fix: handle 0 to 1 threshold (#290)

* fix: handle 0 to 1 threshold

Closes: #288

* feat: allow threshold only from 0 to 1

* chore: fix prettier

* Update src/operations/threshold.ts

Co-authored-by: Michaël Zasso <[email protected]>

* test: fix error messages

---------

Co-authored-by: Michaël Zasso <[email protected]>

Author: opatiny

demo/components/testFunctions/testGetConvexHull.ts

@@ -8,7 +8,7 @@ import { fromMask, Image } from '../../../src';
  */
 export function testGetConvexHull(image: Image): Image {
   const grey = image.convertColor('GREY');
-  const mask = grey.threshold({ threshold: 35 });
+  const mask = grey.threshold({ threshold: 35 / 255 });
   const roiMapManager = fromMask(mask);
 
   const rois = roiMapManager.getRois({ kind: 'black' });

demo/components/testFunctions/testGetFeret.ts

@@ -8,7 +8,7 @@ import { fromMask, Image } from '../../../src';
  */
 export function testGetFeret(image: Image): Image {
   const grey = image.convertColor('GREY');
-  const mask = grey.threshold({ threshold: 35 });
+  const mask = grey.threshold({ threshold: 35 / 255 });
   const roiMapManager = fromMask(mask);
 
   const rois = roiMapManager.getRois({ kind: 'black' });

demo/components/testFunctions/testGetMbr.ts

@@ -8,7 +8,7 @@ import { fromMask, Image } from '../../../src';
  */
 export function testGetMbr(image: Image): Image {
   const grey = image.convertColor('GREY');
-  const mask = grey.threshold({ threshold: 35 });
+  const mask = grey.threshold({ threshold: 35 / 255 });
   const roiMapManager = fromMask(mask);
 
   const rois = roiMapManager.getRois({ kind: 'black' });

demo/components/testFunctions/testPaintMask.ts

@@ -6,7 +6,7 @@ import { fromMask, Image } from '../../../src';
  */
 export function testPaintMask(image: Image): Image {
   const grey = image.convertColor('GREY');
-  const mask = grey.threshold({ threshold: 100 });
+  const mask = grey.threshold({ threshold: 100 / 255 });
 
   const roiMapManager = fromMask(mask);
 

src/maskAnalysis/__tests__/getMbr.test.ts

@@ -208,7 +208,7 @@ test('empty mask', () => {
 test('draw mbr on large image', () => {
   const image = testUtils.load('various/grayscale_by_zimmyrose.png');
   const rgbaImage = image.convertColor('RGBA');
-  const mask = image.threshold({ threshold: 200 });
+  const mask = image.threshold({ threshold: 200 / 255 });
   const roiMapManager = fromMask(mask);
 
   const rois = roiMapManager.getRois({ kind: 'white' });

src/operations/__tests__/threshold.test.ts

@@ -3,7 +3,7 @@ import { computeThreshold, threshold } from '../threshold';
 test('threshold with a fixed value of 100', () => {
   const testImage = testUtils.load('opencv/test.png');
   const grey = testImage.convertColor('GREY');
-  const th = threshold(grey, { threshold: 100 });
+  const th = threshold(grey, { threshold: 100 / 255 });
 
   const expected = testUtils.createMask([
     [1, 1, 1, 1, 1, 1, 1, 1],
@@ -70,7 +70,7 @@ test('threshold in percents', () => {
     [50, 60, 70],
   ]);
 
-  const th = threshold(grey, { threshold: '10%' });
+  const th = threshold(grey, { threshold: 0.1 });
 
   const expected = testUtils.createMask([
     [0, 0, 0],
@@ -87,27 +87,10 @@ test('error too many channels', () => {
     /threshold can only be computed on images with one channel/,
   );
 });
-test('error threshold in percents out of range', () => {
-  const testImage = testUtils.load('opencv/test.png');
-
-  expect(() => threshold(testImage, { threshold: '150%' })).toThrow(
-    /threshold: threshold in percents is out of range 0 to 100/,
-  );
-});
 test('error threshold out of range', () => {
   const testImage = testUtils.load('opencv/test.png');
 
   expect(() => threshold(testImage, { threshold: 450 })).toThrow(
-    /invalid value: 450. It must be a positive value smaller than 256/,
-  );
-});
-test('error threshold string format wrong', () => {
-  const testImage = testUtils.load('opencv/test.png');
-
-  expect(() => threshold(testImage, { threshold: '150' })).toThrow(
-    /threshold: unrecognised threshold format/,
-  );
-  expect(() => threshold(testImage, { threshold: 'abc%' })).toThrow(
-    /threshold: unrecognised threshold format/,
+    /threshold must be a value between 0 and 1/,
   );
 });

src/operations/threshold.ts

@@ -1,7 +1,6 @@
 import { Mask } from '..';
 import { Image } from '../Image';
 import { imageToOutputMask } from '../utils/getOutputImage';
-import { validateValue } from '../utils/validators';
 
 import huang from './thresholds/huang';
 import intermodes from './thresholds/intermodes';
@@ -49,9 +48,10 @@ interface ThresholdOptionsBase {
 
 export interface ThresholdOptionsThreshold extends ThresholdOptionsBase {
   /**
-   * Threshold value that should be used. Should be an integer between 0 and Image.maxValue or a value in percents as a string, like "40%".
+   * Threshold value that should be used. Threshold is a value in range [0,1],
+   * which will be interpreted as a percentage of image.maxValue.
    */
-  threshold: number | string;
+  threshold: number;
 }
 
 export interface ThresholdOptionsAlgorithm extends ThresholdOptionsBase {
@@ -131,29 +131,16 @@ export function computeThreshold(
  */
 export function threshold(image: Image, options: ThresholdOptions = {}): Mask {
   let thresholdValue: number;
+
   if ('threshold' in options) {
     const threshold = options.threshold;
-    if (typeof threshold === 'number') {
-      thresholdValue = threshold;
-    } else if (
-      typeof threshold === 'string' &&
-      threshold.endsWith('%') &&
-      !Number.isNaN(Number(threshold.slice(0, -1)))
-    ) {
-      const percents = Number(threshold.slice(0, -1));
-      if (percents < 0 || percents > 100) {
-        throw new RangeError(
-          'threshold: threshold in percents is out of range 0 to 100',
-        );
-      }
-      thresholdValue = (percents / 100) * image.maxValue;
-    } else {
-      throw new Error('threshold: unrecognised threshold format');
+    if (threshold < 0 || threshold > 1) {
+      throw new RangeError('threshold must be a value between 0 and 1');
     }
+    thresholdValue = threshold * image.maxValue;
   } else {
     thresholdValue = computeThreshold(image, options.algorithm);
   }
-  validateValue(thresholdValue, image);
   const result = imageToOutputMask(image, options);
   for (let i = 0; i < image.size; i++) {
     result.setBitByIndex(

src/roi/__tests__/RoiMapManager.test.ts

@@ -9,7 +9,7 @@ test('should work with crop', () => {
     [0, 0, 0, 0, 0],
   ]);
 
-  const mask = image.threshold({ threshold: 100 });
+  const mask = image.threshold({ threshold: 100 / 255 });
 
   expect(mask).toMatchMaskData([
     [0, 0, 0, 0, 0],