我必须在 Android 中使用 RenderScript 从 ARGB 数组创建 HSV 直方图。这是我第一次使用 RenderScript,我不确定我是否犯了错误,因为性能不是很好。从 1920x1080 位图创建 HSV 直方图需要 100 到 150 毫秒。
渲染脚本代码:
#pragma version(1)
#pragma rs java_package_name(com.test.renderscript)
#pragma rs_fp_relaxed
uchar3 bins;
rs_allocation histogramAllocation;
void __attribute__((kernel)) process(uchar4 in) {
float r = in.r / 255.0;
float g = in.g / 255.0;
float b = in.b / 255.0;
// convert rgb to hsv
float minRGB = min( r, min( g, b ) );
float maxRGB = max( r, max( g, b ) );
float deltaRGB = maxRGB - minRGB;
float h = 0.0;
float s = maxRGB == 0 ? 0 : (maxRGB - minRGB) / maxRGB;
float v = maxRGB;
if (deltaRGB != 0) {
if (r == maxRGB) {
h = (g - b) / deltaRGB;
}
else {
if (g == maxRGB) {
h = 2 + (b - r) / deltaRGB;
}
else {
h = 4 + (r - g) / deltaRGB;
}
}
h *= 60;
if (h < 0) { h += 360; }
if (h == 360) { h = 0; }
}
// quantize hsv
uint qh = h / (360.0 / bins.s0);
uint qs = (s * 100) / (101.0 / bins.s1);
uint qv = (v * 100) / (101.0 / bins.s2);
// calculate bin index and update the count at that index
// (v * bin size H * bin size S) + (s * bin size H) + h;
uint binIndex = (qv * bins.s0 * bins.s1) + (qs * bins.s0) + qh;
uint count = rsGetElementAt_uint(histogramAllocation, binIndex);
rsSetElementAt_uint(histogramAllocation, (count + 1), binIndex);
}
void init() {
uint histogramSize = bins.s0 * bins.s1 * bins.s2;
for (int i=0; i < histogramSize; i++) {
rsSetElementAt_uint(histogramAllocation, 0, i);
}
}
科特林代码:
class RsCreateHsvHistogram {
fun execute(rs: RenderScript, src: ByteArray, bins: HsvHistogram.Bins = HsvHistogram.Bins()): HsvHistogram {
val start = SystemClock.elapsedRealtimeNanos()
val histogramSize = bins.h * bins.s * bins.v
// create input allocation
val typeIn = Type.Builder(rs, Element.U8_4(rs))
.setX(src.size / 4)
.create()
val allocIn = Allocation.createTyped(rs, typeIn)
allocIn.copyFrom(src)
// create output allocation -> the histogram allocation
val typeOut = Type.Builder(rs, Element.I32(rs))
.setX(histogramSize)
.create()
val allocOut = Allocation.createTyped(rs, typeOut)
// run the render script
val script = ScriptC_create_hsv_histogram(rs)
script._bins = Short3(bins.h, bins.s, bins.v)
script._histogramAllocation = allocOut
script.forEach_process(allocIn)
// copy output allocation to histogram array
val histogramData = IntArray(histogramSize)
allocOut.copyTo(histogramData)
val stop = SystemClock.elapsedRealtimeNanos()
Timber.e("duration => ${(stop-start) / 1000000.0} ms")
return HsvHistogram(histogramData, bins)
}
}
我希望你能帮助我提高性能。您认为 HSV 直方图的创建可以在 20 毫秒左右完成吗?这是现实的吗?