is most similar to an initial data sequence;

[0088] [ Figure 2c ] schematically and partially shows the Figure 2a ]and[ Figure 2b ] at the end of the example;

[0089] [ Figure 3 ] schematically and partially illustrates a method for projecting compressed video according to an embodiment of the present invention;

[0090] [ Figure 4 ] schematically and partially illustrates an implementation [ Figure 3 ] a motor vehicle lighting system having a method for projecting a dynamic lighting beam;

[0091] [ Figure 5 ] schematically and partially illustrates a method for decompressing a video compressed using the compression method of the present invention;

[0092] [ Figure 6a ]、[ Figure 6b ]and[ Figure 6c ] schematically and partially shows the structure of three different data blocks compressed in each of the three modes according to an embodiment of the present invention.

[0093] In the following description, elements that are identical in structure or function and appear in several different figures retain the same reference numerals unless otherwise specified.

[0094] [ Figure 1 ] shows a method for compressing an initial video V, for example showing a lighting scene intended to be projected by a motor vehicle.

[0095] First, it is proposed that the operation of the compression method is disclosed by a series of steps forming the compression method. The method for compressing the initial video V implemented by the computing system includes the following steps:

[0096] a. Step 1000: Read each image Pi from the initial video V;

[0097] b. Step 2000: compress each read image Pi to obtain a compressed image PCi, the compression step comprising the following sub-steps:

[0098] i. Sub-step 2001: Read data from the read image Pi, referred to as current data DC;

[0099] ii. Sub-step 2002: Select the first data sequence S1 of the read image Pi from the data sequence set of the read image Pi starting from the current data DC, and select the second data sequence S2 from the previous data sequence set of the read image Pi and the data sequence set of the previous image Pi-1. These two data sequence sets together make the data sequence similarity function maximize;

[0100] iii. Depending on the length of the selected first data sequence S1, sub-step 2003: adding a third data sequence S3 to the compressed image PCi, the third data sequence including the current data DC or a compressed sequence determined based on the original position and length of the selected second data sequence S2;

[0101] iv. each read data from the read image Pi is initially the first data of the read image Pi, then each first data of the read image Pi is located after the first data of the selected first data sequence S1, and steps 2001 to 2003 are repeated for each new read data;

[0102] c. Step 3000: Store each compressed image PCi in the memory of the computing system to form a compressed video VC.

[0103] [ Figure 2a ]and[ Figure 2b ] shows an example of the progress of step 2002, which selects the first data sequence S1 of the read image Pi from the data sequence set of the read image Pi starting from the current data DC, and selects the second data sequence S2 from the data sequence set of the previous image Pi-1, and these two data sequence sets together make the data sequence similarity function maximize.

[0104] like[ Figure 2a ], the previous data sequence set of the read image Pi in which the second data sequence S2 is found is composed of all data sequences of the read image Pi starting from the previous data of the read image Pi, and the distance between the position of the previous data of the read image and the position of the current data DC is at most a first predetermined distance. In other words, in the read image Pi, the second sequence S2 is found from all sequences contained in a sliding window of a predetermined size and ending at the current data DC. Therefore, the second sequence S2 is the longest sequence contained in the sliding window and having the highest degree of similarity with the sequence S1.

[0105] In the simplified [ Figure 2a], the longest data sequence S2 before the current data DC is sequence [7 3], and the first sequence S1 is sequence [4 3]. It should be noted that these sequences are not exactly the same, but the similarity function is used in all data sequences contained in the sliding window of size 3. This therefore introduces a loss of information in the compression process compared to dictionary-based compression algorithms, making it possible to improve the compression ratio while still keeping it acceptable.

[0106] like[ Figure 2b ], the data sequence set of the previous image Pi-1 in which the second data sequence S2 is also sought is composed of all data sequences of the previous image Pi-1 starting from a certain data, the distance between the position of the data and the position of the current data DC being at most a second predetermined distance, and the second predetermined distance is advantageously equal to half of the first distance. In other words, the second sequence S2 is also sought in the previous image Pi-1 from all sequences contained in a sliding window of a predetermined size and centered on the current data DC. Therefore, the second sequence S2 is the longest sequence contained in the sliding window and having the highest degree of similarity with the sequence S1.

[0107] In the simplified [ Figure 2b ], the longest data sequence S2 before the current data DC is the sequence [4 7 0], and the first sequence S1 is the sequence [4 3 0]. It should be noted that these sequences are not exactly the same, and in other respects, the similarity function is used in all data sequences contained in the sliding window of size 6. maximize.

[0108] It should be noted that the search for the second sequence S2 is performed in each of the two sets in order to obtain two intermediate data sequences, each of which has a similarity function relative to the sequence set to which it belongs. maximize, and the second sequence S2 is the function of these two intermediate sequences Maximized sequence.

[0109] Therefore, in [ Figure 2a ]and[ Figure 2b ] example, the sequence [4 7 0] is selected for compression.

[0110] When executing this step, the similarity function of each element in the data sequence set starting from the current data DC of the read image Pi and in the data sequence set of the previous image Pi-1 is The calculation of takes into account the length l of the data sequence. Specifically, a similarity function can be used based on an estimation of the degree of similarity, as shown in equation [Formula 1].

[0111] exist[ Figure 2a ]and[ Figure 2b ], the length l of the selected first sequence S1 is greater than 1. At the end of step 2003, the third sequence S3 to be added to the compressed image PCi will therefore include the original position and length of the selected second data sequence S2 in the previous image PCi-1. Figure 2c ] shows an example of such a third sequence S3.

[0112] The third sequence S3 comprises a header H, which comprises:

[0113] a. a decompression code H1, in four-bit form, indicating that the sequence S1 has been compressed with reference to the second sequence S2, and indicating the length of the sequence S2;

[0114] b. a text copy code H2, encoded in one bit, indicating that the last block of the data sequence S3 should not be copied verbatim during the decompression process;

[0115] c. target code H3, encoded in one bit, indicating that sequence S2 forms part of the previous image PCi-1;

[0116] d. Read direction code H4, encoded in one bit, indicating that sequence S2 is contained in the previous image PCi-1 to the left of the position of the current data DC;

[0117] The third sequence S3 also includes a block containing an original position code O after the header H, which is encoded in 9 bits and indicates the offset of the original position of the second sequence S2 relative to the position of the current data DC. It should be noted that if the length of the second sequence S2 cannot be encoded in four bits, the length will also be encoded in other blocks after the block containing code O of the sequence S3.

[0118] It should be noted that if the sequence S2 forms part of the image being read rather than part of the preceding image, then the direction code H4 does not need to be read, since the sequence S2 is necessarily to the left of the current data DC. In this case, the original position code O can be encoded using 10 bits.

[0119] Finally, if the length l of the chosen first sequence S1 is equal to 1, the third sequence S3 that will be added to the compressed image PCi will contain the current data as well as a header indicating firstly that this sequence S3 contains data to be copied verbatim during the decompression process and secondly the number of blocks that follow the header containing these data to be copied.

[0120] Still in the case of length equal to 1, it should also be noted that when the previous third data sequence has been compressed, for the previous current data (referring to the data sequence of the current image or the previous image), a data block containing the existing current data verbatim can be added to the end of the previous third data sequence. In this case, the literal copy code H2 will indicate that the last block of the data sequence S3 should be copied verbatim during the decompression process.

[0121] [ Figure 3 ] shows a method for projecting a dynamic lighting beam using a lighting system 3 of a motor vehicle.

[0122] [ Figure 4 ] shows the lighting system 3 of a motor vehicle, which includes a memory 4, a control unit 5 and a lighting module 7 and implements the above-mentioned projection method. The memory stores a compressed video 1.1, which includes a plurality of continuous compressed images 2.1, and each compressed image is composed of a plurality of data sequences.

[0123] Compressed video 1.1 can be obtained by Figure 1 ]to[ Figure 2c ] is compressed using the method described in .

[0124] [ Figure 3 ] The method comprises the following steps:

[0125] a. Step 1: Reading each compressed image 2.1 from the compressed video 1.1 stored in the memory 4;

[0126] b. For each read image, step 2: the control unit 5 decompresses the image using a dictionary-based decompression algorithm to obtain a decompressed image 2.2,

[0127] c. Step 3: The illumination module 7 projects a pixelated light beam 6 determined based on each decompressed image 2.2.

[0128] like[ Figure 5 ] as shown, each compressed data read from each compressed image of the compressed video is decompressed in one of three possible modes, depending on whether the data, when compressed, included the original data verbatim, a sequence of references to the current image, or a sequence of references to previous images, as described above.

[0129] [ Figure 5 ] shows that it can be Figure 3 ] method, and enables decompression of a video V compressed using the above compression method. The decompression method comprises the following steps:

[0130] a. Step 500: Read each compressed image from the compressed video,

[0131] b. Step 600: Decompress the image currently being read according to the following sub-steps: For each data sequence that matches the compressed image currently being read,

[0132] i. Sub-step 611: Read decompressed codes 101, 201, 301;

[0133] ii. If the decompression code 201, 301 is equal to the value indicating the second mode or the third mode, and the header includes a text copy code 202, 302 indicating the presence or absence of the first block, then sub-step 612.1: read the text copy code;

[0134] iii. If the decompressed code 101, 201, 301 is equal to a value indicating the first mode, in particular zero, the data sequence comprises a code of the number N1 encoded in 4 bits, then sub-step 612.2: read the code of said number N1;

[0135] iv. If the decompression code 201, 301 indicates the second mode or the third mode, and the header includes a target code 203, 303 indicating the second mode or the third mode, then sub-step 613.1: read the target code 203, 303;

[0136] v. If the decompression code 101, 201, 301 indicates the first mode, then sub-step 613.2: decompressing the data sequence by copying N1 blocks following the code of the number N1 in the decompressed image;

[0137] vi. If the target code 303 indicates the third mode, then sub-step 614.1: read the read direction code 304;

[0138] vii. If the decompressed code 201, 301 is equal to the value indicating the second mode or the third mode, sub-step 615.1: calculate the length L obtained by the sum of the decompressed code 201, 301 and each data 205, 306 after the original position code (until one of these blocks contains data equal to a predetermined value (specifically zero));

[0139] viii. Sub-step 620: Decompressing the current data sequence in accordance with the mode specified by the code set for decompression;

[0140] c. Step 700, creating a decompressed video as a combination of a series of decompressed images, wherein each decompressed image is obtained by adding the last decompressed image and all previous decompressed images pixel by pixel.

[0141] [ Figure 6a] shows an example of a data sequence of a read image 100, which includes a decompression code 101 indicating a first mode and a code 102 of a number N1, which form a header of the data sequence, in particular, correspond to the first byte of the data sequence.

[0142] The decompression code 101 is encoded by 4 bits, specifically 4 zero bits, representing the decimal number 0.

[0143] The code of the quantity N1 is encoded by the 4 bits following the 4 bits that encode the decompression code 101; in the example, the code of said quantity N1 corresponds to the binary number 0010, which corresponds to the decimal number 2. The encoded quantity N1 is therefore equal to 3, obtained by adding one unit to the decimal number of the binary code formed by the four bits previously determined. The quantity N1 corresponds to the number of blocks (in particular bytes) to be copied in the step of decompressing the read data sequence after the code of said quantity N1.

[0144] [ Figure 6b ] shows an example of a data sequence of a read image 200, which includes a decompression code 201 indicating the second mode or the third mode; a text copy code 202, a target code 203, and an original position code 204.

[0145] Therefore, when the header of the data sequence of the read image includes a decompression code 201 indicating the second mode or the third mode, the sequence includes an original position code 204 and codes 201, 205 of length L, so that in the decompression step, the data sequence of the read image is decompressed in the second mode or the third mode by adding L data added to the decompressed image or the previously decompressed image starting from the original position or until the original position to the decompressed image and added to the image decompressed in the second mode or the third mode.

[0146] In addition, when the header of the data sequence of the read image includes a decompression code 201, 301 indicating the second mode or the third mode, in the decompression step, the length L is obtained in the following manner: the value of the decompression code 201 (fifteen in this example) is added to the value of each data block 205 after the original position code 204 until one of these blocks contains data equal to a predetermined value, and the set of blocks forms a code 201, 205 of length L.

[0147] Therefore, when the header of the data sequence of the read image includes a decompression code 201, 301 indicating the second mode or the third mode, the header includes a text copy code 202, 302 indicating whether there is a last block 206, 307 in the sequence, so that in the decompression step, if the text copy code 202, 302 indicates that there is a last block 206, 307 in the sequence, then the last block 206, 307 of the sequence is added to the decompressed image at the end of the L added data, in this example: two hundred and fifty-five, two hundred and fifty-five and two hundred and thirty-seven; that is, a total of seven hundred and sixty-two.

[0148] Therefore, when the header of the data sequence of the read image includes the decompression code 201, 301 indicating the second mode or the third mode, the header includes the target code 203, 303 indicating the second mode or the third mode. Advantageously, in the decompression step, if the target code 203 has a first value (specifically, the zero bit 200 in this example), the data sequence of the read image is decompressed in the second mode by adding L data added to the decompressed image starting from the original position to the decompressed image, or if the target code 203 has a second value (specifically, a bit equal to one), the data sequence of the read image is decompressed in the third mode by adding L data added to the previous decompressed image starting from the original position or up to the original position to the decompressed image.

[0149] When the header of the data sequence of the read image includes a decompression code 201, 301 indicating the second mode or the third mode, the header includes a text copy code 202, 302 indicating whether there is a last block 206, 307 in the sequence.

[0150] In the decompression step, if the literal copy code 202, 302 indicates that there is a last block in the sequence, the last block 206, 307 of the sequence is added to the decompressed image after the L added data.

[0151] [ Figure 6c ] shows an example of a data sequence of a read image 300, which includes a decompression code 301 indicating a second mode or a third mode; a text copy code 302, a target code 303; a reading direction code 304 and an original position code 305.

[0152] Therefore, when the header of the data sequence of the read image includes a decompression code 301 indicating the second mode or the third mode, the sequence includes an original position code 305 and codes 301, 306 of length L, so that in the decompression step, the data sequence of the read image is decompressed in the second mode or the third mode by adding L data added to the decompressed image or the previously decompressed image starting from the original position or until the original position to the decompressed image and added to the image decompressed in the second mode or the third mode.

[0153] In addition, when the header of the data sequence of the read image includes a decompression code indicating the second mode or the third mode, in the decompression step, the length L is obtained in the following manner: the value of the decompression code 301 (fifteen in this example) is added to the value of each data block 305 after the original position code 305 until one of these blocks contains data equal to a predetermined value (specifically zero), and the set of blocks forms a code 301, 306 of length L.

[0154] Therefore, when the header of the data sequence of the read image includes a decompression code 301 indicating the second mode or the third mode, the header includes a text copy code 302 indicating whether there is a last block 307 in the sequence, so that in the decompression step, if the text copy code 302 indicates that there is a last block 307 in the sequence, the last block 307 of the sequence is added to the decompressed image at the end of the L added data, in this example: two hundred and fifty-five, two hundred and fifty-five and two hundred and thirty-seven; that is, a total of seven hundred and sixty-two.

[0155] Therefore, when the header of the data sequence of the read image includes the decompression code 301 indicating the second mode or the third mode, the header includes the target code 303 indicating the second mode or the third mode. Advantageously, in the decompression step, if the target code 303 has a first value (specifically, a zero bit), the data sequence of the read image is decompressed in the second mode by adding L data added to the decompressed image starting from the original position to the decompressed image, or if the target code 303 has a second value (specifically, a bit equal to one in this example), the data sequence of the read image is decompressed in the third mode by adding L data added to the previous decompressed image starting from the original position or up to the original position to the decompressed image.

[0156] When the header of the data sequence of the read image includes a decompression code 301 indicating the second mode or the third mode, the header includes a text copy code 302 indicating whether there is a last block 307 in the sequence, and in the decompression step, if the text copy code 302 indicates that there is a last block in the sequence, the last block 307 of the sequence is added to the decompressed image at the end of the L added data.

[0157] When the header of the data sequence of the read image includes a target code 303 indicating the third mode, the header includes a reading direction code 304 indicating the reading direction of the data to be added to the decompressed image, and in the decompression step, if the reading direction code 304 has a first value (specifically a zero bit), the data sequence of the read image is decompressed in the third mode by adding L data added to the previous decompressed image starting from the original position to the decompressed image, and if the reading direction code has another value (specifically a bit equal to one), the data sequence of the read image is decompressed in the third mode by adding L data added to the previous decompressed image until the original position to the decompressed image.

[0158] Again refer to [ Figure 3 ],exist[ Figure 5 Each decompressed image obtained at the end of the method of ] forms a matrix of grayscale pixels. Therefore, each pixel of the image can be transformed into an emission set point, for example in the form of a duty cycle, depending on the grayscale of the image. Therefore, the emission set point can control the elementary light sources of the lighting module 7, the position of which corresponds to the position of the corresponding pixel in the decompressed image. Therefore, the elementary light sources emit elementary light beams according to the emission set point. The group of elementary light beams then forms a representation of the decompressed image.

[0159] The invention should in no case be considered limited to the embodiments specifically described herein, but in particular extends to any equivalent means and any technically feasible combination of these means.

Claims

1. A method for projecting a dynamic lighting beam using a lighting system (3) of a motor vehicle, the lighting system comprising a memory (4), a control unit (5) and a lighting module (7), the memory storing a compressed video (1.1), the compressed video comprising a plurality of consecutive images (2.1), each image consisting of a plurality of data sequences, characterized in that The method comprises the following steps: a. Step (1): reading each image from the compressed video (1.1) stored in the memory (4); b. for each read image, step (2): the control unit (5) decompresses the image using a dictionary-based decompression algorithm to obtain a decompressed image, each data sequence of the read image is decompressed in a first mode, a second mode, or a third mode, in which a copy of the sequence is added to the decompressed image, in which a data sequence of the previously read image that has been added to the decompressed image is added to the decompressed image, and in which a data sequence of the previously decompressed image is added to the decompressed image in the third mode; c. Step (3): The illumination module (7) projects a pixelated light beam (6) determined based on each decompressed image (2.2).

2. Method for projecting a dynamic lighting beam using a lighting system (3) of a motor vehicle according to the preceding claim, characterized in that Each data sequence of the read image comprises a header containing a decompression code (101, 201, 301), and in the decompression step, each data sequence of the read image is decompressed in the first mode, the second mode or the third mode, depending on the decompression code (101, 201, 301) contained in the header of the sequence.

3. Method for projecting a dynamic lighting beam using a lighting system (3) of a motor vehicle according to the preceding claim, characterized in that When the header of the data sequence of the read image includes a decompression code indicating the first mode, the sequence includes a number N1 of codes (102), and in the decompression step, the data sequence of the read image is decompressed in the first mode by adding N1 data blocks following the number N1 of codes to the decompressed image.

4. A method for projecting a dynamic lighting beam using a lighting system (3) of a motor vehicle according to any one of claims 2 and 3, characterized in that When the header of the data sequence of the read image includes a decompression code (201, 301) indicating the second mode or the third mode, the sequence includes an original position code (204, 305) and a code (201, 205; 301, 306) of length L, and in the decompression step, the data sequence of the read image is decompressed in the second mode or the third mode by adding L data added to the decompressed image or a previously decompressed image starting from or until the original position to the decompressed image.

5. Method for projecting a dynamic lighting beam using a lighting system (3) of a motor vehicle according to the preceding claim, characterized in that When the header of the data sequence of the read image includes a decompression code (201, 301) indicating the second mode or the third mode, the header and the original position code (204, 305) of the sequence together form a predetermined number N2 data blocks, and in the decompression step, the original position is obtained from all remaining data starting from the header in the N2 data blocks, and the remaining data forms the original position code.

6. Method for projecting a dynamic lighting beam using a lighting system (3) of a motor vehicle according to any one of claims 4 and 5, characterized in that When the header of the data sequence of the read image includes a decompression code (201, 301) indicating the second mode or the third mode, in the decompression step, the length L is obtained from the value of the code (201, 205; 301, 306) constituting the length L or the decompression code (201, 301) constituting a part thereof.

7. Method for projecting a dynamic lighting beam using a lighting system (3) of a motor vehicle according to the preceding claim, characterized in that When the header of the data sequence of the read image includes a decompression code (201, 301) indicating the second mode or the third mode, in the decompression step, the length L is obtained in the following manner: the value of the decompression code (201, 301) is added to the value of each data block (205, 306) after the original position code (204, 305) until one of these blocks contains data equal to a predetermined value, and the set of blocks forms a code (201, 205; 301, 306) of length L.

8. Method for projecting a dynamic lighting beam using a lighting system (3) of a motor vehicle according to any one of claims 4 to 7, characterized in that When the header of the data sequence of the read image includes a decompression code (201, 301) indicating the second mode or the third mode, the header includes a text copy code (202, 302) indicating whether there is a last block in the sequence, and in the decompression step, if the text copy code indicates that there is a last block (206, 307) in the sequence, the last block (206, 307) of the sequence is added to the decompressed image at the end of the L added data.

9. Method for projecting a dynamic lighting beam using a lighting system (3) of a motor vehicle according to any one of claims 4 to 8, characterized in that When the header of the data sequence of the read image includes a decompression code (201, 301) indicating the second mode or the third mode, the header includes a target code (203, 303) indicating the second mode or the third mode, and in the decompression step, if the target code (203, 303) has a first value, the data sequence of the read image is decompressed in the second mode by adding L data added to the decompressed image starting from the original position to the decompressed image, or if the target code (203, 303) has a second value, the data sequence of the read image is decompressed in the third mode by adding L data added to the previous decompressed image starting from the original position or up to the original position to the decompressed image.

10. Method for projecting a dynamic lighting beam using a lighting system (3) of a motor vehicle according to the preceding claim, characterized in that When the header of the data sequence of the read image includes a target code (303) indicating the third mode, the header includes a reading direction code (304) indicating the reading direction of the data to be added to the decompressed image, and in the decompression step, if the reading direction code (304) has a first value, the data sequence of the read image is decompressed in the third mode by adding L data added to the previous decompressed image starting from the original position to the decompressed image, and if the reading direction code (304) has another value, the data sequence of the read image is decompressed in the third mode by adding L data added to the previous decompressed image until the original position to the decompressed image.

11. Method for projecting a dynamic lighting beam using a lighting system (3) of a motor vehicle according to the preceding claim, characterized in that For each decompressed image, the pixelated beam (6) is determined based on the sum of the decompressed image and all previous decompressed images.

12. A method for compressing an initial video implemented by a computing system, characterized in that: The method comprises the following steps: a. Step (1000): reading each image from the initial video; b. Step (2000): compressing each read image to obtain a compressed image, for each read data from the read image, referred to as current data, the compression step comprises the following sub-steps: i. Sub-step (2001): reading data from the read image, referred to as current data; ii. Sub-step (2002): selecting a first data sequence of the read image from a data sequence set of the read image starting from the current data, and selecting a second data sequence from a previous data sequence set of the read image and a data sequence set of the previous image, wherein the two data sequence sets together maximize a data sequence similarity function; iii. depending on the length of the selected first data sequence, sub-step (2003): adding a third data sequence to the compressed image, the third data sequence comprising the current data or a compressed sequence determined based on the original position and length of the selected second data sequence; Each read data from the read image is the first data of the read image, and then each first data of the read image is located after the last data of the selected first data sequence; c. Step (3000): Storing each compressed image in the memory of the computing system to form a compressed video.

13. Method for compressing an initial video, implemented by a computing system, according to the preceding claim, characterized in that For two data sequences, the similarity functions of the data sequences are determined based on: the lengths of the data sequences; the differences between two corresponding data in the data sequences; and a predetermined tolerance threshold of the differences.

14. The method for compressing an initial video implemented by a computing system according to any one of claims 12 and 13, characterized in that: The previous data sequence set of the read image in which the second data sequence is sought consists of all data sequences of the read image starting from the previous data of the image, and the distance between the position of the previous data of the image and the position of the current data is at most a first predetermined distance, and the data sequence set of the previous image in which the second data sequence is sought consists of all data sequences of the previous image starting from a certain data, and the distance between the position of the data and the position of the current data is at most a second predetermined distance.

15. The method for compressing an initial video implemented by a computing system according to any one of claims 12 to 14, characterized in that: For each current data, the third data sequence includes a header, and the header includes a decompression code (101, 201, 301) indicating whether the third data sequence includes the current data or the compressed sequence.

16. The method for compressing an initial video implemented by a computing system according to claim 15, wherein: If the decompression code (201, 301) indicates that the third data sequence includes the compressed sequence, the third data sequence includes a code (204, 305) of the original position of the selected second data sequence and a code (201, 205; 301, 306) of the length L of the selected second data sequence.

17. The method for compressing an initial video implemented by a computing system according to any one of claims 15 and 16, characterized in that: For each current data, the compressing step comprises depending on the length of the selected first data sequence: a. adding a third data sequence including the current data to the compressed image, or b. adding a third data sequence comprising a compressed sequence determined based on the original position and length of the selected second data sequence to the compressed image, or c. Adding the current data to the third data sequence previously added to the compressed image.

Images