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Commit eebb8349 authored by Eino-Ville Talvala's avatar Eino-Ville Talvala
Browse files

ImageFormat: Update definition of depth formats for confidence. 

DEPTH16: Use high 3 bits for confidence measurement, with
0 = 100% confidence, 1 = 0% confidence, 2 = 1/7 (14.3%) confidence, etc.

DEPTH_POINT_CLOUD: Add confidence as 4th entry to each point,
with a value in range 0.f - 1.f inclusive.

Bug: 20123879
Change-Id: I23317b922ac727751156fa418ed239a696a898e5
parent 85f4b7b3

graphics/java/android/graphics/ImageFormat.java

+41 −9
Original line number Diff line number Diff line
@@ -587,10 +587,29 @@ public class ImageFormat { 
    public static final int RAW12 = 0x26;



    /**

     * Android dense depth image format.

     *

     * Each pixel is 16 bits, representing a depth ranging measurement from

     * a depth camera or similar sensor.

     * <p>Android dense depth image format.</p>

     *

     * <p>Each pixel is 16 bits, representing a depth ranging measurement from a depth camera or

     * similar sensor. The 16-bit sample consists of a confidence value and the actual ranging

     * measurement.</p>

     *

     * <p>The confidence value is an estimate of correctness for this sample.  It is encoded in the

     * 3 most significant bits of the sample, with a value of 0 representing 100% confidence, a

     * value of 1 representing 0% confidence, a value of 2 representing 1/7, a value of 3

     * representing 2/7, and so on.</p>

     *

     * <p>As an example, the following sample extracts the range and confidence from the first pixel

     * of a DEPTH16-format {@link android.media.Image}, and converts the confidence to a

     * floating-point value between 0 and 1.f inclusive, with 1.f representing maximum confidence:

     *

     * <pre>

     *    ShortBuffer shortDepthBuffer = img.getPlanes()[0].getBuffer().asShortBuffer();

     *    short depthSample = shortDepthBuffer.get()

     *    short depthRange = (short) (depthSample & 0x1FFF);

     *    short depthConfidence = (short) ((depthSample >> 13) & 0x7);

     *    float depthPercentage = depthConfidence == 0 ? 1.f : (depthConfidence - 1) / 7.f;

     * </pre>

     * </p>

     *

     * <p>This format assumes

     * <ul>
@@ -602,19 +621,32 @@ public class ImageFormat { 
     *

     * <pre> y_size = stride * height </pre>

     *

     * When produced by a camera, the units are millimeters.

     * When produced by a camera, the units for the range are millimeters.

     */

    public static final int DEPTH16 = 0x44363159;



    /**

     * Android sparse depth point cloud format.

     *

     * <p>A variable-length list of 3D points, with each point represented

     * by a triple of floats.</p>

     * <p>A variable-length list of 3D points plus a confidence value, with each point represented

     * by four floats; first the X, Y, Z position coordinates, and then the confidence value.</p>

     *

     * <p>The number of points is {@code (size of the buffer in bytes) / 16}.

     *

     * <p>The coordinate system and units of the position values depend on the source of the point

     * cloud data. The confidence value is between 0.f and 1.f, inclusive, with 0 representing 0%

     * confidence and 1.f representing 100% confidence in the measured position values.</p>

     *

     * <p>The number of points is {@code (size of the buffer in bytes) / 12}.

     * <p>As an example, the following code extracts the first depth point in a DEPTH_POINT_CLOUD

     * format {@link android.media.Image}:

     * <pre>

     *    FloatBuffer floatDepthBuffer = img.getPlanes()[0].getBuffer().asFloatBuffer();

     *    float x = floatDepthBuffer.get();

     *    float y = floatDepthBuffer.get();

     *    float z = floatDepthBuffer.get();

     *    float confidence = floatDepthBuffer.get();

     * </pre>

     *

     * The coordinate system and units depend on the source of the point cloud data.

     */

    public static final int DEPTH_POINT_CLOUD = 0x101;