NHN Cloud > SDK User Guide > Document Recognizer > Credit Card (iOS)


  1. Install NHN Cloud SDK.
  2. Enable [AI Service > Document Recognizer] inNHN Cloud Console.
  3. Check Appkey and SecretKey in Document Recognizer Console.

Supported Environment

NHN Cloud OCR operates in iOS 11.0 or higher.

Configuration of NHN Cloud OCR

The configuration of NHN Cloud OCR SDK for iOS is as follows.

Service Cocoapods Pod Name Framework Dependency Build Settings
OCR NHNCloudOCR NHNCloudOCR.framework * Vision.framework
* AVFoundation.framework
Mandatory NHNCloudCore

Apply NHN Cloud OCR SDK to Xcode Project

1. Apply with Cococapods

  • Add Pod for NHN Cloud SDK by creating a pod file.
platform :ios, '11.0'

    pod 'NHNCloudOCR'

Download binaries and apply to NHN Cloud SDK

Set up Framework

  • You can download the full iOS SDK from the NHN Cloud Downloads page.
  • Add NHNCloudOCR.framework, NHNCloudCore.framework, and NHNCloudCommon.framework, vision.framework, AVFoundation.framework to Xcode Project.
  • You can add vision.framework and AVFoundation.framework as follows. linked_vision_frameworks linked_avfoundation_frameworks linked_frameworks_ocr

Set up Project

  • Add -lc++ and -ObjC to Other Linker Flags of Build Settings.
    • Project Target > Build Settings > Linking > Other Linker Flags other_linker_flags


  • Set AppKey and Secret issued from NHN Cloud Console in NHNCloudOCRConfiguration object.
  • AI Service > Document Recognizer > Credit Card
  • NHNCloudOCR uses an NHNCloudOCRConfiguration object as a parameter for initialization.
  • To get a permission to use camera, add the following items to info.plist.
Key : NSCameraUsageDescription
Value : [Camera Permission Request Message]

Specification for Initialization API

// Initialize
+ (void)initWithConfiguration:(NHNCloudOCRConfiguration *)configuration;
// Set Delegate
+ (void)setDelegate:(nullable id<NHNCloudCreditCardRecognizerDelegate>)delegate;
// Initialize and set Delegate
+ (void)initWithConfiguration:(NHNCloudOCRConfiguration *)configuration
                     delegate:(nullable id<NHNCloudCreditCardRecognizerDelegate>)delegate;

Specification for Delegate API

  • You can be notified of the recognition result when NHNCloudCreditCardRecognizerDelegate is registered.
  • When OCR is running, you can receive screen capture and video recording events.
@protocol NHNCloudCreditCardRecognizerDelegate <NSObject>

- (void)didDetectCreditCardInfo:(nullable NHNCloudCreditCardInfo *)cardInfo error:(nullable NSError *)error;
- (void)didDetectSecurityEvent:(NHNCloudSecurityEvent)event;


Set up Detected Image Return

  • NHNCloudCreditCardInfo data, which is the OCR result, can be returned together with the detected image.
    • Default is disabled.

Specification for Setting up Detected Image Return API

@interface NHNCloudOCR : NSObject
+ (void)setDetectedImageReturn:(BOOL)enable;
+ (BOOL)isEnableDetectedImageReturn;

Example of Initialization Process

#import <NHNCloudOCR/NHNCloudOCR.h>

@interface ViewController () <NHNCloudCreditCardRecognizerDelegate>

@implementation ViewController

- (void)initializeOCR {
    // Initialize and set Delegate
    NHNCloudOCRConfiguration *configuration = [NHNCloudOCRConfiguration configurationWithAppKey:@"{AppKey}" secret:@"{Secret}"];

    // Set detected image return 
    [NHNCloudOCR setDetectedImageReturn:YES];

    // Initialize    
    [NHNCloudOCR initWithConfiguration:configuration delegate:self];

// Return credit card recognition result
- (void)didDetectCreditCardInfo:(nullable NHNCloudCreditCardInfo *)cardInfo error:(nullable NSError *)error {
    NSLog(@"didDetectCreditCardInfo : cardInfo : %@", cardInfo);
    NSLog(@"didDetectCreditCardInfo : error : %@", error);

// Receive screen capture event
- (void)didDetectSecurityEvent:(NHNCloudSecurityEvent)event {

    // Example of screen capture warning alert output
    if (event == NHNCloudSecurityEventScreenshot || event == NHNCloudSecurityEventScreenRecordingOn) {
        UIAlertController *alert = [UIAlertController alertControllerWithTitle:nil message:@"Capture is detected." preferredStyle:UIAlertControllerStyleAlert];
        [alert addAction:[UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:nil]];

        [self presentViewController:alert animated:YES completion:nil];

    // Example of blank screen output when recording video
    if (event == NHNCloudSecurityEventScreenRecordingOn || event == NHNCloudSecurityEventScreenRecordingOff) {
        if ([[UIScreen mainScreen] isCaptured] ) {
            [[[UIApplication sharedApplication] windows] firstObject].hidden = YES;
        } else {
            [[[UIApplication sharedApplication] windows] firstObject].hidden = NO;



1. Use Credit-Card Recognizer ViewController

  • You can easily use Credit-Card Recognizer to which the default UI is applied by connecting the Class implemented with inheritance of NHNCloudCreditCardRecognizerViewController to the ViewController of Storyboard.

Create Class

default_viewcontroller * Create ViewController Class that contains NHNCloudCreditCardRecognizerViewController as Subclass.

Connect to Storyboard

create_viewcontroller * Add ViewController to Storyboard.

custom_class * In the added ViewController, configure the class created in Custom Class.

segue_viewcontroller * Set ViewController Segue Event.

  • Set and implement Delegate.

2. Use Test Environment

  • You can test OCR by using the Credit-Card guide provided to test NHNCloudOCR SDK.
  • OCR is initiated when a credit card exists in the Credit-Card guide.
    • Default value is hidden so that there is an invisible guide.
    • You can output a guide for testing by using enableTestGuide.

Specification for Credit-Card Guide

@interface NHNCloudOCRConfiguration : NSObject
- (void)enableTestGuide;

Example of using Credit-Card guide

- (void)initializeOCR {
    // Initialize and set Delegate
    NHNCloudOCRConfiguration *configuration = [NHNCloudOCRConfiguration configurationWithAppKey:@"{AppKey}" secret:@"{Secret}" ];

    [configuration enableTestGuide];

    [NHNCloudOCR initWithConfiguration:configuration delegate:self];

3. Control Credit-Card Recognizer ViewController

1. Open Credit-Card Recognizer ViewController

  • For credit card recognition, open ViewController that includes the credit card recognizer.
  • You can open the Credit-Card Recognizer VIewController the way developers want by receiving the opening method and ViewController as a return from the SDK.
Specification for Open Credit-Card Recognizer ViewControlle API
// Output CreditCard Recognizer ViewController from the SDK.
+ (NHNCloudCreditCardRecognizerViewController *)openCreditCardRecognizerViewController;

// Return CreditCard Recognizer ViewController. The user can output it directly, or the object activated in the SDK can be returned.
+ (nullable NHNCloudCreditCardRecognizerViewController *)creditCardRecognizerViewController;
Example of opening Credit-Card Recognizer ViewController
// Open Recognizer ViewController from the SDK
[NHNCloudOCR openCreditCardRecognizerViewController];

// Let developers open Recognizer ViewController the way they want as the Recognizer ViewController is returned from the SDK.
NHNCloudCreditCardRecognizerViewController *creditCardRecognizerViewController = [NHNCloudOCR creditCardRecognizerViewController];
[self presentViewController:creditCardRecognizerViewController animated:YES completion:nil];

2. Close Credit-Card Recognizer ViewController

  • Close ViewController that includes credit-card recognizer.
Specification for Close Credit-Card Recognizer ViewController API
- (void)dismissViewController;
Example of Close Credit-Card Recognizer ViewController
- (void)closeButton:(id)sender {
    [[NHNCloudOCR creditCardRecognizerViewController] dismissViewController];

3. Credit-Card Recognizer Initiate/Stop

  • Initiate or stop Credit-Card Recognizer.
Specification for Initiate/Stop Credit-Card Recognizer.
- (void)startRunning;
- (void)stopRunning;
- (BOOL)isRunning;
Example of initiate or stop Credit-Card Recognizer

- (void)openAndStart {
  [NHNCloudOCR openCreditCardRecognizerViewController];
  [[NHNCloudOCR creditCardRecognizerViewController] startRunning];

// Return the credit card recognition result
- (void)didDetectCreditCardInfo:(nullable NHNCloudCreditCardInfo *)cardInfo error:(nullable NSError *)error {
    [[NHNCloudOCR creditCardRecognizerViewController] stopRunning];

4. Rotate Credit-Card Guide

  • You can rotate the Credit-Card guide according to the direction of a credit card.
Specification for Rotate Credit-Card Guide
@property (assign, nonatomic, readonly) CGRect creditCardGuide;
@property (assign, nonatomic, readonly) NHNCloudCreditCardOrientation creditCardGuideOrientation;
- (void)rotateCreditCardGuideOrientation;
Example of using Rotate Credit-Card Guide
typedef NS_ENUM(NSInteger, NHNCloudCreditCardOrientation) {

    NHNCloudCreditCardOrientationPortrait = 0,
    NHNCloudCreditCardOrientationLandscape = 1

- (void)rotateButtonAction:(UIButton *)button {

    [[NHNCloudOCR creditCardRecognizerViewController] rotateCreditCardGuideOrientation];

    NSLog(@"x: %f y: %f width: %f height: %f", [NHNCloudOCR creditCardRecognizerViewController].creditCardGuide.origin.x,
          [NHNCloudOCR creditCardRecognizerViewController].creditCardGuide.origin.y,
          [NHNCloudOCR creditCardRecognizerViewController].creditCardGuide.size.width,
          [NHNCloudOCR creditCardRecognizerViewController].creditCardGuide.size.height);

    NSLog(@"creditCardGuideOrientation: %ld", [NHNCloudOCR creditCardRecognizerViewController].creditCardGuideOrientation);

5. Enable/Disable Light

  • Enable or disable the camera light of a device.
Specification for Enable/Disable Light API
- (void)enableTorchMode;
- (void)disableTorchMode;
- (BOOL)isEnableTorchMode;
Example of enabling or disabling the camera light of a device.
- (void)torchButtonAction:(UIButton *)button {    
    if ([[NHNCloudOCR creditCardRecognizerViewController] isEnableTorchMode] == YES) {
        [[NHNCloudOCR creditCardRecognizerViewController] disableTorchMode];
    } else {
        [[NHNCloudOCR creditCardRecognizerViewController] enableTorchMode];

6. Enable/Disable Camera

  • Enable or disable a device‚Äôs camera.
Specification for Enable/Disable Camera
- (void)startRunningCamera;
- (void)stopRunningCamera;
- (BOOL)isRunnginCamera;
Example of enabling or disabling camera
- (void)cameraButtonAction:(UIButton *)button {    
    if ([[NHNCloudOCR creditCardRecognizerViewController] isRunnginCamera] == YES) {
        [[NHNCloudOCR creditCardRecognizerViewController] stopRunningCamera];
    } else {
        [[NHNCloudOCR creditCardRecognizerViewController] startRunningCamera];

Customizing NHNCloudCreditCardRecognizerServiceViewController

  • You can perform customizing of NHNCloudCreditCardRecognizerServiceViewController.
  • The Credit-Card guide cannot be changed because pre-defined values are used.

1. Inherit NHNCloudCreditCardRecognizerServiceViewController

  • You can perform customizing by implementing inheritance of NHNCloudCreditCardRecognizerServiceViewController.

Specification for Override Function

- (void)viewDidLoad;
- (void)viewWillAppear:(BOOL)animated;
- (void)viewWillDisappear:(BOOL)animated;
- (void)viewDidDisappear:(BOOL)animated;
- (void)didUpdateCreditCardGuide:(CGRect)rect orientation:(NHNCloudCreditCardOrientation)orientation;
- (void)imageDidDetect:(BOOL)detected;

Example of using Override

@interface OCRViewController : NHNCloudCreditCardRecognizerServiceViewController <NHNCloudCreditCardRecognizerDelegate>


@implementation OCRViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    [NHNCloudOCR setDelegate:self];
    // Create Custom UI

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];

    [self startRunning];

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];

- (void)viewDidDisappear:(BOOL)animated {
    [super viewDidDisappear:animated];

- (void)didUpdateCreditCardGuide:(CGRect)rect orientation:(NHNCloudCreditCardOrientation)orientation {
    [super didUpdateCreditCardGuide:rect orientation:orientation];

    // Update Custom UI  

- (void)imageDidDetect:(BOOL)detected {
    [super imageDidDetect:detected];

    // Update UI for credit card recognition

- (void)didDetectCreditCardInfo:(nullable NHNCloudCreditCardInfo *)cardInfo error:(nullable NSError *)error {

    NSLog(@"didDetectCreditCardInfo : cardInfo : %@", cardInfo);
    NSLog(@"didDetectCreditCardInfo : error : %@", error);