Software control method for vehicle-mounted dynamic projection

Abstract

This invention provides a software control method for in-vehicle dynamic projection. The method includes: pre-distorting media data on a mobile device; activating a second wireless communication link (e.g., Wi-Fi) of the in-vehicle projection module via a first wireless communication link (e.g., BLE) and obtaining connection credentials; after establishing the second wireless communication link, transmitting the processed media data to the in-vehicle projection module via a secure file transfer protocol (e.g., FTPS); and the in-vehicle projection module receiving real-time control commands via the first wireless communication link and controlling the digital projection unit to perform projection playback. This invention achieves both low-power control and high-bandwidth data transmission through a dual-link communication strategy; ensures projection quality through pre-distortion processing on the mobile device; and ensures data interaction security by introducing a secure file transfer protocol and multiple encryption mechanisms.

Description

Technical Field

[0001] This invention relates to the field of vehicle electronics technology, specifically to a software control method for vehicle-mounted dynamic projection, and more particularly to a software control method for a vehicle-mounted dynamic door control light projection system. Background Technology

[0002] With the development of intelligent and connected vehicles, smart cockpits have become the core of enhancing the user's driving experience. In order to create a more personalized and technologically advanced in-vehicle environment, various in-vehicle display and interactive technologies have emerged, among which in-vehicle projection technologies, such as welcome light carpets and dynamic door control lights, have received widespread attention.

[0003] Existing in-vehicle projection systems typically have pre-set content at the factory. Some solutions attempt to update the content by wirelessly connecting mobile devices like smartphones to the system. However, in terms of security, the communication link between the in-vehicle system and external devices is vulnerable to attack. Without effective security mechanisms, transmitted media data or control commands could be eavesdropped on or tampered with, potentially leading to user privacy breaches and posing security risks to the normal operation of the vehicle system.

[0004] Therefore, how to implement a control method that allows users to safely transmit and update in-vehicle projection content is a technical problem that urgently needs to be solved in the current field. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the purpose of this invention is to provide a software control method for vehicle-mounted dynamic projection.

[0006] A software control method for vehicle-mounted dynamic projection according to the present invention includes the following steps: On mobile devices, the media data used for projection is pre-distorted to compensate for projection distortion of the in-vehicle projection module. On the mobile device, a command is sent to the vehicle projection module via a first wireless communication link to activate the second wireless communication link of the vehicle projection module; wherein, the power consumption of the first wireless communication link is lower than that of the second wireless communication link; On the mobile device, a connection credential for establishing the second wireless communication link is obtained from the vehicle projection module via the first wireless communication link. On the mobile device, after establishing the second wireless communication link with the vehicle projection module, the pre-distorted media data is transmitted to the vehicle projection module through a secure file transfer protocol. At the vehicle-mounted projection module, real-time control commands from the mobile device are received via the first wireless communication link, and the projection playback is controlled according to the real-time control commands. The media data is read from the memory and projected and played at a predetermined frame rate through the digital projection unit at the in-vehicle projection module.

[0007] Preferably, the first wireless communication link is a Bluetooth BLE link, and the second wireless communication link is a Wi-Fi link.

[0008] Preferably, the secure file transfer protocol is the FTPS protocol, and a secure channel for transmitting the media data is established through the TLS handshake protocol.

[0009] Preferably, the pre-distortion processing is trapezoidal correction processing, which preprocesses the media data according to preset calibration data.

[0010] Preferably, the real-time control command is used to perform at least one of the following operations on the projection: speed adjustment, brightness adjustment, playback mode switching, content switching, reversing, and pausing.

[0011] Preferably, during the BLE pairing process between the mobile device and the vehicle projection module, a random verification step based on the advanced encryption standard HMAC-SHA256 is included to verify the user's identity.

[0012] Preferably, the software control method further includes: receiving firmware update packages via the secure file transfer protocol at the vehicle-mounted projection module end, and implementing firmware updates using an A / B partitioning mechanism.

[0013] Preferably, the digital projection unit includes a digital micromirror device (DMD) chip; The software control method further includes: detecting the power supply voltage at the vehicle projection module end, and resetting the DMD chip when the power supply voltage is detected to be lower than a preset threshold.

[0014] Preferably, the steps performed on the vehicle-mounted projection module are scheduled by a software system based on a real-time operating system.

[0015] Preferably, after establishing the BLE pairing connection based on JustWorks, a BLEGATT broadcast verification service is provided at the application layer. The BLE GATT broadcast verification service includes a random number attribute, an HMAC-SHA256 ciphertext attribute, and a verification status attribute. When the projection module starts up, it randomly generates 32 bytes of data and sends it to the mobile device through the BLE GATT broadcast verification service. The mobile device receives the HMAC-SHA256 ciphertext calculated and fed back based on the 32 bytes of data, and performs a validity verification on the HMAC-SHA256 ciphertext to determine the legitimacy of the current BLE connection user.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention constructs a multi-layered security protection system, employing encrypted pairing verification on the low-power control link and a secure file transfer protocol on the high-bandwidth data link, ensuring the security of the entire process from device connection to data transmission and effectively preventing unauthorized control and data leakage.

[0017] 2. By combining mobile devices and utilizing a dual wireless communication link strategy, this invention enables convenient and efficient customization of personalized content. Users can easily transmit media data to the vehicle projection module at high speed and complete pre-distortion processing on the mobile device, simplifying the processing logic on the vehicle side and achieving a "what you see is what you get" projection effect.

[0018] 3. By employing a real-time operating system, A / B partitioning mechanism for firmware updates, and undervoltage protection for core hardware, this invention ensures the long-term stable and reliable operation of the vehicle projection module in complex vehicle environments, significantly improving the system's reliability and robustness. Attached Figure Description

[0019] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a software system architecture diagram of an in-vehicle projection module provided in an embodiment of the present invention.

[0020] Figure 2 This is a flowchart illustrating the secure file transfer process between a mobile device and an in-vehicle projection module, as provided in an embodiment of the present invention.

[0021] Figure 3 A flowchart of a software control method for vehicle-mounted dynamic projection provided in an embodiment of the present invention.

[0022] Figure 4 This is a structural block diagram of an in-vehicle projection module provided in an embodiment of the present invention.

[0023] The diagram shows: Vehicle-mounted projection module 100; processor 110; memory 120; digital projection unit 130; first wireless communication interface 140; second wireless communication interface 150. Detailed Implementation

[0024] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0025] Example 1 like Figure 1 The diagram shows the software system architecture of the vehicle-mounted projection module in this embodiment. This architecture mainly includes a main control module, a DLP control module, a FOTA module, a BLE & Wifi control module, and a memory management and file system module. The main control module is responsible for the initialization, resource allocation, and task scheduling of the entire system. The BLE & Wifi control module manages the establishment, maintenance, and data exchange of the two wireless communication links. The DLP control module is responsible for parsing and playing media data and controlling the physical projection behavior of the digital projection unit. The FOTA module provides the ability to upgrade firmware online, while the memory management and file system modules are responsible for the efficient and reliable management of data in the non-volatile memory. This modular design achieves functional decoupling, improving the stability and maintainability of the system.

[0026] like Figure 2 The diagram shows the workflow of interaction between a mobile application and an in-vehicle projection module. The entire process can be divided into the first wireless communication link communication stage, the second wireless communication link connection stage, the secure file transfer protocol channel establishment stage, and the user request processing stage.

[0027] First, during the initial wireless communication link phase, the mobile device establishes a connection with the vehicle-mounted projection module via the first wireless communication link, performing authentication and an initial handshake. Then, during the second wireless communication link connection phase, the mobile device obtains credentials for connecting to the second wireless communication link via the first wireless communication link and establishes a high-bandwidth connection. Next, during the secure file transfer protocol channel establishment phase, both parties establish an encrypted data transmission channel using a secure file transfer protocol. Finally, during the user request processing phase, the user can perform operations such as uploading media data and sending real-time playback control commands through the mobile device's application interface. This design, which separates control signaling and media data for transmission on different links, ensures both low latency and high real-time performance of control commands while meeting the high bandwidth requirements for large file transfers, thus optimizing the overall system performance.

[0028] like Figure 3 As shown in the figure, this embodiment provides a software control method for vehicle-mounted dynamic projection, and its specific process is as follows.

[0029] In step S301, the media data used for projection is pre-distorted on the mobile device. This step aims to pre-compensate for projection distortion inevitably introduced by the vehicle projection module due to its installation position and angle on the vehicle body (e.g., projecting onto the ground from the bottom of the door). This pre-distortion processing ensures that the image or video finally projected onto the target surface (such as the ground) is free of geometric distortion, thereby improving the viewing experience.

[0030] In step S302, on the mobile device, a command is sent to the vehicle-mounted projection module via the first wireless communication link to activate the second wireless communication link of the vehicle-mounted projection module. In this design, the first wireless communication link is typically in a low-power standby or broadcast state, while the higher-power second wireless communication link is disabled by default to save power. It is only activated by the mobile device when a large amount of data transmission is required. This design effectively reduces the overall power consumption of the vehicle-mounted projection module in standby mode.

[0031] In step S303, on the mobile device, connection credentials for establishing the second wireless communication link are obtained from the vehicle-mounted projection module via the first wireless communication link. These credentials typically include information such as the network name (SSID) and password. Transmitting this connection information via the first wireless communication link simplifies the user's operation process, eliminating the need for the user to manually search for and enter the network password, thus achieving a seamless network switching experience.

[0032] In step S304, after successfully establishing the second wireless communication link with the vehicle-mounted projection module, the mobile device transmits the pre-distorted media data to the vehicle-mounted projection module via a secure file transfer protocol. Using a high-bandwidth second wireless communication link significantly shortens the transmission time of large media files, while the secure file transfer protocol ensures the confidentiality and integrity of the data during transmission, preventing eavesdropping or tampering.

[0033] At the vehicle-mounted projection module, the tasks of receiving and responding to commands are performed in parallel. In step S305, the vehicle-mounted projection module continuously receives real-time control commands from the mobile device through the first wireless communication link. These commands have small data volumes and high real-time requirements, such as playback, pause, and content switching, and are therefore very suitable for transmission through the low-power, low-latency first wireless communication link.

[0034] In step S306, the vehicle-mounted projection module, in response to the received instruction, reads the media data received and stored in step S304 from its internal memory and projects it through the digital projection unit at a predetermined frame rate. This step completes the conversion from digital media to optical images, realistically projecting user-defined content and realizing the core function of software-defined projection.

[0035] In a preferred embodiment, the first wireless communication link can be a Bluetooth Low Energy (BLE) link, while the second wireless communication link can be a Wi-Fi link. BLE technology is known for its extremely low power consumption, fast connection establishment, and robust short-range communication capabilities, making it ideal for transmitting real-time control commands and executing handshake protocols between devices. Wi-Fi technology offers significantly higher data transmission rates, making it ideal for transmitting large amounts of media data such as high-definition video. By combining BLE and Wi-Fi, this invention achieves an excellent balance between system response speed, data transmission efficiency, and energy management.

[0036] To further enhance data transmission security, the secure file transfer protocol can be specifically implemented as a File Transfer Protocol (FTPS) supporting Transport Layer Security (TLS). Before media data transmission, a TLS handshake process is performed between the mobile device and the in-vehicle projection module. This process negotiates cipher suites, exchanges certificates, and generates session keys, thereby establishing an encrypted secure channel on the second wireless communication link. All subsequent media data will be transmitted within this encrypted channel, effectively preventing man-in-the-middle attacks, data eavesdropping, and content tampering, ensuring the privacy and security of user data. In other embodiments, the FTPS protocol can be used instead of the HTTPS Hypertext Transfer Protocol.

[0037] Building upon the above embodiments, to ensure the exclusivity and security of the connection, a random verification step based on the advanced encryption standard HMAC-SHA256 can be added during the pairing process of the first wireless communication link between the mobile device and the vehicle-mounted projection module. Specifically, during pairing, one party generates a random number and sends it to the other party. The receiving party encrypts the random number using a pre-shared HMAC-SHA256 key and returns the encryption result. The sending party performs the same encryption operation and compares the results. Only when the results match can the other party be confirmed as a legitimate and authorized user device, and the connection can be established. This mechanism effectively prevents unauthorized devices from connecting to the vehicle-mounted projection module, enhancing the exclusivity and security of the system.

[0038] Specifically, after establishing a connection based on Justworks, BLE pairing adds a BLE GATT broadcast verification service at the application layer specifically for verifying user identity. The BLE GATT broadcast verification service includes three attributes: a random number, HMAC-SHA256 ciphertext, and verification status. When the projection module starts up, it randomly generates 32 bytes of data and sends it to the mobile device via the BLE GATT broadcast verification service. Upon receiving the data, the mobile device calculates and generates HMAC-SHA256 ciphertext and sends it back to the projection module. The module then verifies the validity of the ciphertext to determine the legitimacy of the current BLE connection user.

[0039] Furthermore, the pre-distortion processing can be specifically a geometric transformation process based on calibration data. For example, when a vehicle-mounted projection module is installed at a certain tilt angle, the projected image will appear trapezoidal if no correction is performed. In this case, the pre-distortion processing is a trapezoidal correction process. The application on the mobile device uses a geometric transformation algorithm to perform inverse geometric distortion on each frame of the image or video to be transmitted, based on pre-stored or communication-acquired calibration data (which describes the precise installation position, pitch angle, and yaw angle of the vehicle-mounted projection module, etc.). This preprocessing ensures that the image after tilted projection can be restored to a standard rectangle on the target surface, thereby achieving precise compensation for projection distortion and ensuring excellent visual effects.

[0040] To provide a rich human-vehicle interaction experience, the real-time control commands can be used to achieve various fine-grained operations on the projection. As a specific implementation, these commands may include: controlling the playback speed of the projected content, such as slowing down at 0.5x or fast-forwarding at 2x; adjusting the brightness of the projected image in stages to adapt to different ambient lighting conditions; switching playback modes, such as looping or single playback; switching between multiple stored media files; and even implementing advanced playback controls such as reversing and pausing. These commands are transmitted via a low-power, low-latency first wireless communication link, enabling the in-vehicle projection module to respond almost instantaneously, providing users with a smooth and flexible control experience.

[0041] To ensure smooth playback of dynamic video content, the predetermined frame rate is set to no less than 25 frames per second (fps). 25 fps is a common standard for ensuring continuous video playback without noticeable stuttering. Upon receiving a playback command, the DLP control module within the vehicle-mounted projection module reads video frame data from memory at a rate no less than this frame rate and drives the digital projection unit to refresh. This design ensures a smooth and natural projection effect even when the user uploads highly dynamic video content.

[0042] The method in this embodiment also includes a firmware over-the-air (FOTA) upgrade process. Specifically, at the vehicle projection module, new firmware update packages can be received from mobile devices or remote servers through the aforementioned established secure file transfer protocol channel. To ensure the security and reliability of the update process, the vehicle projection module's memory employs an A / B partitioning mechanism. The system has two independent system partitions (e.g., partition A and partition B), with the currently running partition being the active partition. Upon receiving a new firmware package, the system writes it to the inactive partition. On the next power-on boot, the bootloader attempts to boot from the partition containing the new firmware. If the new firmware boots successfully, that partition becomes the new active partition; if booting fails, the bootloader automatically rolls back and restarts from the original partition. This mechanism ensures that even if the firmware upgrade fails, the system can recover to its previous stable state, avoiding the risk of the device becoming unusable and improving the system's robustness.

[0043] Specifically, the A / B partitioning mechanism firmware upgrade method runs on the vehicle projection module. The module's storage medium is divided into at least one first application partition and at least one second application partition. When the module starts up, the bootloader reads the first version sorting index and the second version sorting index associated with the first application partition and the second application partition, respectively. Based on a preset sorting rule, it selects and loads the firmware in the application partition whose version sorting index represents the updated version. After the new firmware is written to the inactive application partition and verified successfully, the version sorting index associated with the inactive application partition is updated so that it represents a later or newer version than the version sorting index of the currently active application partition under the preset sorting rule. Then, the status of the inactive application partition is updated to be valid.

[0044] To protect the core hardware from damage, this embodiment also introduces a hardware protection mechanism. Specifically, the core of the digital projection unit can be a digital micromirror device (DMD) chip, which has high requirements for the stability of the power supply voltage. Therefore, a voltage detection circuit is integrated into the vehicle projection module to monitor the system's power supply voltage in real time. When the power supply voltage is detected to be lower than a preset threshold (e.g., 10V), the main control module immediately sends a reset signal to the DMD chip. This operation can put the DMD chip into a safe state before it malfunctions due to undervoltage or suffers permanent damage, thereby significantly extending the lifespan of the core projection device and improving hardware reliability.

[0045] To ensure system stability and real-time performance in a multi-tasking environment, all steps executed on the vehicle-mounted projection module are scheduled by a software system based on a real-time operating system (RTOS). In this embodiment, the lightweight FreeRTOS can be used. Upon system startup, the main control module initializes system resources based on the RTOS kernel and creates independent tasks with different priorities for functions such as projection playback, wireless communication, and system status monitoring. The RTOS kernel is responsible for efficient context switching and priority scheduling between these tasks, ensuring high-priority responses to real-time control commands from mobile devices while guaranteeing the smooth operation of time-consuming tasks such as background data transmission and video decoding, thus achieving parallel task processing and overall system stability.

[0046] Specifically, the real-time operating system is based on FreeRTOS and is divided into BLE communication management tasks, WIFI communication management tasks, system management tasks, and DMD projection tasks. Among them, the DMD projection task is set to the highest priority to achieve real-time output of DMD projection content.

[0047] like Figure 4 As shown, this embodiment also provides a hardware structure for an in-vehicle projection module 100. The in-vehicle projection module 100 includes, but is not limited to, one or more processors 110, a memory 120, a digital projection unit 130, a first wireless communication interface 140, and a second wireless communication interface 150. The processor 110 may be a microcontroller (MCU), a system-on-a-chip (SoC), or other chip with computing capabilities, serving as the control core of the entire module. The memory 120 is used to store execution instructions and user data. The digital projection unit 130 is responsible for converting digital image signals into optical images and projecting them. The first wireless communication interface 140 and the second wireless communication interface 150 are respectively used to implement the aforementioned first and second wireless communication links.

[0048] During operation, the processor 110 is configured to execute computer program instructions stored in the memory 120 to implement all or part of the functions described in the foregoing method. Specifically, the processor 110 receives instructions from the mobile device through a first wireless communication interface 140 and establishes a connection through a second wireless communication interface 150 according to the instructions; it receives media data via a secure file transfer protocol through the second wireless communication interface 150 and stores it in the memory 120; simultaneously, it receives real-time control instructions through the first wireless communication interface 140 and ultimately responds to these instructions to control the digital projection unit 130 to read data from the memory 120 for projection.

[0049] Example 2 Those skilled in the art can understand this embodiment as a more specific description of Embodiment 1.

[0050] like Figure 1 As shown, this embodiment provides a software control method for a vehicle-mounted dynamic door control light projection system, including: The DLP control module can read stored video or image data and play it at a frame rate of at least 25fps. It also accepts control signals from BLE to adjust the playback speed, screen brightness, playback mode, and switch images or videos. It supports reverse playback and pause functions. The DLP control module also implements an undervoltage detection function, which resets the DMD (Digital Micromirror Device) chip when a low voltage is detected to protect the DMD from damage.

[0051] The BLE & Wifi control module integrates the BLE protocol stack and the Wifi protocol stack, along with their corresponding firmware. BLE pairing adds a random verification function using the advanced encryption standard HMAC-SHA256 to verify user identity, enhancing exclusivity and security. The Wifi is compatible with 2.4G and 5G signals, supports over 110 country codes, achieves a peak transmission rate of 10Gb / s, and implements FTPS functionality, enhancing channel security through TLS handshake. Users can view, upload, download, and delete image or video data and related information via FTPS.

[0052] The FOTA module (Firmware Over The Air) implements A and B partitioning functions, uploads the APP and firmware via FTPS, and runs the updated APP and firmware upon power-on.

[0053] The memory management and file system module manages NOR Flash and Nand Flash through address mapping; at the same time, it implements LFS based on Nand Flash to reduce internal fragmentation and improve space utilization for storing image or video data.

[0054] The main control module, based on FreeRTOS, initializes system resources, creates DLP, BLE, Wi-Fi, and System Control tasks, and implements task parallelism and scheduling.

[0055] APK programs for mobile devices (such as Figure 2The APK program of the mobile device implements BLE communication and FTPS transmission functions, and integrates image data conversion algorithm and keystone correction algorithm. It is compatible with various image and video formats, resolutions and frame rates, and automatically performs keystone correction on image data based on the calibrated data of the four corner points. This data is calibrated according to the actual projection effect on site.

[0056] The software control scheme in this embodiment integrates a DMD chip and BLE and Wi-Fi modules, enabling the DLP projection of the vehicle door control lights to be dynamically customized and controlled by the user.

[0057] The software control scheme in this embodiment can support automatic keystone correction by combining with the upper-layer APK.

[0058] The software control scheme in this embodiment integrates advanced encryption standards such as HMAC-SHA256 and TLS for verification, enhancing security and exclusivity.

[0059] This embodiment integrates DLP (Digital Light Processing) projection functionality with Bluetooth and Wi-Fi modules, enabling users to update DLP projection content and data via mobile devices through Bluetooth and Wi-Fi, and to switch projection content and adjust brightness in real time, maximizing the realization of software-defined projection functionality.

[0060] This embodiment, by combining with the upper-layer APK, can be compatible with various image and video formats and achieve keystone correction function, and can place the DLP at, but is not limited to, the bottom of the car door for ground projection.

[0061] This embodiment is based on the BLE (Bluetooth Low Energy) and Wi-Fi control and data transmission system of mobile devices. While establishing a secure Bluetooth connection and implementing data communication encryption, it innovatively introduces the FTPS (File Transfer Protocol with support for Transport Layer Security) data file transfer protocol based on TLS (Transport Layer Security), making Wi-Fi data transmission more secure, faster, and more stable.

[0062] Example 3 Those skilled in the art can understand this embodiment as a more specific description of Embodiment 1.

[0063] This embodiment provides an in-vehicle projection module 100 and its software control method. The module includes: a processor 110 (which may be an MCU / SoC), a memory 120, a digital projection unit 130 (including a DMD chip), a first wireless communication interface 140 (such as BLE), and a second wireless communication interface 150 (such as Wi-Fi). The module only obtains power from the vehicle and has no data connection with the in-vehicle communication network. The user control terminal is a smartphone or tablet. The module uses modular boards and flexible cables to adapt to the vehicle interior space and is uniformly scheduled by an RTOS. In other embodiments, BLE can be replaced with Ethernet or CAN, and Wi-Fi can be replaced with Ethernet.

[0064] The processor 110 serves as the control core, integrating modules such as projection content processing / video decoding, image processing, wireless communication management, DMD drive signal generation, and light source timing control; it also includes a security processing unit for secure startup and key protection.

[0065] The memory 120 is connected via the QSPI interface. Its physical form is a Flash chip with a memory of 512MByte or 1GByte. Logically, it is divided into a first application partition, a second application partition (A / B), and a configuration storage area (such as CPROM), which is the local storage component.

[0066] The digital projection unit 130 includes a DMD chip and a light source driving unit (such as a tri-color LED, i.e., an LED light source). The first wireless communication interface 140 (BLE) and the second wireless communication interface 150 (Wi-Fi) respectively implement the first and second wireless communication links.

[0067] The vehicle's 12V / 24V is progressively reduced to 5V, 3.3V, 1.2V and 1.8V (specifically for the DMD) by the system power supply unit (such as the power management unit) to provide operating voltage for each unit; including the power monitoring module and the DMD power supply and power supply voltage detection circuit.

[0068] The first wireless communication link is a BLE link, which consumes less power than the second link, and is used for pairing, identity verification, activating the second link, obtaining connection credentials, and transmitting real-time control commands. The second wireless communication link is a Wi-Fi link, used for high-speed transmission of projection media data and firmware update packages.

[0069] The user control terminal first pairs with the module via the first link (BLE). After establishing a connection based on JustWorks, the module provides a BLEGATT broadcast verification service at the application layer (including random number attributes, HMAC-SHA256 ciphertext attributes, and verification status attributes). When the module starts up, it randomly generates 32 bytes of data and sends it through this service. The user terminal calculates the returned ciphertext using a pre-shared HMAC-SHA256 key, and the module verifies its legitimacy to determine the user's identity. Subsequently, the user control terminal obtains connection credentials (such as SSID / password) for establishing the second link via the first link and sends a command to activate the second link (Wi-Fi). Control commands are transmitted via BLE (first link) using UART, and media data is transmitted via Wi-Fi (second link) using SDIO, achieving separation of control flow and data flow.

[0070] The processor 110 sends the digital video signal to the DMD chip via the display output interface, controlling the flipping of its micromirrors (each micromirror corresponds to one pixel). The processor controls the light source driving unit via the timing control interface, causing the red, green, and blue LEDs to light up sequentially in a time-division manner, providing a time-division colored light source.

[0071] The processor adjusts the brightness and conduction timing of the three-color LEDs and calibrates the white balance by outputting PWM signals and enable signals to the light source driver unit. A dark transition time (all LEDs off) is inserted between color switching intervals to avoid current surges and aliasing. The dedicated DMD power supply (e.g., 1.8V) is turned off by the processor via an enable signal when the DMD is not operating, reducing standby power consumption. When the power monitoring module detects a pre-set power supply (e.g., 5V) undervoltage, it sends a stop command to the processor, triggering the DMD to stop all micromirrors to a safe state. Furthermore, the module integrates power supply voltage detection; when the power supply voltage falls below a pre-set threshold (e.g., 10V), the processor sends a reset signal to the DMD chip. The projection plays at a predetermined frame rate of no less than 25fps.

[0072] The memory 120 (such as a storage medium) is divided into a first application partition, a second application partition, and a configuration storage area CPROM. The module contains a bootloader that reads the version sorting index (such as a version counter) of the two partitions at startup and loads the updated partition according to the rule of "the one with the larger value is the newer version"; if only one partition is valid, it is loaded directly.

[0073] During a FOTA update, the new firmware is written to the inactive application partition. The processor calls its internal security processing unit (HSM, which can be a Cortex-M4 core running in an isolated secure execution environment; the main processor core can be a Cortex-R5 application processor running in an insecure execution environment) to perform signature verification on the new firmware. After successful verification, the version counter of the inactive partition is updated to "the current active partition version counter value incremented by one" and set to valid (A / B partition mechanism).

[0074] Before critical data is stored in the configuration storage area CPROM, it undergoes integrity verification by the security processing unit and is encrypted and stored using an internal hardware key. When the processor (non-secure execution environment) needs to use critical data in the configuration area (such as the Bluetooth pairing key), it sends a service request to the security processing unit. The security processing unit reads the encrypted data, decrypts it using the hardware key, performs the operation within its own security boundary, and only returns the result, without leaking the plaintext. FOTA update packages can be transmitted to the module via Wi-Fi through FTPS (a secure channel based on TLS handshake) and upgraded using an A / B partitioning mechanism.

[0075] On the mobile device, the media data used for projection is first pre-distorted, specifically by keystone correction: based on preset calibration data (such as module installation position, pitch angle, and yaw angle), each frame is subjected to inverse geometric transformation to compensate for projection distortion.

[0076] Users send real-time control commands via the first link (BLE), supporting operations such as turning the projection on and off, adjusting brightness, selecting content, and adjusting playback speed, playback mode switching, content switching, reversing, and pausing. After establishing a second link (Wi-Fi) with the module, the user control terminal transmits pre-distorted media data to the module via a secure FTPS / TLS channel; the module stores this data in its memory 120. The module continuously receives and responds to real-time control commands via the first link, reads media data from its memory, and projects it onto the digital projection unit at a frame rate of at least 25fps.

[0077] All steps on the module side are scheduled by a software system based on RTOS (such as FreeRTOS), which creates at least BLE communication management tasks, WIFI communication management tasks, system management tasks, and DMD projection tasks. Among them, the DMD projection task is set to the highest priority to ensure real-time projection output.

[0078] The working principle is as follows: The mobile device completes JustWorks pairing and HMAC-SHA256GATT verification via BLE; it obtains Wi-Fi credentials via BLE and sends a command to activate Wi-Fi; after performing keystone correction on the media data, the mobile device uploads it to the module's memory via Wi-Fi through the FTPS / TLS secure channel. The module receives and responds to real-time control commands via BLE, reads media data from the memory, and the processor generates DMD bit plane and timing signals through video decoding and image processing. This drives the DMD micromirrors to flip, and the light source timing control module controls the three-color LEDs to light up in a time-division manner (including dark area transitions) using PWM / enable signals, projecting at a frame rate of no less than 25fps. When the module is powered on, the bootloader selects a new partition for secure startup based on the version counter; FOTA is written to the inactive partition via a secure channel and verified by the secure processing unit (HSM), and the version counter is incremented to take effect; critical data is encrypted and decrypted by the secure processing unit; undervoltage triggers the DMD micromirrors to stop, and low voltage triggers the DMD to reset.

[0079] This invention provides a software control method and a vehicle-mounted dynamic projection module for in-vehicle dynamic projection. The method includes: pre-distorting media data on a mobile device; activating a second wireless communication link (e.g., Wi-Fi) of the in-vehicle projection module via a first wireless communication link (e.g., BLE) and obtaining connection credentials; after establishing the second wireless communication link, transmitting the processed media data to the in-vehicle projection module via a secure file transfer protocol (e.g., FTPS); and the in-vehicle projection module receiving real-time control commands via the first wireless communication link and controlling the digital projection unit to perform projection playback. This invention balances low-power control and high-bandwidth data transmission through a dual-link communication strategy; ensures projection quality through pre-distortion processing on the mobile device; and ensures data interaction security by introducing a secure file transfer protocol and multiple encryption mechanisms. This invention enables users to conveniently and securely customize in-vehicle projection content, greatly enhancing the personalized experience of the smart cockpit and the reliability of the system.

[0080] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A software control method for vehicle-mounted dynamic projection, characterized in that, Includes the following steps: On mobile devices, the media data used for projection is pre-distorted to compensate for projection distortion of the in-vehicle projection module. On the mobile device, a command is sent to the vehicle projection module via a first wireless communication link to activate the second wireless communication link of the vehicle projection module; wherein, the power consumption of the first wireless communication link is lower than that of the second wireless communication link; On the mobile device, a connection credential for establishing the second wireless communication link is obtained from the vehicle projection module via the first wireless communication link. On the mobile device, after establishing the second wireless communication link with the vehicle projection module, the pre-distorted media data is transmitted to the vehicle projection module through a secure file transfer protocol. At the vehicle-mounted projection module, real-time control commands from the mobile device are received via the first wireless communication link, and the projection playback is controlled according to the real-time control commands. The media data is read from the memory and projected and played at a predetermined frame rate through the digital projection unit at the in-vehicle projection module.

2. The software control method for vehicle-mounted dynamic projection according to claim 1, characterized in that, The first wireless communication link is a Bluetooth BLE link, and the second wireless communication link is a Wi-Fi link.

3. The software control method for vehicle-mounted dynamic projection according to claim 2, characterized in that, The secure file transfer protocol is the FTPS protocol, and a secure channel for transmitting the media data is established through the TLS handshake protocol.

4. The software control method for vehicle-mounted dynamic projection according to claim 1, characterized in that, The pre-distortion processing is a keystone correction process, which preprocesses the media data according to preset calibration data.

5. The software control method for vehicle-mounted dynamic projection according to claim 1, characterized in that, The real-time control commands are used to perform at least one of the following operations on the projection: playback speed adjustment, brightness adjustment, playback mode switching, content switching, reversing, and pausing.

6. The software control method for vehicle-mounted dynamic projection according to claim 2, characterized in that, During the BLE pairing process between the mobile device and the vehicle projection module, a random verification step based on the advanced encryption standard HMAC-SHA256 is included to verify the user's identity.

7. The software control method for vehicle-mounted dynamic projection according to claim 1, characterized in that, The software control method further includes: receiving firmware update packages via the secure file transfer protocol at the vehicle-mounted projection module end, and implementing firmware updates using an A / B partitioning mechanism.

8. The software control method for vehicle-mounted dynamic projection according to claim 1, characterized in that, The digital projection unit includes a digital micromirror device (DMD) chip. The software control method further includes: detecting the power supply voltage at the vehicle projection module end, and resetting the DMD chip when the power supply voltage is detected to be lower than a preset threshold.

9. The software control method for vehicle-mounted dynamic projection according to claim 1, characterized in that, The steps performed on the vehicle-mounted projection module are scheduled by a software system based on a real-time operating system.

10. The software control method for vehicle-mounted dynamic projection according to claim 6, characterized in that, After establishing the BLE pairing connection based on JustWorks, a BLE GATT broadcast verification service is provided at the application layer. The BLE GATT broadcast verification service includes a random number attribute, an HMAC-SHA256 ciphertext attribute, and a verification status attribute. When the projection module starts up, it randomly generates 32 bytes of data and sends it to the mobile device through the BLE GATT broadcast verification service. The mobile device receives the HMAC-SHA256 ciphertext calculated based on the 32 bytes of data and performs a validity verification on the HMAC-SHA256 ciphertext to determine the legitimacy of the current BLE connection user.

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