adding video common (correct this time) (#351)

common/BUILD

@@ -105,4 +105,4 @@ cc_test(
     "@bs_thread_pool",
     "@com_google_googletest//:gtest_main",
   ],
-)
+)

common/video/BUILD

@@ -0,0 +1,21 @@
+package(features=["warning_compile_flags"])
+
+cc_library(
+  name = "image_compare",
+  hdrs = ["image_compare.hh"],
+  srcs = ["image_compare.cc"],
+  deps = [
+    "@eigen//:eigen",
+    "@opencv",
+  ],
+  visibility = ["//visibility:public"],
+)
+
+cc_test(
+  name = "image_compare_test",
+  srcs = ["image_compare_test.cc"],
+  deps = [
+    ":image_compare",
+    "@com_google_googletest//:gtest_main",
+  ]
+)

common/video/image_compare.cc

@@ -0,0 +1,15 @@
+#include "opencv2/opencv.hpp"
+
+namespace robot::common::video {
+
+bool images_equal(const cv::Mat& img1, const cv::Mat& img2) {
+    if (img1.size() != img2.size() || img1.type() != img2.type()) {
+        return false;
+    }
+    cv::Mat diff;
+    cv::absdiff(img1, img2, diff);
+    diff = diff.reshape(1);
+    return cv::countNonZero(diff) == 0;
+}
+
+}  // namespace robot::common::video

common/video/image_compare.hh

@@ -0,0 +1,9 @@
+#pragma once
+
+#include "opencv2/opencv.hpp"
+
+namespace robot::common::video {
+
+bool images_equal(const cv::Mat& img1, const cv::Mat& img2);
+
+}

common/video/image_compare_test.cc

@@ -0,0 +1,33 @@
+#include "common/video/image_compare.hh"
+
+#include <gtest/gtest.h>
+
+#include "opencv2/opencv.hpp"
+
+namespace robot::common::video {
+
+TEST(ImageCompareTest, ImagesEqual_SameImages) {
+    cv::Mat img1 = cv::Mat::zeros(100, 100, CV_8UC3);
+    cv::Mat img2 = img1.clone();
+    EXPECT_TRUE(images_equal(img1, img2));
+}
+
+TEST(ImageCompareTest, ImagesEqual_DifferentSizes) {
+    cv::Mat img1 = cv::Mat::zeros(100, 100, CV_8UC3);
+    cv::Mat img2 = cv::Mat::zeros(200, 200, CV_8UC3);
+    EXPECT_FALSE(images_equal(img1, img2));
+}
+
+TEST(ImageCompareTest, ImagesEqual_DifferentTypes) {
+    cv::Mat img1 = cv::Mat::zeros(100, 100, CV_8UC3);
+    cv::Mat img2 = cv::Mat::zeros(100, 100, CV_8UC1);
+    EXPECT_FALSE(images_equal(img1, img2));
+}
+
+TEST(ImageCompareTest, ImagesEqual_DifferentContent) {
+    cv::Mat img1 = cv::Mat::zeros(100, 100, CV_8UC3);
+    cv::Mat img2 = cv::Mat::ones(100, 100, CV_8UC3);
+    EXPECT_FALSE(images_equal(img1, img2));
+}
+
+}  // namespace robot::common::video