Autocapture With OCR

Make Linked Booster benchmarking less painful

This helps:

1. Capture screen at specific regions with interval
2. Read texts from screenshots with OCR
3. Extract benchmark values from OCR-ed text

Built with:

• Tesseract.js: OCR module using AI
• sharp: Used for image processing to help Tesseract read image with higher accuracy

Quick Demo

Demo.OCR.mp4

I. Prerequisites

• Node 14+
• Python 3.8
• Windows OS

II. Installation

Open Terminal, run:

npm install -g node-gyp
npm install -g windows-build-tools

Open project root folder, run:

yarn install

III. Commands

* mean required

1. Capture screen at specific regions with interval

Command

node screen-capture.js

CLI Parameters

Params	Description	Value
dashboard *	Coordinates of Dashboard region	[left]-[top]-[width]-[height]
task-manager *	Coordinates of Task Manager region	[left]-[top]-[width]-[height]
namespace *	Name of the capture	Differentiate different captures
interval	Interval between captures in milliseconds	A number. Default: 1000

Example:

node screen-capture.js --dashboard 627-592-309-88 --task-manager 1032-76-859-283 --namespace snapshots_1

2. Read texts from snapshots with OCR

Command

node extract-texts.js

CLI Parameters

Params	Description	Value
namespace *	Name of the capture do you want to analyze	Capture name: Ex: capture_1
batch-size *	The tool process images in batches. Higher batch size will slightly reduce processing time (about 5 - 10%) but more chance of unexpected error while running	A number. Default: 3

Example:

node extract-texts.js  --batch-size 4 --namespace snapshots_1

3. Extract benchmark values from OCR-ed text

Command

node benchmark.js

CLI Parameters

Params	Description	Value
namespace *	Name of the capture do you want to analyze	Capture name: Ex: capture_1

Example:

node benchmark.js --namespace snapshots_1

IV. Preparation for benchmarking

1. Open Chrome and Chrome Task Manager on your Primary Display, put them to equal grids like this
2. Use some image editing tools to find coordinates of the regions you want to capture. For example.
3. Dashboard region: left: 620, top: 613, width: 309, height: 88
4. Task manager region: left: 1029, top: 75, width: 859, height: 283
5. Open Extensions page and disable others extensions
6. Open Dashboard Devtools. Select display mode as floating windows
7. Focus on the floating Devtools and press Ctrl + Shift + I to open the root Devtools
8. Paste in this code into the Console and Enter. It will throttle CPU in half. Can customize throttling rate with the rate options

let Main = await import('./devtools-frontend/front_end/entrypoints/main/main.js');
await Main.MainImpl.sendOverProtocol('Emulation.setCPUThrottlingRate', { rate: 2 });

V. Start Benchmark

1. After arranging windows and identify capturing regions coordinates
2. Start terminal at root folder
3. Run Command I to capture. Ctrl + C to stop capturing
4. Run command Command II with --namespace same as step 3
5. Run command Command III with --namespace same as step 3
6. The benchmark values will be logged to Terminal

VI. Common Errors

1. createWorker Runtime error

Fix

Find the file with name: eng.traineddata in the root folder and delete it, then run the command again