refactor(ocr): 优化 color_filter.rs

- 重构 `OcrBuilder` 移除is_pixel_matched，filter_image。
 - 优化 `OcrBuilder` 的color_filter方法（部分逻辑转移给merge_to_vec） 。
 - 新增 `ColorFilter` 特征增加merge_to_vec方法。

src/models/ocr.rs

@@ -1,18 +1,21 @@
+use std::borrow::Cow;
 use crate::charset::{TokenFilter, ValidationCtx};
 use crate::model_metadata::ModelMetadata;
 use crate::models::base::ModelArgs;
 use crate::models::loader::{ModelLoader, ModelSession, ModelType};
-use crate::utils::color_filter::{ColorFilter, HsvRange};
+use crate::utils::color_filter::{filter_image, ColorFilter, HsvRange};
 use crate::utils::image_io::png_rgba_white_preprocess;
 use crate::utils::image_processor::{convert_to_grayscale, resize_image};
 use anyhow::Context;
-use image::DynamicImage;
+use anyhow::{anyhow, Result};
+use image::{DynamicImage, ImageBuffer, Rgb};
 use std::collections::HashSet;
 use tract_onnx::prelude::tract_ndarray::s;
 use tract_onnx::prelude::{
     DatumType, Graph, IntoTensor, RunnableModel, Tensor, TypedFact, TypedOp, tract_ndarray, tvec,
 };
-
+// 引入 cv_ops 模块中的 OpenCV HSV 转换算子
+use crate::utils::cv_ops::rgb_to_opencv_hsv;
 // 颜色过滤的自定义范围：(低值RGB, 高值RGB)
 pub type ColorRange = ((u8, u8, u8), (u8, u8, u8));
 
@@ -185,19 +188,16 @@ impl<'a> OcrBuilder<'a> {
                         existing_vec.reserve(total_capacity);
 
                         // 尝试追加倒入
-                        filter.append_ranges(existing_vec) ;
-
+                        filter.append_ranges(existing_vec);
                     }
-
-
                 }
-                if let Some(v) =&mut ranges {
+                if let Some(v) = &mut ranges {
                     v.sort_unstable();
                     v.dedup();
                 }
                 // 5. 更新状态
                 self.color_filter = Ok(ranges);
-            },
+            }
             Err(_) => return self,
         };
         self
@@ -252,7 +252,27 @@ impl<'a> OcrBuilder<'a> {
 }
 impl<'a> OcrBuilder<'a> {
     pub fn predict(&self, image: &DynamicImage) -> anyhow::Result<String> {
-        let tensor = self.preprocess_image(image)?;
+        println!("当前颜色过滤器状态: {:?}", self.color_filter);
+        // =====================================================================
+        // 管道节点 1: 颜色过滤流水线
+        // 使用 Cow (Copy-On-Write) 智能指针。
+        // 如果未开启过滤，img_cow 内部只是持有原图的【只读借用】，发生【零内存分配】！
+        // =====================================================================
+        let img_cow = match &self.color_filter {
+            Err(err_msg) => {
+                return Err(anyhow::anyhow!("颜色过滤器初始化失败，全链路短路: {}", err_msg));
+            }
+            Ok(None) => {
+                // 核心优化点：直接借用原图，不发生任何克隆
+                Cow::Borrowed(image)
+            }
+            Ok(Some(ranges)) => {
+                // 只有真正需要过滤时，才在内部提取像素并生成清洗后的 Owned 新图
+                let filtered_img = filter_image(image, ranges)?;
+                Cow::Owned(filtered_img)
+            }
+        };
+        let tensor = self.preprocess_image(&img_cow)?;
 
         let raw_tensor = self.ocr.inference(tensor)?;
         let raw_indices = self.ocr.extract_indices_from_tensor(&raw_tensor)?;
@@ -266,15 +286,17 @@ impl<'a> OcrBuilder<'a> {
     /// 负责：透明背景修复 -> 灰度化 -> 按比例 Resize -> 归一化 -> 4维张量转换
     fn preprocess_image(&self, img: &DynamicImage) -> anyhow::Result<Tensor> {
         // A. 修复 PNG 透明背景 (内部逻辑你之前已实现)
-        let _ = if self.png_fix && img.color().has_alpha() {
-            png_rgba_white_preprocess(img)
+        let current_img = if self.png_fix && img.color().has_alpha() {
+            // 只有满足条件才去触发分配，生成新图
+            Cow::Owned(png_rgba_white_preprocess(img))
         } else {
-            img.clone()
+            // 正常情况下，仅仅是再次安全借用，无开销
+            Cow::Borrowed(img)
         };
 
         let h = 64u32;
-        let w = (img.width() as f32 * (h as f32 / img.height() as f32)) as u32;
-        let gray_img = convert_to_grayscale(img);
+        let w = (current_img.width() as f32 * (h as f32 / current_img.height() as f32)) as u32;
+        let gray_img = convert_to_grayscale(&current_img);
         let resized = resize_image(&gray_img, w, h);
         // resized.save("debug_preprocessed.png").unwrap();
         // 1. 预处理：转灰度 -> Resize -> 归一化
@@ -291,6 +313,10 @@ impl<'a> OcrBuilder<'a> {
 
         Ok(tensor)
     }
+
+
+
+
 }
 impl<'a> OcrBuilder<'a> {
     pub fn get_valid_indices(&self) -> HashSet<usize> {