Abstract: In general, the disclosure is directed to lightweight sensors that enable privacy preserving detection of objects or related information present in image data. One aspect of the disclosure includes detection methods that do not require information such as motion or thermal in determining object detection. Rather, implementations can utilize a machine-learned model to determine whether objects of a type are present in an image. To account for possible generation of private data, example implementations can include hardware and/or a computing architecture configured to only maintain or transmit sensor signals generated based at least in part on output of the machine-learned model.