# Mono Preview This example shows how to set up a pipeline that outputs the left and right grayscale camera images, connects over XLink to transfer these to the host real-time, and displays both using OpenCV. ### Similar samples: * [RGB Preview](https://docs.luxonis.com/software-v3/depthai/examples/rgb_preview.md) * [Stereo Depth](https://docs.luxonis.com/software-v3/depthai/examples/stereo_depth/stereo_depth.md) ## Demo This example requires the DepthAI v3 API, see [installation instructions](https://docs.luxonis.com/software-v3/depthai.md). ## Source code #### Python ```python #!/usr/bin/env python3 import cv2 import depthai as dai # Create pipeline pipeline = dai.Pipeline() # Define sources and outputs monoLeft = pipeline.create(dai.node.MonoCamera) monoRight = pipeline.create(dai.node.MonoCamera) xoutLeft = pipeline.create(dai.node.XLinkOut) xoutRight = pipeline.create(dai.node.XLinkOut) xoutLeft.setStreamName('left') xoutRight.setStreamName('right') # Properties monoLeft.setCamera("left") monoLeft.setResolution(dai.MonoCameraProperties.SensorResolution.THE_720_P) monoRight.setCamera("right") monoRight.setResolution(dai.MonoCameraProperties.SensorResolution.THE_720_P) # Linking monoRight.out.link(xoutRight.input) monoLeft.out.link(xoutLeft.input) # Connect to device and start pipeline with dai.Device(pipeline) as device: # Output queues will be used to get the grayscale frames from the outputs defined above qLeft = device.getOutputQueue(name="left", maxSize=4, blocking=False) qRight = device.getOutputQueue(name="right", maxSize=4, blocking=False) while True: # Instead of get (blocking), we use tryGet (non-blocking) which will return the available data or None otherwise inLeft = qLeft.tryGet() inRight = qRight.tryGet() if inLeft is not None: cv2.imshow("left", inLeft.getCvFrame()) if inRight is not None: cv2.imshow("right", inRight.getCvFrame()) if cv2.waitKey(1) == ord('q'): break ``` #### C++ ```cpp #include // Includes common necessary includes for development using depthai library #include "depthai/depthai.hpp" int main() { // Create pipeline dai::Pipeline pipeline; // Define sources and outputs auto monoLeft = pipeline.create(); auto monoRight = pipeline.create(); auto xoutLeft = pipeline.create(); auto xoutRight = pipeline.create(); xoutLeft->setStreamName("left"); xoutRight->setStreamName("right"); // Properties monoLeft->setCamera("left"); monoLeft->setResolution(dai::MonoCameraProperties::SensorResolution::THE_720_P); monoRight->setCamera("right"); monoRight->setResolution(dai::MonoCameraProperties::SensorResolution::THE_720_P); // Linking monoRight->out.link(xoutRight->input); monoLeft->out.link(xoutLeft->input); // Connect to device and start pipeline dai::Device device(pipeline); // Output queues will be used to get the grayscale frames from the outputs defined above auto qLeft = device.getOutputQueue("left", 4, false); auto qRight = device.getOutputQueue("right", 4, false); while(true) { // Instead of get (blocking), we use tryGet (non-blocking) which will return the available data or None otherwise auto inLeft = qLeft->tryGet(); auto inRight = qRight->tryGet(); if(inLeft) { cv::imshow("left", inLeft->getCvFrame()); } if(inRight) { cv::imshow("right", inRight->getCvFrame()); } int key = cv::waitKey(1); if(key == 'q' || key == 'Q') { return 0; } } return 0; } ``` ## Pipeline ### examples/mono_preview.pipeline.json ```json { "pipeline": { "connections": [ { "node1Id": 1, "node1Output": "out", "node1OutputGroup": "", "node2Id": 3, "node2Input": "in", "node2InputGroup": "" }, { "node1Id": 0, "node1Output": "out", "node1OutputGroup": "", "node2Id": 2, "node2Input": "in", "node2InputGroup": "" } ], "globalProperties": { "calibData": null, "cameraTuningBlobSize": null, "cameraTuningBlobUri": "", "leonCssFrequencyHz": 700000000.0, "leonMssFrequencyHz": 700000000.0, "pipelineName": null, "pipelineVersion": null, "sippBufferSize": 18432, "sippDmaBufferSize": 16384, "xlinkChunkSize": -1 }, "nodes": [ [ 0, { "id": 0, "ioInfo": [ [ [ "", "inputControl" ], { "blocking": true, "group": "", "id": 1, "name": "inputControl", "queueSize": 8, "type": 3, "waitForMessage": false } ], [ [ "", "out" ], { "blocking": false, "group": "", "id": 2, "name": "out", "queueSize": 8, "type": 0, "waitForMessage": false } ], [ [ "", "raw" ], { "blocking": false, "group": "", "id": 3, "name": "raw", "queueSize": 8, "type": 0, "waitForMessage": false } ], [ [ "", "frameEvent" ], { "blocking": false, "group": "", "id": 4, "name": "frameEvent", "queueSize": 8, "type": 0, "waitForMessage": false } ] ], "name": "MonoCamera", "properties": { "boardSocket": -1, "cameraName": "left", "fps": 30.0, "imageOrientation": -1, "initialControl": { "aeLockMode": false, "aeMaxExposureTimeUs": 0, "aeRegion": { "height": 0, "priority": 0, "width": 0, "x": 0, "y": 0 }, "afRegion": { "height": 0, "priority": 0, "width": 0, "x": 0, "y": 0 }, "antiBandingMode": 0, "autoFocusMode": 3, "awbLockMode": false, "awbMode": 0, "brightness": 0, "captureIntent": 0, "chromaDenoise": 0, "cmdMask": 0, "contrast": 0, "controlMode": 0, "effectMode": 0, "expCompensation": 0, "expManual": { "exposureTimeUs": 0, "frameDurationUs": 0, "sensitivityIso": 0 }, "frameSyncMode": 0, "lensPosAutoInfinity": 0, "lensPosAutoMacro": 0, "lensPosition": 0, "lensPositionRaw": 0.0, "lowPowerNumFramesBurst": 0, "lowPowerNumFramesDiscard": 0, "lumaDenoise": 0, "saturation": 0, "sceneMode": 0, "sharpness": 0, "strobeConfig": { "activeLevel": 0, "enable": 0, "gpioNumber": 0 }, "strobeTimings": { "durationUs": 0, "exposureBeginOffsetUs": 0, "exposureEndOffsetUs": 0 }, "wbColorTemp": 0 }, "isp3aFps": 0, "numFramesPool": 3, "numFramesPoolRaw": 3, "rawPacked": null, "resolution": 0 } } ], [ 1, { "id": 1, "ioInfo": [ [ [ "", "inputControl" ], { "blocking": true, "group": "", "id": 5, "name": "inputControl", "queueSize": 8, "type": 3, "waitForMessage": false } ], [ [ "", "out" ], { "blocking": false, "group": "", "id": 6, "name": "out", "queueSize": 8, "type": 0, "waitForMessage": false } ], [ [ "", "raw" ], { "blocking": false, "group": "", "id": 7, "name": "raw", "queueSize": 8, "type": 0, "waitForMessage": false } ], [ [ "", "frameEvent" ], { "blocking": false, "group": "", "id": 8, "name": "frameEvent", "queueSize": 8, "type": 0, "waitForMessage": false } ] ], "name": "MonoCamera", "properties": { "boardSocket": -1, "cameraName": "right", "fps": 30.0, "imageOrientation": -1, "initialControl": { "aeLockMode": false, "aeMaxExposureTimeUs": 0, "aeRegion": { "height": 0, "priority": 0, "width": 0, "x": 0, "y": 0 }, "afRegion": { "height": 0, "priority": 0, "width": 0, "x": 0, "y": 0 }, "antiBandingMode": 0, "autoFocusMode": 3, "awbLockMode": false, "awbMode": 0, "brightness": 0, "captureIntent": 0, "chromaDenoise": 0, "cmdMask": 0, "contrast": 0, "controlMode": 0, "effectMode": 0, "expCompensation": 0, "expManual": { "exposureTimeUs": 0, "frameDurationUs": 0, "sensitivityIso": 0 }, "frameSyncMode": 0, "lensPosAutoInfinity": 0, "lensPosAutoMacro": 0, "lensPosition": 0, "lensPositionRaw": 0.0, "lowPowerNumFramesBurst": 0, "lowPowerNumFramesDiscard": 0, "lumaDenoise": 0, "saturation": 0, "sceneMode": 0, "sharpness": 0, "strobeConfig": { "activeLevel": 0, "enable": 0, "gpioNumber": 0 }, "strobeTimings": { "durationUs": 0, "exposureBeginOffsetUs": 0, "exposureEndOffsetUs": 0 }, "wbColorTemp": 0 }, "isp3aFps": 0, "numFramesPool": 3, "numFramesPoolRaw": 3, "rawPacked": null, "resolution": 0 } } ], [ 2, { "id": 2, "ioInfo": [ [ [ "", "in" ], { "blocking": true, "group": "", "id": 9, "name": "in", "queueSize": 8, "type": 3, "waitForMessage": true } ] ], "name": "XLinkOut", "properties": { "maxFpsLimit": -1.0, "metadataOnly": false, "streamName": "left" } } ], [ 3, { "id": 3, "ioInfo": [ [ [ "", "in" ], { "blocking": true, "group": "", "id": 10, "name": "in", "queueSize": 8, "type": 3, "waitForMessage": true } ] ], "name": "XLinkOut", "properties": { "maxFpsLimit": -1.0, "metadataOnly": false, "streamName": "right" } } ] ] } } ``` ### Need assistance? 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