Abstract: A display (101) is controlled by a display drive signal (S2) generated based on an input signal (S1) encoding a safety-critical quantity. A checksum (S4) is computed based on the display drive signal and is used to verify the rendering process by which the display drive signal has been produced. In order for the checksum to depend on the safety-critical quantity only, the checksum is computed based on a filtered display drive signal (S3) in which pixels with a certain value have been excluded. In embodiments of the invention, safety-noncritical quantities are represented using colors that are due to be excluded. Similarly, a checksum for verifying a given quantity can be made independent of other quantities represented in adjacent screen areas by representing the latter using excluded colors. In other embodiments, pixel values corresponding to particular pixel positions may be excluded from contributing.

Abstract: The present invention relates to an audio processing system (100) for providing safe audio playback. An audio controller (110) outputs an intermediate audio signal (M) having a predefined test segment comprising a predefined test frequency component. An audio synthesis stage (120) provides, based on the intermediate audio signal, an output audio signal (P) for use in audio playback. An audio test is performed based on a first segment of the output audio signal corresponding to the test segment of the intermediate audio signal, and a safety processor (150) declares correct the operation of the audio synthesis stage in case the result of the audio test is positive. The safety processor declares correct the operation of a frequency monitor (130) if both the frequency monitor and a frequency-selective audio sensor (140) detect the test frequency in the first segment of the output audio signal.

Abstract: The present invention relates to an audio processing system (100) for providing safe audio playback. An audio controller (110) outputs an intermediate audio signal (M) having a predefined test segment comprising a predefined test frequency component. An audio synthesis stage (120) provides, based on the intermediate audio signal, an output audio signal (P) for use in audio playback. An audio test is performed based on a first segment of the output audio signal corresponding to the test segment of the intermediate audio signal, and a safety processor (150) declares correct the operation of the audio synthesis stage in case the result of the audio test is positive. The safety processor declares correct the operation of a frequency monitor (130) if both the frequency monitor and a frequency-selective audio sensor (140) detect the test frequency in the first segment of the output audio signal.

Abstract: A display (101) is controlled by a display drive signal (S2) generated based on an input signal (S1) encoding a safety-critical quantity. A checksum (S4) is computed based on the display drive signal and is used to verify the rendering process by which the display drive signal has been produced. In order for the checksum to depend on the safety-critical quantity only, the checksum is computed based on a filtered display drive signal (S3) in which pixels with a certain value have been excluded. In embodiments of the invention, safety-noncritical quantities are represented using colours that are due to be excluded. Similarly, a checksum for verifying a given quantity can be made independent of other quantities represented in adjacent screen areas by representing the latter using excluded colours. In other embodiments, pixel values corresponding to particular pixel positions may be excluded from contributing.