To address the inefficiencies and subjectivity of manual testing, an automatic test system for high-definition television (HDTV) main control boards was developed using LabVIEW. This system leverages LabVIEW's powerful graphical processing capabilities, including signal processing and virtual instrumentation, to create audio and video image evaluation software. A gradient-based structural similarity image evaluation algorithm (GSSIM) was implemented to enhance the accuracy of identifying fuzzy distortion in images during testing. As a result, the automated system significantly improves testing efficiency while ensuring objective and consistent test results.
With HDTV now dominating the color TV market, the main control board remains its core component. However, current factory testing methods still rely heavily on manual procedures, which suffer from several limitations. First, manual testing is time-consuming and labor-intensive, as it requires frequent replacement of test tools. Second, subjective evaluations based on human perception can lead to inconsistent quality assessments. These issues highlight the urgent need for automated testing solutions that can streamline the process and improve reliability.
This paper presents an automated testing approach focused on a liquid crystal HDTV main control board. Using LabVIEW’s graphical programming environment, the system was designed to analyze and evaluate audio and video signals collected during testing. The software includes a user-friendly interface and efficient data management features, ultimately enhancing the overall testing efficiency and ensuring more accurate and consistent product quality analysis.
1. Overall Design of the Automatic Test System
Figure 1 illustrates the block diagram of a typical HDTV system. The main control board consists of two key components: the control circuit and the sequential circuit. The control circuit processes incoming audio and video signals, converting them into a mini-LVDS standard signal. Meanwhile, the sequential circuit generates timing pulses, allowing digital image signals to be sent to the display screen via row and column driver circuits in real time.
As the core component of an HDTV, the main control board must undergo rigorous testing before leaving the factory. The automatic test system described in this paper comprises an industrial computer, an audio and video signal source, an audio capture card, a video capture card, and a learnable remote control module. The system architecture is illustrated in Figure 2.
In Figure 2, CHROMA serves as the audio and video signal source, communicating with the host computer via RS-232. It outputs the corresponding signals based on commands from the host. The audio and video signals generated by the main control board are then captured and analyzed by the upper industrial computer through the audio and video capture cards. During testing, the learnable remote control module simulates infrared signals and uses microcontroller development to enable automatic test flow switching. This paper primarily focuses on the design of the LabVIEW-based test software, emphasizing its role in improving the overall testing process.
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