JP7739449B2 - Method for managing video data and lighting device for a motor vehicle - Google Patents

Description

The present invention relates to the field of automotive vehicle lighting systems, and more particularly to the management of electronic data resulting from the control of lighting sources.

Current lighting devices have an increasing number of light sources that must be controlled to provide adaptive lighting functions.

This number of light sources inevitably entails a large amount of data that must be managed by the control unit. To transmit data between the PCM and the light module, the CAN protocol, in some of its variants (one of the most common is CAN-FD), is often used. However, some car manufacturers have decided to limit the bandwidth of the CAN protocol, which impacts management operations, which typically require around 5 Mbps.

Current compression methods are not very effective for high-beam patterns, which jeopardizes the bandwidth reductions demanded by automakers.

This problem is exacerbated by modern high-resolution modules, where the amount of information is much greater but the bandwidth limitations do not increase.

A solution to this problem is needed.

The present invention provides a solution to these problems by providing a method for managing video data in a lighting device of a motor vehicle, the method comprising:
- providing an image pattern comprising a plurality of pixels, each pixel being characterized by a numerical value related to the luminous intensity of said pixel;
dividing the image pattern into rows or columns of pixels to create a plurality of row patterns;
- providing a plurality of luminous intensity ranges, the numerical value for each pixel being contained within one and only one of the luminous intensity ranges, each luminous intensity range having a representative value;
- replacing the numerical value of each pixel by a representative value of the corresponding luminous intensity range, so that each pixel is characterized by a representative value;
- finding pixels having a representative value that is different from the representative values of their neighboring pixels, these pixels being sudden change pixels;
- providing for each row pattern a number of linear segments, each linear segment being contained between two abruptly changing pixels;
characterizing each linear segment by two characterization values;
- compressing the characterization values;
sending the compressed data to a write module;
This is achieved by a method that includes the following:

The method aims to manage video data exchanged between a control unit and a light module. The control unit is responsible for calculating the video pattern and compressed data and may be located anywhere in the motor vehicle (not necessarily physically inside the lighting device). The lighting module is intended to provide light patterns for either illumination or signaling and is located inside the lighting device.

The main advantage of this method is the increased compression ratio without significant loss of quality, due to the optimization of the localization of abruptly changing pixels. The method described above provides a fast and reliable way to extend a segment until the condition is no longer met. Thus, it results in a smaller amount of data compared to the original pixels replaced by the method, especially when the image pattern is called a high beam pattern. The quasi-Gaussian shape of the row pattern also contributes to the increased compression ratio, since there are some parts of the row pattern that can be replaced by a linear approximation without significant loss of data.

In some specific embodiments, each light pixel in the video pattern is a grayscale pixel, and more specifically, the luminous intensity of each pixel follows a scale from 0 to 255.

The light module typically defines a light pattern on a gray scale, where luminous intensity ranges from 0 to 255. This is a way to quantify the light pattern so that it can be converted into light data, which can then be transmitted and managed by the vehicle's control unit.

In some specific embodiments, the number of intensity ranges is between 4 and 20.

A smaller number of luminosity ranges will substantially improve compression ratios, as those ranges will have fewer abrupt transitions and more possibilities to be linearized with less loss. A larger number of luminosity ranges will improve quality and reduce data loss, but at the cost of a lower compression ratio.

In some particular embodiments, the step of finding the pixel in the preceding claims comprises:
a sub-step of finding all pixels having a representative value that differs from the representative values of their neighboring pixels;
a sub-step of selecting, for each row pattern, a group of relevant pixels by selecting only those pixels whose representative value differs from the representative values of their neighboring pixels in the same row pattern.

The number of abrupt change points is crucial to the balance between a high compression ratio but high data loss and a lower compression ratio but low data loss. When performing the step of finding a pixel with a different representative value from the representative values of its neighboring pixels, it may mean that the pixel in question has neighboring pixels in neighboring row patterns with different representative values. However, the entire row pattern may have the same representative value. If neighboring row patterns have a different representative value, it may result in all pixels in a row pattern being selected as abrupt change pixels, but this is not required. The substep of selecting relevant abrupt change pixels is useful because it reduces the number of abrupt change pixels (improving compression ratio) but without any further data loss, since all those abrupt change pixels in the same row pattern do not add any valuable information.

In some specific embodiments, the two characterization values are the numerical value of one of the abrupt change pixels that define the linear segment and the distance between the two abrupt change pixels that define the linear segment.

These two values are simply essential to define a linear approximation for the intensity values of each linear segment. Each abrupt change is chosen as a key point where the intensity gradient undergoes a substantial change. These abrupt changes are used to store these changes so that no image quality is lost. To recreate the linear approximation, it is sufficient to store the intensity value at the first abrupt change (the start of the linear segment) and the number of pixels to the next abrupt change (where the linear segment ends). The intensity value at the end of this linear segment is given by the intensity value of the next abrupt change, which is also stored because it is the start of the next linear segment. This saves data and improves compression.

In some specific embodiments, all of the luminous intensity ranges have the same size.

Thus, the model is consistent, as all sudden change points are picked out by the equivalence criterion.

In some specific embodiments, the method further comprises decompressing the compressed data.

This step is useful if the original image should be projected by the light module.

In some specific embodiments, the compressed data is associated only with specific portions of the video pattern.

This clipping step is useful when large parts of the image are completely dark, so that the compression step only focuses on the parts that contain representative values.

In a second inventive aspect, the present invention provides a method for producing a method of manufacturing a semiconductor device comprising:
a light module comprising a plurality of light sources;
a control unit for carrying out the steps of the method according to the first inventive aspect;
The present invention provides a lighting device comprising:

This lighting device can operate at a narrower bandwidth than conventional devices.

In some specific embodiments, the light module further comprises a processor unit, the processor unit configured to decompress the compressed data.

By using a decompression stage in the appropriate light module, the bandwidth is narrowed all the way up to the module itself.

In some specific embodiments, the light source is a solid-state light source, such as an LED.

The term "solid state" refers to light emitted by solid-state electroluminescence, which uses semiconductors to convert electrical power into light. Compared to incandescent lighting, solid-state lighting generates less heat and dissipates less energy to produce visible light. The generally smaller bulk of solid-state electronic lighting devices makes them more resistant to shock and vibration than brittle glass tubes/bulbs or long, thin filament wires. They also eliminate filament evaporation, potentially extending the life of the light-emitting device. Some examples of these types of lighting use semiconductor light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), or polymer light-emitting diodes (PLEDs) as the light source, rather than electric filaments, plasmas, or gases.

Unless otherwise defined, all terms (including technical and scientific terms) used herein should be interpreted in a manner customary in the relevant art. Furthermore, terms of general usage should also be interpreted in a manner customary in the relevant art, and should not be interpreted in an idealized or overly formal sense unless expressly defined herein.

In this text, the term "comprises" and its derivatives (e.g., "comprising") should not be construed in an exclusive sense; that is, these terms should not be interpreted to exclude the possibility that what is being described or defined may include additional elements, steps, etc.

To complete this specification and to provide a better understanding of the present invention, a series of drawings are provided. The drawings form an integral part of this specification and illustrate embodiments of the present invention, but should not be construed as limiting the scope of the invention, but merely as an example of how the invention may be practiced. The drawings include the following figures:

3 shows a first image of the photometric values of a high beam module projected by a lighting device of a motor vehicle according to the invention; FIG. 10 is a diagram showing a portion of a pixel matrix representing an example of photometric values. 1 shows a row pattern illustration of the method according to the invention; 1A-1C illustrate some steps of the method according to the invention; FIG. 4 shows the result of the linearization step when the method according to the invention is used; 1 shows a lighting device for a motor vehicle according to the present invention;

The following reference symbols are used in these figures:

1. Image pattern 2. Line pattern 3. Image pattern pixels 4. Light module 5. LED
6 Control unit 7 Processor unit 8 Representative value 9 Boundary 10 Lighting device of motor vehicle 11 Sudden change pixel 100 Motor vehicle

The exemplary embodiments are described in sufficient detail to enable those skilled in the art to implement and practice the systems and processes described herein. It is important to understand that each embodiment may be provided in many alternative forms and should not be construed as limited to the examples set forth herein.

Accordingly, while the embodiments may be modified in various ways and may take various alternative forms, specific embodiments thereof are shown by way of example in the drawings and are described in detail below. There is no intention to limit the embodiments to the particular forms disclosed. On the contrary, all modifications, equivalents, and alternatives falling within the scope of the appended claims should be embraced.

Figure 1 shows an initial image of the photometric values of a high beam module projected by a lighting device for a motor vehicle according to the present invention.

This initial image can be divided into pixels, each of which can be characterized by its luminous intensity on a scale from 0 (which would correspond to black) to 255 (which would correspond to white).

Figure 2 shows a portion of such a pixel matrix (called Image Pattern 1). Each pixel 3 of this Image Pattern 1 is characterized by a number according to the scale described above. Compression of this Image Pattern 1 using commercially available software products would result in a compression ratio of less than 50%, which is unacceptable to some automobile manufacturers.

In this image, the pixels are divided into row patterns 2. Each pattern has a set of data (numbered between 0 and 255) corresponding to the luminous intensity of the associated pixel. Obviously, these pixel values are a simplified example chosen solely for the purpose of enhancing understanding of the invention, and do not correspond to the luminous intensity of the light patterns in Figure 1.

3 shows a further step in the method according to the invention, in which a number of luminous intensity ranges are provided for quantizing the original luminous intensity values. As a result, the original luminous intensity value of each pixel is replaced by a representative value of 8. Each pixel is therefore now characterized by a single representative value of 8. In the original photometric pattern, each pixel could take any value between 0 and 255. However, after this step, the luminous intensity values can be, for example,
- 0 to 31 (the typical value is set to 16),
- 32 to 63 (the typical value is set at 48),
- 64 to 95 (the typical value is set at 80),
- 96 to 127 (the typical value is set at 112),
- 128 to 159 (the typical value is set to 144),
- 160 to 191 (the typical value is set at 176),
- 192 to 223 (the typical value is set at 208), and
- 224 to 255 (the typical value is set to 240),
They are classified into eight different ranges.

Here, instead of 256 different values, only eight different representative values are allowed, and any pixel can have one of these eight representative values: 16, 48, 80, 112, 144, 176, 208, or 240.

Figure 4 shows the quantized map of the light pattern after this step has been performed. This figure corresponds to the light map of Figure 1, but after it has been quantized into 10 different luminous intensity ranges.

This quantization step is performed solely to find the optimal turning points for linearizing the original light map. The quantized map is not sent to the lighting device for projection, but is only used as an intermediate step.

Each quantized portion has a boundary 9. The boundary 9 is defined by pixels whose representative values are different from the representative values of adjacent pixels.

However, it turns out that this is a fairly large number of pixels. It is advantageous to reduce the number of pixels and select the most relevant ones. This is done by selecting, for this group of abruptly changing pixels, only those pixels whose representative value differs from the representative value of their neighbors in the same row.

Figure 5 shows the selected abrupt change pixels 11. These pixels will be used to linearize the original light pattern (not the quantized version, which is calculated only to obtain the abrupt change points).

Once the abrupt change points are found, multiple linear segments are defined for each row. In other words, each row is divided into multiple linear segments. Each linear segment is defined by a start pixel and an end pixel. As a result, the number of pixels is known (the number of pixels between the start pixel and the end pixel). Therefore, since all segments are contiguous and span the entire row, the start value and the number of pixels are sufficient to define a segment, since the end value will be the same as the start value of the next segment. Therefore, only two values are needed to define each segment. The abrupt change points are selected as the starting points for every segment. As a result, for each row, there will be as many linear segments as there are abrupt change points in this row.

Particular embodiments of the method of the present invention may include calculating the gradient for each pixel in this row pattern.

Only these two values per segment are sent to the lighting device to recreate a linear pattern that will be an approximation of the original light pattern shown in Figure 1.

6 shows a lighting device for a motor vehicle according to the invention, which comprises:
a light module 4 equipped with a number of LEDs 5;
a control unit 6 for carrying out the stages of compression described in the previous figures to produce compressed data;
a processor unit 7 adapted to decompress the compressed data;
This processor unit is located in the light module 4.

This light module will achieve superior quality projection with improved transmission bandwidth.

Claims (9)

A method for managing video data in a lighting device (10) of a motor vehicle, comprising:
- providing an image pattern (1) comprising a plurality of pixels (3), each pixel being characterized by a numerical value related to the luminous intensity of said pixel (3);
- dividing said image pattern (1) into rows or columns of pixels (2) to create a plurality of row patterns (2);
providing a plurality of luminous intensity ranges, the numerical value for each pixel being contained within one and only one of the luminous intensity ranges, each luminous intensity range having a representative value;
- replacing the numerical value of each pixel by the representative value of the corresponding luminous intensity range, so that each pixel is characterized by a representative value;
- finding all pixels having a representative value of a pixel that is different from the representative values of the neighboring pixels, these pixels being sudden change pixels;
- dividing each row pattern into a plurality of linear segments , each linear segment being defined between two adjacent abrupt-changing pixels;
characterizing each linear segment by only two characterization values;
compressing said characterization values;
sending the compressed data to a write module;
Equipped with
A method in which the pixels at both ends of each linear segment are called the start pixel and the end pixel, respectively, and the two characterizing values that characterize each linear segment are a representative value of the start pixel and the number of pixels between the start pixel and the end pixel . The method of claim 1, wherein each light pixel (3) of the image pattern (1) is a grayscale pixel, and more particularly, the luminous intensity of each pixel (3) is characterized by a number according to a scale from 0 to 255. The method of claim 1 or 2, wherein the number of luminous intensity ranges is between 4 and 20. 4. The method of claim 1 , wherein all of the luminous intensity ranges have the same magnitude. The method of claim 1 , further comprising the step of decompressing the compressed data. 6. The method according to any one of claims 1 to 5 , wherein the compressed data is associated only with a specific part of the video pattern (1). a light module (4) equipped with a number of light sources (5),
- a control unit (6) for carrying out the steps of the method according to any one of claims 1 to 6 ;
A lighting device (10) for a motor vehicle comprising: 8. The lighting device (10) for a motor vehicle according to claim 7 , wherein the light module (4) further comprises a processor unit (7), the processor unit (7) being configured to decompress the compressed data. 9. A lighting device (10) for a motor vehicle according to claim 7 or 8 , wherein the light source (5) is a solid -state light source.