Reduce initial connection bandwidth (#1200)

Reduces bandwidth requirements by being much lazier about how much calibration data is sent to the UI.
2026-06-30 02:31:40 +00:00 · 2024-02-01 21:42:54 -05:00
parent c7508fea46
commit 62112cd2fd
15 changed files with 275 additions and 88 deletions
--- a/photon-client/src/components/cameras/CameraCalibrationCard.vue
+++ b/photon-client/src/components/cameras/CameraCalibrationCard.vue
@@ -25,15 +25,8 @@ const getUniqueVideoFormatsByResolution = (): VideoFormat[] => {

      const calib = useCameraSettingsStore().getCalibrationCoeffs(format.resolution);
      if (calib !== undefined) {
-        // Is this the right formula for RMS error? who knows! not me!
-        const perViewSumSquareReprojectionError = calib.observations.flatMap((it) =>
-          it.reprojectionErrors.flatMap((it2) => [it2.x, it2.y])
-        );
        // For each error, square it, sum the squares, and divide by total points N
-        format.mean = Math.sqrt(
-          perViewSumSquareReprojectionError.map((it) => Math.pow(it, 2)).reduce((a, b) => a + b, 0) /
-            perViewSumSquareReprojectionError.length
-        );
+        format.mean = calib.meanErrors.reduce((a, b) => a + b) / calib.meanErrors.length;

        format.horizontalFOV =
          2 * Math.atan2(format.resolution.width / 2, calib.cameraIntrinsics.data[0]) * (180 / Math.PI);
--- a/photon-client/src/components/cameras/CameraCalibrationInfoCard.vue
+++ b/photon-client/src/components/cameras/CameraCalibrationInfoCard.vue
@@ -1,51 +1,19 @@
 <script setup lang="ts">
-import type { BoardObservation, CameraCalibrationResult, VideoFormat } from "@/types/SettingTypes";
+import type { CameraCalibrationResult, VideoFormat } from "@/types/SettingTypes";
 import { useCameraSettingsStore } from "@/stores/settings/CameraSettingsStore";
 import { useStateStore } from "@/stores/StateStore";
-import { ref } from "vue";
-import loadingImage from "@/assets/images/loading.svg";
+import { computed, inject, ref } from "vue";
 import { getResolutionString, parseJsonFile } from "@/lib/PhotonUtils";

 const props = defineProps<{
  videoFormat: VideoFormat;
 }>();

-const getMeanFromView = (o: BoardObservation) => {
-  // Is this the right formula for RMS error? who knows! not me!
-  const perViewSumSquareReprojectionError = o.reprojectionErrors.flatMap((it2) => [it2.x, it2.y]);
-
-  // For each error, square it, sum the squares, and divide by total points N
-  return Math.sqrt(
-    perViewSumSquareReprojectionError.map((it) => Math.pow(it, 2)).reduce((a, b) => a + b, 0) /
-      perViewSumSquareReprojectionError.length
-  );
+const exportCalibration = ref();
+const openExportCalibrationPrompt = () => {
+  exportCalibration.value.click();
 };

-// Import and export functions
-const downloadCalibration = () => {
-  const calibData = useCameraSettingsStore().getCalibrationCoeffs(props.videoFormat.resolution);
-  if (calibData === undefined) {
-    useStateStore().showSnackbarMessage({
-      color: "error",
-      message:
-        "Calibration data isn't available for the requested resolution, please calibrate the requested resolution first"
-    });
-    return;
-  }
-
-  const camUniqueName = useCameraSettingsStore().currentCameraSettings.uniqueName;
-  const filename = `photon_calibration_${camUniqueName}_${calibData.resolution.width}x${calibData.resolution.height}.json`;
-  const fileData = JSON.stringify(calibData);
-
-  const element = document.createElement("a");
-  element.style.display = "none";
-  element.setAttribute("href", "data:text/plain;charset=utf-8," + encodeURIComponent(fileData));
-  element.setAttribute("download", filename);
-
-  document.body.appendChild(element);
-  element.click();
-  document.body.removeChild(element);
-};
 const importCalibrationFromPhotonJson = ref();
 const openUploadPhotonCalibJsonPrompt = () => {
  importCalibrationFromPhotonJson.value.click();
@@ -97,19 +65,28 @@ const importCalibration = async () => {
 };

 interface ObservationDetails {
-  snapshotSrc: any;
  mean: number;
  index: number;
 }
+
+const currentCalibrationCoeffs = computed<CameraCalibrationResult | undefined>(() =>
+  useCameraSettingsStore().getCalibrationCoeffs(props.videoFormat.resolution)
+);
+
 const getObservationDetails = (): ObservationDetails[] | undefined => {
-  return useCameraSettingsStore()
-    .getCalibrationCoeffs(props.videoFormat.resolution)
-    ?.observations.map((o, i) => ({
-      index: i,
-      mean: parseFloat(getMeanFromView(o).toFixed(2)),
-      snapshotSrc: o.includeObservationInCalibration ? "data:image/png;base64," + o.snapshotData.data : loadingImage
-    }));
+  const coefficients = currentCalibrationCoeffs.value;
+
+  return coefficients?.meanErrors.map((m, i) => ({
+    index: i,
+    mean: parseFloat(m.toFixed(2))
+  }));
 };
+
+const exportCalibrationURL = computed<string>(() =>
+  useCameraSettingsStore().getCalJSONUrl(inject("backendHost") as string, props.videoFormat.resolution)
+);
+const calibrationImageURL = (index: number) =>
+  useCameraSettingsStore().getCalImageUrl(inject<string>("backendHost") as string, props.videoFormat.resolution, index);
 </script>

 <template>
@@ -140,19 +117,22 @@ const getObservationDetails = (): ObservationDetails[] | undefined => {
        <v-btn
          color="secondary"
          class="mt-4"
-          :disabled="useCameraSettingsStore().getCalibrationCoeffs(props.videoFormat.resolution) === undefined"
+          :disabled="!currentCalibrationCoeffs"
          style="width: 100%"
-          @click="downloadCalibration"
+          @click="openExportCalibrationPrompt"
        >
          <v-icon left>mdi-export</v-icon>
          <span>Export</span>
        </v-btn>
+        <a
+          ref="exportCalibration"
+          style="color: black; text-decoration: none; display: none"
+          :href="exportCalibrationURL"
+          target="_blank"
+        />
      </v-col>
    </v-row>
-    <v-row
-      v-if="useCameraSettingsStore().getCalibrationCoeffs(props.videoFormat.resolution) !== undefined"
-      class="pt-2"
-    >
+    <v-row v-if="!currentCalibrationCoeffs" class="pt-2">
      <v-card-subtitle>Calibration Details</v-card-subtitle>
      <v-simple-table dense style="width: 100%" class="pl-2 pr-2">
        <template #default>
@@ -231,7 +211,9 @@ const getObservationDetails = (): ObservationDetails[] | undefined => {
            </tr>
            <tr>
              <td>Horizontal FOV</td>
-              <td>{{ videoFormat.horizontalFOV !== undefined ? videoFormat.horizontalFOV.toFixed(2) + "°" : "-" }}</td>
+              <td>
+                {{ videoFormat.horizontalFOV !== undefined ? videoFormat.horizontalFOV.toFixed(2) + "°" : "-" }}
+              </td>
            </tr>
            <tr>
              <td>Vertical FOV</td>
@@ -242,11 +224,7 @@ const getObservationDetails = (): ObservationDetails[] | undefined => {
              <td>{{ videoFormat.diagonalFOV !== undefined ? videoFormat.diagonalFOV.toFixed(2) + "°" : "-" }}</td>
            </tr>
            <!-- Board warp, only shown for mrcal-calibrated cameras -->
-            <tr
-              v-if="
-                useCameraSettingsStore().getCalibrationCoeffs(props.videoFormat.resolution)?.calobjectWarp?.length === 2
-              "
-            >
+            <tr v-if="currentCalibrationCoeffs?.calobjectWarp?.length === 2">
              <td>Board warp, X/Y</td>
              <td>
                {{
@@ -278,7 +256,7 @@ const getObservationDetails = (): ObservationDetails[] | undefined => {
        <template #expanded-item="{ headers, item }">
          <td :colspan="headers.length">
            <div style="display: flex; justify-content: center; width: 100%">
-              <img :src="item.snapshotSrc" alt="observation image" class="snapshot-preview pt-2 pb-2" />
+              <img :src="calibrationImageURL(item.index)" alt="observation image" class="snapshot-preview pt-2 pb-2" />
            </div>
          </td>
        </template>
--- a/photon-client/src/stores/settings/CameraSettingsStore.ts
+++ b/photon-client/src/stores/settings/CameraSettingsStore.ts
@@ -416,6 +416,23 @@ export const useCameraSettingsStore = defineStore("cameraSettings", {
      cameraIndex: number = useStateStore().currentCameraIndex
    ): CameraCalibrationResult | undefined {
      return this.cameras[cameraIndex].completeCalibrations.find((v) => resolutionsAreEqual(v.resolution, resolution));
+    },
+    getCalImageUrl(host: string, resolution: Resolution, idx: number, cameraIdx = useStateStore().currentCameraIndex) {
+      const url = new URL(`http://${host}/api/utils/getCalSnapshot`);
+      url.searchParams.set("width", Math.round(resolution.width).toFixed(0));
+      url.searchParams.set("height", Math.round(resolution.height).toFixed(0));
+      url.searchParams.set("snapshotIdx", Math.round(idx).toFixed(0));
+      url.searchParams.set("cameraIdx", Math.round(cameraIdx).toFixed(0));
+
+      return url.href;
+    },
+    getCalJSONUrl(host: string, resolution: Resolution, cameraIdx = useStateStore().currentCameraIndex) {
+      const url = new URL(`http://${host}/api/utils/getCalibrationJSON`);
+      url.searchParams.set("width", Math.round(resolution.width).toFixed(0));
+      url.searchParams.set("height", Math.round(resolution.height).toFixed(0));
+      url.searchParams.set("cameraIdx", Math.round(cameraIdx).toFixed(0));
+
+      return url.href;
    }
  }
 });
--- a/photon-client/src/types/SettingTypes.ts
+++ b/photon-client/src/types/SettingTypes.ts
@@ -138,6 +138,9 @@ export interface CameraCalibrationResult {
  distCoeffs: JsonMatOfDouble;
  observations: BoardObservation[];
  calobjectWarp?: number[];
+  // We might have to omit observations for bandwith, so backend will send us this
+  numSnapshots: number;
+  meanErrors: number[];
 }

 export enum ValidQuirks {
@@ -255,7 +258,9 @@ export const PlaceholderCameraSettings: CameraSettings = {
          snapshotName: "img0.png",
          snapshotData: { rows: 480, cols: 640, type: CvType.CV_8U, data: "" }
        }
-      ]
+      ],
+      numSnapshots: 1,
+      meanErrors: [123.45]
    }
  ],
  pipelineNicknames: ["Placeholder Pipeline"],
--- a/photon-core/src/main/java/org/photonvision/common/configuration/PhotonConfiguration.java
+++ b/photon-core/src/main/java/org/photonvision/common/configuration/PhotonConfiguration.java
@@ -31,7 +31,7 @@ import org.photonvision.common.util.SerializationUtils;
 import org.photonvision.jni.RknnDetectorJNI;
 import org.photonvision.mrcal.MrCalJNILoader;
 import org.photonvision.raspi.LibCameraJNILoader;
-import org.photonvision.vision.calibration.CameraCalibrationCoefficients;
+import org.photonvision.vision.calibration.UICameraCalibrationCoefficients;
 import org.photonvision.vision.camera.QuirkyCamera;
 import org.photonvision.vision.processes.VisionModule;
 import org.photonvision.vision.processes.VisionModuleManager;
@@ -126,13 +126,6 @@ public class PhotonConfiguration {

        settingsSubmap.put("networkSettings", netConfigMap);

-        map.put(
-                "cameraSettings",
-                VisionModuleManager.getInstance().getModules().stream()
-                        .map(VisionModule::toUICameraConfig)
-                        .map(SerializationUtils::objectToHashMap)
-                        .collect(Collectors.toList()));
-
        var lightingConfig = new UILightingConfig();
        lightingConfig.brightness = hardwareSettings.ledBrightnessPercentage;
        lightingConfig.supported = !hardwareConfig.ledPins.isEmpty();
@@ -181,7 +174,7 @@ public class PhotonConfiguration {
        public HashMap<Integer, HashMap<String, Object>> videoFormatList;
        public int outputStreamPort;
        public int inputStreamPort;
-        public List<CameraCalibrationCoefficients> calibrations;
+        public List<UICameraCalibrationCoefficients> calibrations;
        public boolean isFovConfigurable = true;
        public QuirkyCamera cameraQuirks;
        public boolean isCSICamera;
--- a/photon-core/src/main/java/org/photonvision/common/dataflow/websocket/UIDataPublisher.java
+++ b/photon-core/src/main/java/org/photonvision/common/dataflow/websocket/UIDataPublisher.java
@@ -26,6 +26,7 @@ import org.photonvision.common.logging.LogGroup;
 import org.photonvision.common.logging.Logger;
 import org.photonvision.common.util.SerializationUtils;
 import org.photonvision.vision.pipeline.result.CVPipelineResult;
+import org.photonvision.vision.pipeline.result.CalibrationPipelineResult;

 public class UIDataPublisher implements CVPipelineResultConsumer {
    private static final Logger logger = new Logger(UIDataPublisher.class, LogGroup.VisionModule);
@@ -41,16 +42,22 @@ public class UIDataPublisher implements CVPipelineResultConsumer {
    public void accept(CVPipelineResult result) {
        long now = System.currentTimeMillis();

-        // only update the UI at 15hz
+        // only update the UI at 10hz
        if (lastUIResultUpdateTime + 1000.0 / 10.0 > now) return;

        var dataMap = new HashMap<String, Object>();
        dataMap.put("fps", result.fps);
        dataMap.put("latency", result.getLatencyMillis());
        var uiTargets = new ArrayList<HashMap<String, Object>>(result.targets.size());
-        for (var t : result.targets) {
-            uiTargets.add(t.toHashMap());
+
+        // We don't actually need to send targets during calibration and it can take up a lot (up to
+        // 1.2Mbps for 60 snapshots) of target results with no pitch/yaw/etc set
+        if (!(result instanceof CalibrationPipelineResult)) {
+            for (var t : result.targets) {
+                uiTargets.add(t.toHashMap());
+            }
        }
+
        dataMap.put("targets", uiTargets);
        dataMap.put("classNames", result.objectDetectionClassNames);

--- a/photon-core/src/main/java/org/photonvision/vision/calibration/BoardObservation.java
+++ b/photon-core/src/main/java/org/photonvision/vision/calibration/BoardObservation.java
@@ -24,7 +24,7 @@ import java.util.List;
 import org.opencv.core.Point;
 import org.opencv.core.Point3;

-public final class BoardObservation {
+public final class BoardObservation implements Cloneable {
    // Expected feature 3d location in the camera frame
    @JsonProperty("locationInObjectSpace")
    public List<Point3> locationInObjectSpace;
@@ -68,4 +68,33 @@ public final class BoardObservation {
        this.snapshotName = snapshotName;
        this.snapshotData = snapshotData;
    }
+
+    @Override
+    public String toString() {
+        return "BoardObservation [locationInObjectSpace="
+                + locationInObjectSpace
+                + ", locationInImageSpace="
+                + locationInImageSpace
+                + ", reprojectionErrors="
+                + reprojectionErrors
+                + ", optimisedCameraToObject="
+                + optimisedCameraToObject
+                + ", includeObservationInCalibration="
+                + includeObservationInCalibration
+                + ", snapshotName="
+                + snapshotName
+                + ", snapshotData="
+                + snapshotData
+                + "]";
+    }
+
+    @Override
+    public BoardObservation clone() {
+        try {
+            return (BoardObservation) super.clone();
+        } catch (CloneNotSupportedException e) {
+            System.err.println("Guhhh clone buh");
+            return null;
+        }
+    }
 }
--- a/photon-core/src/main/java/org/photonvision/vision/calibration/CameraCalibrationCoefficients.java
+++ b/photon-core/src/main/java/org/photonvision/vision/calibration/CameraCalibrationCoefficients.java
@@ -191,8 +191,8 @@ public class CameraCalibrationCoefficients implements Releasable {
                + cameraIntrinsics
                + ", distCoeffs="
                + distCoeffs
-                + ", observations="
-                + observations
+                + ", observationslen="
+                + observations.size()
                + ", calobjectWarp="
                + Arrays.toString(calobjectWarp)
                + ", intrinsicsArr="
@@ -201,4 +201,16 @@ public class CameraCalibrationCoefficients implements Releasable {
                + Arrays.toString(distCoeffsArr)
                + "]";
    }
+
+    public UICameraCalibrationCoefficients cloneWithoutObservations() {
+        return new UICameraCalibrationCoefficients(
+                resolution,
+                cameraIntrinsics,
+                distCoeffs,
+                calobjectWarp,
+                observations,
+                calobjectSize,
+                calobjectSpacing,
+                lensmodel);
+    }
 }
--- a/photon-core/src/main/java/org/photonvision/vision/calibration/JsonImageMat.java
+++ b/photon-core/src/main/java/org/photonvision/vision/calibration/JsonImageMat.java
@@ -76,4 +76,17 @@ public class JsonImageMat implements Releasable {
    public void release() {
        if (wrappedMat != null) wrappedMat.release();
    }
+
+    @Override
+    public String toString() {
+        return "JsonImageMat [rows="
+                + rows
+                + ", cols="
+                + cols
+                + ", type="
+                + type
+                + ", datalen="
+                + data.length()
+                + "]";
+    }
 }
--- a/photon-core/src/main/java/org/photonvision/vision/calibration/JsonMatOfDouble.java
+++ b/photon-core/src/main/java/org/photonvision/vision/calibration/JsonMatOfDouble.java
@@ -40,7 +40,7 @@ public class JsonMatOfDouble implements Releasable {
    @JsonIgnore private Mat wrappedMat = null;
    @JsonIgnore private Matrix wpilibMat = null;

-    private MatOfDouble wrappedMatOfDouble;
+    @JsonIgnore private MatOfDouble wrappedMatOfDouble;

    public JsonMatOfDouble(int rows, int cols, double[] data) {
        this(rows, cols, CvType.CV_64FC1, data);
--- a/photon-core/src/main/java/org/photonvision/vision/calibration/UICameraCalibrationCoefficients.java
+++ b/photon-core/src/main/java/org/photonvision/vision/calibration/UICameraCalibrationCoefficients.java
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) Photon Vision.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package org.photonvision.vision.calibration;
+
+import java.util.List;
+import java.util.stream.Collectors;
+import org.opencv.core.Size;
+
+public class UICameraCalibrationCoefficients extends CameraCalibrationCoefficients {
+    public int numSnapshots;
+    public List<Double> meanErrors;
+
+    public UICameraCalibrationCoefficients(
+            Size resolution,
+            JsonMatOfDouble cameraIntrinsics,
+            JsonMatOfDouble distCoeffs,
+            double[] calobjectWarp,
+            List<BoardObservation> observations,
+            Size calobjectSize,
+            double calobjectSpacing,
+            CameraLensModel lensmodel) {
+        // yeet observations, keep all else
+        super(
+                resolution,
+                cameraIntrinsics,
+                distCoeffs,
+                calobjectWarp,
+                List.of(),
+                calobjectSize,
+                calobjectSpacing,
+                lensmodel);
+
+        this.numSnapshots = observations.size();
+        this.meanErrors =
+                observations.stream()
+                        .map(
+                                it2 ->
+                                        it2.reprojectionErrors.stream()
+                                                .mapToDouble(it -> Math.sqrt(it.x * it.x + it.y * it.y))
+                                                .average()
+                                                .orElse(0))
+                        .collect(Collectors.toList());
+    }
+}
--- a/photon-core/src/main/java/org/photonvision/vision/processes/VisionModule.java
+++ b/photon-core/src/main/java/org/photonvision/vision/processes/VisionModule.java
@@ -26,6 +26,7 @@ import java.util.HashMap;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.function.BiConsumer;
+import java.util.stream.Collectors;
 import org.opencv.core.Size;
 import org.photonvision.common.configuration.CameraConfiguration;
 import org.photonvision.common.configuration.ConfigManager;
@@ -536,7 +537,10 @@ public class VisionModule {
        ret.outputStreamPort = this.outputStreamPort;
        ret.inputStreamPort = this.inputStreamPort;

-        ret.calibrations = visionSource.getSettables().getConfiguration().calibrations;
+        ret.calibrations =
+                visionSource.getSettables().getConfiguration().calibrations.stream()
+                        .map(CameraCalibrationCoefficients::cloneWithoutObservations)
+                        .collect(Collectors.toList());

        ret.isFovConfigurable =
                !(ConfigManager.getInstance().getConfig().getHardwareConfig().hasPresetFOV()
--- a/photon-server/src/main/java/org/photonvision/server/DataSocketHandler.java
+++ b/photon-server/src/main/java/org/photonvision/server/DataSocketHandler.java
@@ -350,8 +350,7 @@ public class DataSocketHandler {
        }
    }

-    private void sendMessage(Object message, WsContext user) throws JsonProcessingException {
-        ByteBuffer b = ByteBuffer.wrap(objectMapper.writeValueAsBytes(message));
+    private void sendMessage(ByteBuffer b, WsContext user) throws JsonProcessingException {
        if (user.session.isOpen()) {
            user.send(b);
        }
@@ -359,16 +358,18 @@ public class DataSocketHandler {

    public void broadcastMessage(Object message, WsContext userToSkip)
            throws JsonProcessingException {
+        ByteBuffer b = ByteBuffer.wrap(objectMapper.writeValueAsBytes(message));
+
        if (userToSkip == null) {
            for (WsContext user : users) {
-                sendMessage(message, user);
+                sendMessage(b, user);
            }
        } else {
            var skipUserPort = ((InetSocketAddress) userToSkip.session.getRemoteAddress()).getPort();
            for (WsContext user : users) {
                var userPort = ((InetSocketAddress) user.session.getRemoteAddress()).getPort();
                if (userPort != skipUserPort) {
-                    sendMessage(message, user);
+                    sendMessage(b, user);
                }
            }
        }
--- a/photon-server/src/main/java/org/photonvision/server/RequestHandler.java
+++ b/photon-server/src/main/java/org/photonvision/server/RequestHandler.java
@@ -31,6 +31,9 @@ import java.util.HashMap;
 import java.util.Optional;
 import javax.imageio.ImageIO;
 import org.apache.commons.io.FileUtils;
+import org.opencv.core.MatOfByte;
+import org.opencv.core.MatOfInt;
+import org.opencv.imgcodecs.Imgcodecs;
 import org.photonvision.common.configuration.ConfigManager;
 import org.photonvision.common.configuration.NetworkConfig;
 import org.photonvision.common.dataflow.DataChangeDestination;
@@ -580,6 +583,77 @@ public class RequestHandler {
        ctx.status(204);
    }

+    public static void onCalibrationSnapshotRequest(Context ctx) {
+        logger.info(ctx.queryString().toString());
+
+        int idx = Integer.parseInt(ctx.queryParam("cameraIdx"));
+        var width = Integer.parseInt(ctx.queryParam("width"));
+        var height = Integer.parseInt(ctx.queryParam("height"));
+        var observationIdx = Integer.parseInt(ctx.queryParam("snapshotIdx"));
+
+        CameraCalibrationCoefficients calList =
+                VisionModuleManager.getInstance()
+                        .getModule(idx)
+                        .getStateAsCameraConfig()
+                        .calibrations
+                        .stream()
+                        .filter(
+                                it ->
+                                        Math.abs(it.resolution.width - width) < 1e-4
+                                                && Math.abs(it.resolution.height - height) < 1e-4)
+                        .findFirst()
+                        .orElse(null);
+
+        if (calList == null || calList.observations.size() < observationIdx) {
+            ctx.status(404);
+            return;
+        }
+
+        // encode as jpeg to save even more space. reduces size of a 1280p image from 300k to 25k
+        var jpegBytes = new MatOfByte();
+        Imgcodecs.imencode(
+                ".jpg",
+                calList.observations.get(observationIdx).snapshotData.getAsMat(),
+                jpegBytes,
+                new MatOfInt(Imgcodecs.IMWRITE_JPEG_QUALITY, 60));
+
+        ctx.result(jpegBytes.toArray());
+        jpegBytes.release();
+
+        ctx.status(200);
+    }
+
+    public static void onCalibrationExportRequest(Context ctx) {
+        logger.info(ctx.queryString().toString());
+
+        int idx = Integer.parseInt(ctx.queryParam("cameraIdx"));
+        var width = Integer.parseInt(ctx.queryParam("width"));
+        var height = Integer.parseInt(ctx.queryParam("height"));
+
+        var cc = VisionModuleManager.getInstance().getModule(idx).getStateAsCameraConfig();
+
+        CameraCalibrationCoefficients calList =
+                cc.calibrations.stream()
+                        .filter(
+                                it ->
+                                        Math.abs(it.resolution.width - width) < 1e-4
+                                                && Math.abs(it.resolution.height - height) < 1e-4)
+                        .findFirst()
+                        .orElse(null);
+
+        if (calList == null) {
+            ctx.status(404);
+            return;
+        }
+
+        var filename = "photon_calibration_" + cc.uniqueName + "_" + width + "x" + height + ".json";
+        ctx.contentType("application/zip");
+        ctx.header("Content-Disposition", "attachment; filename=\"" + filename + "\"");
+        ctx.json(calList);
+
+        ctx.status(200);
+    }
+
    public static void onImageSnapshotsRequest(Context ctx) {
        var snapshots = new ArrayList<HashMap<String, Object>>();
        var cameraDirs = ConfigManager.getInstance().getImageSavePath().toFile().listFiles();
--- a/photon-server/src/main/java/org/photonvision/server/Server.java
+++ b/photon-server/src/main/java/org/photonvision/server/Server.java
@@ -130,6 +130,8 @@ public class Server {
        app.post("/api/utils/restartDevice", RequestHandler::onDeviceRestartRequest);
        app.post("/api/utils/publishMetrics", RequestHandler::onMetricsPublishRequest);
        app.get("/api/utils/getImageSnapshots", RequestHandler::onImageSnapshotsRequest);
+        app.get("/api/utils/getCalSnapshot", RequestHandler::onCalibrationSnapshotRequest);
+        app.get("/api/utils/getCalibrationJSON", RequestHandler::onCalibrationExportRequest);

        // Calibration
        app.post("/api/calibration/end", RequestHandler::onCalibrationEndRequest);