FR3102628A1 - Image data management method and automotive lighting device - Google Patents

Abstract

The invention provides a method of managing image data in an automotive lighting device (10). This method comprises the steps of providing an image pattern (1), dividing the image pattern (1) into rows or columns of pixels (2), providing, for each row pattern (2), a plurality of line segments, compressing the data of the line segments and sending the compressed data to the lighting module. The invention also provides an automotive lighting device (10) for performing the steps of such a method.

Description

Image data management method and automotive lighting device

This invention is related to the field of automobile lighting devices, and more particularly to the management of electronic data derived from the control of lighting sources.

Current lighting devices include an increasing number of light sources that need to be controlled in order to provide adaptive lighting functionality.

This number of light sources implies a large amount of data, which must be managed by the control unit. The CAN protocol is often used, in some of its variants (CAN-FD is one of the most used) to transfer data between the PCM and the light module. However, some car manufacturers decide to limit the bandwidth of the CAN protocol, which affects management operations, which generally require around 5 Mbps.

Current compression methods are not very efficient for high beams, compromising the bandwidth reduction demanded by car manufacturers.

A solution to this problem is sought.

The invention provides a solution to these problems by means of an image data management method according to claim 1 and an automotive lighting device according to claim 7. Preferred embodiments of the invention are defined in dependent claims.

Unless otherwise defined, all terms (including technical and scientific terms) used in this document should be interpreted in accordance with the usages of the profession. It is also understood that terms in common use are to be construed as customary in the relevant art and not in an idealized or overly formal sense, except as expressly defined herein.

In this text, the term "includes" and its derivatives (such as "comprising", etc.) should not be understood in an excluding sense, i.e. these terms should not be interpreted as excluding the possibility that what is described and defined may include other elements, steps, etc.

• fournir un motif d'image comprenant une pluralité de pixels, dans lequel chaque pixel est caractérisé par un nombre lié à l'intensité lumineuse du pixel ;
• diviser le motif de l'image en rangées ou en colonnes de pixels, créant ainsi une pluralité de motifs de rangées ;
• fournir, pour chaque motif de ligne, une pluralité de segments linéaires, chaque segment linéaire fournissant une approximation linéaire d'un groupe de pixels ;
• compresser les données des segments linéaires ; et
• envoyer les données compressées au module d’éclairage.

In a first inventive aspect, the invention provides a method for managing image data in an automotive lighting device, the method comprising the following steps

• providing an image pattern comprising a plurality of pixels, wherein each pixel is characterized by a number related to the light intensity of the pixel;
• dividing the image pattern into rows or columns of pixels, thereby creating a plurality of row patterns;
• providing, for each line pattern, a plurality of line segments, each line segment providing a linear approximation of a group of pixels;
• compress line segment data; And
• send the compressed data to the lighting module.

This process aims to manage the image data that is exchanged between a control unit and a lighting module. The control unit is responsible for calculating the image pattern and the compression data, and can be located anywhere in the motor vehicle, not necessarily physically inside the lighting device. The lighting module is intended to provide a light pattern, either for illumination or for signaling, and is located inside the lighting device.

The main advantage of this method is the increase in the compression rate, due to the fact that the linear segments include a lower quantity of data than that of the original pixels replaced by this method, in particular when the pattern of the image is refers to a high beam pattern. The pseudo-Gaussian shape of the line patterns also contributes to the increased compression rate, as parts of the line pattern can be replaced by a linear approximation without significant loss of data.

In certain particular embodiments, the luminous pixels of the pattern of the image are pixels in gray scale, and more particularly, the luminous intensity of each pixel is according to a scale from 0 to 255.

Light modules typically define the light pattern on a gray scale, where the light intensity is graduated from 0 to 255. This is a way of quantifying the light pattern so that it can be converted into light data, and then transmitted and managed by the vehicle control unit.

In certain particular embodiments, each linear segment is defined by a start value, an end value and the number of pixels comprised between the start value and the end value.

It is a way to save data: for example, a string of n values is replaced by only 3 values: the value of the light intensity in the first pixel, the value in the last pixel and the number of pixels between the first and last pixel. If there are regions where a linear approximation is valid for a portion of 30 or 40 pixels, data registration is obvious.

In certain particular embodiments, the start value of the linear segment coincides with a first value of the group of pixels and the end value of the linear segment coincides with a last value of the group of pixels.

This is done to provide continuity between adjacent line segments.

In certain particular embodiments, the method further comprises the step of decompressing the compressed data.

This step is convenient when the original image is to be projected by the lighting module.

In some embodiments, the compressed data relates only to a particular part of the pattern of the image.

This cropping step is useful when a large part of the image is completely dark, so the compression step only focuses on the part that includes representative values.

In a second inventive aspect, the invention provides a lighting device comprising
- a lighting module comprising a plurality of light sources
- a control unit for carrying out the steps of a method according to the first inventive aspect.

This lighting device is able to operate with lower bandwidth than traditional devices.

In certain particular embodiments, the lighting module further comprises a processing unit, the processing unit being configured to decompress the compressed data.

With a decompression step in the appropriate lighting module, the bandwidth is reduced to the module itself.

In some particular embodiments, the light sources are solid-state light sources, such as LEDs.

The term "solid state" refers to light emitted by solid state electroluminescence, which uses semiconductors to convert electricity into light. Compared to incandescent lighting, solid state lighting creates visible light with reduced heat generation and energy dissipation. The generally low mass of a solid state electronic lighting device provides greater resistance to shock and vibration than brittle glass tubes/bulbs and long, thin filament wires. They also eliminate filament evaporation, which can increase the life of the lighting device. Some examples of these types of lighting include solid state light emitting diodes (LEDs), organic light emitting diodes (OLEDs) or polymer light emitting diodes (PLEDs) as lighting sources rather than electric filaments, plasma or gas.

To complete the description and to allow a better understanding of the invention, a set of drawings is provided. These drawings form an integral part of the description and illustrate one embodiment of the invention, which should not be interpreted as limiting the scope of the invention, but simply as an example of how the invention can be carried out. The drawings include the following figures:

shows a first image of the photometry of a high beam module which is projected by an automotive lighting device according to the invention.

shows part of a pixel matrix representing the photometry of [Fig 1].

shows a graphical representation of the row patterns of a method according to the invention.

shows a particular example of an error mapping of an image pattern which followed a method according to the invention.

shows an automotive lighting device according to the invention.

In these figures, the following reference numbers have been used:

1 Picture Pattern

11 Pixel of the image pattern

2 Row

4 Lighting module

5 LEDs

6 Control unit

7 Processing unit

10 Automotive lighting device

100 Motor vehicle

The exemplary embodiments are described in sufficient detail to enable those of ordinary skill in the art to understand and implement the systems and processes described herein. It is important to understand that embodiments may be provided in many alternative forms and should not be construed as being limited to the examples presented herein.

Accordingly, although the embodiment may be modified in various ways and take various alternative forms, specific embodiments thereof are shown in the drawings and described in detail below by way of example. It is not intended to be limited to the particular forms disclosed. Rather, all modifications, equivalents and alternatives falling within the scope of the appended claims are to be included.

shows a first image of the photometry of a high beam module which is to be projected by an automotive lighting device according to the invention.

This first image can be divided into pixels and each pixel can be characterized by its light intensity, on a scale ranging from 0, which would correspond to black, to 255, which would correspond to white.

shows a part of such a matrix of pixels, called image pattern 1. Each pixel 11 of this image pattern 1 is characterized by a number according to the aforementioned scale. Compression of this image pattern 1 according to commercially available software would offer a compression rate of less than 50%, which is unacceptable for certain automobile manufacturers.

In this image, the pixels are divided into 2 rows. Each pattern comprises a string of data, with numbers between 0 and 255, depending on the light intensity of the associated pixels.

shows a graphical representation of a line of one of these patterns. The horizontal axis represents row length and the vertical axis represents light intensity, on a scale of 0 to 255. In addition, there are 3 line segments that attempt to approximate the different groups of pixels.

Pixel data is replaced by line segment data, resulting in considerable data savings.

For example, in a group of 15 pixels, with a light intensity of 5 - 5.5 - 6 - 7 - 7.5 - 8 - 9 - 9.5 - 10 - 11 - 12 - 12.5 - 13 - 14 - 15, this data is replaced by the coordinates of a linear segment, which would be 5, 15, 15. With this data, the segment that would be interpreted by the light module would be 5 - 5.71 - 6.43 - 7.14 - 7.86 - 8.57 - 9.29 - 10 - 10.71 - 11.43 - 12.14 - 12.86 - 13.57 - 14.29 - 15. The maximum error would be 0.71 out of 256 (0.3%) and the average error would be 0.33 out of 256. Saving the data corresponds to sending 3 data instead of 15. The first value of the linear segment coincides with the first value of the pixel group and the last value of the linear segment coincide with the last value of the pixel group, in order to ensure continuity between adjacent linear segments.

shows a particular example of mapping of the errors of an image pattern which has been discretized, linearized, compressed, decompressed and converted into an image pattern, according to a method in accordance with the invention.

As can be seen in this example, the maximum error over the entire map is 5, and the average error is less than 2 (out of 256). This lossy process is quite acceptable, as it provides a light projection that meets the same rules as the original process.

Once these linearization steps are performed, the data is compressed, thus creating compressed data.

The compression rate of this data is much higher than if the same compression process was applied to the original. As a result, this compressed data can be sent to the lighting module under restrictive bandwidth conditions.

shows an automotive lighting device according to the invention, this lighting device comprising:
- a lighting module 4 comprising a plurality of LEDs 5;
- a control unit 6 to perform the compression steps described in the previous figures, generating the compressed data
- a processing unit 7, the processing unit 7 being configured to decompress the compressed data, this processing unit being located in the lighting module 4.

This lighting module would provide good quality projection with improved transmission bandwidth.

Claims (9)

A method of managing image data in an automotive lighting device (10), the method comprising the following steps
- providing an image pattern (1) comprising a plurality of pixels (11), in which each pixel is characterized by a number related to the light intensity of the pixel (11);
- dividing the pattern of the image (1) into rows or columns of pixels (2), thus creating a plurality of row patterns (2);
- providing, for each line pattern (2), a plurality of linear segments, each linear segment providing a linear approximation of a group of pixels;
- compress the data of the linear segments; And
- send the compressed data to the lighting module. Method according to Claim 1, in which the luminous pixels (11) of the image pattern (1) are grayscale pixels, and more particularly, the luminous intensity of each pixel (11) is characterized by a number according to a scale from 0 to 255. Method according to one of the preceding claims, in which each linear segment is defined by a start value, an end value and the number of pixels between the start value and the end value. A method according to claim 3, wherein the start value of the linear segment coincides with a first value of the group of pixels and the end value of the linear segment coincides with a last value of the group of pixels. Method according to one of the preceding claims, further comprising the step of decompressing the compressed data. Method according to one of the preceding claims, in which the compressed data is only linked to a particular part of the pattern of the image (1). Automotive lighting device (10) comprising:
- a lighting module (4) comprising a plurality of light sources (5); And
- a control unit (6) for carrying out the steps of a method according to one of the preceding claims. An automotive lighting device (10) according to claim 7, wherein the lighting module (4) further comprises a processor unit (7), the processor unit (7) being configured to decompress the compressed data. Automotive lighting device (10) according to one of the claims 7 or 8, in which the light sources (5) are solid-state light sources, such as LEDs.