There's a setting for the level of confidence that each AWS AI service has in the accuracy of the extracted content. This is defined as the minimum confidence level and has a default value of 80% (i.e. 0.8). Here are the settings in alfresco-global.properties:
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# Alfresco-AI Parameters #
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ai.transformations.aiLabels.minConfidence=0.8
ai.transformations.aiFeatures.minConfidence=0.8
ai.transformations.aiTextract.minConfidence=0.8
ai.transformations.aiPiiEntities.minConfidence=0.8
ai.transformations.aiSpeechToText.minConfidence=0.8