From 47897da6fb31426dc2cd841d8b5b91dbf31b2892 Mon Sep 17 00:00:00 2001
From: Koushik Dutta <koushd@gmail.com>
Date: Thu, 18 Apr 2024 08:41:49 -0700
Subject: [PATCH] videoanalysis: improve similar character checker

---
 plugins/objectdetector/package-lock.json    |  4 +-
 plugins/objectdetector/package.json         |  2 +-
 plugins/objectdetector/src/edit-distance.ts | 98 ++++++++++++++-------
 3 files changed, 68 insertions(+), 36 deletions(-)

diff --git a/plugins/objectdetector/package-lock.json b/plugins/objectdetector/package-lock.json
index b1b23cca7f..639e557fe4 100644
--- a/plugins/objectdetector/package-lock.json
+++ b/plugins/objectdetector/package-lock.json
@@ -1,12 +1,12 @@
 {
    "name": "@scrypted/objectdetector",
-   "version": "0.1.35",
+   "version": "0.1.36",
    "lockfileVersion": 2,
    "requires": true,
    "packages": {
       "": {
          "name": "@scrypted/objectdetector",
-         "version": "0.1.35",
+         "version": "0.1.36",
          "license": "Apache-2.0",
          "dependencies": {
             "@scrypted/common": "file:../../common",
diff --git a/plugins/objectdetector/package.json b/plugins/objectdetector/package.json
index de13240b5b..8c3a9419dc 100644
--- a/plugins/objectdetector/package.json
+++ b/plugins/objectdetector/package.json
@@ -1,6 +1,6 @@
 {
    "name": "@scrypted/objectdetector",
-   "version": "0.1.35",
+   "version": "0.1.36",
    "description": "Scrypted Video Analysis Plugin. Installed alongside a detection service like OpenCV or TensorFlow.",
    "author": "Scrypted",
    "license": "Apache-2.0",
diff --git a/plugins/objectdetector/src/edit-distance.ts b/plugins/objectdetector/src/edit-distance.ts
index c050d3bc62..be9430c162 100644
--- a/plugins/objectdetector/src/edit-distance.ts
+++ b/plugins/objectdetector/src/edit-distance.ts
@@ -1,36 +1,68 @@
-export function levenshteinDistance(str1: string, str2: string): number {
-    const len1 = str1.length;
-    const len2 = str2.length;
-  
-    // If either string is empty, the distance is the length of the other string
-    if (len1 === 0) return len2;
-    if (len2 === 0) return len1;
-  
-    let prev: number[] = new Array(len2 + 1);
-    let curr: number[] = new Array(len2 + 1);
-  
-    // Initialize the first row of the matrix to be the index of the second string
-    for (let i = 0; i <= len2; i++) {
-      prev[i] = i;
+const similarCharacters = [
+  ['0', 'O', 'D'],
+  ['1', 'I'],
+  ['2', 'Z'],
+  ['4', 'A'],
+  ['5', 'S'],
+  ['8', 'B'],
+  ['6', 'G'],
+  // not sure about this one.
+  ['A', '4'],
+  ['C', 'G'],
+  ['E', 'F'],
+];
+
+const similarCharactersMap = new Map<string, Set<string>>();
+for (const similarCharacter of similarCharacters) {
+  for (const character of similarCharacter) {
+    if (!similarCharactersMap.has(character)) {
+      similarCharactersMap.set(character, new Set());
+    }
+    for (const similar of similarCharacter) {
+      similarCharactersMap.get(character)!.add(similar);
     }
-  
-    for (let i = 1; i <= len1; i++) {
-      // Initialize the current row with the distance from the previous row's first element
-      curr[0] = i;
-  
-      for (let j = 1; j <= len2; j++) {
-        let cost = str1.charAt(i - 1) === str2.charAt(j - 1) ? 0 : 1;
-  
-        // Compute the minimum of three possible operations: insertion, deletion, or substitution
-        curr[j] = Math.min(prev[j] + 1, curr[j - 1] + 1, prev[j - 1] + cost);
-      }
-  
-      // Swap the previous and current rows for the next iteration
-      const temp = prev;
-      prev = curr;
-      curr = temp;
+  }
+}
+
+function isSameCharacter(c1: string, c2: string) {
+  if (c1 === c2)
+    return true;
+
+  return similarCharactersMap.get(c1)?.has(c2);
+}
+
+export function levenshteinDistance(str1: string, str2: string): number {
+  const len1 = str1.length;
+  const len2 = str2.length;
+
+  // If either string is empty, the distance is the length of the other string
+  if (len1 === 0) return len2;
+  if (len2 === 0) return len1;
+
+  let prev: number[] = new Array(len2 + 1);
+  let curr: number[] = new Array(len2 + 1);
+
+  // Initialize the first row of the matrix to be the index of the second string
+  for (let i = 0; i <= len2; i++) {
+    prev[i] = i;
+  }
+
+  for (let i = 1; i <= len1; i++) {
+    // Initialize the current row with the distance from the previous row's first element
+    curr[0] = i;
+
+    for (let j = 1; j <= len2; j++) {
+      let cost = isSameCharacter(str1.charAt(i - 1), str2.charAt(j - 1)) ? 0 : 1;
+
+      // Compute the minimum of three possible operations: insertion, deletion, or substitution
+      curr[j] = Math.min(prev[j] + 1, curr[j - 1] + 1, prev[j - 1] + cost);
     }
-  
-    return prev[len2];
+
+    // Swap the previous and current rows for the next iteration
+    const temp = prev;
+    prev = curr;
+    curr = temp;
   }
-  
\ No newline at end of file
+
+  return prev[len2];
+}