From d2047d066a65f95b439c28df4e3886404f0e5dd0 Mon Sep 17 00:00:00 2001 From: Ayrat Hudaygulov Date: Mon, 5 Oct 2026 09:25:16 +0100 Subject: [PATCH] Reduce managed coupon barcode decoding CPU and latency Read cropped and rotated luminance through shared pixel views and vectorize the ZXing row threshold while preserving scalar behavior. Run crop attempts with per-worker readers bounded by Environment.ProcessorCount and retain the original success priority. Add fallback, concurrent-recognition, and patterned-image coverage. Include attribution for the adapted ZXing threshold algorithm. --- src/CouponHubBot/CouponHubBot.fsproj | 6 + src/CouponHubBot/Services/BarcodeBinarizer.fs | 107 +++++++++ .../Services/BarcodeLuminanceSource.fs | 44 ++++ src/CouponHubBot/Services/CouponOcrEngine.fs | 58 +++-- src/CouponHubBot/ThirdPartyNotices.txt | 206 ++++++++++++++++++ tests/CouponHubBot.Ocr.Tests/OcrTests.fs | 60 ++++- 6 files changed, 462 insertions(+), 19 deletions(-) create mode 100644 src/CouponHubBot/Services/BarcodeBinarizer.fs create mode 100644 src/CouponHubBot/Services/BarcodeLuminanceSource.fs create mode 100644 src/CouponHubBot/ThirdPartyNotices.txt diff --git a/src/CouponHubBot/CouponHubBot.fsproj b/src/CouponHubBot/CouponHubBot.fsproj index 4f2f9e1..ed38af0 100644 --- a/src/CouponHubBot/CouponHubBot.fsproj +++ b/src/CouponHubBot/CouponHubBot.fsproj @@ -8,6 +8,8 @@ + + @@ -33,6 +35,10 @@ + + + + diff --git a/src/CouponHubBot/Services/BarcodeBinarizer.fs b/src/CouponHubBot/Services/BarcodeBinarizer.fs new file mode 100644 index 0000000..b2a5d2e --- /dev/null +++ b/src/CouponHubBot/Services/BarcodeBinarizer.fs @@ -0,0 +1,107 @@ +namespace CouponHubBot.Services + +open System +open System.Runtime.InteropServices +open System.Runtime.Intrinsics +open ZXing +open ZXing.Common + +type internal BarcodeBinarizer(source: LuminanceSource) = + inherit GlobalHistogramBinarizer(source) + + let mutable luminances = Array.empty + let buckets = Array.zeroCreate 32 + + // Histogram and valley selection follow ZXing.Net; see ThirdPartyNotices.txt. + let estimateThreshold () = + let mutable firstPeak = 0 + let mutable firstPeakSize = 0 + let mutable maxBucketCount = 0 + for x = 0 to buckets.Length - 1 do + if buckets[x] > firstPeakSize then + firstPeak <- x + firstPeakSize <- buckets[x] + maxBucketCount <- max maxBucketCount buckets[x] + + let mutable secondPeak = 0 + let mutable secondPeakScore = 0 + for x = 0 to buckets.Length - 1 do + let distance = x - firstPeak + let score = buckets[x] * distance * distance + if score > secondPeakScore then + secondPeak <- x + secondPeakScore <- score + + let lowPeak = min firstPeak secondPeak + let highPeak = max firstPeak secondPeak + if highPeak - lowPeak <= (buckets.Length >>> 4) then + None + else + let mutable valley = highPeak - 1 + let mutable valleyScore = -1 + for x = highPeak - 1 downto lowPeak + 1 do + let distance = x - lowPeak + let score = distance * distance * (highPeak - x) * (maxBucketCount - buckets[x]) + if score > valleyScore then + valley <- x + valleyScore <- score + Some (valley <<< 3) + + override _.createBinarizer(nextSource) = BarcodeBinarizer(nextSource) + + override _.getBlackRow(y, row) = + let width = source.Width + let result = + if isNull row || row.Size < width then + BitArray(width) + else + row.clear() + row + if luminances.Length < width then + luminances <- Array.zeroCreate width + let pixels = source.getRow(y, luminances) + Array.Clear buckets + for x = 0 to width - 1 do + let bucket = int pixels[x] >>> 3 + buckets[bucket] <- buckets[bucket] + 1 + + match estimateThreshold () with + | None -> null + | Some threshold -> + match width with + | 1 | 2 -> + for x = 0 to width - 1 do + if int pixels[x] < threshold then + result[x] <- true + | _ -> + let mutable x = 1 + if Vector128.IsHardwareAccelerated then + // Comparing before division preserves truncation toward zero at threshold zero. + let bound = Vector128.Create(int16 (if threshold = 0 then -1 else threshold * 2)) + while x + 16 <= width - 1 do + let left = MemoryMarshal.Read>(ReadOnlySpan(pixels, x - 1, 16)) + let center = MemoryMarshal.Read>(ReadOnlySpan(pixels, x, 16)) + let right = MemoryMarshal.Read>(ReadOnlySpan(pixels, x + 1, 16)) + let low = + Vector128.ShiftLeft(Vector128.WidenLower(center).AsInt16(), 2) + - Vector128.WidenLower(left).AsInt16() - Vector128.WidenLower(right).AsInt16() + let high = + Vector128.ShiftLeft(Vector128.WidenUpper(center).AsInt16(), 2) + - Vector128.WidenUpper(left).AsInt16() - Vector128.WidenUpper(right).AsInt16() + let bits = + Vector128.Narrow( + Vector128.LessThan(low, bound).AsUInt16(), + Vector128.LessThan(high, bound).AsUInt16()) + let mask = Vector128.ExtractMostSignificantBits bits + let word = x >>> 5 + let shift = x &&& 31 + result.Array[word] <- result.Array[word] ||| int (mask <<< shift) + if shift > 16 then + result.Array[word + 1] <- result.Array[word + 1] ||| int (mask >>> (32 - shift)) + x <- x + 16 + while x < width - 1 do + let sharpened = (4 * int pixels[x] - int pixels[x - 1] - int pixels[x + 1]) / 2 + if sharpened < threshold then + result[x] <- true + x <- x + 1 + result diff --git a/src/CouponHubBot/Services/BarcodeLuminanceSource.fs b/src/CouponHubBot/Services/BarcodeLuminanceSource.fs new file mode 100644 index 0000000..cf726b7 --- /dev/null +++ b/src/CouponHubBot/Services/BarcodeLuminanceSource.fs @@ -0,0 +1,44 @@ +namespace CouponHubBot.Services + +open System +open ZXing + +type internal BarcodeLuminanceSource private + (pixels: byte[], width: int, height: int, offset: int, xStride: int, yStride: int) = + inherit LuminanceSource(width, height) + + new(source: LuminanceSource) = + BarcodeLuminanceSource(source.Matrix, source.Width, source.Height, 0, 1, source.Width) + + override _.getRow(y, row) = + if y < 0 || y >= height then + invalidArg (nameof y) "Row must be within the image." + let result = if isNull row || row.Length < width then Array.zeroCreate width else row + let start = offset + y * yStride + match xStride with + | 1 -> pixels.AsSpan(start, width).CopyTo(result.AsSpan()) + | _ -> + for x = 0 to width - 1 do + result[x] <- pixels[start + x * xStride] + result + + override this.Matrix = + let result = Array.zeroCreate (width * height) + let row = Array.zeroCreate width + for y = 0 to height - 1 do + this.getRow(y, row).AsSpan(0, width).CopyTo(result.AsSpan(y * width, width)) + result + + override _.CropSupported = true + override _.RotateSupported = true + override _.InversionSupported = true + override this.invert() = InvertedLuminanceSource(this) + + override _.crop(left, top, cropWidth, cropHeight) = + if left < 0 || top < 0 || cropWidth <= 0 || cropHeight <= 0 + || left > width - cropWidth || top > height - cropHeight then + invalidArg (nameof cropWidth) "Crop must fit within the image." + BarcodeLuminanceSource(pixels, cropWidth, cropHeight, offset + left * xStride + top * yStride, xStride, yStride) + + override _.rotateCounterClockwise() = + BarcodeLuminanceSource(pixels, height, width, offset + (width - 1) * xStride, yStride, -xStride) diff --git a/src/CouponHubBot/Services/CouponOcrEngine.fs b/src/CouponHubBot/Services/CouponOcrEngine.fs index b2d8653..c807998 100644 --- a/src/CouponHubBot/Services/CouponOcrEngine.fs +++ b/src/CouponHubBot/Services/CouponOcrEngine.fs @@ -5,6 +5,7 @@ open System.Diagnostics open System.Globalization open System.IO open System.Text.RegularExpressions +open System.Threading open System.Threading.Tasks open Microsoft.Extensions.Logging open CouponHubBot @@ -235,22 +236,27 @@ type CouponOcrEngine(azureTextOcr: IBotOcr, logger: ILogger, ti if not (isNull activity) then %activity.SetTag("image.width", original.Width) %activity.SetTag("image.height", original.Height) - let opts = DecodingOptions() - opts.TryHarder <- true - opts.PossibleFormats <- [| BarcodeFormat.EAN_13 |] - opts.TryInverted <- false - let reader = BarcodeReader() - reader.Options <- opts - reader.AutoRotate <- true - - let decode (label: string) (img: LuminanceSource) = + let createReader () = + let opts = DecodingOptions() + opts.TryHarder <- true + opts.PossibleFormats <- [| BarcodeFormat.EAN_13 |] + opts.TryInverted <- false + let reader = BarcodeReaderGeneric(null, (fun source -> BarcodeBinarizer(source) :> Binarizer), null) + reader.Options <- opts + reader.AutoRotate <- true + reader + + let reader = createReader () + let parallelOptions = ParallelOptions(MaxDegreeOfParallelism = Environment.ProcessorCount) + + let decode (decoder: BarcodeReaderGeneric) (label: string) (img: LuminanceSource) = use attempt = botActivity.StartActivity("couponOcr.barcode.decode") - attempts <- attempts + 1 + %Interlocked.Increment(&attempts) if not (isNull attempt) then %attempt.SetTag("barcode.strategy", label) %attempt.SetTag("image.width", img.Width) %attempt.SetTag("image.height", img.Height) - let res = reader.Decode(img) + let res = decoder.Decode(img) if not (isNull attempt) then %attempt.SetTag("barcode.found", not (isNull res) && not (String.IsNullOrWhiteSpace res.Text)) if isNull res || String.IsNullOrWhiteSpace res.Text then @@ -262,13 +268,13 @@ type CouponOcrEngine(azureTextOcr: IBotOcr, logger: ILogger, ti let clamp (v: int) (minv: int) (maxv: int) = max minv (min maxv v) - let cropTry (baseLabel: string) (img: LuminanceSource) (rect: Rectangle) = + let cropTry (decoder: BarcodeReaderGeneric) (baseLabel: string) (img: LuminanceSource) (rect: Rectangle) = let x = clamp rect.X 0 (img.Width - 1) let y = clamp rect.Y 0 (img.Height - 1) let w = clamp rect.Width 1 (img.Width - x) let h = clamp rect.Height 1 (img.Height - y) let cropped = img.crop(x, y, w, h) - decode baseLabel cropped + decode decoder baseLabel cropped let tryOnImage (labelPrefix: string) (img: Image) = // Strategy: @@ -277,8 +283,8 @@ type CouponOcrEngine(azureTextOcr: IBotOcr, logger: ILogger, ti // - Middle band crops (covers centre region) // - Bottom crops (useful for app screenshots) // - Center-narrowed variants of the above (avoid noise on sides) - let luminance = ImageSharpLuminanceSource(img) - match decode (labelPrefix + ":full") luminance with + let luminance = BarcodeLuminanceSource(ImageSharpLuminanceSource(img)) + match decode reader (labelPrefix + ":full") luminance with | Some t -> Some t | None -> let w = img.Width @@ -325,9 +331,25 @@ type CouponOcrEngine(azureTextOcr: IBotOcr, logger: ILogger, ti let allRects = Array.append fullWidthCrops centerCrops - allRects - |> Array.mapi (fun i r -> (i, r)) - |> Array.tryPick (fun (i, r) -> cropTry $"{labelPrefix}:crop{i}" luminance r) + match parallelOptions.MaxDegreeOfParallelism with + | 1 -> + allRects + |> Array.mapi (fun i r -> (i, r)) + |> Array.tryPick (fun (i, r) -> cropTry reader $"{labelPrefix}:crop{i}" luminance r) + | _ -> + let results = Array.create allRects.Length None + %Parallel.For( + 0, allRects.Length, parallelOptions, + Func(createReader), + Func(fun i state decoder -> + let result = cropTry decoder $"{labelPrefix}:crop{i}" luminance allRects[i] + results[i] <- result + if result.IsSome then + state.Break() + decoder), + Action(fun _ -> ())) + // Break completes lower indices so crop priority is independent of scheduling. + results |> Array.tryPick id let tryAll () = match tryOnImage "orig" original with diff --git a/src/CouponHubBot/ThirdPartyNotices.txt b/src/CouponHubBot/ThirdPartyNotices.txt new file mode 100644 index 0000000..8bce16d --- /dev/null +++ b/src/CouponHubBot/ThirdPartyNotices.txt @@ -0,0 +1,206 @@ +BarcodeBinarizer.fs adapts the row binarization and threshold selection from +ZXing.Net GlobalHistogramBinarizer, with F# translation and SIMD row processing. +Copyright 2009 ZXing authors. Licensed under the Apache License, Version 2.0. +Source: https://github.com/micjahn/ZXing.Net/blob/master/Source/lib/common/GlobalHistogramBinarizer.cs + + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + + TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + + 1. Definitions. + + "License" shall mean the terms and conditions for use, reproduction, + and distribution as defined by Sections 1 through 9 of this document. + + "Licensor" shall mean the copyright owner or entity authorized by + the copyright owner that is granting the License. + + "Legal Entity" shall mean the union of the acting entity and all + other entities that control, are controlled by, or are under common + control with that entity. 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We also recommend that a + file or class name and description of purpose be included on the + same "printed page" as the copyright notice for easier + identification within third-party archives. + + Copyright [yyyy] [name of copyright owner] + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. diff --git a/tests/CouponHubBot.Ocr.Tests/OcrTests.fs b/tests/CouponHubBot.Ocr.Tests/OcrTests.fs index d54a001..2fbb395 100644 --- a/tests/CouponHubBot.Ocr.Tests/OcrTests.fs +++ b/tests/CouponHubBot.Ocr.Tests/OcrTests.fs @@ -6,6 +6,7 @@ open System.IO open System.Net open System.Net.Http open System.Text +open System.Threading.Tasks open Microsoft.Extensions.Logging open Microsoft.Extensions.Options open SixLabors.ImageSharp @@ -46,7 +47,7 @@ module private XUnitLogging = else "\n" + ex.ToString() let line = $"[{logLevel}] {category}: {msg}{exText}" - sink.Add(line) + lock sink (fun () -> sink.Add(line)) output.WriteLine(line) with _ -> // Never let logging break tests @@ -263,6 +264,63 @@ type OcrTests(output: ITestOutputHelper) = Assert.Equal("2706602781191", result.barcode) } + [] + [] + [] + member _.``Low contrast coupon is recognized without OCR upright or inverted``(angle: int) = + task { + let path = Path.Combine(AppContext.BaseDirectory, "Images", "5_25_2026-02-08_2026-02-14_2706726228947.jpg") + use image = Image.Load(path) + image.Mutate(fun ctx -> %ctx.Rotate(float32 angle)) + use stream = new MemoryStream() + image.SaveAsPng(stream) + let! result = (buildCpuOnlyEngine ()).Recognize(ReadOnlyMemory(stream.ToArray())) + Assert.Equal("2706726228947", result.barcode) + } + + [] + member _.``Concurrent recognition keeps coupon barcodes separate``() = + task { + let files = + [| "5_25_2026-02-08_2026-02-14_2706726228947.jpg" + "10_50_01-04_01-13_2706602781191.jpg" |] + let engine = buildCpuOnlyEngine () + let inputs = + files + |> Array.map (fun file -> + let bytes = File.ReadAllBytes(Path.Combine(AppContext.BaseDirectory, "Images", file)) + let expected = Path.GetFileNameWithoutExtension(file).Split('_') |> Array.last + bytes, expected) + let jobs = + Array.init 8 (fun i -> + Task.Run(Func(fun () -> + task { + let bytes, expected = inputs[i % inputs.Length] + let! result = engine.Recognize(ReadOnlyMemory(bytes)) + Assert.Equal(expected, result.barcode) + } :> Task))) + do! Task.WhenAll jobs + } + + [] + [] + [] + [] + member _.``Patterned images do not invent a barcode``(width: int) = + task { + use image = new Image(width, 49) + image.ProcessPixelRows(fun pixels -> + for y = 0 to pixels.Height - 1 do + let row = pixels.GetRowSpan y + for x = 0 to row.Length - 1 do + let value = if (x / 3 + y / 4) % 2 = 0 then 32uy else 224uy + row[x] <- Rgba32(value, value, value)) + use stream = new MemoryStream() + image.SaveAsPng(stream) + let! result = (buildCpuOnlyEngine ()).Recognize(ReadOnlyMemory(stream.ToArray())) + Assert.Null(result.barcode) + } + [] [] []