Android Face Detection APIs, Page 2
Android Face Detection: Color vs. Grayscale
Generally speaking, face detection is mostly achieved by searching for high-contrast areas that resemble facial features, so results from grayscale images are usually not too far off those from color images. However, some researchers are still trying to improve the accuracy of face detection in color images. In reality, other factors such as lighting and occlusion will have an even bigger impact on the accuracy of face detection.
We ran through some sample grayscale and color images and got similar results from the Android APIs. Therefore, the APIs seem to ignore the factor of different color channels. One example is shown below in Figure 4.
Figure 4: Grayscale Face Detected in Android
In this tutorial, we introduced the simple face detector in Android APIs and worked through a real example. The entire software package is available for download; you can import it into Eclipse by selecting "Creating project from existing source." If you are interested in exploring Android face detection further, here are some helpful considerations:
- Many applications can potentially make good use of face detection. For example, it can be used to remove the red eye defect, count the number of people, correct camera focus, align face features, or create face databases.
- There are many publicly available face databases you can use for your own implementations. Find a listing here.
- In terms of real-time applications (e.g. live camera stream), the face detection performance from Android APIs could be less than satisfactory. Consider looking into OpenCV for Android.
Android Face Detection Code Download
About the Author
Chunyen Liu has been a software professional for many years. Some of his applications were among winners at programming contests administered by Sun, ACM, and IBM. He has co-authored software patents, written 20+ articles, reviewed books, and also created numerous hobby apps at Androidlet and The J Maker. He holds advanced degrees in Computer Science with knowledge from 20+ graduate-level courses. On the non-technical side, he is a tournament-ranked table tennis player, certified umpire, and certified coach of USA Table Tennis.