我正在使用public float calculateMeanFG(int[] histogram, int t) {
float sumI = 0;
int total = 0;
//cumulate the histogram for < 256
for (int i = t; i < 256; i++) {
sumI += histogram[i] * i;
total = i;
}
return sumI / total;
}
public float calculateMeanBG(int[] histogram, int t) {
float sumI = 0;
//cumulate the histogram for < t
for (int i = 0; i < t; i++) {
sumI += histogram[i] * i;
}
return sumI;
}
public float calculateWeightFG(int[] histogram, int t, int total) {
int sum = 0;
for (int i = t; i < 256; i++) {
sum += histogram[i];
}
return sum / total;
}
public int[] getHistogram(ImageProcessor ip, int height, int width) {
byte[] outP = ((byte[]) ip.getPixels()).clone();
int[][] inDataArr = new int[width][height];
int[] histogram = new int[256];
int idx = 0;
for (int y = 0; y < height; y++) {
for (int x = 0; x < width; x++) {
// fill in values
inDataArr[x][y] = outP[idx];
if (inDataArr[x][y] < 0) {
inDataArr[x][y] += 256;
} // if
histogram[inDataArr[x][y]] += 1; // count grayscale occurrences
idx++;
} // for x
} // for y
return histogram;
}
public int[][] convergeOptThresh(int[][] imgArr, int width, int height) {
int BG_VAL = 0;
int FG_VAL = 255;
int[] histogram = getHistogram(ip, height, width);
// total number of pixels
int total = imgArr.length;
// cumulative hist
float sum = 0;
for (int i = 0; i < 256; i++)
sum += i * histogram[i];
float sumBG = 0; // sum background
float weightBG = 0;
float weightFG = 0;
float varMax = 0;
int threshold = 0;
for (int t = 0; t < 256; t++) {
weightBG = calculateMeanBG(histogram, t);
weightBG /= total;
weightFG = calculateWeightFG(histogram, t, total);
if ((int)weightFG == 0)
break;
sumBG += (float) (t * histogram[t]);
float meanBG = sumBG / t;
float meanFG = calculateMeanFG(histogram, t);
// calculate between class variance
float varBetween = weightBG * weightFG * (meanBG - meanFG) * (meanBG - meanFG);
// check if new max found
if (varBetween > varMax) {
varMax = varBetween;
threshold = t;
}
}
IJ.log("optimal threshold: " + threshold);
int[][] retArr = new int[width][height];
for (int x = 0; x < width; x++) {
for (int y = 0; y < height; y++) {
if (imgArr[x][y] <= threshold) {
retArr[x][y] = BG_VAL;
} else {
retArr[x][y] = FG_VAL;
}
}
}
return retArr;
}
动态地将子组件添加到父组件，因此不要在父选择器模板或html中使用子选择器。
在这种情况下如何将数据从子组件传递到父组件？
答案 0 :(得分：0)
所以基本上让我们假设您拥有：
export class ChildComponent {
...
outputData: EventEmitter<any> = new EventEmitter<any>();
...
triggerChange() {
// here you just emit some data using event emitter
this.outputData.emit(someData);
}
}
然后在父组件中，您可以像这样从EventEmitter访问数据：
export class ParentComponent {
attachChild() {
...
let componentRef = viewContainerRef.createComponent(componentFactory);
(<ChildComponent>componentRef.instance).outputData.subscribe(this.outputData.bind(this));
}
onDataChange(someData) {
// here you can access child's data when event emitter triggers
// so basically it's the same if you subscribed on @Output field from template like (outputData)="onDataChange($event)"
console.log(someData);
}
}
希望有帮助。