Method for projecting dynamic lighting beams using an automotive lighting system

Abstract

The present invention relates to a method for projecting a dynamic lighting beam using an automotive lighting system (3) based on compressed video (1.1), the method comprising the following steps: a step (1) of reading each image from the compressed video (1.1); and for each read image, a step (2) of decompressing the image using a dictionary-based decompression algorithm, each data sequence being decompressed in either a first mode in which the decompressed image is appended with a copy of the sequence, or a second mode including appending a data sequence of the previously read image to the decompressed image, or a third mode including appending a data sequence of a previously decompressed image, step (2); and a step (3) of projecting a light beam (6) based on each decompressed image.

Description

Technical Field

[0001] The present invention relates to the field of automotive lighting and the projection of dynamic light beams using automotive lighting devices. More particularly, the present invention relates to a method for projecting a dynamic lighting beam using an automotive lighting system.

Background Art

[0002] Modern automotive lighting systems include an ever increasing number of light sources that must be controlled in order to provide adaptive lighting functionality.

[0003] Thanks to the miniaturization of electronic lighting components and the wide variety of emission colors and intensities that can be generated by such systems, nowadays it is possible to use a vehicle lighting system as a headlight in order to project a sequence of one or more successive images onto the road acting as a projection surface. The above-mentioned successive images may thus form an "adaptive lighting" function, a "driving assistance" function, a transition function between two separate photometric functions, or a "welcome or farewell scenario" function. Thus, the projected images may address, for example, security information communication, comfort or aesthetic needs, especially for the driver of the vehicle or for the driver of a nearby vehicle.

[0004] Typically, the lighting system is controlled by a control unit called a PCM ("Pixel controller Module") that can command the lighting module of the lighting system. A sequence of digital images pre-stored in the vehicle's memory is provided to the control unit so that it can be projected by the lighting module in the form of a dynamic light beam.

[0005] The CAN protocol is often used in one of its variants (CAN-FD being one of the most commonly used) to transfer data between the memory and the control unit. However, some automotive manufacturers have decided to limit the bandwidth of the CAN protocol, which affects management tasks that typically require around 5 Mbps. Therefore, to comply with these limitations, it is common to store video and digital images in compressed video and image formats. The vehicle's control unit is then responsible for decompressing these images so that it can control the lighting modules.

[0006] However, in this type of lighting system, the projection speed, along with the cost of the system's components, are two important parameters of the system. In fact, to maximize the projection speed of the dynamic light beam, it is necessary for the compressed image to be decompressed as quickly as possible.

[0007] Therefore, there is a need for a method to project a dynamic light beam based on a sequence of compressed images that is more responsive than currently known methods.

[0008] This invention falls within the scope of this background and aims to address these needs. [Overview of the Initiative]

[0009] For these purposes, one subject of the present invention is a method for projecting a dynamic illumination beam using an automotive lighting system, the lighting system comprising a memory storing compressed video containing multiple consecutive images, each consisting of multiple data sequences, a control unit, and a lighting module, the method comprising the following steps: a. A step of reading each image from the compressed video stored in memory, b. For each image read, the control unit decompresses the image using a dictionary-based decompression algorithm to obtain a decompressed image, wherein each data sequence of the read image is decompressed in one of the following ways: a first mode in which the decompressed image has a copy of the above sequence added to it; a second mode in which the decompressed image has a data sequence of an image read before it was added to the decompressed image added to it; or a third mode in which the decompressed image has a data sequence of an image that was previously decompressed added to it. c. The lighting module projects a pixelated light beam determined based on each decompressed image. It is characterized by including.

[0010] This invention specifically proposes the use of dictionary-based compression systems, such as LZx compression, also known as Lempel-Ziv compression. Therefore, it should be understood that, thanks to this invention, each image is decompressed based on a compression sequence formed from a dictionary consisting of the currently read compressed image and previously compressed images. Previously added images may be the last image decompressed before the read image, or another image previously decompressed before the read image.

[0011] As is well known, one of the main drawbacks of dictionary-based compression algorithms is that they achieve poor compression rates when the proportion of similar data in the images to be compressed is low. This invention is noteworthy in that it uses the fact that two consecutive images of a video are very similar in order to increase the compression rate of the video and thereby increase the decompression speed of the corresponding compressed video. In fact, the image resulting from the difference between any two consecutive images of a video contains a significant amount of similar data, in particular, null data. It should also be understood that by doing this, the compressed video contains significantly less data compared to compression performed directly on each image of the video, and therefore improves the decompression speed.

[0012] In the context of this invention, namely the projection of a dynamic light beam using an automotive lighting device, the primary limiting factor is the decompression speed of the video to be projected. In fact, excessively slow decompression of compressed video negatively affects the visual quality of the projected light beam. Furthermore, it should be understood that, given the problems that this invention aims to solve, the video compression time does not constitute a limiting factor.

[0013] In this invention, "data sequence" is understood to mean a finite and ordered set of units of information, in particular bits or bytes or hexadecimal data of information.

[0014] In this invention, “dynamic illumination beam” is understood to mean a light beam whose photometric properties, in particular, its illuminance distribution, change over time in a predetermined manner. For example, such a dynamic illumination beam may represent a visual animation, such as a logo, image, or pattern change. The visual animation may, in particular, include at least 100 consecutive images that follow one another at a frequency of at least 20 Hz. Still as an example, a dynamic illumination beam may be projected onto a road or displayed on a screen.

[0015] In the present invention, “control unit” is understood to mean a computing module capable of manipulating digital data, in particular a computer processor, and communicating with memory storage devices and / or electronic devices, in particular via cables or wireless links, such as automotive headlights.

[0016] In the present invention, “data sequence comparison” is understood to mean determining the similarity between two data sequences, and the similarity may be a numerical value determined using a mathematical method relating in particular to the units of information of the sequences. In the present invention, “similarity function” is understood to mean such a mathematical method for implementing data sequence comparison, and the procedure involves receiving two data sequences of the same length in input and returning a numerical value corresponding to the similarity between the sequences.

[0017] The similarity function can determine the similarity between two data sequences, in particular, by using an exact comparison between pairs of units of information of these sequences or by using a comparison of the norms between pairs of units of information of these sequences with respect to a given maximum difference, where the difference can be the same for each pair of data or specific to each pair of data. Where applicable, the similarity function can take into account the length of the data sequence.

[0018] Advantageously, the similarity d between a sequence σ and a reference sequence S of the same length as the sequence σ , s1 , , , ,

[0024] , ,

[0023] can be calculated using the following formula:

[0019] [Equation 1]

[0020] [Number]

[0021] where the term L(σ) corresponds to the length of the sequence σ, and σ i corresponds to the i-th element of the sequence σ, the coefficient w is a penalty parameter with respect to the length of the sequence, and ε max is a given maximum difference. At this time, assuming two given data sequences of the same length s1 and s2, the similarity function associated with the similarity from Equation [Equation 1] is

[0022] [Equation 2] ​​​​​​​​​​In the present invention, two compared data sequences are considered "similar" when their degree of similarity determined by a given similarity function is greater than a predefined tolerance threshold. Thus, this threshold is a numerical value representing a margin, according to which it is possible to consider two separate sequences as either similar or dissimilar.

[0025] In the present invention, the reading, decompression, and projection steps can be performed sequentially, i.e., for each image. As a variant, multiple images can be read continuously and stored in a buffer memory, and at this time, the decompression and projection steps are performed on the images stored in the buffer memory. As another variant, the reading and decompression steps can be performed sequentially, i.e., for each image, and at this time, the decompressed images are stored in the buffer memory, and at this time, the projection step is performed on the decompressed images stored in the buffer memory.

[0026] In the present invention, an "illumination module" is understood to mean a module that can emit a pixelated light beam, particularly arranged within the front headlights of a motor vehicle, and arranged such that the pixelated light beam is a light beam comprising at least 2500 pixels distributed in a plurality of rows and columns, for example, 50 rows and 50 columns, with pixel dimensions of, for example, 0.05° to 0.3°. As a variant, the illumination module can be a screen, particularly arranged within the front headlights or taillights of a vehicle, and capable of displaying an image of at least 2500 pixels with dimensions of 0.05° to 0.3°, distributed in a plurality of rows and columns, for example, 50 rows and 50 columns.

[0027] For example, the illumination module can include a plurality of basic light sources. Where applicable, a controller can be arranged to selectively control each of the basic light sources of the illumination module such that the light source emits a basic light beam that forms one of the pixels of the pixelated light beam or one of the pixels of the image.

[0028] "Light source" is understood to mean any light source, possibly associated with an electro-optic element, that can be selectively activated and controlled to emit a fundamental light beam, the intensity of which is controllable. This could 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 excited by a light source, or a light source associated with a liquid crystal or micromirror.

[0029] In the present invention, each data sequence of a read image includes a header containing a decompression code, and in the decompression step, each data sequence of a read image is decompressed in a first, second, or third mode depending on the decompression code contained in the header of the sequence.

[0030] Thanks to the decompression code, each data sequence of the read image is decompressed separately, depending on whether the compressed data sequence needs to be copied literally to the decompression stack, or whether the data sequence to be copied to the decompression stack corresponds to the image data sequence currently being decompressed and preceding the data sequence currently being decompressed, or whether the data sequence to be copied to the decompression stack corresponds to previously decompressed image data sequences, and in particular to images preceding the image currently being decompressed.

[0031] In the first mode, a copy of the sequence may be a partial copy, and in particular, a copy of the sequence excluding the header of that sequence.

[0032] Advantageously, when the header of the data sequence of the read image includes a decompression code indicating a first mode, the sequence includes a code for a number N1, and in the decompression step, the data sequence of the read image is decompressed in the first mode by adding N1 data blocks to the decompressed image following the code for a number N1.

[0033] Thanks to the code for number N1, the amount of data required to reconstruct the decompressed image is minimized, while at the same time it is possible to decompress a precise amount of information about the image's decompression stack. Advantageously, the header may consist of a data sequence, specifically bits, consisting of two supplemental subsequences, each of which is encoded for the decompression code and the code for number N1, respectively.

[0034] Advantageously, the decompression code can consist of a 4-bit sequence, in particular, where all bits have the value zero.

[0035] In one alternative or additional embodiment of the present invention, the sequence includes a code for a location code O and a code for length L, where the header of the data sequence of the read image includes a decompression code indicating a second or third mode. Advantageously, in the decompression step, the data sequence of the read image is decompressed in the second or third mode by adding L data to the decompressed image, which is added to the decompressed image or to a previously decompressed image from or up to the location.

[0036] Thanks to the position and length codes, it is possible to indicate the precise address of a data sequence, and in particular, the starting position indicates the beginning of a sequence that should be copied sequentially until the number of copied data corresponds to the length indicated by the length code L.

[0037] The decompression code could, for example, correspond to four pieces of data, specifically four bits with a value of zero.

[0038] If desired, when the header of the data sequence of the read image contains a decompression code indicating a second or third mode, the header of the sequence and the code for the original position together form a predetermined number of N2 data blocks. Advantageously, in the decompression step, the original position is obtained from all the remaining data of the N2 data blocks from the header, forming the code for the original position O.

[0039] Thanks to this configuration, header encoding ensures the continuity of the data sequence and minimizes the memory space occupied.

[0040] In one alternative or additional embodiment of the present invention, when the header of the data sequence of the read image includes a decompression code indicating a second or third mode, the length L is obtained from a value of the decompression code that forms or is part of the code for length L.

[0041] Thanks to this configuration, header encoding ensures the continuity of the data sequence and minimizes the memory space occupied.

[0042] Advantageously, when the header of the data sequence of the read image includes a decompression code indicating a second or third mode, in the decompression step, the length L is obtained by adding the value of the decompression code and the value of each data block following the code for the original position O until one of these blocks contains data equal to a default value, and the set of blocks forms the code for length L.

[0043] Thanks to this iterative procedure, it is possible to encode any length within a data sequence, and each element forming the sequence, such as a byte, can contain only a limited amount of information. In this case, the present invention should be understood as utilizing encoding that makes it possible to overcome the information storage capacity constraints of the elements.

[0044] In one alternative or additional embodiment of the present invention, when the header of the data sequence of the read image includes a decompression code indicating a second or third mode, the header includes a literal copy code indicating the presence or absence of a last block in the sequence, and in the decompression step, if the literal copy code indicates the presence of a last block in the sequence, the last block of the sequence is added to the decompressed image at the end of the L additional data.

[0045] Thanks to this configuration, the header encoding ensures the correct decompression of all information contained within the compressed data blocks while simultaneously ensuring the continuity of the data sequence. Advantageously, the data blocks can correspond to bytes of information.

[0046] In one embodiment of the present invention, when the header of the data sequence of a read image includes a decompression code indicating a second or third mode, the header includes a target code indicating a second or third mode. Advantageously, in the decompression step, the data sequence of the read image is decompressed in a second mode by adding L data to the decompressed image from the original position, if the target code has a first value, or in a third mode by adding L data to the decompressed image from or to a previously decompressed image up to the original position, if the target code has a second value.

[0047] Thanks to this configuration, the header encoding ensures the correct decompression of all information contained within the compressed data blocks while simultaneously ensuring the continuity of the data sequence. Advantageously, the data blocks can correspond to bytes of information.

[0048] According to one exemplary embodiment of the present invention, when the header of the data sequence of a read image includes a target code indicating a third mode, the header includes a reading direction code indicating the reading direction of data to be added to the decompressed image, and in the decompression step, the data sequence of the read image is decompressed in the third mode by adding L data to the decompressed image, starting from the original position if the reading direction code has a first value, or to the original position if the reading direction code has another value.

[0049] Thanks to this feature, it is possible to use a read direction code to distinguish the copy direction in which the decompressed data should be added to the decompression stack.

[0050] Advantageously, for each decompressed image, the pixelation beam is determined based on the sum of this decompressed image and all previously decompressed images.

[0051] Thanks to this feature, it is possible to completely reconstruct the video as an additional superposition of consecutive decompressed images, and in addition, the digital decoding of the images allows the lighting module to project the above video onto any surface, especially the ground.

[0052] Advantageously, each decompressed image can be formed from a grayscale pixel matrix. Where applicable, the illumination system may include an illumination module controller capable of controlling each of the illumination modules, and the projection step may include the controller converting the grayscale of each pixel of the decompressed image to a radiation setpoint, in particular a duty cycle, and the controller controlling each illumination source, whose position corresponds to the position of a pixel in the decompressed image, to emit an illumination beam according to a radiation setpoint established based on this corresponding pixel. In other words, the set of illumination beams forms a depiction of the decompressed image. Since the compressed video contains three channels, red, green, and blue, it is possible to intend that the reading, decompression, and projection steps be performed for each of the channels.

[0053] Another subject of the present invention is a method for compressing initial video, which is carried out by a computing system, and the method comprises the following steps: a. Steps to read each image from the initial video, b. A step of compressing each read image in order to obtain a compressed image, wherein the compression step involves the following steps for each read data from the read image, called the current data: c. A step to read data from the image, called the current data. d. A step of selecting a first data sequence of a read image from a set of data sequences of a read image that begins with the current data, and a second data sequence from a set of preceding data sequences of the read image and a set of data sequences of preceding images, wherein the first data sequence and the second data sequence maximize a data sequence similarity function together. e. Depending on the length of the selected first data sequence, the compressed image includes adding a third data sequence containing the current data, or a compressed sequence determined based on the lengths of the in-situ and selected second data sequences, f. Each data point read from the read image is the first data point of the read image, and each first data point of the read image is located after the last data point of the selected first data sequence, in step, g. A step of storing each compressed image in the memory of the computing system in order to form a compressed video. It is characterized by including.

[0054] In other words, the present invention proposes compressing video by sequentially compressing each image of the video using a dictionary created on the fly based on a data sequence extracted from the currently compressed image or from a preceding image, particularly the last image read. In addition, it is possible to improve the final compression rate of the initial video thanks to the maximum similarity features between the sequences used in the stepwise creation of the compression dictionary. As a variation, the method may use a buffer memory that stores multiple images simultaneously, which are read from the buffer memory, then decompressed and projected sequentially. As another variation, the method may perform sequential reading and decompression of images of a compressed video that are stored in a buffer memory and then projected directly from the buffer memory.

[0055] 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 the two corresponding data in these data sequences, and a default tolerance threshold for the above difference.

[0056] By doing so, the calculation of similarity between two data sequences using a similarity function takes into account the quantitative characteristics of the sequences, particularly the length of the sequences and the numerical difference between the data forming the sequences and a reference threshold. Furthermore, the present invention seeks to increase the overall compression rate of the initial video by maximizing the multi-criteria data sequence similarity function, by allowing the difference between the two sequences to be smaller than a predetermined tolerance threshold.

[0057] In one alternative or additional embodiment of the present invention, the set of preceding data sequences of a read image from which a second data sequence is sought comprises all data sequences of a read image that begin with preceding data of an image whose position is spaced at a maximum of a first predetermined distance from the position of the current data. Advantageously, the set of preceding data sequences of a read image from which a second data sequence is sought comprises all data sequences of a read image that begin with data whose position is spaced at a second predetermined distance, which is spaced at a maximum of, in particular, half of the first predetermined distance from the position of the current data.

[0058] In other words, the search for the second data sequence is performed using a slide window, thereby reducing the computational cost of searching for similar data sequences and, consequently, the compression time of the initial video.

[0059] In one alternative or additional embodiment of the present invention, for each current data, a third data sequence includes a header, the header includes a decompression code indicating whether the third data sequence includes current data or a compressed sequence.

[0060] In other words, the decompression code in the header specifies the type of compression information found at the end of the code above, and therefore allows us to determine how the decompression should continue.

[0061] Advantageously, if the decompression code indicates that the third data sequence includes a compressed sequence, the third data sequence includes a code for the original position of the selected second data sequence and a code for the length L of the selected second data sequence.

[0062] By doing this, the code for the original position and length L allows the data sequence to be copied during the decompression of the compressed video to be precisely pointed to in order to partially reconstruct it.

[0063] Advantageously, if the decompression code indicates a third mode, the structure of the image data sequence is organized sequentially as follows: a. A decompression code indicating the first or second / third mode, the decompression code may be encoded in a 4-bit form, in particular, all zeros in the first mode and including at least one non-zero bit in the second or third mode. b. A literal copy code, specifically encoded in one bit, which, depending on the value of the above code, indicates the presence or absence of the last block of the data sequence to be added to the last position of the decompressed data sequence. c. A target code, specifically encoded in 1 bit, which, depending on the value of the above code, indicates whether the sequence should be decompressed in a second or third mode, corresponding to decompression based on the current image or a preceding image. d. A read direction code, specifically encoded in 1 bit, which indicates the read direction of the data to be added to the decompressed image, depending on the value of the above code. e. Position code, encoded in 9 or 10 bits, indicating the source of the data to be copied during the decompression step, depending on whether the sequence should be decompressed in a second or third mode.

[0064] Advantageously, when the decompression code indicates the second mode, the structure of the image data sequence is organized in the same way as in the third mode, although the difference is that a read direction code is not required. In fact, the second mode refers to the data present in the image currently being decompressed, and there cannot be two read directions; therefore, the presence of the read direction code is unnecessary.

[0065] According to one alternative or additional exemplary embodiment of the present invention, the compression step is performed for each current data, depending on the length of the selected first data sequence, a. Add a third data sequence containing the current data to the compressed image. b. Adding a third data sequence to the compressed image, which includes a compression sequence determined based on the original position and the length of the selected second data sequence, or c. This includes adding the current data to a third data sequence previously added to the compressed image.

[0066] By doing this, the compression method constructs the compressed video as a concatenation of compressed data sequences, such that each of the above sequences is compressed in one of the three modes described, or in just one mode.

[0067] The present invention will now be described using examples that are merely illustrative and do not in any way limit the scope of the invention, and with reference to the accompanying drawings that illustrate various figures. [Brief explanation of the drawing]

[0068] [Figure 1] This figure schematically and partially illustrates a method for compressing video according to one embodiment of the present invention.

[0069] [Figure 2a]This diagram schematically and partially illustrates the search for the best data sequence similar to the initial data sequence from the current data sequence and other data sequences. [Figure 2b] This diagram schematically and partially illustrates the search for the best data sequence similar to the initial data sequence from the current data sequence and other data sequences.

[0070] [Figure 2c] This figure schematically and partially shows the compression sequence obtained at the end of the examples in Figures 2a and 2b.

[0071] [Figure 3] This figure schematically and partially illustrates a method for projecting compressed video according to one embodiment of the present invention.

[0072] [Figure 4] Figure 3 is a schematic and partial diagram illustrating a vehicle lighting system that implements the method for projecting a dynamic lighting beam.

[0073] [Figure 5] This figure schematically and partially illustrates a method for decompressing a video compressed using the compression method of the present invention.

[0074] [Figure 6a] This figure schematically and partially illustrates the structure of a data block compressed in one mode as described, according to one embodiment of the present invention. [Figure 6b] This figure schematically and partially illustrates the structure of a data block compressed in one mode as described, according to one embodiment of the present invention. [Figure 6c] This figure schematically and partially illustrates the structure of a data block compressed in one mode as described, according to one embodiment of the present invention.

[0075] In the following description, elements that are identical in structure or function and appear in various diagrams will retain the same reference numerals unless otherwise specified.

[0076] Figure 1 shows a method for compressing the initial video V, illustrating a lighting scenario intended, for example, to be projected by an automobile.

[0077] First, the operation of the compression method will be disclosed through a sequence of steps that make it so. The method for compressing the initial video, as performed by a computing system, consists of the following steps: a. Step 1000 reads each image Pi from the initial video V, b. Step 2000 to compress each read image Pi in order to obtain a compressed image PCI, wherein the compression step comprises the following substeps: i. Substep 2001 reads the data from the read image Pi, called the current data DC. ii. A substep 2002 in which, from the set of data sequences of the read image Pi starting with the current data DC, a first data sequence S1 of the read image Pi, and from the set of preceding data sequences of the read image Pi and the set of data sequences of the preceding image Pi-1, a second data sequence S2 is selected, wherein the first data sequence S1 and the second data sequence S2 together maximize the data sequence similarity function φ. iii. A substep 2003 is included in which, depending on the length of the first data sequence S1 selected above, a third data sequence S3 containing the current data DC, or a compression sequence determined based on the length of the in-situ and the selected second data sequence S2, is added to the compressed image. iv. Each data read from the read image Pi is initially the first data of the read image Pi, and 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 data read, step 2000 and... c. Step 3000 to store each compressed image PCI in the memory of the computing system so as to form a compressed video VC. Includes.

[0078] Figures 2a and 2b show an example of the progression of step 2002, in which a first data sequence S1 of the read image Pi is selected from a set of data sequences of the read image Pi starting with the current data DC, and a second data sequence S2 is selected from a set of data sequences of the preceding image Pi-1, wherein the first data sequence S1 and the second data sequence S2 together maximize the data sequence similarity function φ.

[0079] As shown in Figure 2a, the set of preceding data sequences of the read image Pi from which the second data sequence S2 is searched consists of all data sequences of the read image Pi that begin with data preceding the read image Pi, whose position is at most a first default distance away from the position of the current data DC. In other words, the second sequence S2 is searched within the read image Pi from all sequences that are contained within a slide window of a default size and end with the current data DC. Thus, this second sequence S2 is the longest sequence that is contained within the slide window and has the highest similarity to sequence S1.

[0080] In the simplified example in Figure 2a, the longest data sequence S2 preceding the current data DC is sequence

[73] , while the first sequence S1 is sequence

[43] . These sequences are not identical, but they maximize the similarity function φ among all data sequences contained within a slide window of size 3. Thus, this results in a loss of information during compression, which allows for an improved compression rate while remaining acceptable compared to dictionary-based compression algorithms.

[0081] As shown in Figure 2b, the set of data sequences of the preceding image Pi-1, from which the second data sequence S2 is also searched, consists of all data sequences of the preceding image Pi-1 that begin with data located at a second predetermined distance, at the maximum and favorably equal to half the first distance from the current data DC. In other words, the second sequence S2 is also contained within a slide window of a predetermined size and searched within the preceding image Pi-1 from among all sequences centered on the current data DC. Thus, this second sequence S2 is the longest sequence contained within the slide window and has the highest similarity to sequence S1.

[0082] In the simplified example in Figure 2b, the longest data sequence S2 preceding the current data DC is sequence

[0470] , while the first sequence S1 is sequence

[0430] . These sequences are not identical, but the similarity function φ is separately maximized from all data sequences contained within a slide window of size 6.

[0083] Note that the search for the second sequence S2 is performed in each of the two sets to arrive at two intermediate data sequences, each of which maximizes a similarity function φ with respect to the set of sequences to which it belongs, and that the second sequence S2 is the sequence from among these two intermediate sequences that maximize the above function φ.

[0084] Therefore, in the examples in Figures 2a and 2b, the sequence selected for compression is

[0470] .

[0085] When performing this step, the calculation of the similarity function φ for each element of the set of data sequences of the image Pi read from the current data DC, and the set of data sequences of the preceding image Pi-1, takes into account the length l of the data sequences. In particular, it is possible to use the similarity function based on the similarity prediction expressed in equation [Equation 1].

[0086] In the examples in Figures 2a and 2b, the length l of the selected first sequence S1 is greater than 1. At the end of step 2003, the third sequence S3 added to the compressed image PCI therefore contains the original position and length of the selected second data sequence S2 in the preceding image PCI-1. Figure 2c shows an example of such a third sequence S3.

[0087] This third sequence S3 includes header H, which is, a. Decompression code H1 in 4-bit form, indicating both that sequence S1 is compressed relative to a second sequence S2, and the length of this sequence S2. b. A literal copy code H2, encoded in 1 bit, indicating that the last block of data sequence S3 should not be copied literally during decompression. c.1 bit is encoded, indicating that sequence S2 forms part of the preceding image PCI-1, target code H3. d.Includes a read direction code H4, encoded in 1 bits, indicating that sequence S2 is contained within image PCI-1 preceding to the left of the current data DC position.

[0088] This third sequence S3 also includes, after the header H, a block containing a position code O, which is coded into 9 bits and indicates the offset of the position of the second sequence S2 relative to the current data DC. Note that if the length of the second sequence S2 cannot be coded into 4 bits, this length can also be coded within other blocks of sequence S3 following the block containing code O.

[0089] Note that if sequence S2 forms part of the read image but not part of the preceding image, the reading direction code H4 is not necessary because sequence S2 is always located to the left of the current data DC. In this case, the original position code O can be coded to 10 bits.

[0090] Finally, if the length l of the selected first sequence S1 is equal to 1, the third sequence S3 added to the compressed image PCI will contain, firstly, the current data, along with a header indicating the number of blocks following the header containing the data to be copied during decompression.

[0091] It should also be noted that, if the length is still equal to 1, when the preceding third data sequence is compressed, it is possible to append a data block containing the existing current data literally to the end of this preceding third data sequence, by referring to the current image or the data sequence of the preceding image, for the preceding current data. In this case, the literal copy code H2 indicates that the last block of data sequence S3 should not be copied literally during decompression.

[0092] Figure 3 shows a method for projecting a dynamic lighting beam using the automotive lighting system 3.

[0093] Figure 4 shows this lighting system 3 for an automobile, which includes a memory 4 that stores compressed video 1.1, each containing multiple consecutive compressed images 2.1, each consisting of multiple data sequences, a control unit 5, and a lighting module 7, and implements the projection method described above.

[0094] Compressed video 1.1 may be compressed using, for example, the methods described in Figures 1 to 2c.

[0095] The method shown in Figure 3 involves the following steps: a. Step 1: Read each compressed image 2.1 from the compressed video 1.1 stored in memory 4. b. For each image read, the control unit 5 performs step 2, which involves decompressing the image using a dictionary-based decompression algorithm to obtain the decompressed image 2.2. c. The lighting module 7 projects a pixelated light beam 6 determined based on each decompressed image 2.2, which is part of step 3.

[0096] As shown in Figure 5, 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 was compressed while literally containing the original data, either by referring to the current image sequence or a preceding image sequence, as described above.

[0097] Figure 5 shows a decompression method that can be used in step 2 of the method in Figure 3 and allows decompression of video V compressed using the compression method described above. This decompression method consists of the following steps: a. Step 500 reads each compressed image from the compressed video, b. For each data sequence that matches the currently read compressed image, i. Substep 611 reads decompression codes 101, 201, and 301. ii. If the decompression codes 201, 301 are equal to values ​​indicating a second or third mode, and the header contains literal copy codes 202, 302 indicating the presence or absence of a first block, then substep 612.1 reads the above literal copy codes. iii. If the decompression codes 101, 201, and 301 are equal to a value indicating the first mode, in particular zero, and the data sequence contains a code for a number N1 that is coded into 4 bits, then substep 612.2 reads the above code for the number N1. iv. If decompression codes 201, 301 indicate a second or third mode, and the header contains target codes 203, 303 indicating a second or third mode, then substep 613.1 reads the target codes 203, 303. v. If the decompression codes 101, 201, and 301 indicate the first mode, substep 613.2 decompresses the above data sequence by copying the N1 block following the above code for the number N1 in the decompressed image. vi. If the target code 303 indicates a third mode, read the reading direction code 304 in substep 614.1. vii. If the decompression codes 201, 301 are equal to values ​​indicating a second or third mode, the length L obtained from the sum of each of the decompression codes 201, 301 and the data 205, 306 following the code for the original position is calculated in substep 615.1 until one of these blocks contains data equal to a default value, in particular zero. viii. Step 600 decompresses the currently read image according to substep 620, which decompresses the current data sequence in a mode specified by the set of codes used for decompression, c. The step 700 includes creating a decompressed video as a set of consecutive decompressed images, each obtained pixel by pixel as the sum of the last decompressed image and all previously decompressed images.

[0098] Figure 6a shows an example of a data sequence of a read image 100, including a decompression code 101 indicating a first mode and a code 102 for number N1, where these two codes form the header of the data sequence, specifically corresponding to the first byte of the data sequence.

[0099] The decompression code 101 is encoded using 4 bits, specifically 4 zero bits, to represent the number 0 in decimal.

[0100] The code for number N1 is encoded using four bits followed by four bits that encode the decompression code 101. In the example, the above code for number N1 corresponds to the number 0010 in binary, which corresponds to the number 2 in decimal. Thus, the encoded number N1 is equal to 3, which is obtained by adding one unit to the decimal number of the binary code formed by the previously identified four bits. Number N1 corresponds to the number of blocks, in particular the number of bytes, following the above code for number N1, which will be copied in the step of decompressing the read data sequence.

[0101] Figure 6b shows an example of a data sequence of a read image 200, including a decompression code 201, a literal copy code 202, a target code 203, and a locative code 204, indicating a second or third mode.

[0102] Therefore, when the header of the data sequence of the read image includes a decompression code 201 indicating a second or third mode, the sequence includes a position code 204 and codes 201, 205 for length L, and as a result, in the decompression step, the data sequence of the read image is decompressed in the second or third mode by adding L data to the decompressed image, which is added to the decompressed image or to a previously decompressed image from or up to the position, thereby adding to the image decompressed in the second or third mode.

[0103] In addition, when the header of the data sequence of the read image includes decompression codes 201, 301 indicating a second or third mode, in the decompression step, the length L is obtained by adding the value of the decompression code 201, for example 15, and the value of each of the data blocks 205 following the code for the original position 204, until one of these blocks contains data equal to a default value, and the set of blocks forms the codes 201, 205 for length L.

[0104] Therefore, when the header of the data sequence of the read image includes decompression codes 201, 301 indicating a second or third mode, the header includes literal copy codes 202, 302 indicating the presence or absence of the last block 206, 307 in the sequence, and as a result, in the decompression step, if the literal copy codes 202, 302 indicate the presence of the 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 additional data, for example 255, 255, and 237, i.e., 762 in total.

[0105] Therefore, when the header of the data sequence of the read image includes decompression codes 201, 301 indicating a second or third mode, the header includes target codes 203, 303 indicating a second or third mode. Advantageously, in the decompression step, the data sequence of the read image is decompressed in a second mode by adding L data to the decompressed image from the original position to the decompressed image, when the target code 203 has a first value, in particular a zero bit 200, for example, or in a third mode by adding L data to the decompressed image from the original position to a previously decompressed image, when the target code 203 has a second value, in particular a bit equal to 1.

[0106] When the header of the data sequence of the read image includes decompression codes 201, 301 indicating a second or third mode, the header also includes literal copy codes 202, 302 indicating the presence or absence of the last block 206, 307 in the sequence.

[0107] In the decompression step, if the literal copy codes 202 and 302 indicate the presence of the last block in the sequence, the last blocks 206 and 307 of the sequence are added to the decompressed image after the L additional data.

[0108] Figure 6c shows an example of a data sequence of a read image 300, including a decompression code 301, a literal copy code 302, a target code 303, a reading direction code 304, and a locating code 305, indicating a second or third mode.

[0109] Therefore, when the header of the data sequence of the read image includes a decompression code 301 indicating a second or third mode, the sequence includes a position code 305 and codes 301, 306 for length L, and as a result, in the decompression step, the data sequence of the read image is decompressed in the second or third mode by adding L data to the decompressed image, which is added to the decompressed image or to a previously decompressed image from or up to the position, thereby adding to the image decompressed in the second or third mode.

[0110] In addition, when the header of the data sequence of the read image includes a decompression code indicating a second or third mode, in the decompression step, the length L is obtained by adding the value of the decompression code, for example 15, and the value of each data block 205 following the code for the original position 305, until one of these blocks contains data equal to a default value, in particular zero, and the set of blocks forms the codes 301, 306 for length L.

[0111] Therefore, when the header of the data sequence of the read image includes a decompression code 301 indicating a second or third mode, the header includes a literal copy code 302 indicating the presence or absence of the last block 307 in the sequence, and as a result, in the decompression step, if the literal copy code 302 indicates the presence of the last block 307 in the sequence, the last block of the sequence 307 is added to the decompressed image at the end of the L additional data, for example 255, 255, and 237, i.e., 762 in total.

[0112] Therefore, when the header of the data sequence of the read image includes a decompression code 301 indicating a second or third mode, the header includes a target code 303 indicating a second or third mode. Advantageously, in the decompression step, the data sequence of the read image is decompressed in a second mode by adding L data to the decompressed image from the original position, when the target code 303 has a first value, particularly a zero bit, or in a third mode by adding L data to the decompressed image from or to a previously decompressed image leading up to the original position, when the target code 303 has a second value, particularly a bit equal to 1 in this example.

[0113] When the header of the data sequence of the read image includes a decompression code 301 indicating a second or third mode, the header includes a literal copy code 302 indicating the presence or absence of the last block 307 in the sequence, and in the decompression step, if the literal copy code 302 indicates the presence of the last block 307 in the sequence, the last block of the sequence is added to the decompressed image at the end of the L additional data.

[0114] When the header of the data sequence of the read image includes a target code 303 indicating a 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, the data sequence of the read image is decompressed in a third mode by adding L data to the decompressed image, which is to be added to the previously decompressed image, from the original position if the reading direction code 304 has a first value, in particular zero bits, or up to the original position if the reading direction code has another value, in particular bits equal to 1.

[0115] Referring again to Figure 3, each decompressed image obtained at the end of the method in Figure 5 forms a grayscale pixel matrix. Each pixel in this image can therefore be converted, for example, into a radiating setpoint in the form of a duty cycle, depending on its grayscale. This radiating setpoint can therefore control the basic light source of the illumination module 7, and the position of the illumination module 7 corresponds to the position of the corresponding pixel in the decompressed image. This basic light source therefore emits a basic light beam according to this radiating setpoint. The set of basic beams then forms a depiction of the decompressed image.

[0116] In any case, the present invention should not be considered limited to the embodiments specifically described herein, but in particular extends to any equivalent means and any technically feasible combination thereof.

Claims

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

2. A method for projecting a dynamic illumination beam using the automotive lighting system (3) according to claim 1, characterized in that each data sequence of the read image includes a header containing decompression codes (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 codes (101, 201, 301) contained in the header of the data sequence.

3. A method for projecting a dynamic illumination beam using an automotive lighting system (3) according to claim 2, characterized in that when the header of the data sequence of the read image includes a decompression code indicating the first mode, the data sequence includes a code for number N1 (102), and in the decompression step, the data sequence of the read image is decompressed in the first mode by adding the N1 data block following the code for number N1 to the decompressed image.

4. A method for projecting a dynamic illumination beam using an automotive lighting system (3) according to claim 2, wherein the header of the data sequence of the read image includes decompression codes (201, 301) indicating the second or third mode, the data sequence includes a location code (204, 305) and a code for length L (201, 205; 301, 306), and in the decompression step, the data sequence of the read image is decompressed in the second or third mode by adding the L data to the decompressed image which is added to a previously decompressed image or to the decompressed image from or to the location.

5. A method for projecting a dynamic illumination beam using an automotive lighting system (3) according to claim 4, characterized in that when the header of the data sequence of the image read includes decompression codes (201, 301) indicating the second mode or the third mode, the header of the data sequence and the codes (204, 305) for the original position together form a predetermined number of N2 data blocks, and in the decompression step, the original position is obtained from all the remaining data of the N2 data blocks from the header that form the codes for the original position.

6. A method for projecting a dynamic illumination beam using an automotive lighting system (3) according to claim 4, characterized in that, when the header of the data sequence of the image read includes decompression codes (201, 301) indicating the second mode or the third mode, in the decompression step, the length L is obtained from the values ​​of the decompression codes (201, 301) that form or part of the codes (201, 205; 301, 306) for the length L.

7. A method for projecting a dynamic illumination beam using an automotive lighting system (3) according to claim 6, characterized in that, when the header of the data sequence of the image read includes decompression codes (201, 301) indicating the second mode or the third mode, in the decompression step, the length L is obtained by adding the values ​​of the decompression codes (201, 301) and the values ​​of each of the data blocks (205, 306) following the codes (204, 305) for the original position until one of these blocks contains data equal to a predetermined value, the set of blocks forming the codes (201, 205; 301, 306) for the length L.

8. A method for projecting a dynamic illumination beam using an automotive lighting system (3) according to claim 4, characterized in that when the header of the data sequence of the image read includes decompression codes (201, 301) indicating the second or third mode, the header includes literal copy codes (202, 302) indicating the presence or absence of a last block in the data sequence, and in the decompression step, if the literal copy codes indicate the presence of a last block (206, 307) in the data sequence, the last block (206, 307) of the data sequence is added to the decompressed image at the end of the L data.

9. A method for projecting a dynamic illumination beam using an automotive lighting system (3) according to claim 4, 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, the data sequence of the read image is decompressed in the second mode by adding the L data added to the decompressed image from the original position to the decompressed image when the target code (203, 303) has a first value, or in the third mode by adding the L data added to the decompressed image from or to a previously decompressed image up to the original position to the decompressed image when the target code (203, 303) has a second value.

10. A method for projecting a dynamic illumination beam using an automotive lighting system (3) according to claim 9, wherein the header of the data sequence of the read image includes a target code indicating the third mode (303), the header includes a reading direction code (304) indicating the reading direction of data to be added to the decompressed image, and in the decompression step, the data sequence of the read image is decompressed in the third mode by adding L data to be added to the decompressed image, from the original position if the reading direction code (304) has a first value, or to the original position if the reading direction code (304) has another value.

11. A method for projecting a dynamic illumination beam using an automotive lighting system (3) according to claim 10, characterized in that for each defrosted image, the pixelated light beam (6) is determined based on the sum of the defrosted image and all previously defrosted images.

12. A method for compressing an initial video, performed by a computing system, the method comprising the following steps: a. A step (1000) of reading each image from the initial video, b. Compression step (2000) to obtain a compressed image, wherein each read image is compressed, and the following substeps are performed for each data read from the read image: i. A substep (2001) to read data from the image read, called the current data. ii. A substep (2002) in which a first data sequence of the read image is selected from a set of data sequences of the read image that begins with the current data, and a second data sequence is selected from a set of preceding data sequences of the read image and a set of data sequences of preceding images, wherein the first data sequence and the second data sequence together maximize a data sequence similarity function. iii. A substep (2003) in which, depending on the length of the first data sequence, a third data sequence containing the current data, or a compression sequence determined based on the lengths of the original position and the second data sequence, is added to the compressed image. Each data read from the image is the first data of the image, and each first data of the image is located after the last data of the first data sequence, step (2000). c. A method for compressing an initial video, performed by a computing system, comprising the step (3000) of storing each compressed image in the memory of the computing system so as to form a compressed video.

13. A method for compressing initial video, as performed by the computing system according to claim 12, characterized in that, 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 these data sequences, and a predetermined tolerance threshold for the difference.

14. A method for compressing an initial video, performed by a computing system according to claim 12, characterized in that the set of preceding data sequences of the read image from which the second data sequence is searched consists of all of the data sequences of the read image that begin with data preceding the image whose position is spaced at a maximum of a first predetermined distance from the position of the current data, and the set of preceding data sequences of the image from which the second data sequence is searched consists of all of the data sequences of the preceding image that begin with data whose position is spaced at a maximum of a second predetermined distance from the position of the current data.

15. A method for compressing initial video, performed by the computing system according to claim 12, characterized in that, for each current data, the third data sequence includes a header, the header includes decompression codes (101, 201, 301) indicating whether the third data sequence includes the current data or the compression sequence.

16. A method for compressing initial video, as performed by a computing system according to claim 15, characterized in that, if the decompression code (201, 301) indicates that the third data sequence includes the compression sequence, the third data sequence includes a code (204, 305) for the original position of the second data sequence, and a code (201, 205; 301, 306) for the length L of the second data sequence.

17. The compression step is performed for each current data according to the length of the first data sequence. a. Adding a third data sequence containing the current data to the compressed image, b. Adding a third data sequence to the compressed image, which includes a compression sequence determined based on the original position and the length of the second data sequence, or c. A method for compressing an initial video, performed by the computing system according to claim 15, characterized by comprising adding the current data to a third data sequence previously added to the compressed image.

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