1.開發(fā)環(huán)境及運行效果

硬件平臺：Ubuntu18.04、USB免驅(qū)攝像頭
UI界面：GTK+_2.0
開發(fā)語言：C/C++

2.GTK簡介

GTK（GIMP Toolkit)是一套源碼以LGPL許可協(xié)議分發(fā)、跨平臺的圖形工具包。最初是為GIMP寫的，已成為一個功能強大、設(shè)計靈活的一個通用圖形庫，是GNU/Linux下開發(fā)圖形界面的應(yīng)用程序的主流開發(fā)工具之一。當(dāng)然，GTK也是支持跨平臺的，支持Unix類的系統(tǒng)、Windows，甚至手機平臺。
GTK是使用C語言寫的，所以其原生API都是面向C的，同時GTK的一大特點是，在C語言層面實現(xiàn)了面向?qū)ο蟮奶匦浴TK是完全免費的，而且基于LGPL協(xié)議，這可以保證私有軟件通過鏈接使用GTK可以不把軟件源代碼開放，對商業(yè)應(yīng)用較友好，這跟GPL協(xié)議是不一樣的。也正是LGPL協(xié)議，使得早些年Gnome（基于GTK編寫）風(fēng)頭勝過KDE（基于QT編寫）。

3.開發(fā)流程

3.1 GTK初始化和攝像頭初始化

??初始化GTK，創(chuàng)建窗口，初始化攝像頭設(shè)備，檢測攝像頭設(shè)備是否正常。

int main(int argc,char **argv)
{
	GtkWidget *dialog;
	/*gtk初始化*/
	gtk_init(&argc,&argv);
	/*創(chuàng)建窗口*/
	window=gtk_window_new(GTK_WINDOW_TOPLEVEL);
	gtk_window_set_title(GTK_WINDOW(window),"人臉識別");
	/*固定窗口大小*/
	gtk_window_set_resizable (GTK_WINDOW(window),FALSE);
	/*設(shè)置窗口大小*/
	gtk_widget_set_size_request(window,800,480);
	gtk_window_set_position(GTK_WINDOW(window),GTK_WIN_POS_CENTER_ALWAYS);//居中顯示
	/*連接信號*/
	g_signal_connect(G_OBJECT(window),"destroy",G_CALLBACK(on_delete_event),NULL);
	/*創(chuàng)建標(biāo)簽*/
	GdkColor color;
	color.red=0xffff;
	color.green=0;
	color.blue=0;
	label=gtk_label_new("");
	/*設(shè)置字體大小和顏色*/
	gtk_label_set_markup(GTK_LABEL(label),"正在啟動攝像頭，請稍等...");
	g_timeout_add(500,timer_func, label);//開啟定時器1s時間
	gtk_label_set_justify (GTK_LABEL(label),GTK_JUSTIFY_CENTER);
	gtk_container_add(GTK_CONTAINER(window), label);
	gtk_widget_show(label);
	 change_background(window, 800, 480, "1.bmp");
	gtk_widget_show(window);
	gtk_main();
	return 0;
}

??在定時器中等待攝像頭啟動成功，完成人臉識別UI界面配置。

等待攝像頭啟動界面

攝像頭啟動成功界面

/*定時器處理函數(shù)*/

GtkWidget *window;
gboolean timer_func(gpointer data)
{
	GtkWidget *widget=(GtkWidget *)data;
	int ret;
	ret=Camera_Init(&video_info);
	if(ret==0)
	{
		g_print("攝像頭啟動成功n");
		gtk_widget_destroy(label);//關(guān)閉對話框
		
		GtkWidget *hbox;
		GtkWidget *vbox,*box;
		GtkWidget *button;
		GtkTooltips *tiptool;
		/*圖像寬高*/
		width=video_info.image_w;
		height=video_info.image_h;
		rgbbuf=malloc(width*height*3);	
		jpg_data=malloc(width*height*3);//保存RGB顏色數(shù)據(jù)
		imagebase64_data=malloc((height*width*3)*8/6);/*base64編碼后數(shù)據(jù)*/
		
		/*創(chuàng)建橫向盒*/
		hbox=gtk_hbox_new(FALSE,0);
		gtk_container_add(GTK_CONTAINER(window),hbox);
		gtk_widget_show(hbox);

		/*初始化gdk的rgb*/
		gdk_rgb_init();
		/*將gdk視件和顏色表放入gtk構(gòu)件中*/
		gtk_widget_push_visual(gdk_rgb_get_visual());
		gtk_widget_push_colormap(gdk_rgb_get_cmap());
		/*創(chuàng)建繪圖區(qū)域*/
		drawarea=gtk_drawing_area_new();
		gtk_widget_pop_visual();
		gtk_widget_pop_colormap();
		gtk_box_pack_start(GTK_BOX(hbox),drawarea,FALSE,FALSE,0);
		g_signal_connect(G_OBJECT(drawarea),"expose_event",G_CALLBACK(draw_image),NULL);
		guint id=gtk_idle_add((GtkFunction)read_data,NULL);
		/*設(shè)置窗口大小*/
		gtk_widget_set_size_request(GTK_WIDGET(drawarea),width,height);

		/*創(chuàng)建縱向盒*/
		vbox=gtk_vbox_new(FALSE,0);
		gtk_box_pack_start(GTK_BOX(hbox),vbox,TRUE,FALSE,0);
		gtk_widget_show(vbox);
		/*人臉注冊時輸入姓名*/
		box=gtk_hbox_new(FALSE,0);
		gtk_box_pack_start(GTK_BOX(vbox),box,FALSE,TRUE,30);
		gtk_widget_show(box);
		label=gtk_label_new("姓名:");
		gtk_box_pack_start(GTK_BOX(box),label,FALSE,TRUE,0);
		gtk_widget_show(label);
		/*創(chuàng)建輸入文本框*/
		entry1=gtk_entry_new();
		/*設(shè)置輸入文本框尺寸*/
		gtk_widget_set_size_request(entry1,120,-1);
		gtk_entry_set_max_length(GTK_ENTRY(entry1),20);
		gtk_box_pack_start(GTK_BOX(box),entry1,FALSE,FALSE,0);
		g_signal_connect(G_OBJECT(entry1),"key-press-event", G_CALLBACK(entry_callback),"1");
		gtk_widget_show(entry1);
		/*創(chuàng)建提示對象工具*/
		tiptool=gtk_tooltips_new();
		/*添加提示信息到按鈕*/
		gtk_tooltips_set_tip(tiptool,entry1,"填寫姓名",NULL);
		
		/*人臉注冊時輸入手機號*/
		box=gtk_hbox_new(FALSE,0);
		gtk_box_pack_start(GTK_BOX(vbox),box,FALSE,TRUE,15);
		gtk_widget_show(box);
		label=gtk_label_new("電話:");
		gtk_box_pack_start(GTK_BOX(box),label,FALSE,TRUE,0);
		gtk_widget_show(label);
		/*創(chuàng)建輸入文本框*/
		entry2=gtk_entry_new();
		/*設(shè)置輸入文本框尺寸*/
		gtk_widget_set_size_request(entry2,120,-1);
		gtk_entry_set_max_length(GTK_ENTRY(entry2),20);
		gtk_box_pack_start(GTK_BOX(box),entry2,FALSE,FALSE,0);
		g_signal_connect(G_OBJECT(entry2),"key-press-event", G_CALLBACK(entry_callback),"2");
		gtk_widget_show(entry2);
		/*創(chuàng)建提示對象工具*/
		tiptool=gtk_tooltips_new();
		/*添加提示信息到按鈕*/
		gtk_tooltips_set_tip(tiptool,entry2,"填寫手機號",NULL);
		/*設(shè)置標(biāo)簽，用于顯示狀態(tài)信息*/
		box=gtk_hbox_new(FALSE,0);
		gtk_box_pack_start(GTK_BOX(vbox),box,FALSE,FALSE,80);
		gtk_widget_show(box);
		label=gtk_label_new("");
		gtk_label_set_justify (GTK_LABEL(label),GTK_JUSTIFY_CENTER);
		gtk_box_pack_start(GTK_BOX(box),label,TRUE,FALSE,20);	
		gtk_widget_show(label);

		box=gtk_hbox_new(FALSE,0);
		gtk_box_pack_end(GTK_BOX(vbox),box,FALSE,FALSE,20);
		gtk_widget_show(box);
		button=gtk_button_new_with_label("人臉識別");
		gtk_box_pack_start(GTK_BOX(box),button,TRUE,TRUE,0);
		g_signal_connect(G_OBJECT(button),"clicked",G_CALLBACK(button_callback),"1");
		gtk_widget_show(button);

		box=gtk_hbox_new(FALSE,0);
		gtk_box_pack_end(GTK_BOX(vbox),box,FALSE,FALSE,20);
		gtk_widget_show(box);
		button=gtk_button_new_with_label("人臉注冊");
		gtk_box_pack_start(GTK_BOX(box),button,TRUE,TRUE,0);
		g_signal_connect(G_OBJECT(button),"clicked",G_CALLBACK(button_callback),"2");
		gtk_widget_show(button);
		gtk_widget_show_all(window);
		return FALSE;//返回FALSE結(jié)束定時器
	}
	g_print("攝像頭打開失敗ret=%dn",ret);
	gtk_label_set_markup(GTK_LABEL(widget),"攝像頭啟動失敗，請檢測設(shè)備是否正常！");
	return TRUE;//返回TURE繼續(xù)觸發(fā)定時器
}

6.2 人臉識別和人臉注冊

??將攝像頭采集的圖像進行Base64編碼，然后調(diào)用百度AI接口進行人臉注冊和人臉比對。

1.百度智能云接口及簡介

/*按鈕處理函數(shù)*/
void button_callback(GtkWidget *widget,gpointer data)
{
	gint res=0;
	gchar format_data[512];
	gchar *p=(gchar *)data;
	guint size=(height*width*3)*8/6;
	gchar *imagebase64=malloc(size);/*base64編碼后數(shù)據(jù)*/
	if(strcmp(p,"1"))//人臉注冊
	{
		g_print("人臉注冊n");
		/*保證線程安全，上鎖*/
		gdk_threads_enter();
		memcpy(imagebase64,imagebase64_data,size);
		/*保證線程安全，釋放*/
		gdk_threads_leave();
		if(user_info.name[0]=='' || user_info.phone[0]=='' || strlen(user_info.phone)!=11)
		{
			//g_print("請正常填寫名字手機號碼n");
			gtk_label_set_markup(GTK_LABEL(label),"請正常填寫名字n手機號碼");
			//開啟定時器1s時間
			time_flag=g_timeout_add(1000,timer_func2,label);
			free(imagebase64);
			return ;
		}
		/*人臉注冊*/
		g_print("phone:%s,name:%sn",user_info.phone,user_info.name);
		snprintf(format_data,512,""group_id":"wbyq","user_id":"%s","user_info":"%s","quality_control":"LOW","liveness_control":"NORMAL"}",user_info.phone,user_info.name);
		g_print("format=%sn",format_data);
		faceDetect(request_url,access_token,imagebase64,format_data);
    	if(res)/*訪問服務(wù)器失敗*/
		{
			gtk_label_set_markup(GTK_LABEL(label),"注冊失敗");
		}
    	/*
        {"error_code":0,"error_msg":"SUCCESS","log_id":9465001899925,"timestamp":1641801995,"cached":0,"result":{"face_token":"66d2d1512ec57835ec4ef25ed95bec77",
        "location":{"left":265.38,"top":251.49,"width":201,"height":192,"rotation":0}}}
   		 */
	   	else if(JsonData_analysis(platform_data,""error_msg"",format_data))/*查找“error_msg”標(biāo)志失敗*/
	    {
			gtk_label_set_markup(GTK_LABEL(label),"注冊失敗");
		}
	    else if(strcmp(format_data,"SUCCESS"))/*返回狀態(tài)標(biāo)志失敗*/
	    {
			gtk_label_set_markup(GTK_LABEL(label),"注冊失敗");
		}
		else gtk_label_set_markup(GTK_LABEL(label),"注冊成功");
	}
	else if(strcmp(p,"2"))//人臉識別
	{
		if(time_flag)g_source_remove(time_flag);//關(guān)閉定時器
		/*保證線程安全，上鎖*/
		gdk_threads_enter();
		memcpy(imagebase64,imagebase64_data,size);
		/*保證線程安全，釋放*/
		gdk_threads_leave();
		snprintf(format_data,sizeof(format_data),""group_id_list":"wbyq","quality_control":"LOW","liveness_control":"NORMAL"}");
        res=faceDetect(face_search,access_token,imagebase64,format_data);//人臉比對 
		if(res==0)
		{
			struct USER user_data;
			if(Josn_faceSearch(platform_data,&user_data))
			{
				//g_print("比對失敗n");
				gtk_label_set_markup(GTK_LABEL(label),"請重試");
				gtk_entry_set_text(GTK_ENTRY(entry1),"");
				gtk_entry_set_text(GTK_ENTRY(entry2),"");
			}
			else
			{
				//g_print("比對成功:%sn",format_data);
				gtk_label_set_markup(GTK_LABEL(label),"識別成功");
				gtk_entry_set_text(GTK_ENTRY(entry1),user_data.name);
				gtk_entry_set_text(GTK_ENTRY(entry2),user_data.phone);
			}
		}
	}
	free(imagebase64);
}

3.3 base64格式編碼

Base64是網(wǎng)絡(luò)上最常見的用于傳輸8Bit字節(jié)碼的編碼方式之一，Base64就是一種基于64個可打印字符來表示二進制數(shù)據(jù)的方法。可查看RFC2045～RFC2049，上面有MIME的詳細規(guī)范。

Base64編碼是從二進制到字符的過程，可用于在HTTP環(huán)境下傳遞較長的標(biāo)識信息。采用Base64編碼具有不可讀性，需要解碼后才能閱讀。

Base64由于以上優(yōu)點被廣泛應(yīng)用于計算機的各個領(lǐng)域，然而由于輸出內(nèi)容中包括兩個以上“符號類”字符（+, /, =)，不同的應(yīng)用場景又分別研制了Base64的各種“變種”。為統(tǒng)一和規(guī)范化Base64的輸出，Base62x被視為無符號化的改進版本。

Base64要求把每三個8Bit的字節(jié)轉(zhuǎn)換為四個6Bit的字節(jié)（38 = 46 = 24），然后把6Bit再添兩位高位0，組成四個8Bit的字節(jié)，也就是說，轉(zhuǎn)換后的字符串理論上將要比原來的長1/3。

3.3.1 base64編碼示例

static const char * base64char = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
char * base64_encode( const unsigned char * bindata, char * base64, int binlength )
{
    int i, j;
    unsigned char current;
    for ( i = 0, j = 0 ; i < binlength ; i += 3 )
    {
        current = (bindata[i] >> 2) ;
        current &= (unsigned char)0x3F;
        base64[j++] = base64char[(int)current];
        current = ( (unsigned char)(bindata[i] << 4 ) ) & ( (unsigned char)0x30 ) ;
        if ( i + 1 >= binlength )
        {
            base64[j++] = base64char[(int)current];
            base64[j++] = '=';
            base64[j++] = '=';
            break;
        }
        current |= ( (unsigned char)(bindata[i+1] >> 4) ) & ( (unsigned char) 0x0F );
        base64[j++] = base64char[(int)current];
        current = ( (unsigned char)(bindata[i+1] << 2) ) & ( (unsigned char)0x3C ) ;
        if ( i + 2 >= binlength )
        {
            base64[j++] = base64char[(int)current];
            base64[j++] = '=';
            break;
        }
        current |= ( (unsigned char)(bindata[i+2] >> 6) ) & ( (unsigned char) 0x03 );
        base64[j++] = base64char[(int)current];
        current = ( (unsigned char)bindata[i+2] ) & ( (unsigned char)0x3F ) ;
        base64[j++] = base64char[(int)current];
    }
    base64[j] = '';
    return base64;
}

3.3.2 base64解碼示例

int base64_decode( const char * base64, unsigned char * bindata )
{
    int i, j;
    unsigned char k;
    unsigned char temp[4];
    for ( i = 0, j = 0; base64[i] != '' ; i += 4 )
    {
        memset( temp, 0xFF, sizeof(temp) );
        for ( k = 0 ; k < 64 ; k ++ )
        {
            if ( base64char[k] == base64[i] )
                temp[0]= k;
        }
        for ( k = 0 ; k < 64 ; k ++ )
        {
            if ( base64char[k] == base64[i+1] )
                temp[1]= k;
        }
        for ( k = 0 ; k < 64 ; k ++ )
        {
            if ( base64char[k] == base64[i+2] )
                temp[2]= k;
        }
        for ( k = 0 ; k < 64 ; k ++ )
        {
            if ( base64char[k] == base64[i+3] )
                temp[3]= k;
        }
        bindata[j++] = ((unsigned char)(((unsigned char)(temp[0] << 2))&0xFC)) |
                ((unsigned char)((unsigned char)(temp[1]>>4)&0x03));
        if ( base64[i+2] == '=' )
            break;
        bindata[j++] = ((unsigned char)(((unsigned char)(temp[1] << 4))&0xF0)) |
                ((unsigned char)((unsigned char)(temp[2]>>2)&0x0F));
        if ( base64[i+3] == '=' )
            break;
        bindata[j++] = ((unsigned char)(((unsigned char)(temp[2] << 6))&0xF0)) |
                ((unsigned char)(temp[3]&0x3F));
    }
    return j;
}

3.4 CJSON格式數(shù)據(jù)解析

JSON（JavaScript Object Notation, JS對象簡譜）是一種輕量級的數(shù)據(jù)交換格式。它基于 ECMAScript（European Computer Manufacturers Association, 歐洲計算機協(xié)會制定的js規(guī)范）的一個子集，采用完全獨立于編程語言的文本格式來存儲和表示數(shù)據(jù)。簡潔和清晰的層次結(jié)構(gòu)使得 JSON 成為理想的數(shù)據(jù)交換語言。 易于人閱讀和編寫，同時也易于機器解析和生成，并有效地提升網(wǎng)絡(luò)傳輸效率

JSON是一個標(biāo)記符的序列。這套標(biāo)記符包含六個構(gòu)造字符、字符串、數(shù)字和三個字面名。

? JSON是一個序列化的對象或數(shù)組。

JSON格式數(shù)據(jù)解析示例

/******************json數(shù)據(jù)解析****************
形參：u8* buff原始數(shù)據(jù)
			u8 *flag數(shù)據(jù)標(biāo)志
			u8 *data解析獲取到的數(shù)據(jù)
返回值：0---成功，其他值---失敗
************************************************/
guchar JsonData_analysis(guchar* buff,guchar *flag,guchar *data)
{
	guchar *p=NULL;
	guint i=0;
	p=strstr((char *)buff,(char *)flag);
	if(p)
	{
		p+=strlen((char *)flag)+2;
		i=0;
		while(*p!='"' && *p!='')
		{
			data[i++]=*p++;
		}
		data[i]='';
		return 0;
	}
	else return -1;
}

/*
josn數(shù)據(jù)解析
buff --要解析的內(nèi)
user_info--解析成功返回用戶名和id
返回值：成功返回0，失敗返回其它值

*/
int Josn_faceSearch(const char *buff,struct USER *user_info)
{
    /*
     data={"error_code":0,"error_msg":"SUCCESS","log_id":2014555550012,"timestamp":1641792320,"cached":0,
    "result":{"face_token":"6473abd658b76d6843de9a0820aeb2d2","user_list":[{"group_id":"wbyq","user_id":"18172864683","user_info":"u738bu65b0u6c34","score":99.232490539551}]}}
    */
    /*創(chuàng)建cJSON對象*/
	cJSON *root=cJSON_CreateObject();
	char *p=strstr(buff,"{"error_code"");
	root=cJSON_Parse(p);/*載入JSON數(shù)據(jù)*/
    if(root==NULL)return -1;
    /*2.解析字段*/
	cJSON *item;
    item=cJSON_GetObjectItem(root,"error_msg");
    if(item)
	{
		printf("error_code:%sn",item->valuestring);
        if(strcmp(item->valuestring,"SUCCESS"))return -2;
	}
    item=cJSON_GetObjectItem(root,"result");
    if(item)
    {
        item=cJSON_GetObjectItem(item,"user_list");
        cJSON *array_item=cJSON_GetArrayItem(item,0);
        if(array_item==NULL)return -1;
        cJSON *obj=cJSON_GetObjectItem(array_item,"user_info");
		if(obj)printf("info=%sn",obj->valuestring);
        strcpy(user_info->name,obj->valuestring);
		obj=cJSON_GetObjectItem(array_item,"user_id");
		strcpy(user_info->phone,obj->valuestring);
    }
    cJSON_Delete(root);//釋放空間
    return 0;
}

4.人臉識別和人臉注冊運行效果