fix: remove DC offset if AQ_mod is qsim (#1804)

cheminfo · Oct 13, 2022 · 135a072 · 135a072
1 parent bc1bd11
commit 135a072
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Showing 2 changed files with 32 additions and 5 deletions.
diff --git a/src/component/panels/SpectrumsPanel/base/setting/processSnapPlot.ts b/src/component/panels/SpectrumsPanel/base/setting/processSnapPlot.ts
@@ -2,7 +2,6 @@ import { xyReduce } from 'ml-spectra-processing';
 
 import { Data1D } from '../../../../../data/types/data1d';
 import { Data2D } from '../../../../../data/types/data2d';
-
 import { calculateSanPlot } from '../../../../../data/utilities/calculateSanPlot';
 
 export function processSnapPlot<T extends '1D' | '2D'>(

diff --git a/src/data/data1d/filter1d/fft.ts b/src/data/data1d/filter1d/fft.ts
@@ -1,4 +1,4 @@
-import { reimFFT, reimPhaseCorrection } from 'ml-spectra-processing';
+import { reimFFT, reimPhaseCorrection, xMean } from 'ml-spectra-processing';
 
 import { Datum1D } from '../../types/data1d/Datum1D';
 
@@ -21,21 +21,26 @@ export function apply(datum1D: Datum1D) {
     (e) => e.name === 'digitalFilter' && e.flag,
   );
 
-  const { data } = datum1D;
+  const data =
+    datum1D.meta.AQ_mod === 1
+      ? removeDCOffset(datum1D, digitalFilterApplied)
+      : { ...datum1D.data };
+
   if (data.x.length !== data.re.length || data.x.length !== data.im.length) {
     throw new Error('The length of data should be equal');
   } else if (!isPowerOfTwo(datum1D.data.x.length)) {
     padDataToNextPowerOfTwo(datum1D, digitalFilterApplied);
   }
 
-  Object.assign(datum1D.data, reimFFT(datum1D.data, { applyZeroShift: true }));
+  Object.assign(data, reimFFT(data, { applyZeroShift: true }));
 
   if (digitalFilterApplied) {
     let { digitalFilter = 0 } = datum1D.info;
     let ph1 = (digitalFilter - Math.floor(digitalFilter)) * Math.PI * 2;
-    Object.assign(datum1D.data, reimPhaseCorrection(datum1D.data, 0, ph1));
+    Object.assign(data, reimPhaseCorrection(data, 0, ph1));
   }
 
+  Object.assign(datum1D.data, data);
   datum1D.data.x = generateXAxis(datum1D);
   datum1D.info = { ...datum1D.info, isFid: false, isFt: true };
 }
@@ -73,3 +78,26 @@ function generateXAxis(datum1D) {
 function isPowerOfTwo(n) {
   return n !== 0 && (n & (n - 1)) === 0;
 }
+
+function removeDCOffset(datum1D, digitalFilterApplied) {
+  let { digitalFilter = 0 } = digitalFilterApplied ? datum1D.info : {};
+  const data = { ...datum1D.data };
+  const nbPoints = data.re.length;
+  const newRe = new Float64Array(data.re);
+  const newIm = new Float64Array(data.im);
+  const averageRe = xMean(
+    data.re.slice((nbPoints * 0.75) >> 0, nbPoints - digitalFilter),
+  );
+  const averageIm = xMean(
+    data.im.slice((nbPoints * 0.75) >> 0, nbPoints - digitalFilter),
+  );
+  for (
+    let i = digitalFilterApplied ? 0 : digitalFilter;
+    i < nbPoints - digitalFilter;
+    i++
+  ) {
+    newRe[i] -= averageRe;
+    newIm[i] -= averageIm;
+  }
+  return { x: data.x, re: newRe, im: newIm };
+}