A sensor unit utilized in an autonomous driving vehicle, the sensor unit comprising: a sensor interface coupled to a plurality of cameras mounted on a plurality of locations of an autonomous driving vehicle; a host interface coupled to a host system, wherein the host system is configured to perceive a driving environment surrounding the ADV based on at least image data obtained from the cameras and to plan a path to autonomously drive the ADV; and a plurality of data acquisition modules, each corresponding to one of the plurality of cameras, wherein each of the data acquisition modules comprises: a pixel alignment module to reformat pixels of image data from an original format associated with a corresponding camera to a predetermined format, and a frame processing module coupled to the pixel alignment module, wherein the frame processing module is configured to generate an image frame based on the image data received from the pixel alignment module and to transmit the image frame to the host system via the host interface, wherein data structure representing the image frame includes a data region for storing the image data and metadata fields for storing metadata, and the host system processes the image frame in view of the metadata, wherein the metadata fields comprise a trigger count, a trigger timestamp, a receive timestamp, a frame marker, and an error code, the error code storing a code or data indicating whether the image frame is a normal frame or an irregular frame, and the irregular frame is a short frame or a long frame; and wherein a processing logic pads a predetermined pixel value to fill up the remaining empty area for the short frame, and the processing logic cuts and limits the image data to an expected frame size for the long frame. a sensor interface coupled to a plurality of cameras mounted on a plurality of locations of an autonomous driving vehicle; a host interface coupled to a host system, wherein the host system is configured to perceive a driving environment surrounding the ADV based on at least image data obtained from the cameras and to plan a path to autonomously drive the ADV; and a plurality of data acquisition modules, each corresponding to one of the plurality of cameras, wherein each of the data acquisition modules comprises: a pixel alignment module to reformat pixels of image data from an original format associated with a corresponding camera to a predetermined format, and a frame processing module coupled to the pixel alignment module, wherein the frame processing module is configured to generate an image frame based on the image data received from the pixel alignment module and to transmit the image frame to the host system via the host interface, wherein data structure representing the image frame includes a data region for storing the image data and metadata fields for storing metadata, and the host system processes the image frame in view of the metadata, wherein the metadata fields comprise a trigger count, a trigger timestamp, a receive timestamp, a frame marker, and an error code, the error code storing a code or data indicating whether the image frame is a normal frame or an irregular frame, and the irregular frame is a short frame or a long frame; and wherein a processing logic pads a predetermined pixel value to fill up the remaining empty area for the short frame, and the processing logic cuts and limits the image data to an expected frame size for the long frame. a pixel alignment module to reformat pixels of image data from an original format associated with a corresponding camera to a predetermined format, and a frame processing module coupled to the pixel alignment module, wherein the frame processing module is configured to generate an image frame based on the image data received from the pixel alignment module and to transmit the image frame to the host system via the host interface, wherein data structure representing the image frame includes a data region for storing the image data and metadata fields for storing metadata, and the host system processes the image frame in view of the metadata, wherein the metadata fields comprise a trigger count, a trigger timestamp, a receive timestamp, a frame marker, and an error code, the error code storing a code or data indicating whether the image frame is a normal frame or an irregular frame, and the irregular frame is a short frame or a long frame; and wherein a processing logic pads a predetermined pixel value to fill up the remaining empty area for the short frame, and the processing logic cuts and limits the image data to an expected frame size for the long frame.