The atmosphere light is also known as LED atmosphere light, which is mainly used to create atmosphere for people's needs in theme parks, hotels, homes and art lighting. The atmosphere mode can be realized by adjusting the color, brightness and frequency of LED lights according to the needs of the scene. At present, the TV atmosphere light is basically pasted on the back shell of the TV through double-sided adhesive tape, which presents a visual enjoyment to people in the form of wall reflection. This paper discusses the color controlled atmosphere lamp scheme of existing TV, and compares the advantages and disadvantages of the existing technology and application scheme, so as to select the best atmosphere lamp scheme in the future.

1 Existing technical scheme of TV color controlled atmosphere light

1.1 HDMI input source processing technology

Now many televisions are connected to set-top boxes/OTT boxes and displayed through HDMI interfaces. Therefore, the first solution is to perform signal processing at the HDMI signal input end.

1.1.1 HDMI loop out design

Considering that all existing TVs have 4K resolution, HDMI loop out IC selection is required to support HDMI2.0 input/output, and Longxun LT86102UX or equivalent chip scheme can be selected. This chip receives HDMI2.0 signals output from the source end (set-top box/OTT box/other video sources) and converts them into two channels of synchronous HDMI2.0 signals without degrading signal quality, one of which is bypassed to the TV end, The other way is to process the video data to the FPGA at the back end.

1.1.2 FPGA video data processing

FPGA is mainly used to extract the color brightness and other information in HDMI signal, generate the color information required by the light strip after algorithm processing, and then send it to the back-end IOT module through serial port or SPI and other interfaces. The selection of FPGA can be based on actual needs, such as the number of light partitions, delay requirements, input and output interface requirements, etc. Taking XILINX FPGA chip xc6slx16 as an example, it can provide color data of more than 200 partitions, each partition provides a 3-byte RGB data, and the partition refresh rate is ≥ 30 fps. Because the highest specification of HDMI2.0 supports 4k 60 Hz, it is necessary to ensure the refresh rate of the color data of the partition, so that the color of the atmosphere light can be synchronized with the color of TV video playback from the visual effect. In the end, if the LED light strip partition is set according to the 16:9 partition, that is, the upper and lower zones are 16, and the left and right zones are 9, that is, the data of 50 zones are required. According to the different algorithm processing, the data of 50 zones may need FPGA to calculate the color information of nearly 200 zones at the edge of the image. In addition, because the normal atmosphere light is turned on in the movie viewing, the effect is good, and most movies are 21:9, with black edges up and down, so the FPGA algorithm should also be able to support the black edge removal algorithm.

1.1.3 IOT module control

After receiving the light control information from the front-end FPGA, the IOT module outputs it through the SPI data interface, connects it to the external light strip through the USB interface after the conversion chip, and controls the external light strip from it. In addition, the IOT module completes the detection of input and output signals and the control lamp function of FPGA working mode. Another function of the IOT module is to enable mobile APP such as mobile phone/PAD to control and add entertainment functions, such as customizing the color of the light band, and setting the LED light band to turn off or on according to the music rhythm of the mobile phone.

The above scheme is to process the signal from the HDMI input source to achieve the high-precision LED atmosphere light control.

1.2 SOC soft processing technology

SOC soft processing technology refers to the use of the TV's own SOC processing capacity, through built-in APK and other methods, the image information to be displayed is color partitioned in the CPU, and the processed data information is sent to the atmosphere light bar through the IOT module. Compared with the HDMI input source processing technology, this is mainly to occupy CPU resources, and the software needs to be integrated and adapted. The performance requirements for the TV's own SOC are high, In this way, the IOT module can be built in the TV as an accessory.

1.3 Camera shooting image processing technology

Camera processing technology refers to using the camera to shoot the TV display picture, and then sending the camera shooting picture information to the FPGA as MIPI data. After the FPGA processing is completed, the atmosphere light strip is also controlled through the IOT module. In this scheme, the placement position of the camera and the selection of FPGA need to be considered.

2 Comparison of advantages and disadvantages of various schemes

The above three schemes are compared from the aspects of maturity, cost, compatibility, user experience, ease of adaptation, and ease of installation. Maturity refers to whether there are relevant products in the current market scheme that have been produced in batches. Compatibility refers to whether the scheme contains various information source input scenarios. The user experience is mainly determined from the delay time of atmosphere lights and display images, Adaptation convenience refers to whether TV master SOC adaptation is required, and installation convenience refers to whether there are specific requirements for installation mode and routing.

3 Conclusion

Different from the traditional voice controlled atmosphere light, the color controlled atmosphere light can naturally expand the image display effect, so it has a broader application prospect in television. This paper briefly analyzes and compares several technical solutions of the existing color controlled atmosphere light. In view of the huge TV market and the uneven TV solutions, it is difficult to choose the best and the worst. TV manufacturers and smart home solution providers can choose their own technical solutions. I believe that different innovative solutions can bring different experience effects.