ios开发照相机,ios的相机

iOS开发 调用相机拍照时 如何获取环境光线的亮度

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“在光线暗”的环境中拍照时不能按下不能拍照快门--- 相机无法对焦时,快门是不会启动的。

除了采用夜间模式、打开闪光灯、打开对焦辅助灯外,还可以采取下列措施,提高对焦成功率:

1、提高ISO值(比如提高为ISO400、800、1600甚至更高)。

ISO数值的大小是数码相机对光线反应的敏感程度测量值,通常以ISO数值表示,数值越大表示感光性越强,数值越小表示感光性越弱。

在室内光线不足或拍摄夜景时,使用高ISO值能使对焦成功率大为增加。但照片的噪点也会相应增加。

2、如果环境光源偏暗,即可增加曝光值(如调整为+1EV、+2EV)以突显画面的清晰度。

数码相机在拍摄的过程中,如果按下半截快门,液晶屏上就会显示和最终效果图差不多的图片,对焦,曝光一起启动。这个时候的曝光,正是最终图片的曝光度。

图片如果明显偏亮或偏暗,说明相机的自动测光准确度有较大偏差,要强制进行曝光补偿,不过有的时候,拍摄时显示的亮度与实际拍摄结果有一定出入。

数码相机可以在拍摄后立即浏览画面,此时,可以更加准确地看到拍摄出来的画面的明暗程度,不会再有出入。如果拍摄结果明显偏亮或偏暗,则要重新拍摄,强制进行曝光补偿。

另外,关于相机锁定焦点的操作也要注意:

拍摄时,应该先半按下快门,不要松手,将取景屏里的锁焦框对焦拍摄的焦点(比如人物的脸部),待取景屏里的锁焦框一下收小变绿色或相机发出“嘀”一声,就表明焦点已经锁定,此时再加力完全按下快门就行了。

拍照时,还必须保证持机的稳定,机身的抖动也会致使照片失焦而模糊。

ios开发中有没有一种技术能在二维码中间嵌套一个二维码让相机能够识别区分这两个二维码呢

可以实现的,二维码包含的信息是由你控制的,对这两个二维码做不同标示,扫描时根据这个标示做个判断就可以实现

ios开发中怎样调用相机实现拍照功能

打开相机:

[cpp] view plain copy

//先设定sourceType为相机,然后判断相机是否可用(ipod)没相机,不可用将sourceType设定为相片库

UIImagePickerControllerSourceType sourceType = UIImagePickerControllerSourceTypeCamera;

// if (![UIImagePickerController isSourceTypeAvailable: UIImagePickerControllerSourceTypeCamera]) {

// sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

// }

//sourceType = UIImagePickerControllerSourceTypeCamera; //照相机

//sourceType = UIImagePickerControllerSourceTypePhotoLibrary; //图片库

//sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum; //保存的相片

UIImagePickerController *picker = [[UIImagePickerController alloc] init];//初始化

picker.delegate = self;

picker.allowsEditing = YES;//设置可编辑

picker.sourceType = sourceType;

[self presentModalViewController:picker animated:YES];//进入照相界面

[picker release];

打开相册:(区分pad和iphone)

for iphone:

[cpp] view plain copy

UIImagePickerController *pickerImage = [[UIImagePickerController alloc] init];

if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]) {

pickerImage.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

//pickerImage.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;

pickerImage.mediaTypes = [UIImagePickerController availableMediaTypesForSourceType:pickerImage.sourceType];

}

pickerImage.delegate = self;

pickerImage.allowsEditing = NO;

[self presentModalViewController:pickerImage animated:YES];

[pickerImage release];

for ipad:

[cpp] view plain copy

UIImagePickerControllerSourceType sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

//sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum; //保存的相片

UIImagePickerController *picker = [[UIImagePickerController alloc] init];

picker.delegate = self;

picker.allowsEditing = NO;//是否允许编辑

picker.sourceType = sourceType;

/*

如果从一个导航按钮处呈现,使用:

presentPopoverFromBarButtonItem:permittedArrowDirections:animated:;

如果要从一个视图出呈现,使用:

presentPopoverFromRect:inView:permittedArrowDirections:animated:

如果设备旋转以后,位置定位错误需要在父视图控制器的下面方法里面重新定位:

didRotateFromInterfaceOrientation:(在这个方法体里面重新设置rect)

然后再次调用:

- (void)presentPopoverFromRect:(CGRect)rect inView:(UIView *)view permittedArrowDirections:(UIPopoverArrowDirection)arrowDirections animated:(BOOL)animated

*/

//UIPopoverController只能在ipad设备上面使用;作用是用于显示临时内容,特点是总是显示在当前视图最前端,当单击界面的其他地方时自动消失。

UIPopoverController *popover = [[UIPopoverController alloc]initWithContentViewController:picker];

self.imagePicker = popover;

//permittedArrowDirections 设置箭头方向

[self.imagePicker presentPopoverFromRect:CGRectMake(0, 0, 300, 300) inView:self.view permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];

[picker release];

[popover release];

点击相册中的图片 货照相机照完后点击use 后触发的方法

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary

*)info

点击cancel 调用的方法

- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker

ios开发 系统调用照相机使用的按钮怎么调用

if (is_ios7) {

AVAuthorizationStatus authstatus = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];

if (authstatus ==AVAuthorizationStatusRestricted || authstatus ==AVAuthorizationStatusDenied) //用户关闭了权限

{

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"提示" message:@"请在设备的设置-隐私-相机中允许访问相机。" delegate:self cancelButtonTitle:@"确定" otherButtonTitles:nil];

[alert show];

return;

}

ALAuthorizationStatus author = [ALAssetsLibrary authorizationStatus];

if (author == kCLAuthorizationStatusRestricted || author ==kCLAuthorizationStatusDenied)//用户关闭了权限

{

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"提示" message:@"请在设备的设置-隐私-照片中允许访问照片。" delegate:self cancelButtonTitle:@"确定" otherButtonTitles:nil];

[alert show];

return;

}

}

if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {

//相册是可以用模拟器打开

if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]) {

UIImagePickerController *picker = [[UIImagePickerController alloc] init];

picker.delegate = self;

picker.sourceType = UIImagePickerControllerSourceTypeCamera;

picker.allowsEditing = YES;

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

}else{

UIAlertView *alter = [[UIAlertView alloc] initWithTitle:@"Error" message:@"没有相册" delegate:nil cancelButtonTitle:@"取消" otherButtonTitles:nil, nil];

[alter show];

}

}else{

[MBProgressHUD showMessag:@"无法打开相机" toView:Main_WINDOW];

NSLog(@"模拟器无法打开相机");

}


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