Add timing table in README.md

Author: hollaus

README.md

@@ -1,36 +1,11 @@
-# DocScan
-App for document scanning.
+# peed comparison between native and Java OpenCV calls
+This is just a quick and dirty branch for measuring OpenCV timings.
 
-<a href='https://play.google.com/store/apps/details?id=at.ac.tuwien.caa.docscan&pcampaignid=MKT-Other-global-all-co-prtnr-py-PartBadge-Mar2515-1'><img alt='Get it on Google Play' src='https://play.google.com/intl/en_us/badges/images/generic/en_badge_web_generic.png' width="250px"/></a>
+Results gained on Pixel 4A (in seconds). Mat size is 3000x4000.
 
-## Authors
-Fabian Hollaus,
-Florian Kleber,
-Markus Diem
-
-### Build Instructions
-DocScan makes use of native (C++) OpenCV and OpenCV Java API. The Java part is automatically downloaded after syncing,
-the native part is imported as a git submodule from `https://github.com/hollaus/opencv_libs.git` which also automatically
-downloads the resources.
-
-### Sync and build the project
-
-## API keys
-The app makes use of two APIs that require keys which are not published in the repository and should never be provided to the public. Instead not working dummy keys are provided in the following files:
-- `gradle.properties`: contains the key for Dropbox integration
-- `google-services.json`: contains the key for Firebase integration (needed for OCR)
-
-You can get the API key if you send a mail to docscan@cvl.tuwien.ac.at. Before you replace the dummy keys, assure that you do not commit the keys with the following commands:
-- `git update-index --assume-unchanged google-services.json`
-- `git update-index --assume-unchanged gradle.properties`
-
-## Cheatsheet
-In case you need a more detailed error message for build errors, try: ``.\gradlew clean build``
-
-## Visual Studio Project (C++ Library)
-- Optional for testing the C++ module
-- C++ lib for page segmentation and focus measure
-- use CMake to create a Visual Studio Project
-  - source code path: DocScan/app/src/main
-  - binaries path e.g.: DocScan/build2015-x64
-  - Specify OpenCV_DIR
+| Operation                     | C++   | Java  |
+| -------------                 |:-----:|:-----:|
+| Accessing mat pixel-wise     | 0.3   | 6     |
+| cv::remap (INTER_LANCZOS4)    | 0.75  | 0.75  |
+| cv::remap (INTER_LINEAR)      | 0.08  | 0.08  |
+| cv::remap (INTER_CUBIC)       | 0.05  | 0.05  |

app/src/main/cpp/PageSegmentation.cpp

@@ -489,7 +489,7 @@ namespace dsc {
         Utils::print("C++ updateMap took: " + std::to_string(secs) + " seconds", "DkPageSegmentation");
 
         t0 = cv::getTickCount();
-        remap( input, dst, map_x, map_y, cv::INTER_LANCZOS4, cv::BORDER_CONSTANT, cv::Scalar(0, 0, 0) );
+        remap( input, dst, map_x, map_y, cv::INTER_NEAREST, cv::BORDER_CONSTANT, cv::Scalar(0, 0, 0) );
         t1 = cv::getTickCount();
         secs = (t1-t0)/cv::getTickFrequency();
         Utils::print("C++ remap took: " + std::to_string(secs) + " seconds", "DkPageSegmentation");

app/src/main/java/at/ac/tuwien/caa/docscan/camera/cv/Remap.java

@@ -70,7 +70,7 @@ public void run(Mat src) {
         Log.d("Remap", "Java updateMap took: " + secs + " seconds");
 
         t0 = Core.getTickCount();
-        Imgproc.remap(input, dst, mapX, mapY, Imgproc.INTER_LANCZOS4);
+        Imgproc.remap(input, dst, mapX, mapY, Imgproc.INTER_NEAREST);
         t1 = Core.getTickCount();
         secs = (t1-t0) / Core.getTickFrequency();
         Log.d("Remap", "Java remap took: " + secs + " seconds");