{"id":19299,"date":"2017-10-20T15:02:58","date_gmt":"2017-10-20T19:02:58","guid":{"rendered":"https:\/\/mjtsai.com\/blog\/?p=19299"},"modified":"2017-10-20T15:02:58","modified_gmt":"2017-10-20T19:02:58","slug":"how-hey-siriworks","status":"publish","type":"post","link":"https:\/\/mjtsai.com\/blog\/2017\/10\/20\/how-hey-siriworks\/","title":{"rendered":"How &ldquo;Hey Siri&rdquo;&nbsp;Works"},"content":{"rendered":"<p><a href=\"https:\/\/machinelearning.apple.com\/2017\/10\/01\/hey-siri.html\">Apple<\/a>:<\/p>\n<blockquote cite=\"https:\/\/machinelearning.apple.com\/2017\/10\/01\/hey-siri.html\">\n<p>To avoid running the main processor all day just to listen for the trigger phrase, the iPhone&rsquo;s Always On Processor (AOP) (a small, low-power auxiliary processor, that is, the embedded Motion Coprocessor) has access to the microphone signal (on 6S and later). We use a small proportion of the AOP&rsquo;s limited processing power to run a detector with a small version of the acoustic model (DNN). When the score exceeds a threshold the motion coprocessor wakes up the main processor, which analyzes the signal using a larger DNN. In the first versions with AOP support, the first detector used a DNN with 5 layers of 32 hidden units and the second detector had 5 layers of 192 hidden units.<\/p>\n<p>Apple Watch presents some special challenges because of the much smaller battery. Apple Watch uses a single-pass &ldquo;Hey Siri&rdquo; detector with an acoustic model intermediate in size between those used for the first and second passes on other iOS devices. The &ldquo;Hey Siri&rdquo; detector runs only when the watch motion coprocessor detects a wrist raise gesture, which turns the screen on. At that point there is a lot for WatchOS to do&mdash;power up, prepare the screen, etc.&mdash;so the system allocates &ldquo;Hey Siri&rdquo; only a small proportion (~5%) of the rather limited compute budget. It is a challenge to start audio capture in time to catch the start of the trigger phrase, so we make allowances for possible truncation in the way that we initialize the detector.<\/p>\n<\/blockquote>","protected":false},"excerpt":{"rendered":"<p>Apple: To avoid running the main processor all day just to listen for the trigger phrase, the iPhone&rsquo;s Always On Processor (AOP) (a small, low-power auxiliary processor, that is, the embedded Motion Coprocessor) has access to the microphone signal (on 6S and later). We use a small proportion of the AOP&rsquo;s limited processing power to [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"apple_news_api_created_at":"","apple_news_api_id":"","apple_news_api_modified_at":"","apple_news_api_revision":"","apple_news_api_share_url":"","apple_news_coverimage":0,"apple_news_coverimage_caption":"","apple_news_is_hidden":false,"apple_news_is_paid":false,"apple_news_is_preview":false,"apple_news_is_sponsored":false,"apple_news_maturity_rating":"","apple_news_metadata":"\"\"","apple_news_pullquote":"","apple_news_pullquote_position":"","apple_news_slug":"","apple_news_sections":"\"\"","apple_news_suppress_video_url":false,"apple_news_use_image_component":false,"footnotes":""},"categories":[2],"tags":[992,1351,31,1472,247],"class_list":["post-19299","post","type-post","status-publish","format-standard","hentry","category-technology","tag-apple-watch","tag-artificial-intelligence","tag-ios","tag-ios-11","tag-siri"],"apple_news_notices":[],"_links":{"self":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/19299","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/comments?post=19299"}],"version-history":[{"count":1,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/19299\/revisions"}],"predecessor-version":[{"id":19300,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/19299\/revisions\/19300"}],"wp:attachment":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/media?parent=19299"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/categories?post=19299"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/tags?post=19299"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}